Western North American Naturalist

Volume 65 Number 3 Article 15

7-28-2005

Full Issue, Vol 65 No. 3

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A COMPREHENSIVE ECOLOGICAL LAND CLASSIFICATION FOR UTAH’S WEST DESERT

Neil E. West1, Frank L. Dougher1,2, Gerald S. Manis1,3, and R. Douglas Ramsey1

ABSTRACT.—Land managers and scientists need context in which to interpolate between or extrapolate beyond discrete field points in space and time. Ecological classification of land (ECL) is one way by which these relationships can be made. Until regional issues emerged and calls were made for ecosystem management (EM), each land management institution chose its own ECLs. The need for economic efficiency and the increasing availability of geographic informa- tion systems (GIS) compel the creation of a national ECL so that communication across ownership boundaries can occur. ECOMAP, an 8-level, top-down, nested, hierarchical, multivariable approach designed to solve this problem has been endorsed by the Federal Geographic Data Committee. While the coarsest, upper 4 levels of ECOMAP have been produced for the entire U.S., the task of completing the 4 finer-grained levels has been left to local practitioners. We tried to apply the suggestions of ECOMAP for completing an ECL for a 4.5-million-hectare area centered in western Utah. Due to the lack of complete and consistent sets of spatial databases suggested as necessary by ECOMAP for com- pleting the ECL for this area, we developed alternatives to complete the ECL using extant information. We stressed 1 dominant landscape feature per hierarchical level, using repeatable protocols to identify landscape units. We added 2 additional levels below the 8 suggested by ECOMAP. Ecological sites (ESs), the 9th level, are designed to overcome the nestedness of ECOMAP that we found prevented us from using important data on ESs already available from the Nat- ural Resources Conservation Service. Vegetation stands (VSs), the 10th and finest-grain level, are subdivisions of indi- vidual polygons of ESs based on differences in disturbance histories that have led to differing current vegetation struc- ture and composition. The ECL we created should help federal, state, and private land managers in western Utah more easily communicate about issues that cross ownership boundaries.

Key words: Great Basin, desert, military, Air Force, Army, Bureau of Land Management, Natural Resources Conser- vation Service, climate, geological formations, land forms, watersheds, soils, vegetation, ecological sites, Lake Bonneville, Great Salt Lake.

It is logistically impossible and financially The traditional method for accomplishing unfeasible to make complete inventories of these extensions of information is through eco- and monitor changes in all biotic species, com- logical classifications of land (ECL) based on munities, or physical and chemical features of similarities within and dissimilarities between the environment across large land areas. While pieces of land, usually viewed at a variety of scientists can randomly or systematically sub- scales in space and time and organized into a sample and use statistical or geostatistical hierarchical structure (Carpenter et al. 1999). inference to estimate characteristics of bio- The history of land classification is extensive, physical resources over a large land area, the especially in forested or agriculturally impor- location of the usually point- or quadrat-based tant parts of the temperate zone. Geographers subsamples will only coincidentally match up and ecologists have tended to create synthetic with areas on the ground where managers multivariable classificatory approaches which have to make decisions or scientists consider are difficult to repeat. Specialists have usually possible generalities. Accordingly, there needs focused only on features of special interest to be a method of interpolating between and (e.g., soils). Before the development of geo- extrapolating beyond points in space and time graphic information systems (GIS) and the call where previous data were collected if manage- for ecosystem management (EM), each disci- ment or science is to be based on more than pline and each land management entity devel- limited sampling and personal experience and oped its own preferred or legislatively man- intuition. dated ways of classifying land. However, this

1Department of Forest, Range and Wildlife Sciences, Utah State University, Logan, UT 84322-5230. 2Present address: Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717-3120. 3Present address: HC64, Box 2915, Moab, UT 84532.

281 282 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 1. Naming of the 8 proposed levels of the National Hierarchical Framework of Ecological Units (NHEU) our proxies at finer scales, and approximate size of an average mapped polygon at each level. NHEU is from ECOMAP (1993). Level ______Approximate size of an average NHEU Ours mapped polygon Domain 106 mi2 Division 105 mi2 Province 104 mi2 Section 103 mi2 Subsection Bolson segments 102 mi2 Landtype Association Macroterrain units 1000 ac Landtype Mesoterrain units 100 ac Landtype Phase Microterrain units 10 ac

has led to what Boulding (1980) called “special- however, the advent of progressively more ized deafness,” wherein different groups fail to workable GIS, budgetary restraints, and the use any information except that offered within possibility of sharing databases electronically their own discipline or institution. Because over the Internet that accelerated the debate ecosystem management (EM) requires consid- and eased the tendencies to always first pro- eration of broad issues, regardless of land tect institutional traditions. Creation of the ownership or preferred or mandated ways of Federal Geographic Data Committee (FGDC) collecting, analyzing, and labeling data, com- in 1990 provided focus to critical discussion promises in the approaches to land classifica- of nationally applied standards of measure- tion are necessary to make the collaboration ment and mapping. For a conceptual basis of required during EM possible. land classification, FGDC has accepted the The recent development of GIS has made National Hierarchy of Ecological Units (NHEU; much more feasible the attainment of a land ECOMAP 1993), begun by the U.S. Forest Ser- classification serving many users. Thus, if we vice (USFS). can agree on how to classify land, managers NHEU is an 8-level, hierarchical approach can more easily repeat successful actions on (Table 1) focused on climatic, geologic, geo- similar lands and avoid repeating mistakes by morphic, edaphic, and vegetational character- identifying dissimilar land elsewhere and not istics. The major demonstrations to date have overextending actions where they will not be employed top-down, nested hierarchicality, al- successful. Scientists will also find it easier to though alternate approaches are not conceptu- generalize if they can place their data in an ally forbidden by the NHEU design. Maps of ECL. We hope eventually to have inexpensive the first 4 coarsest levels of this nationwide and reliable landscape-level monitoring so as approach have already been published (Bailey to use each study and accidental and manage- et al. 1994, Bailey 1995, McNab and Bailey ment-induced action as a “quasi-experiment” 1994, McNab and Avers 1994). Delineation of from which we can learn and thus move toward the remaining, finer-grained subdivisions has more predictable responses in the future—a been left for local development with scant sug- process called adaptive resource management gestions about how that should be accom- (ARM; Szaro 1999, Thomas and Birchfield plished. Very little of this more detailed work 2000). has been completed, particularly for the drier, To make ARM and EM more feasible, a less productive parts of the nation where the broadly accepted land classification system is USFS is not a major land steward. required. This is because managers, scientists, and other stakeholders need to be able to de- STUDY AREA scribe and communicate, in commonly under- stood terminology, the ecological contexts of In 1995 the authors, as part of a larger Utah their concerns. Since the 1972 passage of the State University group, were funded by the Resources Planning Act, the executive branch U.S. Air Force (AF) to find already extant in- of the U.S. government has formally recog- formation and collect new data on the occur- nized these needs (Driscoll et al. 1984). It was, rence of threatened, endangered, and sensitive 2005] UTAH’S WEST DESERT ECL 283

(T,E&S) species in a 4.5-million-hectare (11.2- of the MOA representing the Deep Creek million-acre, 17,400-mi2) area centered in Mountains (Figs. 1, 2B). Utah’s West Desert (Fig. 1). In assembling both The MOA intersects 3 provinces (Fig. 2C): old and new information relevant to our main the Intermountain Desert and Semidesert Pro- objectives, we were faced with the task of ad- vince in the south and east, the Intermountain vising the AF on how well the inevitably in- Semidesert Province to the north, and Nevada– complete information could be either inter- Utah Mountains Semidesert Coniferous Forest– polated between the field-sampled points or Alpine Province centered on the Deep Creek extrapolated beyond. We undertook 2 alter- Mountains on the western edge of the MOA. nate approaches to fill this need—modeling The NHEU (ECOMAP 1993:4) states: and land classification. Examples of the species- by-species–oriented modeling approach can be Provinces (are) climatic subzones, controlled pri- found elsewhere (Scott et al. 1993, Edwards et marily by continental weather patterns such as length of dry season and duration of cold tempera- al. 1995). We deal here with the more general tures. Provinces are also characterized by similar approach through ECL. soil orders. The climatic subzones are evident as Our study area is called the Hill Air Force extensive areas of similar potential natural vegeta- Base Military Operations Area (MOA), where tion such as those mapped by Küchler (1964). training of pilots and related ground activities of the AF take place (Fig. 1). The proportion of Other criteria used in mapping provinces in- land within the MOA where ground access is clude gross patterns in physiography, such as controlled by the DOD, including the U.S. glaciated versus non-glaciated regions, prox- Army’s Dugway Proving Ground, is 15% of the imity to major bodies of water, and so forth. total land. The Bureau of Land Management Thus, provinces are mapped using multiple (BLM), U.S. Department of the Interior, con- biotic and abiotic factors that change at this trols 63% of the MOA. Included within the spatial scale. MOA are sovereign Indian lands (Goshute and The NHEU (ECOMAP 1993:4) states: Skull Valley Reservations) that make up about Sections [are] broad areas of similar sub-regional 1%, and 1 federal wildlife refuge (Fish Springs) climate, geomorphic process, stratigraphy, geologic that makes up about 0.4% of the area. The origin, topography, and drainage networks. Such State of Utah controls 8%, and private land- areas are often inferred by relating geologic maps holders control slightly over 12% of the land to potential natural vegetation “series” groupings within the MOA. Thus, if this landscape is such as those mapped by Küchler (1964). In recent years, numerical analyses of weather station and ever going to be managed without primary remotely sensed climatic information have assisted regard to land ownership (e.g., through EM in determining Section boundaries. and ARM), then communication and coordina- tion between these different owners and their Thus, sections are mapped using multiple biotic managers must be facilitated. We contend that and abiotic factors that change at this spatial an ECL applying to all of these lands, regard- scale. less of ownership, is a necessary 1st step. The Four different sections occur in the MOA AF provided the resources to make that attempt (McNab and Avers 1994; Fig. 2D). The one for the MOA over a 5-year period. occupying the greatest area is the Bonneville Basin Section. The others all involve much ECOMAP’s Legacy less area: Northeastern Great Basin, North- We began by applying the already pub- western Basin and Range, and Central Great lished NHEU products to our study area (Fig. Basin Mountain Sections. 2). Gross physiography and climate at conti- While the large polygons created by map- nental scales explain most of the delineation of ping the 4 upper levels in the NHEU hierarchy domains (Fig. 2A). The MOA is entirely within may be of interest to planners with national the Dry Domain. Divisions (Fig. 2B) are sub- and regional perspectives, they are of only divisions of domains based primarily on regional moderate interest to most local managers and climatic patterns. Most of the land area of the scientists. This is because there are too few MOA is within the Temperate Desert Divi- delineations subdividing the obviously hetero- sion. The Temperate Desert Regime Moun- geneous lands for which they are managerially tains Division occurs on the western boundary responsible or scientifically interested. Thus, 284 WESTERN NORTH AMERICAN NATURALIST [Volume 65 it is largely the remaining, lower levels and terminology for the finer-grained levels of finer subdivisions that local land managers the ECL we produced so that readers will and scientists can relate to in their day-to-day not be confused with the terms suggested in efforts. These lower, locally important levels, ECOMAP’s literature. Table 1 shows the cor- however, have generally not been delineated, respondences between approaches. Descrip- especially in desert regions. tions of our complete ECL can be found in Since the task of finishing the NHEU to its Table 2. finest grain has been passed on to local exper- Bolson Segments tise, we began by trying to do just that. Only rudimentary suggestions were available in the Bailey (1996) and Omernik (1997) warn that ECOMAP literature on how to accomplish watershed boundaries are not appropriate for this task. Furthermore, examples of how this all needs of land managers and scientists to has been done in other areas usually do not stratify their information. We assert that nei- involve arid landscapes, especially those that ther are the multivariable-derived boundaries do not drain surface waters to the sea (endo- of the NHEU. We have used watershed bound- rheic), the situation for most of the MOA. aries at the next level in the nested hierarchi- Some of the suggested information ECOMAP cal part of our ECL because watershed-based recommends as needed to develop the rest of concerns are paramount to people living in a the classification scheme (e.g., fine-grain and largely arid region. The watershed concept is high-resolution geologic and geomorphic maps, understood by most interested parties, and most potential and actual vegetation maps) was nei- management actions consider watersheds first ther available, consistently done, nor inexpen- and foremost in the Interior West. sive and easy to develop over the short run. In desert terrain the term “bolson” (Peterson Faced with these impediments to progress, we 1981, West 1995) applies well. A bolson is the turned to our own ingenuity to fill local needs. entire area, from surrounding mountaintops, where water and sediments are shed, through Our Modifications mountain-flanking slopes, diminishing with Having accepted the NHEU legacy of an distance from the ridgelines, to the center of already established classification with published either a river valley or, in case of nearly all the maps down through the section level, we thus MOA, terminal lake (endorrheic) basins now focused our efforts on producing finer-grained mostly dry (called playas). categories and smaller mapped polygons to Because the mountains surrounding our bol- approximate subsections, landtype associations, sons usually have highly variable elevations and landtypes, and landtype phases (Table 1). The especially differing exposure of geologic strata ECOMAP approach has been described as a (due to the horst and graben topography created top-down, qualitative, visual-pattern, weight- by the common extensional faulting of this of-evidence approach (McMahon et al. 2001). region; Fiero 1986), we decided to create our While that characterization oversimplifies what substitute for NHEU subsections from bolsons the NHEU recommends (ECOMAP 1993) and cleaved into approximate halves. We called is actually practiced in more densely invento- these half-bolsons “bolson segments.” Bolson ried and productive regions, we lacked most segments were defined first by the main ridge- of the information needed for such refinements. line of the many, usually north–south trending Instead, we chose to hierarchically build these mountain ranges in the region and all the land 4 next lower levels from dominant features, draining to the prevailing slopes, (generally preferably 1 per level. Furthermore, we opted east- or west-facing exposures), and a “wedge” for the simplest, most repeatable and transpar- of appended playa (in proportion to the area ent methods possible. This approach should and height [mass] of nearest mountain) where make it easier for others to understand, apply, sediments have been accumulating over eons. and improve upon our efforts in the future Our approach thus contrasts with that taken in when environmental and biotic data bases im- California where Goudey and Smith (1994) prove. McMahon et al. (2001) describe this as used the boundaries of the lower limits of fan a quantitative, data-driven approach. Because skirts surrounding entire mountain ranges to we deviated substantially from the NHEU demarcate subsections in the Mojave Desert. (ECOMAP 1993) approach, we introduce new The 60 bolson segments completely within 2005] UTAH’S WEST DESERT ECL 285 2,029,456 ha–402,799,860 ha 2,029,456 ha–110,158,058 ha 952,590 ha–75,399,068 ha 577,699 ha–22514,140 ha ed from coarsest to finest. 102,174 46 ha, 95 ∼ Number of polygons potential vegetation(NRCS’s county soil surveyplus ecological site descriptions overlain on Ecological Sites orthophoto quads) involving ~130 (NRCS 1997) 1.0 ha–3485 ha middle portion of the west slope of Grassy Mountains surface adjacent to middle portion of the west slope of Grassy Mountains tail shrubsteppe converted to cheatgrass polygon (orthophoto quads plus field inspection) 14 ha–167 ha segments connected bajadas and salt flats watersheds (DEMs) 18,400 ha–467,900 ha units depositional surface adjacent to (Geological Map of Utah) 38,020 ha–1870 ha ECOMAP Our alternate Dominant environmental intersecting or entirely sizes, standard Average Associations units west slope of Grassy Mountains and average slope (DEMs) 203 ha–240,006 ha Phases units erosional/depositional of mixed 2.0–52,214 ha cological Sites Desert gravelly loam Major soil family and about 800 268 ha, 454 2. Outline of hierarchical levels for the ecological classification scheme developed Hill AFB MOA. The listing is order Domains — Dry Domain Climate 1 259,207,650 ha, 223,227,599 Divisions — Lowlands Dry Temperature Climate 3 40,927,523 ha, 37,078,014 Provinces — Intermountain Semideserts Climate 3 22,836,520 ha, 19,672,139 Sections — Basins Bonneville and Adjacent Topography 4 4,770,693 ha, 4,079,581 SubsectionsLandtype Bolson Macroterrain slope of Grassy Mountains and West Alluvial fan adjacent to massif on Intermediate scale position Topographic 60 574 110,200 ha, 100,100 7896 ha, 24,976 Landtypes MesoterrainLandtype erosional/ Eolian sediments of mixed Microterrain Major soil parent material Loess terrace of aeolian sediments 4) Landforms (see Table 2460 1834 ha, 6501 44673 101 ha, 1270 ABLE T 1 2 3 4 5 6 7 8 9E Level name designation Example name character (database) within Hill AFB MOA deviation, and range 10 Stands Vegetation Recently burned shadscale/squirrel- vegetation Actual 286 WESTERN NORTH AMERICAN NATURALIST [Volume 65 or intersecting the MOA near its edges are process produces polygons that encompass all mapped in Figure 3. Names of all 60 bolson the area most likely affected by shedding of segments can be found in the Appendix. water and sediment from a given side of a The minimal mapping unit (MMU) size used mountain range. for bolson segments is 100 km2. The average As we moved down the ECL hierarchy and size of the bolson segments delineated is 1102 thus produced more map polygons per unit km2, with a standard deviation of 1001 km2 area, we were forced to deal sequentially with and a range of 184–4679 km2. Bolson segment only parts of the vast MOA because of the names were derived from the names of major need for decreasing map scale to illustrate the mountain ranges and lowlands (“true” valleys remainder of our discussion. Thus, we will ex- do not occur in endorheic basins and are thus emplify how we classified 1 corner of the MOA, designated with quotation marks) found on the part known as the North Unit of the Utah relevant USGS 7.5-minute topographic maps. Test and Training Range (UTTR), the north- Long, compound word names are necessary ernmost block of land indicated in yellow in to be explicit and reduce ambiguities in ECLs. Figure 3 and the smaller inset map in Figure 4. If this is bothersome, the frequent user could At this location, we encountered typical topog- replace the names with a “zip code”-like num- raphy of the MOA that was transected by a bering system where placement of the num- boundary fence separating AF- from BLM-con- bers in the sequence could indicate what clas- trolled property. An example of Bolson Seg- sification level was being referred to. Use of ments 32 and 33 on the eastern and western differing colors for the various portions of the slopes of the Grassy Mountains, respectively, numerical address would also ease use of such is presented in Figure 4. A 2-mile-wide strip numerical designations. A completed ECL must (dashed line) straddling the fenceline along be in place, however, before reliable replace- the AF-BLM property and extending over ment of names with numbers can be done. 30.15 miles (Fig. 4) was used to exemplify our The basic data needed to develop bolson ECL down to a finer grain. segments were 30-m-resolution Digital Eleva- tion Models (DEMs). By draping contour lines Macroterrain Units over a shaded relief model derived from DEMs, Macroterrain units are subsets of bolson seg- we identified the ridgeline along the water- ments delineated using ideas developed in shed divide separating 2 adjacent bolson seg- ments. We then defined the portion of the bol- hydrology, namely the nested hierarchicality son segment extending from the mountain of watersheds and their erosion cells in which massif, across the fan skirts, and into the river each has source, transfer, and sink components valley or terminal lake basin (playa). The low- at multiple scales (Pickup 1985). We recognized est-elevation “wedge” of bolson segment most that the highest, steepest, and wettest portions relevant to the adjoining mountains can be of each bolson segment would have the great- determined by computing the mass in an est weathering and gravitational gradients and imaginary slice of the mountain upslope from thus usually experience the most erosion by the farthest extension of adjoining playa or water and produce the most new sediment in valley up to the highest point on the ridgeline, each bolson segment. These major waterborne at relatively coarse scales, and then position- sediment source zones were called mountain ing the lowest point in proportion to the masses massif macroterrain units. The coalesced fan in adjoining bolson segment polygons (Fig. 3). skirts (bajadas), with gentler slopes usually This algorithm is necessary because the preci- fringing each mountain massif (Peterson 1981, sion of 30-m DEMs is usually insufficient to West 1995), are a mixed erosional and deposi- find distinct drainage lines in the generally flat tional, or transfer, zone which we called the terrain of the playas. While the precision of “mixed” macroterrain units. Finally, we identi- such DEMs in the intervening lower moun- fied the flattest, depositional-process-dominated, tain slopes and fan skirts (bajadas) is also low, but occasionally surface-water-connected, piece it is sufficient to connect the prevailing expo- of the bolson segment on the playas or salt sure of roughly half of the entire mountain flats (West 1995) as “sinks.” Wind erosion re- massif and intervening fanskirt to the appro- works the details of these depositional macro- priate adjoining “wedge” of valley or playa. This terrain units much more than those of the 2005] UTAH’S WEST DESERT ECL 287

TABLE 3. Summary of mean size, standard deviations, and range for the source, transfer, and sink macroterrain units. Type Mean size (ha) Standard deviation Range (ha) Source 2980 6023 203–32,116 Transfer 8683 17,699 203–104,199 Sink 13,189 39,980 208–240,006 Overall 7896 24,976 203–240,006

uplands, but that issue was deferred to lower, the erosional landscape on the west-facing finer levels of our ECL. slope of the Grassy Mountains (red in Fig. 6) Our algorithm to determine macroterrain where the macroterrain units intersecting the units employed elevation and relative change sampling strip are shown in more detail. in apparent elevation (slope) from adjacent 30- Average macroterrain unit size was 7896 ha m DEM cells and classifying cells upslope of with a standard deviation of 27,976 ha and a equal or higher slope position. Thus, most range of 203–240,006 ha. The MMU for these “mixed” macroterrain unit cells will have “ero- was 200 ha. Mean macroterrain unit size was sional” cells upslope and “depositional” cells least in source (erosional) macroterrain units, downslope from their position. This principle intermediate in mixed (transfer) macroterrain of “superposition” is enforced by the applica- units, and greatest in sink (depositional) macro- tion of macroterrain class by watershed func- terrain units (Table 3). tions, wherein all cells draining into a given Mesoterrain Units cell must have a similar or higher-elevation macroterrain slope position. It is possible that Since macroterrain units are still relatively macroterrain units may be found upslope of large, and thus too heterogeneous for some units of higher slope position (e.g., mini-playa needs, we further divided them into mesoter- lakes kept from moving downslope by remnant, rain units. It is at this level that the colluvial unbreached bay bars created by Lake Bonne- and eolian processes ignored within the macro- ville [Benson et al. 1990]), but these units rep- terrain units are considered. This was done by resent topographical sinks superposed upon focusing on the major geologic formations or predominately mixed or source units. Such ex- sediments that were exposed at the land sur- ceptions to the superposition rule are rare face within the various macroterrain units. In under the 200-ha MMU rule at this level of the Great Basin relatively narrow, generally the ECL. north–south trending mountains with exposed Figure 5 shows how the 60 bolson seg- bedrock rise like “islands in a sea” of uncon- ments were subdivided into 574 macroterrain solidated segments up to several thousands of units across the entire MOA. Ideally, there is a meters deep at the center of broader, individ- 3-fold subdivision of bolson segments into ual basins (Fiero 1986). macroterrain units because there is at least 1 Because the exposure of geologic forma- mountain massif, fan skirt, and playa or river tions in this largely horst- and graben-created valley within each bolson segment. However, landscape will usually be different along the heterogeneous terrain frequently results from longest axes of the mountain ranges, we sub- variable elevations, slopes, and exposures of divided the macroterrain units based on the mountain massifs and fan skirts which result dominant exposed bedrock in the case of moun- in a need to create more and smaller macro- tain massifs. We used a digitized map of Hintze terrain units than one would expect under ideal (1980) for exposure of geological formations at conditions. The 574 macroterrain units for the 1:500,000 scale. Hintze’s map shows 43 geo- MOA resulted in an approximate 9-fold sub- logic formations or complexes within the Utah division. The names for these macroterrain portion of the MOA. Some combinations of polygons can be constructed by taking the similar materials (e.g., limestones and dolo- names of the bolson segments and adding mites; Table 4) were necessary to obtain a rea- “erosional, mixed, or depositional” plus a poly- sonable (less than 10-fold) increase in number gon number to each (Table 2). Examples are of polygons from the macro- to the mesoter- the 4 polygons, oriented north to south, across rain level (Table 2). Since each mesoterrain 288 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 4. Summary of geologic groups used to identify and map mesoterrain units of the Hill AFB MOA in Utah.

BEDROCK GROUPS Hard igneous and metamorphic rock; includes all Pre-Cambrian and Cambrian age rocks, including Cambrian limestone and Jurassic and Tertiary age intrusives Moderately hard sedimentary rocks; includes all Triassic through Ordovician age sediments Soft sedimentary and volcanic rocks; includes tuff and weakly consolidated sediments of Tertiary age Rhyolites and andesites; Quaternary through Tertiary age volcanics Basalt; Quaternary through Tertiary age volcanics SEDIMENT GROUPS Alluvium: Quaternary and Tertiary unconsolidated alluvium Lake Bonneville sediments; Quaternary lacustrine sediments Glacial sediments; Quaternary glacial till (very limited extent) Eolian sediments; Quaternary sand dunes

unit had to be nested within its appropriate cesses. Specifically, soils with high content of macroterrain unit, the shape and size of poly- coarse, rounded rock fragments (gravel and gons on Hintze’s original map will not be the larger) are highly likely to be alluvial. Another same as on our map of mountain massif meso- clue to alluvial origin is clear textural stratifi- terrain units. cation. Colluvial soils were grouped with allu- For the mixed and depositional mesoterrain vial soils at this level due to their limited units, we relied on the Soil Survey Geographic extent and the sometimes uncertain differentia (SSURGO) database (Natural Resources Con- in soils data. servation Service 1998). These data occur at a Soils lacking coarse fragments could still be 1:24,000 scale for most of the MOA (Loerch et alluvial; however, large deposits of uniformly al. 1997, Trickler et al. 2000). While SSURGO- fine-textured alluvium could not only be ex- derived maps fail to adequately differentiate pected in backwater areas of major floodplains, bedrock types in mountain massifs, they do a but are dominant on the playas/salt flats of the superior job of identifying different kinds of basin bottoms once covered by pluvial Lake sediment in fan skirts and playas. This infor- Bonneville (Benson et al. 1990). The elevation mation was crucial in delineating polygons of of the uppermost beachline of Lake Bonne- similar soil-forming potential and grossly simi- ville (about 1580 m, depending on degree of lar potential vegetation, particularly for the isostatic rebound) generally marked the upper mixed and deposition-dominated mesoterrain boundary of where lacustrine influences on units. Using the SSURGO coverage, it was pos- mixing of sediments occurred below and cre- sible to derive 5 sediment groups: glacial sedi- ated larger and more homogeneous polygons. ments, alluvium (degrading), eolian sediments Where the Pre-Wisconsinan soils are ex- (Quaternary sand dunes and loess), degrading posed, about 0.67 m of reddish clay is under- lake sediments, and aggrading lake sediments. lain by about a similar depth of lime-enriched Only 1 small polygon of glacial till was identi- weathered parent material. Wisconsinan de- fied in the highest elevations of the Deep Creek posits have had less time for their cobbles and Mountains. boulders to be weathered to clay than older SSURGO soil-mapping units were felt to materials (Hunt 1972). best match the units within the geologic groups DEM modeling was not functional for delin- of Table 4, by a rationale based on probability. eating landforms on the low-relief landscapes First, exposed bedrock units were identified of basin bottoms due to a lack of precision in by steeper slope classes, the presence of rock the 30-m-resolution DEM. It is possible that outcrop, and/or soils of <1 m depth to bedrock exposure, slope, and elevation modeling of land- as dominant components of mapped complexes. form units could provide further definition Eolian, lake, and alluvial sediments were when DEMs of greater resolution become differentiated by comparing soil textural fami- available. Small (<20 ha) polygons of bedrock lies, slope classes, and the presence or absence or detritus were ignored when found sur- of subsoil development with known relation- rounded by vast areas of playa. These island- ships of these properties to land-forming pro- like features are accounted for at lower levels 2005] UTAH’S WEST DESERT ECL 289

Fig. 1. Map of the Hill Air Force Base Military Operations Area (MOA) showing important natural and state (inset) boundaries. 290 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Fig. 2A, Map of entire U.S. showing the Dry Domain within which the MOA is located. Outer MOA boundary is indi- cated by the red line. Great Salt Lake, in blue, occurs at its northeastern corner. B, Map of entire U.S. showing its divi- sion boundaries. The 2 divisions intersecting the MOA are in different colors. The outer boundary of the MOA is indi- cated by a red line. Great Salt Lake is in blue, at its northeastern corner. C, Map of entire U.S. showing its province 2005] UTAH’S WEST DESERT ECL 291

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boundaries. The 3 provinces intersecting the MOA are in different colors. The outer boundary of the MOA is indicated by the red line. Great Salt Lake, in blue, occurs at its northeastern corner. D, Map of entire U.S. showing section bound- aries. These 4 sections intersecting the MOA are in different colors. The outer boundary of the MOA is indicated by the red line. Great Salt Lake, in blue, is at its northeastern corner. 292 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Fig. 3. Map of entire MOA showing boundaries of all 60 bolson segments. See Appendix for names of each of the numbered bolson segments. 2005] UTAH’S WEST DESERT ECL 293

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Fig. 4. Map of the Utah Test and Training Range (UTTR) and Bolson Segments 32 and 33 intersecting the example transect. in our ECL. Extending this process across UTTR in the northern part of the MOA. Here state lines will require assembling similar geo- we focus on the southwesternmost spur of the logic and soils maps in the other states (Nevada Grassy Range called Finger Ridge. Mesoter- and Idaho) within the MOA. rain Polygon #4 is the most elevated erosional Figure 7, as an example, shows the meso- surface dominated by moderately hard, sedi- terrain units that straddle a portion of the mentary bedrock (Table 4). Degrading alluvium more intensively sampled strip along the is found at intermediate elevations, mainly in southern boundary of the North Unit of the the saddle between Finger Ridge and the 294 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Fig. 5. Map of macroterrain units over the entire MOA. 2005] UTAH’S WEST DESERT ECL 295

Fig. 6. Map of macroterrain units within Bolson Segments 32 and 33. 296 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Fig. 7. Map of mesoterrain units in Bolson Segment 33. largest, main mountain massif polygon (#3 in but further apart to the east or south because Fig. 6) along the westerly exposure of the main of the gentler topographic gradients in those axis of the Grassy Range. Because of the steep directions. topographic gradients on the westernmost At the level of detail used in delineating extent of Finger Ridge, depositional polygons mesoterrain-unit polygons, geographic descrip- are closer to each other to the north and west, tors are not always available on the 7.5-minute 2005] UTAH’S WEST DESERT ECL 297

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Fig. 8. Map of microterrain units over the entire UTTR North Unit and adjacent lands to the south administered by the Bureau of Land Management. 298 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Fig. 9. Map of microterrain units over 2 example mesoterrain unit polygons.

USGS topographic quadrangle maps; thus, we (see arrow in Fig. 7). If the entire MOA could resorted to numerical descriptors for mesoter- have been similarly mapped, we would expect rain units. An example of the naming of meso- 2460 mesoterrain polygons to be delineated, terrain units would be “Mesoterrain polygon with a 1834-ha mean size, 6501-ha standard #4, moderately hard sedimentary erosional unit deviation, and a range of 20.0 (the MMU) to on Middle West Slope of Grassy Mountains” 138,020 ha. 2005] UTAH’S WEST DESERT ECL 299

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Fig. 10. Map of the individual polygons associated with ecological sites (ESs) intersecting the sampling strip along the southern boundary of the UTTR, North Unit.

Microterrain Units am14_1.html) gave us slope position for ero- Since the detail needed to solve problems sional landscapes, classified as ridge, side slope, tends to escalate through time, we thought it toe slope, foot slope, and basin bottom. This wise to extend our ECL beyond the level classification is achieved by an iterative process where most current needs exist and thus show wherein the topographic position of each cell the abilities of this approach to apply into the is compared to that of its neighbors. These future. We thus divided mesoterrain units into attributes and landforms, outlined in Table 5, subdivisions called microterrain units. Micro- were combined with the attributes of the terrain units are further nested subdivisions of mesoterrain classification to produce microter- mesoterrain units which we largely based on rain units. Relationships of phases of the soil landforms for the erosion-dominated surfaces series with landscape processes, geologic and landforms plus soils for the mixed and groups, and landforms are summarized in deposition-dominated landscapes. Table 6. Landforms for the mountain massifs were Figure 8 shows microterrain units for the identified by modeling DEMs. Since the mixed entire UTTR North Unit, plus some BLM land and deposition-dominated portions of our land- outside its southern boundary. Because of the scapes lack striking relief, landforms and asso- differing topography, we identified 24 ⋅ km–2 ciated soils for these landscapes had to be (38 ⋅ mi–2) microterrain units on the mountain inferred from the SSURGO database (NRCS, massifs, 0.7 ⋅ km–2 (2 ⋅ mi–2) on the fan skirts, 1998). The attributes we utilized were textural and 0.07 ⋅ km–2 (0.2 ⋅ mi–2) on the playas. If family, degree of subsoil development, and this landscape is typical, then we would ex- slope. Toposcale AML software (see http://www pect to find 44,673 microterrain units over the .wsl.ch/staff.niklaus.zimmermann/programs/ entire MOA. The mean size of a microterrain 300 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Fig. 11. Map of Vegetation Stand (VS) polygons delineated in the demonstration strip.

unit polygon in our sample was 101 ha, with a Further Differentiations standard deviation of 1270 ha, and a range of While the above satisfied the objective of 2.0–52,214 ha. The MMU at this level was developing a “shortcut” means to complete 2.0 ha. the lower ecological units in a nested, top- Figure 9 shows an enlarged version of Fin- down, hierarchical way, somewhat analogous ger Ridge where mesoterrain polygons within mountain massif (erosional) units were subdi- to those suggested by ECOMAP for the vided into ridge, side slope, and foot slope NHEU (Table 1), it did not leave us with a microterrain units. For mixed mesoterrain units, sense that we had finished the ECL nor made divisions into either recent or reworked allu- it user-friendly for the local land manager. vial fans or loessial terraces were identified. Also, we had discovered some serious limita- Depositional units were either low lake plains tions of the ECOMAP approach, as so far or playas (salt flats). Since there usually were developed in the West, and decided that most no unique existing place names on 7.5-minute land managers would need more generalizable USGS quadrangles associated with areas as land classifications at local levels. small as most microterrain unit polygons, we ECOMAP is a top-down regionalization developed numerical designators. An example that is hierarchically nested and explicitly geo- is Microterrain Unit Polygon #13, a piece of graphic (Bailey 1995). While hierarchical struc- ridge on the moderately hard sedimentary ero- tures allow related land classification units to sional bedrock of the middle northwest side of be used at scales appropriate to various needs, Finger Ridge (see arrow in Fig. 9). from national to local, a consequence of the 2005] UTAH’S WEST DESERT ECL 301

Bolson Class Segments

Data

Slope Data Slope Model

Model

Geological Macroterrain Data Units

Mesoterrain Units

SSURGO Slope Elevation Data Position Data Model

Microterrain Units

Ecological Site Descriptions Ecological Site Polygons

Management Vegetation History Data

Vegetation Stand Polygons

Fig. 12. Flow diagram summarizing the major features of our Ecological Classification of Lands (ECL) process from Bolson Segments to Vegetation Stands. The bold line between Microterrain Units and Ecological Site Polygons is inserted to emphasize a switch from nested above to nonnested below. 302 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 5. Summary of landforms used for defining microterrain units on the Hill AFB MOA. Erosion-dominated macroterrain units (source areas, mountain massifs) Ridges Side slopes Toe slopes Foot slopes Mixed erosional-deposition macroterrain units (bajadas, fan skirts) Recent alluvial fans Relict alluvial fans Older Lake Bonneville terraces Recent very fine sand and silt deposits Active dunes Vegetated dunes Inset flood plains Deposition-dominated macroterrain units (sinks) Valley bottoms Low lake plains Playas/salt flats top-down, nested hierarchicality that domi- than nested hierarchicality (O’Neill et al. 1986) nates the NHEU is that perimeters of outer could be employed, we propose a simpler, more polygons created at lower levels have to be straightforward solution. vertically integrated (congruent) with the delin- The Natural Resources Conservation Ser- eation of polygons occurring at upper levels. vice (NRCS) over the past 50 years has been One consequence of this “top-down” process building a vast set of information that applies is that if the lowest levels are produced inde- to the above need. For instance, the NRCS has pendently of higher levels, one should logi- identified 532 ecological sites (ESs) in Utah cally readjust (merge from the “bottom up”) (Natural Resources Conservation Service 1997). the congruent polygon boundaries involved in Each ES is a distinctive category of land with all affected polygons created at higher levels. the potential to produce and sustain similar Another consequence of the strictly top- kinds and amounts of vegetation under its par- down nested hierarchical design of ECOMAP ticular combination of environmental factors, is that progressively more, smaller and unique especially climate, soils, and associated native polygons are created for each level. While this biota (Shiflet 1973, Bedell 1998, Creque et al. tidiness may please scientists, it misserves man- 1999). Thus, all polygons that are similar in agers who need means to relate research and these respects, nested within NRCS’s Major personal experience between similar types of Land Resource Areas (McMahon et al. 2001) land regardless of how they fit in an ECL. In and somewhat similar to ECOMAP’s Sections, other words, the ECOMAP process applied so can be aggregated into these managerially useful far prevents one from easily relating features categories. Furthermore, NRCS site descriptions at one location to those within other microter- include information about vegetation fluctua- rain, mesoterrain, macroterrain units, or bolson tions expected under climatic variability and segments. For example, responses of vegeta- successional responses to various kinds of non- tion and animals to wildfires in 2 particular anthropogenic (e.g., wildfire) and anthropogenic microterrain unit polygons on the flanks of 2 (e.g., livestock grazing) disturbances (Grazing different mountain ranges occurring within Lands Technology Institute 1997). This impor- different bolson segments of the MOA are likely tant information is helpful to both managers to be similar, provided elevations, slopes, ex- and researchers (Creque et al. 1999). We there- posures, geological materials, and soil charac- fore devised a way to integrate these NRCS teristics are similar. If such comparisons were databases with our ECL of the MOA. facilitated, the manager could extrapolate Our actions do not violate the well-known knowledge from one polygon to others that are principle (Rowe 1961) that an entire hierarchi- highly similar, but relatively distant, if only the cal land classification cannot be built induc- nestedness of the ECL were modified to over- tively (from the bottom up). We have simply come this limitation. While networked rather pointed out that following a top-down nested 2005] UTAH’S WEST DESERT ECL 303

TABLE 6. Summary of the bases of classification of macroterrain, mesoterrain, and microterrain units for the Hill AFB MOA. Divisions/classes Classification bases

MACROTERRAIN Erosional landscapes Selection of all SSURGO units of shallow soils and/or slope of greater than 30% (high range) Mixed landscapes Selection of all SSURGO units of deep soils ranging from 1% (low range) to 30% (high range) slopes Depositional landscapes Selection of all SSURGO units of deep soils ranging from 0% (low range) to 2% slopes MESOTERRAIN Hard igneous/metamorphic rock Ti, Ji, C3, C2, C1, PCs, Pci, Pcm on geology layer Moderately hard sedimentary TR1, TR2, JTR, K3, K2, D, S, M3, M2, PNP, P2, P1, PN on geology layer Soft sedimentary/volcanic clastics T4, T3, T2, T1, Tvu, Tov, TK on geology layer Rhyolites/andesites Qr, Tmr, Tma, on geology layer Basalts Qb, Tmb, Tpb on geology layer Glacial deposits Qe on geology matched to soil unit from SSURGO layer Eolian deposits Dunes, Torripsamments, and coarse-loamy and fine- silty Torriorthents from SSURGO layer Alluvium (degrading) Very deep loamy-skeletal and sandy skeletal soils plus associated small floodplains from SSURGO layer Lake deposits (degrading) Very deep, fine-silty and fine-loamy developed soils, slopes 1%–8%, from SSURGO layer Lake deposits (aggrading) Very deep, fine-silty and fine-loamy developed soils, slopes 0%–2%, from SSURGO layer Ridges Identify from landform model MICROTERRAIN Side slope Identify from landform model Toe slope Identify from landform model Foot slope Identify from landform model Valley bottom Identify from landform model Ground moraine SSURGO unit correlated to geology layer Relict alluvial fans Loamy-skeletal and sandy-skeletal Torriorthents, from SSURGO layer Inset alluvial flood plain Identified from position and flooding frequency from SSURGO layer Lake Bonneville terraces Fine-silty and fine-loamy families with diagnostic surface and subsoil horizons, from SSURGO layer Low lake plain Fine-silty and families, natric and sodic subsoils, 0%–2%, from SSURGO layer Playa/salt flat SSURGO layer, “playa,” “salt flat”

hierarchy to its finest subdivisions counters land as plant succession is allowed to proceed common sense and practicality. or actively managed for. Delineation of ESs focuses on potential VSs are subdivisions of ESs where the rela- vegetation. Since late successional vegetation tive homogeneity of the vegetation has been is frequently not found on the land because of changed by relatively uniform kinds and inci- disturbances, soils information is utilized to dences of disturbance (Aber and Melillo 2001). crosswalk to expected potential vegetation. In other words, disturbance history dominates Managers and scientists, however, also fre- over site potential at the stand level. Thus, VSs quently need to know what the current vege- are where our classification system turns its tation is to deal with immediate problems. attention from potential to actual vegetation Accordingly, we added vegetational stands (VSs) created because of differing land use and dis- as the 10th and final level to our classification. turbance histories. It is also at this finest de- Managers are faced with dealing with both the gree of resolution that the influences of aspect current situation and what once was or could and slope and how they alter local effective eventually be found on particular pieces of environments can be accommodated. 304 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 7. Relationships of ecological sites to soil series and polygons shown in Figure 10. Ecological site name Soil series Polygon numbers Semidesert Shallow Loam (Utah Juniper–Salina Wildrye) Amtoft 1, 8, 11, 13, 25, 28, 41, 58 Desert Gravelly Loam (Shadscale) Cliffdown 2, 7, 10, 17, 18, 26, 27, 29, 40, 44 Gravel Pit (vegetation absent) soil removed 3 Desert Loam (Shadscale) Tooele 4, 6, 9, 12, 20, 30, 45, 51 Desert Loam (Shadscale) Timpie 5, 16, 21, 43, 46 Semidesert Shallow Loam (Utah Juniper–Bluebunch Wheatgrass) Amtoft 14, 15, 37, 48, 50, 52 Desert Gravelly Sandy Loam (Indian Ricegrass) Izamatch 19, 24, 42 Alkali Flat (Black Greasewood) Skumpah 22 Desert Flat (Shadscale) Skumpah 23, 47 Desert Flat (Black Greasewood) Timpie 31, 33 Desert Alkali Bench (Bud Sagebrush) Cliffdown 32, 49 Desert Salty Silt (Pickleweed) Saltair 34, 38, 39, 57 Desert Oolithic Dunes (Black Greasewood) Dynal 35, 36, 53, 56

We focus our demonstrations here on how to senting an ES. We expected to see vegetation delineate ESs and VSs in only a small portion recovery following livestock removal on the of the MOA, the southeastern corner of the AF side, whereas the successional status of North Unit of the UTTR (Fig. 4). Within the 2- VSs on the opposite side of the fence (BLM), mile-wide by 30.15-mile-long (60.3-mile2) area but still in the same ES, should be earlier seral straddling (1-mile wide on the AF side, 1-mile because livestock grazing continues (Mayne wide on the BLM side) the southeastern and West 2001). boundary fence, we identified ESs and VSs to We had a prepublication version of the soils illustrate our procedures. We did this because map that became more recently available to generally many more and smaller polygons the public in Trickler et al. (2000). We ignored occur at these lowest levels, requiring larger potential polygons <1 ha that may involve map- map scales for illustration. Another reason is ping errors, but still found soil mapping units that the identity and boundaries of ES and VS that either occurred totally within (15 polygons) polygons can be verified in the field. If field- or that partially intercepted (43 polygons) the based procedures are used to check the sampling strip (Fig. 10). In Table 5 of Trickler boundaries for ES and VS polygons, the process et al. (2000), the correspondences of all ES becomes much more expensive, but also more polygons to soil series and their potential nat- reliable. We could afford to field check ESs ural vegetation are found. Using the names of and VSs in only 1 area under the temporal and relevant ESs and consulting condition and monetary constraints of the project. trend guides available from the State Office of We chose the demonstration area to map the NRCS, we have summarized in Table 7 ESs and VSs because it had landscapes with a these correspondences and the identification combination of mountain massif, bajada, and numbers of the individual ES polygons we playa macroterrain units typical of the entire found in the sampling strip (Fig. 10). MOA. The relatively low elevation of Grassy Modern “county” soil surveys like Trickler Mountains and Greyback Hills had fringing et al. (2000) have no unique polygons smaller bajadas, as well as playas, in the intervening than about 2 ha (MMU) separately delineated. Puddle and Ripple “Valleys.” Secondly, because Mapping units with a single named compo- the AF constructed a fence in 1968 along the nent are expected to contain at least 85% of boundary of the land they control, livestock that and similar soils. The remaining 15% have been excluded from the AF land where could be dissimilar soils, if discussed in the they had grazed previously. Livestock grazing, description of that mapping unit in the report. however, continues on the BLM side of the Soil mapping units may have up to 49% of the fence. Where ES polygons straddled the AF- total area within it actually occupied by up to BLM boundary, we saw this as an opportunity 3 other soil series besides the major series to pair up VSs within the same polygon repre- (Soil Survey Staff 1993). 2005] UTAH’S WEST DESERT ECL 305

Another potential problem (involving about VS polygons were drawn in the field on 15% of our study area) is that of mapped soil mylar overlays of the aerial photographs used complexes. These are situations where 2 or for the soil surveys. For practical reasons, we more kinds of soils occur in such small and ignored small unique areas <1 ha (MMU) intricate patterns that it is impractical to map and considered them inclusions. Furthermore, them separately (Soil Survey Staff 1993). These where a lobe or protrusion of a polygon nar- complexities can pose problems to inadequately rowed to <100 m in width, we drew the trained and inexperienced managers or re- boundary short of these narrow “tongues.” searchers, especially if field checking is fore- Thus, long, slim features such as linear rock gone. We have found that it is usually feasible outcrops and drainage lines with possibly dif- to have managers or investigators who know ferent landforms, soils, and vegetation were how soil maps are made, can read soil reports, not separately delineated, but included as part and can identify plants; they are thus able to of the dominant situation within the polygon. sort out these issues with minor amounts of If we had done otherwise, the cost of adding fieldwork. information at this level would have greatly Field validation during July 1996 was per- escalated. The user should realize, however, formed to check boundaries of the ES poly- that a few phenomena will be missed by such gons, note the degree of patterning of soil compromises (e.g., connection of some rare or series within these polygons, and subdivide T,E&S animals and plants to narrow rock out- them into VSs. Using the prepublication copies crops or riparian zones). of maps now found in Trickler et al. (2000), We found 75 VS polygons entirely within or plus both conventional aerial photography intersecting the sampled strip (Fig. 11). The (from the 1970s) and digital orthophotographic sampling strip VS polygons had a mean size of quadrangle photo-maps (DOQs) from 1995, 46 ha but varied between 14 ha and 167 ha we focused on differences in image brightness with a standard deviation of 95 ha. Where the and texture to delineate polygon boundaries. ES polygons straddled the ownership bound- The boundaries of most ES polygons were ary, at least 2 VSs were automatically created confirmed in the field, but a few minor modifi- because of differences in livestock grazing his- cations were made in the delinations of some tories created by the boundary fence (Mayne of these boundaries (Fig. 10). Please note that and West 2001). If there were obvious recent a conservative view of ESs was taken; where fires and mechanical disturbances within a VS there were differences in either the dominant polygon occurring totally on one side of the plants or soil series, distinctive ESs were used fence or the other, additional VS polygon (e.g., Desert Loam [Shadscale] on either Tooele boundaries were drawn. For instance, VS poly- or Timpie Series soils; Table 7). We did this in- gon 13C (hachured polygon in the upper right asmuch as differing approaches to management of Fig. 11) had significantly lower condition actions such as reseeding need to be taken on vegetation and soils than the other 2 larger these 2 ESs because of the soil differences. 13A and B polygons because it is closer to a The mean size of an ES polygon was 268 livestock watering point. Another example in- ha, with a standard deviation of 454 ha and a volves VS polygons 23C and D, which had evi- range between 1.0 ha and 3485 ha. Smaller dence of bombing craters and vehicle tracks polygons were located on mountain massifs, (probably created before 1968 when the AF- the largest on the depositional surfaces of the controlled property boundary extended much playas, and intermediate-sized ES polygons further southward), more introduced annuals, occurred on the mixed (transfer) zone of the and fewer native perennial plants on the ground fan skirts. We estimate that about 130 kinds of than VS polygons 23A or B. VS Polygons 23B ESs (in the NRCS sense) and about 800 ES and D are outside the fence and continue to polygons will be found on the entire MOA, if experience livestock grazing that adds to the the process we started is completed. This is a higher proportion of exotic to native plants than much more practical number of differing kinds the otherwise comparable VS polygons within of land for either the manager or scientists to the AF fence. deal with than the nearly 45,000 unique micro- If this sample is representative, 102,174 VS terrain units produced by following the strict polygons could be expected to be found over interpretations of ECOMAP. the entire MOA. The largest VS polygons were 306 WESTERN NORTH AMERICAN NATURALIST [Volume 65 found on depositional surfaces of the playa, tracked through GIS and other information- the smallest on erosional surfaces of the moun- retrieval systems. As we gained more experi- tain massifs. VS size was intermediate on the ence, the speed and ease of building this land mixed locations on the foothills and fan skirts. classification increased. Future expansions or The name of each VS polygon combines the refinements of the classification should there- common name of the dominant plant in the fore be more economical to produce. Demon- canopy layer, separated by a slash for under- stration of the utility of the classification awaits story strata, plus a unique number for each its application by land use planners and man- polygon (Table 2). agers in charge of lands under various owner- ships. Our efforts, however, should make EM CONCLUSIONS and ARM more feasible in the “West Desert.”

Our objective, to develop an ECL for the ACKNOWLEDGMENTS 4.5-million-hectare MOA, was accomplished. We did not modify the NHEU approach for This work was funded by the U.S. Air Force the upper 4 levels (in order of increasing grain: as part of a task order to the Bureau of Land domains, divisions, provinces, and sections). Management’s Landscape Ecology, Modeling However, because the information recom- and Analysis Unit located at Utah State Uni- mended to complete the lower levels of the versity. Terry Sharik was the principal investi- NHEUs for our area was too coarse and in- gator and strongly supported our efforts from consistent and not easy in either time or bud- beginning to end. Marcus Blood, environmental get to create, we largely developed from already officer at Hill Air Force Base, coordinated our extant information (Fig. 12) the next 4 lower activities on military lands. Many employees levels (bolson segments, macroterrain units, of the U.S. Departments of Interior and Agri- mesoterrain units, microterrain units) to com- culture and state resource agencies, too num- plete the NHEU and 2 additional levels (eco- erous to mention individually, provided infor- logical sites and vegetation stands). We stressed, mation crucial to our synthesis. wherever possible, a single dominant feature at each of these lower levels and repeatable, LITERATURE CITED transparent protocols. This contrasts with the ABER, J.D., AND J.M. MELILLO. 2001. Terrestrial ecosys- multivariable, difficult-to-repeat approach used tems. 2nd edition. Harcourt Academic Press, New by ECOMAP. Our 2 lowest levels go beyond York. what NHEU proposed but allow the constraints BAILEY, R.G. 1995. Description of the ecoregions of the of regionalization and “top-down” nested hier- United States. U.S. Department of Agriculture, For- est Service, Miscellaneous Publication 1391 (map archicality to be overcome without invoking scale 1:7,500,000). the complexities of networked hierarchies. ______. 1996. Ecosystem geography. Springer-Verlag, New Our approach to an ECL should make it York. easier for local managers to use the vast infor- BAILEY, R.G., P.E. AVERS, T. KING, AND W.H. MCNAB. 1994. mational databases already assembled by the Ecoregions and subregions of the United States (map scale 1:7,500,000). U.S. Department of Agricul- NRCS. These more detailed levels should also ture, Forest Service, Washington, DC. make the classification less abstract and there- BEDELL, T.E., CHAIRMAN. 1998. Glossary of terms used in fore more appealing to most managers and sci- range management. Society for Range Management, entists with only local interests. Furthermore, Denver, CO. 32 pp. BENSON, L.V., D.R. CURREY, R.I. DORN, K.R. LAJORE, C.G. these finest-grained units could be validated OVIATT, S.W. ROBINSON, G.I. SMITH, AND S. STINE. through some fieldwork. While these additions 1990. Chronology of expansion and contraction of four make the entire classification more expensive Great Basin Lake systems during the past 35,000 to produce, considerable error is corrected years. Paleogeography, Paleoclimatology, Paleoecol- and confidence gained to support it. Those with ogy 78:241–286. BOULDING, K.E. 1980. Science: our common heritage. interests only at coarser levels can simply ignore Science 207:831–836. these local distinctions if they wish. CARPENTER, C.A., W.N. BUSCH, D.T. CLELAND, J. GALLEGOS, We have produced maps with example poly- R. HARRIS, R. HOLM, C. TOPIK, AND A. WILLIAMSON. gons at all levels in the classification. We have 1999. Use of ecological classification in manage- ment. Pages 395–430 in R.C. Szaro et al., editors, also developed a hierarchical nomenclature Ecological stewardship. Volume II. Elsevier Science such that all existing and new data can be Publishers, Amsterdam, The Netherlands. 2005] UTAH’S WEST DESERT ECL 307

CREQUE, J.A., S.D. BASSETT, AND N.E. WEST. 1999. View- U.S. Department of Agriculture, Forest Service, point: delineating ecological sites. Journal of Range Washington, DC. Management 52:546–549. NATURAL RESOURCES CONSERVATION SERVICE. 1997. DRISCOLL, R.S., D.L. MERKEL, D.L. RADLOFF, D.E. SNYDER, Guides to ecological sites of Utah. NRCS, State Office, AND J.S. HAGIHARA. 1984. An ecological classification Salt Lake City, UT. framework for the United States. U.S. Forest Service, ______. 1998. SSURGO database for military lands in west- Miscellaneous Publication 1439. Washington, DC. ern Utah. Natural Resources Conservation Service, ECOMAP. 1993. National hierarchial framework of eco- Salt Lake City, UT. logical units. U.S. Department of Agriculture, Forest OMERNIK, J.M., AND R.G. BAILEY. 1997. Distinguishing be- Service, Washington, DC. tween watersheds and ecoregions. Journal of the EDWARDS, T.C., JR., C.G. HOMER, S.D. BASSETT, A. FAL- American Water Resources Association 33:935–949. CONER, R.D. RAMSEY, AND D.W. WIGHT. 1995. Utah O’NEILL, R.V., D.L. DEANGELIS, J.B. WAIDE, AND T.F.H. Gap analyses: an environmental information system. ALLEN. 1986. A hierarchical concept of ecosystems. U.S. Department of the Interior, National Biological Princeton University Press, Princeton, NJ. Service. PETERSON, F.F. 1981. Landforms of the Basin and Range FIERO, B. 1986. Geology of the Great Basin. University of Province defined for soil survey. Technical Bulletin Nevada Press, Reno. 28, Nevada Agricultural Experiment Station, Uni- GOUDEY, C.B., AND D.W. SMITH, EDITORS. 1994. Ecologi- versity of Nevada, Reno. 52 pp. cal units of California: subsections. U.S. Department PICKUP, G. 1985. The erosion cell—a geomorphic approach of Agriculture, Forest Service, Region 5, San Fran- to landscape classification in range assessment. Aus- cisco. Map 1:100,000 scale colored. tralian Rangeland Journal 11:114–121. GRAZING LANDS TECHNOLOGY INSTITUTE. 1997. National ROWE, J.S. 1961. The level of integration concept and ecol- range and pasture handbook. U.S. Department of ogy. Ecology 42:420–427. Agriculture, Natural Resources Conservation Service, SCOTT, J.M., F. DAVIS, B. CSUTI, R. NOSS, B. BUTTERFIELD, Washington, DC. H.A.C. GROVES, S. CAICCO, ET AL. 1993. Gap analy- HINTZE, L.F. 1980. Geologic map of Utah 1:500,000 scale, sis: a geographic approach to protection of biological colored with cross sections and stratigraphic columns. diversity. Wildlife Monographs 123:1–41 Privately published. SHIFLET, T.N. 1973. Range sites and soils in the United HUNT, C.B. 1972. Geology of soils: their evolution, classifi- States. Pages 26–33 in H.F. Heady, editor, Arid shrub- cation and uses. W.H. Freeman, San Francisco, CA. lands: proceedings of the Third Worship of the United LOERCH, J.C., K.D. ADAMS, AND V.L. PARSLOW. 1997. Soil States/Australia Rangelands Panel, Tucson, AZ, 26 survey of Box Elder County, Utah, western part. U.S. March–5 April 1973. Department of Agriculture, Natural Resources Con- SOIL SURVEY STAFF. 1993. National soil survey handbook. servation Service, Salt Lake City, UT. Title 430-IV, Soil Conservation Service, U.S. Depart- MAYNE, S., AND N.E. WEST. 2001. A field test of a new ment of Agriculture, U.S. Government Printing Office, Australian method of rangeland monitoring. Pages Washington, DC. 315–317 in E.D. McArthur and D.J. Fairbanks, com- SZARO, R. 1999. Monitoring and evaluation. Pages 223– pilers, Proceedings: shrubland ecosystem genetics 230 in N.C. Johnson et al., editors, Ecological stew- and biodiversity. General Technical Report RMRS- ardship. Volume I. Elsevier Science Publishers, P-21, U.S. Department of Agriculture, Forest Ser- Amsterdam, The Netherlands. vice, Rocky Mountain Research Station, Ogden, UT. THOMAS, J.W., AND J. BIRCHFIELD. 2000. Science, politics MCMAHON, G., S.M. GREGONIS, S.W. WALTMAN, J.M. OMER- and land management. Rangelands 22(4):45–51. NIK, T.D. THORSON, J.A. FREEOUF, A.H. FORICK, AND TRICKLER, D.L., D.T. HALL, C.D. FRANKS, S.K. FERGUSON, J.E. KEYS. 2001. Developing a spatial framework of L.D. CAMPBELL, P.J. SAVAGE, AND J.E. BREWER.2000. common ecological regions for the conterminous Soil survey of Tooele area, Utah. U.S. Department of United States. Environmental Management 28: Agriculture, Natural Resources Conservation Ser- 293–316. vice, Salt Lake City, UT. MCNAB, W.H., AND P.E. AVERS. 1994. Ecological subre- WEST, N.E. 1995. Deserts. Pages 475–492 in W.A. Niren- gions of the United States: section descriptions. U.S. berg, editor, Encyclopedia of environmental biology. Department of Agriculture, Forest Service, WO- Academic Press, Orlando, FL. WSA-5. MCNAB, W.H., AND R.G. BAILEY. 1994. Map unit descrip- Received 22 September 2003 tions of subregions (sections) of the United States. Accepted 6 December 2004

Appendix follows on pages 308–309. 308 WESTERN NORTH AMERICAN NATURALIST [Volume 65

APPENDIX. Names of numbered bolson segments in Figure 3. Number Name 1 East slope of Dove Creek–Grouse Creek Mountains and adjoining bajadas. 2West slope of Cedar Hills–Albion Mountains and east side of Junction Creek. 3 East slope of Middle and Goose Creek Mountains and west side of upper Junction Creek Valley. 4West slope of Middle and Goose Creek Mountains and eastern-valley portion of upper Goose Creek. 5 North slope of Raft River Mountains and adjoining bajadas. 6West slope of Cedar Mountains and eastern portion of Rock Spring Creek Valley. 7 South and west slopes of Grouse Creek Mountains and eastern portion of adjoining Grouse Creek Valley. 8 South slope of Raft River Mountains and adjoining Park and Curlew Valleys. 9 East slope of White Rock–China Jim Hills and adjoining Grouse Creek Valley. 10 East slope of Matlin Mountains and adjoining pediments. 11 East slope of Delano Peak and adjoining western portion of Crittenden Creek Valley. 12 West slope of White Rock–China Jim Hills and eastern portion of valley draining Crittenden Creek. 13 West slope of Matlin Mountains and adjoining pediments. 14 West slope of Delano Peak and adjoining eastern portion of valley where 1000 Springs and Rock Spring Creeks meet. 15 East slope of Hogup Mountains, adjoining bajadas, and salt flats of northwestern Great Salt Lake Desert. 16 West slope of Hogup Mountains and adjoining bajadas of northern Great Salt Lake Desert. 17 South slopes of Ninemile Mountain and Ninemile Ridge and western portion of 21-Mile Draw Valley. 18 East slope of Mineral Mountain and adjoining eastern side of 21-Mile Draw Valley. 19 West slope of Toana Mountains and adjoining eastern side of northern Goshute Valley. 20 East slope of Toana Mountains, adjoining bajadas, and western side of Pilot Creek Valley. 21 West slope of Pilot Mountain Range, adjoining bajadas, and eastern side of Pilot Creek Valley. 22 East slope of Pilot Mountain Range, adjoining bajadas, and salt flats of northern Great Salt Lake Desert. 23 West slope of Newfoundland Mountains, adjoining bajadas, and salt flats of northern Great Salt Lake Desert. 24 West slope of Goshute Mountains, adjoining bajadas, and salt flats on eastern side of northern Great Salt Lake Desert. 25 East slope of Newfoundland Mountains, adjoining bajadas, and salt flats of northern Great Salt Lake Desert. 26 East slope of Goshute Mountains, adjoining bajadas, and salt flats of western Great Salt Lake Desert. 27 East slope of Pequop Mountains, adjoining bajadas, and salt flats on eastern side of Goshute Valley. 28 West slope of Lakeside Mountains, adjoining bajadas, and salt flats of eastern Puddle Valley. 29 West slope of Lakeside Mountains, adjoining bajadas, and salt flats of northern Great Salt Lake Desert. 30 East slope of Lakeside Mountains, adjoining bajadas, and salt flats on west side of northern Great Salt Lake Desert. 31 West slope of Silver Island Mountains, adjoining bajadas, and salt flats of Great Salt Lake Desert. 32 East slope of Grassy Mountains, adjoining bajadas, and salt flats of west side of Puddle Valley. 33 West slope of Grassy Mountains, adjoining bajadas, and salt flats of eastern Great Salt Lake Desert. 34 West slope of Silver Island Mountains, adjoining bajadas, and salt flats of Great Salt Lake Desert. 35 East slope of Cedar Mountains, adjoining bajadas, and salt flats of western Skull Valley. 2005] UTAH’S WEST DESERT ECL 309

36 East slope of Stansbury Mountains, adjoining bajadas, and salt flats of western portions of Rush and Tooele Valleys. 37 West slope of Stansbury Mountains, adjoining bajadas, and salt flats on the eastern side of Antelope Valley. 38 East slope of the Antelope Range, adjoining bajadas, and salt flats of eastern side of Skull Valley. 39 West slope of the Antelope Range and adjoining bajadas on eastern side of Spring Valley. 40 West slope of Deep Creek, Kern, Moriah, and Snake Mountains, adjoining bajadas, and salt flats of western Antelope and Spring Valleys. 41 East slope of Deep Creek, Kern, Moriah, and Snake Mountains and adjoining salt flats of southern Great Salt Lake Desert and Snake and Hamblin Valleys. 42 West slope of Granite Dugway and Thomas Mountain Ranges, adjoining bajadas, and salt flats of southern Great Salt Lake Desert and Dugway Valley. 43 East slope of Granite Dugway and Thomas Mountain Ranges, adjoining bajadas, and salt flats of southern Great Salt Lake Desert and eastern Fish Springs. 44 West slope of Simpson and Desert Mountain Ranges and adjoining bajadas of eastern riverbed area. 45 East slope of Simpson and Desert Mountain Ranges and adjoining bajadas. 46 West and north slopes of Keg Mountain and adjoining bajadas in eastern Dugway Valley. 47 East slope of Schell Creek and Fortification Ranges, adjoining bajadas, and salt flats of eastern side of Spring Valley. 48 West slope of Fish Spring Mountain Range, adjoining bajadas, and salt flats of northeastern Snake Valley. 49 East slope of Fish Spring Mountain Range and adjoining bajada and salt flats of western Fish Springs Valley. 50 West slope of Confusion, Wah Wah, and Conger Mountain Ranges and adjoining bajadas of eastern side of Snake, Ferguson, and Pine Valleys. 51 East and south slopes of Keg Mountain and adjoining bajadas in Sevier Desert. 52 East slope of Confusion and Wah Wah Mountain Ranges and adjoining bajadas of eastern side of Tule and Wah Wah Valleys. 53 East slope of House and Swasey Mountain Ranges, adjoining bajadas, and salt flats on eastern side of Whirlwind and Sevier Lake Valleys. 54 West slope of House and Swasey Mountain Ranges, adjoining bajadas, and salt flats on eastern side of Tule Valley. 55 West slope of Cricket and San Francisco Mountain Ranges, adjoining bajadas, and salt flats on eastern sides of Sevier Lake and Tule Valley. 56 East slope of Cricket and San Francisco Mountain Ranges, adjoining bajadas, and salt flats of western Clear Lake Valley and western Beaver River bottoms. 57 North and west slopes of Burbank Hills and Tunnel Spring Mountain and adjoining bajadas in Ferguson Desert. 58 South and west slopes of Burbank Hills–Tunnel Springs Mountain and adjoining bajadas in Antelope and northern Pine Valleys. 59 East slope of Mountain Home–Needle Mountain Ranges, adjoining bajadas, and valley plains on western side of Pine Valley. 60 East slope of Cedar Hills and adjoining upper Raft River Valley. Western North American Naturalist 65(3), © 2005, pp. 310–320

EVALUATING LEK OCCUPANCY OF GREATER SAGE-GROUSE IN RELATION TO LANDSCAPE CULTIVATION IN THE DAKOTAS

Joe T. Smith1,5, Lester D. Flake1,6, Kenneth F. Higgins2, Gerald D. Kobriger3, and Collin G. Homer4

ABSTRACT.—Greater Sage-Grouse (Centrocercus urophasianus) have been declining in many states and provinces of North America, and North and South Dakota hold no exception to these declines. We studied effects of cultivated land on Greater Sage-Grouse lek abandonment in North and South Dakota. Landscape-level data were assessed using satel- lite imagery within a geographic information system. Comparisons were made of 1972–1976 and 1999–2000 percent cul- tivated and noncultivated land. These comparisons were made between land uses surrounding active leks versus inac- tive leks, active leks versus random locations, and abandoned regions versus active regions. The 1999–2000 imagery illustrated that percent cultivated land was greater near abandoned leks (4-km buffers) than near active leks in North Dakota or random sites, but this did not hold true in South Dakota. Comparison of an extensive region of abandoned leks with a region of active leks in North Dakota illustrated a similar increase as well as dispersion of cultivation within the abandoned region. However, 1972–1976 imagery revealed that this relationship between percentage of cultivated land and lek activity in North Dakota has been static over the last 30 years. Thus, if the decline of Greater Sage-Grouse is the result of cultivated land infringements, it occurred prior to 1972 in North Dakota.

Key words: Greater Sage-Grouse, lek, North Dakota, satellite imagery, South Dakota.

Greater Sage-Grouse (Centrocercus urophas- Information on historical Greater Sage-Grouse ianus) populations in western North America distribution and landscape trends is vital to were once widely distributed through 13 states understanding the bird’s decline and to Greater as far south as Arizona and north into 3 pro- Sage-Grouse conservation efforts. vinces of Canada (Braun 1995, Connelly and Greater Sage-Grouse generally use open Braun 1997, Schroeder et al. 1999, Young et areas with good visibility for their breeding al. 2000). The overall decline of this species and display sites (Patterson 1952, Gill 1966), began near the onset of the 20th century, otherwise known as leks. Depending on when probably due to agricultural practices, over- they are made, Greater Sage-Grouse counts shooting, and increasing numbers of livestock are the best index to breeding population (Patterson 1952, Dalke et al. 1963, Gill 1966). numbers (Connelly and Braun 1997). Greater This decline continued throughout the 1900s Sage-Grouse need sagebrush cover and/or other in most of the Greater Sage-Grouse range and shrubs adjacent to leks for escape cover from has been primarily attributed to decreasing predators, particularly Golden Eagles (Aquila amounts of sagebrush (Artemisia spp.) due to chrysaetos; Scott 1942, Enyeart 1956). Daily agriculture (i.e., cash crops), herbicides, over- movements of male Greater Sage-Grouse from grazing, energy development, fire, and/or the lek during the breeding season were found drought (Patterson 1952, Homer et al. 1993, to average 1.3 km in Montana (Wallestad and Gregg et al. 1994, Connelly and Braun 1997, Schladweiler 1974). When shrub coverage near Braun 1998, Connelly et al. 2000). There have leks is removed due to tillage, fire, or spraying, been documented decreases in Greater Sage- it leaves Greater Sage-Grouse at these sites Grouse populations after the plowing of sage- vulnerable to harassment from predators (e.g., brush habitat in Montana (Swenson et al. 1987). Golden Eagles) and may cause abandonment

1Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings, SD 57007. 2U.S. Geological Survey/Biological Resources Division, South Dakota Cooperative Fish and Wildlife Research Unit, South Dakota State University, Brook- ings, SD 57007. 3North Dakota Game and Fish Department, Dickinson, ND 58601. 4Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, SD 57198. 5Present address: Box 212, Lawton, IA 51030. 6Present address: 1652 E. 550 S., Springville, UT 84663.

310 2005] LEK OCCUPANCY AND LANDSCAPE CULTIVATION 311

(Enyeart 1956, Peterson 1970) or changes in ravines, and gullies associated with the Bad- timing and size of male Greater Sage-Grouse lands (Opdahl et al. 1975, Thompson 1978, lek attendance (Boyko et al. 2004). Sagebrush Aziz 1989). Annual precipitation ranges from coverage is not only important for breeding 35.6 cm to 40.6 cm, with approximately 80% activities, but nesting activities as well (Con- occurring from April to September (Opdahl et nelly et al. 1991, 2000). Wallestad and Pyrah al. 1975, Thompson 1978, Aziz 1989). Annual (1974) observed that 68% of nests were within summer temperature ranges from 9.9° to 2.5 km of the lek site where females bred in 27.5°C and winter temperature ranges from central Montana. Aldridge (2000) found an aver- –15.6° to 0.2°C (Opdahl et al. 1975, Thompson age lek-to-nest distance of 4.7 km in Alberta. 1978, Aziz 1989). Our study area vegetation Wakkinen et al. (1992) discerned that 92% of communities consisted of a mixture of shrubs nests were ≤3 km from leks where females including big sagebrush (A. tridentata), silver bred in Idaho. Breeding to nesting site move- sagebrush (A. cana), and greasewood (Sarco- ments generally range from 1.1 km to 6.2 km, batus vermiculatus); perennial grasses includ- but can be >20.0 km (Connelly et al. 2000). ing Kentucky bluegrass (Poa pratensis), western To identify habitat/land use change in large wheatgrass (Agropyron smithii), and Japanese areas, such as those that Greater Sage-Grouse brome (Bromus japonicus); forbs including encounter, many scientists are now incorporat- common dandelion (Achillea millefolium), com- ing satellite imagery as a valuable tool (Homer mon yarrow (Taraxacum officinale), and cud- et al. 1993, De’ath and Fabricius 2000, Debel- weed sagewort (Artemisia ludoviciana); cash jak et al. 2001). One approach, as used in our crops (corn, wheat, and alfalfa); cultivated land; study, is to apply satellite imagery in making and open grassland. The study area falls within landscape-scale comparisons between areas the big sagebrush–wheatgrass plains vegeta- around historical but now abandoned Greater tion type (Johnson and Larson 1999). Sage-Grouse leks and areas with currently active leks. The objective of this study was to METHODS compare current and historical (prior to 2000) Background distributions of Greater Sage-Grouse leks in relation to landscape cultivation in North and An active Greater Sage-Grouse lek is a tra- South Dakota. ditional communal display ground for breeding Greater Sage-Grouse that “has been attended STUDY AREA by ≥2 male Sage-Grouse [sic] in ≥2 of the pre- vious 5 years” (Connelly et al. 2000:9). A The study area was located in extreme west- Greater Sage-Grouse lek would be labeled in- ern South Dakota in Fall River, Butte, and active when the criteria for an active lek do Harding Counties and in southwestern North not hold true. A historically active lek would Dakota in Bowman, Slope, and Golden Valley have been active at one time but was inactive Counties. Elevation in the South Dakota study at the time of the study. Statistical significance area ranges from 525 m to 1050 m above sea was set at α = 0.10. level; the area has an overall topography of un- glaciated rolling prairie with occasional buttes Cultivated Land and intermittent streams (Johnson 1976, 1988, Classification Kalvels 1982). Annual precipitation ranges from We recorded and assessed landscape-level 37.4 cm to 41.8 cm, with approximately 80% of data within 4-km buffers and regions using precipitation from April to September (John- satellite imagery [i.e., LANDSAT 7 Thematic son 1976, 1988, Kalvels 1982). Annual summer Mapper (TM) Imagery] obtained from Earth temperature ranges from a low of 14.3° to a Resources Observation Systems (EROS) Data high of 31.1°C and winter temperature ranges Center in Sioux Falls, South Dakota, within a from –14.6° to 1.4°C (Johnson 1976, 1988, geographic information system (GIS). GIS cov- Kalvels 1982). erages permitted evaluation of landscape-level Elevation in the North Dakota study area is differences between active and inactive leks 640 m to 1045 m above sea level; general topog- (Oklahoma Department of Wildlife Conserva- raphy is much like the South Dakota study tion 1998). Satellite imagery was classified into area but with pinnacles, domes, canyons, gorges, 2 categories: cultivated land and noncultivated 312 WESTERN NORTH AMERICAN NATURALIST [Volume 65 land. Three scenes of 1972–1976 and 1999– because we felt that the area within the inac- 2000 satellite imagery that covered our study tive buffer may still be used by Greater Sage- areas were classified into cultivated and non- Grouse from the active lek. If both were inac- cultivated land using ERDAS Imagine Software tive or active, we assigned one buffered area 8.5 (ERDAS® Inc., Atlanta, GA, USA). The odd numbers and the other area even num- 1972–1976 year range was selected because it bers and used a random number generator to was the farthest we could go back with usable choose the one to be ignored. If they over- satellite imagery for our study area with differ- lapped <1 km, the buffers were treated as if ent years available for different counties, and they were independent. We used ArcView 3.2a the 1999–2000 year range was selected because random point generator to select random loca- it was the most current satellite imagery we tions in the study area within the historical range could obtain with different years available for (Schroeder et al. 2004) of Greater Sage-Grouse different counties from EROS Data Center. leks in North and South Dakota. Because of We used the area of interest tools in ERDAS extensive coverage of leks in North Dakota, Imagine to perform a supervised classification random points were selected without regard on areas believed to be cultivated land. We to overlap with 4-km buffers of active or inac- then used aerial photos obtained from county tive lek sites. We compared current (1999–2000) Natural Resources Conservation Service and percent cultivated and noncultivated land with Farm Service Agency offices to check our in- active and historically active buffered areas. terpretation of the imagery. Ground truthing We also compared historic (1972–1976) per- of imagery was also incorporated with >80% cent cultivated and percent noncultivated land mapping accuracy within the analyzed areas. within 4-km buffers of leks that were active in These classified satellite images were converted 1972–1976 with those that were inactive in to a 60 × 60-m grid within Imagine. The grid 1999–2000. Leks that have remained active in was then brought into ArcView 3.2a for analy- sis. We calculated percentage of total cultivated the comparison have not moved significantly and noncultivated area within 4-km buffers (>0.5 km) from their location in the early around active and inactive leks in North and 1970s. We overlaid our buffers onto our grids South Dakota, within 2-km buffers around ran- of 1972–1976 and 1999–2000 cultivated and dom points in an extensive active region and noncultivated land in North Dakota and South inactive region in North Dakota, and for the Dakota within ArcView 3.2a (Environmental entire active versus inactive region in North Systems Research Institute, Inc., Redlands, Dakota for years 1972–1976 and 1999–2000. California, USA, 1992–2002). Percent area of All data were analyzed in SAS (SAS Institute cultivated and noncultivated land was then 1999) and maps were displayed using Clarke calculated using the tabulate area option within 1866 ellipsoid, North American Datum 1927, the grid analyst extension of ArcView 3.2a. and projection UTM Zone 13. Active, inactive, and random buffers were then compared using a paired t test. Due to unequal 4-km Buffer variances determined from the folded F-statis- Comparisons tic, a degrees-of-freedom adjustment using the Active and inactive leks were plotted onto a Satterthwaite method was used on t tests (SAS map of the study area in North and South Institute 1999). Additionally, we compared Dakota (Fig. 1). We buffered active and inac- (paired t tests) the percentage of cultivated tive leks and randomly selected points by a 4- land within the 4-km buffers around active km radius. Using the low end and the high leks in North Dakota and South Dakota with end of the average nest distance from the that of leks with ≥40 male Greater Sage-Grouse nearest lek (Connelly et al. 2000), we took the (we considered this a good active lek) in east- mean of these 2 distances which rounded up ern Montana. We used large Greater Sage- to 4 km. Preliminary landscape-level plotting Grouse leks in Montana to obtain a compari- indicated that buffering >4 km also caused son of the habitat around large leks more in too much overlap between sites for significant the central part of the Greater Sage-Grouse comparisons to be made. If an active 4-km range. We obtained and classified Montana buffer overlapped an inactive 4-km buffer by satellite imagery in the same way as North and more than 1 km, we ignored the inactive one South Dakota imagery explained previously. 2005] LEK OCCUPANCY AND LANDSCAPE CULTIVATION 313

Fig. 1. Inactive and active Greater Sage-Grouse lek locations within North and South Dakota.

Region Comparisons inactive regions we created in North Dakota were overlaid onto the grid of cultivated land. In North Dakota we identified 2 geographic Percent cultivated and noncultivated lands were regions, 1 with 100% inactive leks and 1 with calculated within each region using the tabu- 73% active leks, and enclosed each within a late area method. These percentages were then polygon (Fig. 2). We were unable to identify compared between regions and between years similar active and inactive lek regions in South using a goodness-of-fit chi-square test. Dakota due to lack of historical lek location Random points were established within the information and defined regions of lek aban- active and inactive regions in North Dakota to donment and activity. These regions in North evaluate dispersion of cultivation. An increase Dakota were compared relative to the current in proportion of buffered random points with (1999–2000; Fig. 3B) and historic (1972–1976; cultivation would also relate directly to in- Fig. 3A) percent cultivated land within each creased shrubland-cultivation edge, an indica- region. Within ArcView 3.2a, the active and tion of shrubland fragmentation. We created 314 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 2. Regions created in North Dakota by placing polygons around 4-km buffers of Greater Sage-Grouse leks. Buffers are designated as active (light gray filled circles) or inactive (dark gray filled circles).

2-km buffers around 15 randomly placed points RESULTS within each region and overlaid them onto the Comparisons of 4-km Buffers grids of 1972–1976 (Fig. 4A) and 1999–2000 for 1999–2000 (Fig. 4B) percent cultivated land. For regional comparisons we used 2-km buffers to balance Comparisons of percent cultivated land with- the need to sample landscapes with the need in 4-km buffers around active leks and inactive for more points to better sample area. The leks (Table 1) in North Dakota revealed that percentage of the 15 randomly placed buffers inactive leks had a higher (|t| = 3.03, 12 df, P within each region containing cultivated land = 0.0105) percentage of cultivated land than (>0 ha) and the percentage of the 15 ran- active leks. Percent cultivated land within 4- domly placed buffers containing no cultivated km buffers around random points (Table 1) land within each region were compared be- was also found to be higher (|t| = 2.47, 25 df, tween regions and between years using a chi- P = 0.0204) than 4-km buffers around active square test. sites in North Dakota. 2005] LEK OCCUPANCY AND LANDSCAPE CULTIVATION 315

A B

Fig. 3. Active (polygon with solid outline) and inactive (dotted outline) regions in North Dakota overlaid onto 1972–1976 (A) and 1999–2000 (B) grids of cultivated (black areas) and noncultivated (white areas) ground. Only culti- vated ground intersecting or within regions is shown on 1972–1976 grid.

Comparisons of percent cultivated and non- 1.14, 4 df, P = 0.3188; South Dakota: |t| = cultivated land within 4-km buffers placed –1.00, 5 df, P = 0.3632) between periods. The around active leks and inactive leks (Table 1) percentage of cultivated land within 4-km in South Dakota revealed that inactive leks buffers around leks that were active in 1972– showed no difference (|t| = 0.35, 17 df, P = 1976 and were still active in 1999–2000 (Table 0.7327) in percentage of cultivated land from 2) also showed no difference (North Dakota: that within 4-km buffers of active leks. Percent |t| = 0.91, 3 df, P = 0.4290; South Dakota: cultivated land within 4-km buffers around |t| = –1.00, 3 df, P = 0.3910) between periods. random points (Table 1) was no different (|t| Region Comparisons = 1.20, 23 df, P = 0.2427) from percent culti- vated land within 4-km buffers around active Region comparisons in North Dakota re- sites in South Dakota. Comparisons of percent vealed that the proportion of cultivated land cultivated land within 4-km buffers placed (area of cultivated/area of noncultivated) in around active leks in eastern Montana (Table 1999–2000 was greater (χ2 = 2.9563, 1 df, P = 1) versus active leks in the Dakotas showed no 0.0855) within the inactive region than within difference (North Dakota: |t| = 0.24, 12 df, P the active region (Fig. 5A). The landscape in = 0.8141; South Dakota: |t| = 1.36, 11 df, P 1999–2000 within the inactive region also had = 0.2012). a greater (χ2 = 59.2741, 1 df, P < 0.0001) per- centage of occurrence of cultivated land (i.e., Comparisons of 4-km Buffers buffers with cultivated land/15) within the 15 Between 1972–1976 random 2-km buffers than the 15 random 2-km and 1999–2000 buffers within the active region (Fig. 5B). The percentage of cultivated land within 4- Between 1972–1976 and 1999–2000, the km buffers around leks that were active in proportion of cultivated land to noncultivated 1972–1976 and inactive in 1999–2000 (Table 2) land within the inactive and active region of showed no difference (North Dakota: |t| = North Dakota (Fig. 5A) showed no change 316 WESTERN NORTH AMERICAN NATURALIST [Volume 65

AB

Fig. 4. Random points (n = 15) buffered by 2 km (circles) within each region (solid-line polygon = active; dotted-line polygon = inactive) and overlaid onto 1972–1976 (A) and 1999–2000 (B) grids of cultivated (black areas) and nonculti- vated (white areas) ground. Only tilled ground intersecting or within regions is shown on 1972–1976 grid.

(inactive: χ2 = 0.0725, 1 df, P = 0.7877; active: (Nelle et al. 2000), or other disturbances of χ2 = 0.0398, 1 df, P = 0.8418). Buffers around sagebrush ecosystems (Haegen et al. 2002). our 15 randomly placed points within the in- Increases in cultivation activity have been active and active regions of North Dakota (Fig. found to cause Greater Sage-Grouse declines 5B) also showed no change in cultivation in the State of Washington (Schroeder et al. (inactive: χ2 = 1.6017, 1 df, P = 0.2057; active: 2000). These disturbances may affect female χ2 = 0.9579, 1 df, P = 0.3277) between 1972– nesting sites (Call and Maser 1985), causing 1976 and 1999–2000. females to shift to undisturbed areas and thus decreasing lek size or resulting in abandon- DISCUSSION ment if males shift the lek site closer to the location of high female abundance (Bradbury From current (1999–2000) satellite imagery, et al. 1986, Gibson 1996). it appears that cultivated land plays a role in We cannot detect a relationship between lek abandonment in North Dakota. However, cultivated land and abandonment of leks in when we investigated the relationship, com- South Dakota; however, from the limited his- paring early satellite imagery (1972–1976) to torical information available, more leks may more recent imagery (1999–2000), there was have been present in regions farther east where no increase in the amount of cultivated land cultivation has been more common. In South associated with the inactive areas since the Dakota, removal of sagebrush through cultiva- early to mid-1970s. If cultivated land is a factor tion and herbicides may still be a factor in the in the abandonment of leks, its effects likely abandonment of Greater Sage-Grouse leks. In began before 1972–1976. Greater Sage-Grouse North Dakota there are historical leks but no are influenced by landscape-scale changes (Con- known active leks located in areas of Bowman nelly et al. 1988, Crawford et al. 2004) that County where intensive cultivation practices may result from tillage (Peterson 1970), fire are present. The same relationship may hold 2005] LEK OCCUPANCY AND LANDSCAPE CULTIVATION 317

TABLE 1. Percent cultivated land within 4-km buffers placed around active leks, inactive leks, and random points in North Dakota (ND), South Dakota (SD), and Montana (MT), 1999–2000.

______% cultivated a – State Status nxsx– ND A 12 3.79 0.83 I1010.47 2.04 R18 8.08 1.52 SD A 11 0.95 0.44 I80.83 0.64 R18 2.04 0.96 MT A 11 4.43 2.52 aA = active lek, I = inactive lek, and R = random points.

TABLE 2. Percent cultivated land within 4-km buffers placed around leks active in 1972–1976 that were active or inac- tive in 1999–2000 in North Dakota (ND) and South Dakota (SD).

______% cultivated ______1972–1976 ______1999–2000 a – – State Status nxsx– x sx– ND A 4 2.44 1.46 2.07 1.15 I58.53 3.54 5.16 1.69 SD A 4 0.19 0.19 0.23 0.23 I50.00 0.00 0.61 0.61 aA = active lek, I = inactive lek.

true for South Dakota. No active leks were Wallestad 1975). Further, disturbance to the found in northeastern Harding County and central part of the Greater Sage-Grouse range southeastern Butte County, both regions of and adjoining areas of Montana and Wyoming higher cultivation than other regions of these could be weakening peripheral populations in counties with active leks. However, we lack North and South Dakota. Other activities known consistent historical records to determine if to affect fidelity to displaying areas are min- leks were ever present in these regions of Butte ing, oil wells, and military disturbance (Rogers and Harding Counties. 1964, Eng et al. 1979, Tate et al. 1979, Call and Other studies suggest that Greater Sage- Maser 1985, Schroeder et al. 1999), mainly due Grouse movement from one lek to another could to the noise level (Rogers 1964) or to new be in response to a combination of factors. perching sites provided for raptors that may Distance may not be a factor in movements, disturb Greater Sage-Grouse breeding displays. but prior habitat alterations and topography Increased disturbance to Greater Sage- might play important roles (Emmons and Braun Grouse leks by roads, oil and natural gas wells/ 1984). Habitat alterations around the lek (e.g., pumps, and associated noises may be playing a plowing, spraying, burning, and overgrazing) role in lek abandonment in North Dakota. could initiate abandonment (Wallestad and These wells and pumps have sometimes been Schladweiler 1974, Call and Maser 1985, within 100 m of, if not directly on, Greater Crawford et al. 2004). These disturbances may Sage-Grouse lek sites. Oil well development not directly harm Greater Sage-Grouse, but within 200 m may have caused abandonment when these activities cause the eradication of of at least 1 lek in North Dakota (Jerry Kobriger, sagebrush and fragmentation of habitat around personal communication, North Dakota Game strutting grounds, they have been documented and Fish Department). However, oil/natural to cause abandonment and an overall decrease gas wells and power lines are located within in the population of that area (Enyeart 1956, 500 m of both currently active leks (6) and 318 WESTERN NORTH AMERICAN NATURALIST [Volume 65

be justified to examine the proximity of such disturbances to Greater Sage-Grouse activities. In the Dakotas most of the Greater Sage- Grouse breeding range falls on private land, so working locally and inviting all potential stakeholders to conservation planning meet- ings is a must and may prove crucial in accom- plishing habitat recovery. Some leks may need to be managed differently from others to meet conservation goals as well as local landowner objectives. Sustained efforts at restoration of Greater Sage-Grouse habitat are needed to minimize degradation and further habitat loss on private and even public lands (Wisdom et al. 2002). Programs like the Conservation Reserve Program have helped in grassland bird habitat recovery (Herkert 1998, McCoy et al. 1999). Similar programs to reestablish sage- brush communities or systems in areas con- verted to cropland might be beneficial to Greater Sage-Grouse. Areas that have soils suited to establishing sagebrush will have the best potential for Greater Sage-Grouse habitat reclamation. By translating the conservation value of sagebrush range to economic values (Olson 1996) captured by the landowner through innovative processes and habitat restoration incentive programs, we can help residents of Fig. 5. Comparison of 1972–1976 and 1999–2000 percent rural communities meet their needs of earning cultivated land within active and inactive regions in North a living while maintaining Greater Sage-Grouse Dakota. A, Total percent of cultivated land within each population. region; B, percent of the 15 random 2-km buffers that had cultivated land within them. Same letters indicate no sig- nificant difference. ACKNOWLEDGMENTS We thank the North Dakota Game and Fish Department and the South Dakota Department inactive leks (4) in the Dakotas. We observed 2 of Game, Fish and Parks for providing lek locations. Appreciation is expressed to the strutting grounds within 200 m of oil wells South Dakota State University GIS Laboratory that were erected during the 2 years of the for providing digital state maps and to all the study. Whether these leks will remain active landowners for allowing access. We would like in these same areas is yet to be determined. to thank A.D. Apa and D. Bunnell for review- Proximity of oil/natural gas wells is also associ- ing this manuscript. Funding for this project ated with other disturbances and landscape was provided by the South Dakota Department changes that could discourage lek use. To ex- of Game, Fish and Parks, Federal Aid to Wild- tract their product from these wells, companies life Restoration Fund (Project W-107-R, Amend- have been building numerous roads through ment 14, No. 1012); North Dakota Game and areas occupied by Greater Sage-Grouse. The Fish Department, Federal Aid to Wildlife physical presence of roads themselves may Restoration Fund (Project W-67-R-40, No. B- not immediately detract male and female V-4); U.S. Forest Service Agreement 00-CS- Greater Sage-Grouse from an area, but dust 1102; Bureau of Land Management Contract and noise may eventually cause shifts or aban- Agreement ESA000013, Task Order 1; and donment. Future studies in the Dakotas may South Dakota State University. 2005] LEK OCCUPANCY AND LANDSCAPE CULTIVATION 319

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PETERSON, J.G. 1970. The food habits and summer distri- THOMPSON, K.W. 1978. Soil survey of Slope County, North bution of juvenile Sage-Grouse in central Montana. Dakota. U.S. Department of Agriculture, Soil Conser- Journal of Wildlife Management 34:147–155. vation Service and Forest Service, North Dakota ROGERS, G.E. 1964. Sage-Grouse investigations in Colo- Agricultural Experiment Station, Fargo. rado. Colorado Game, Fish and Parks, Game Research WAKKINEN, W.L., K.P. REESE, AND J.W. CONNELLY. 1992. Division, Denver. Sage-Grouse nest locations in relation to leks. Jour- SAS INSTITUTE. 1999. SAS/STAT user’s guide. Version 8.0. nal of Wildlife Mangement 56:381–383. SAS Institute, Cary, NC. WALLESTAD, R.O. 1975. Male Sage-Grouse responses to SCHROEDER, M.A., J.R. YOUNG, AND C.E. BRAUN. 1999. sagebrush treatment. Journal of Wildlife Manage- Sage-Grouse (Centrocercus urophasianus). Pages 1–28 ment 39:482–484. in A. Poole and F. Gill, editors, The birds of North WALLESTAD, R.O., AND D. PYRAH. 1974. Movement and America, No. 425. The Birds of North America, Inc., nesting of Sage-Grouse hens in central Montana. Philadelphia, PA. Journal of Wildlife Management 38:630–633. SCHROEDER, M.A., D.W. HAYS, M.F. LIVINGSTON, L.E. WALLESTAD, R.O., AND P. S CHLADWEILER. 1974. Breeding STREAN, J.E. JACOBSON, AND D.J. PIERCE. 2000. season movements and habitat selection of male Sage- Changes in the distribution and abundance of Sage Grouse. Journal of Wildlife Management 38:634–637. Grouse in Washington. Northwestern Naturalist 81: WISDOM, M.J., M.M. ROWLAND, B.C. WALES, M.A. HEM- 104–112. STROM, W.J. HANN, M.C. RAPHAEL, R.S. HOLTHAUSEN, SCHROEDER, M.A., C.L. ALDRIDGE, A.D. APA, J.R. BOHNE, ET AL. 2002. Modeled effects of sagebrush-steppe C.E. BRAUN, S.D. BUNNELL, J.W. CONNELLY, ET AL. restoration on Greater Sage-Grouse in the interior 2004. Distribution of Sage-Grouse in North Amer- Columbia Basin, U.S.A. Conservation Biology 16: ica. Condor 106:363–376. 1223–1231. SCOTT, J.W. 1942. Mating behavior of the Sage-Grouse. YOUNG, J.R., C.E. BRAUN, S.J. OYLER-MCCANCE, J.W. HUPP, Auk 59:477–498. AND T.W. Q UINN. 2000. A new species of Sage-Grouse SWENSON, J.E. 1987. Decrease of Sage Grouse Centrocer- (Phasianidae: Centrocercus) from southwestern Col- cus urophasianus after ploughing of sagebrush steppe. orado. Wilson Bulletin 112:445–453. Biology Conservation 41:125–132. TATE, J., JR., M.S. BOYCE, AND T.R. SMITH. 1979. Response Received 31 March 2004 of Sage-Grouse to artificially created display ground. Accepted 20 December 2004 Pages 459–463 in G.A. Swanson, editor, Proceedings of the Mitigation Symposium. U.S. Forest Service, General Technical Report RM-65. Western North American Naturalist 65(3), © 2005, pp. 321–328

COMPARING THE EFFECTS OF GRANIVOROUS RODENTS ON PERSISTENCE OF INDIAN RICEGRASS (ORYZOPSIS HYMENOIDES) SEEDS IN MIXED AND MONOSPECIFIC SEED PATCHES

Joseph A. Veech1,3 and Stephen H. Jenkins2

ABSTRACT.—In desert environments seeds are often heterogeneously distributed in small patches that vary in number of seed species and in seed density. Because seed harvest by rodents is often density dependent (a larger proportion of seeds is removed from high-density seed patches than from low-density patches), the proportion of residual or post-har- vest seeds should be greater in low-density patches. In addition, seed preference can affect harvest. We tested whether the residual proportion of a highly preferred seed (Indian ricegrass, Oryzopsis hymenoides) was less when in a seed patch with a 2nd species (mixed-species patch) than when in a monospecific seed patch. We predicted that the increased overall seed density due to the presence of 2 species in a patch would result in a lower residual proportion of ricegrass seeds in the mixed-species seed patches than in the monospecific patches. As predicted, the residual proportions of Indian ricegrass seeds were less each time ricegrass was paired with one of 6 other species in mixed-species patches. Similarly, the residual proportion of each of those 6 species was less when paired with ricegrass than when in a mono- specific patch. We speculate on the potential implications of these results for the population dynamics of plant species and the physical structure of plant communities.

Key words: heteromyid rodent, Indian ricegrass, Oryzopsis hymenoides, density-dependent foraging, seed-tray experiment.

Indian ricegrass (Oryzopsis hymenoides) is component in sustaining populations of grani- a perennial bunchgrass found throughout west- vorous rodents and, in some years, the caching ern North America. It is often associated with of seeds by rodents may serve as a source of loose substrates such as the sand typical of sand recruitment for ricegrass populations (McAdoo dunes and other arid habitats (Jones 1990). It et al. 1983, Young et al. 1983, Longland et al. shares this habitat affinity with heteromyid 2001). rodents (family Heteromyidae), such as kanga- Regardless of whether rodents have an over- roo rats (Dipodomys) and pocket mice (Chae- all positive effect on Indian ricegrass popula- todipus and Perognathus), also widespread and tions by caching seeds that subsequently ger- locally abundant in arid parts of western North minate, or a negative effect due to seed con- America. Indian ricegrass usually produces sumption, the 1st step in this interaction is the seeds during the summer months. Heteromyid harvest of seeds from the immediate area around rodents are capable of harvesting a large portion adult plants. This area may be no larger than a of the seed crop of some plant species (Soholt dinner plate as the seeds are heavy and not 1973, Nelson and Chew 1977, McAdoo et al. likely to be dispersed by wind. Furthermore, 1983, Longland et al. 2001), which they either the spatial distribution of seeds in desert eco- immediately consume or cache for later use systems is often heterogeneous (Reichman 1976, (McAdoo et al. 1983, Longland et al. 2001, Veech Nelson and Chew 1977, Price and Reichman 2001). Many rodent species prefer seeds of 1987, Henderson et al. 1988, Price and Joyner Indian ricegrass over seeds of other plant 1997, Anderson and MacMahon 2001); relatively species (McAdoo et al. 1983, Kelrick et al. 1986, dense concentrations of seeds of different Henderson 1990, Jenkins and Ascanio 1993, species occur in depressions in the soil surface Longland and Bateman 1998, Veech 2001). or against objects (e.g., small rocks, shrubs) Thus, Indian ricegrass may be an important that block the wind. Thus, the seed resource

1Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, CO 80523. 2Ecology, Evolution, and Conservation Biology Program, Department of Biology, University of Nevada–Reno, Reno, NV 89557. 3Present address: Department of Biological Sciences, University of Northern Colorado, Greeley, CO 80639.

321 322 WESTERN NORTH AMERICAN NATURALIST [Volume 65 of granivorous rodents can be viewed as existing tion dynamics of plants producing seeds that within distinct small spatial patches. Rodents are foraged by rodents. forage for seeds in and among these patches. We predicted that the residual number of The harvesting of seeds by heteromyid Indian ricegrass seeds would be greater in rodents is sometimes density dependent (Price monospecific patches than in mixed-species and Heinz 1984, Brown 1988, Bowers 1990, seed patches. We also compared the residual Mitchell and Brown 1990, Veech 2000, 2001). seed numbers of the other 6 species when In the present study we define density-depen- paired with Indian ricegrass and when in a dent foraging as the harvest (i.e., removal) of a monospecific seed patch. Again, we predicted larger proportion of seeds (of a given species) a greater number of residual seeds in mono- from patches with high overall seed densities specific seed patches because their lower total than from patches with low densities. Overall seed density induces less foraging. seed density is defined as the combined den- sity of seeds of all species. If the proportion of METHODS seeds harvested is density dependent, then Description of the proportion of seeds that are not harvested Study Site is also density dependent. We refer to this lat- ter proportion as residual seeds. We tested for We measured rodent harvesting of seeds of differences in the residual number of Indian Oryzopsis and 6 other plant species at a study ricegrass seeds in patches consisting solely of site about 80 km northeast of Reno, Nevada, ricegrass (monospecific patches) and patches USA. These species were Astragalus cicer, consisting of ricegrass and seeds of 1 of 6 other Panicum miliaceum, Sphaeralcea coccinea, Stan- species (mixed-species patches). The initial leya pinnata, an unidentified species of Lupi- number of ricegrass seeds was the same in both nus, and an unidentified species of Penstemon. types of patches; thus, the mixed-species patches All of the species were found at or near the represented a higher initial seed density than study site except for Panicum and Astragalus, the monospecific patches. although a congener of A. cicer (A. lentigeno- We were primarily interested in testing sus) was found at the study site. We used Pan- whether the presence of a 2nd seed species icum (millet) as a proxy for a seed type that is could, by increasing overall seed density, affect highly preferred by rodents; Panicum is often the residual number of Indian ricegrass seeds. used to trap rodents and to study their forag- Previously, it was demonstrated that density- ing behavior. We collected seeds of Lupinus, dependent harvest occurs when rodents forage Penstemon, Sphaeralcea, and Stanleya at the in monospecific patches with substantially dif- study site while seeds of the other 3 species ferent initial seed densities (Brown 1988, were obtained from a commercial supplier. Mitchell and Brown 1990, Veech 2000). Indeed, The heteromyid rodent community at the this type of density-dependent foraging is some- study site was diverse. Extensive trapping by what easy to demonstrate. However, density- other researchers has revealed the existence of dependent harvest may also occur under a dif- 8 species: Chaetodipus formosus, Dipodomys ferent (and perhaps more realistic) scenario deserti, D. merriami, D. microps, D. ordii, Micro- where differences in seed densities among dipodops pallidus, Perognathus longimembris, patches are due to the presence of additional and P. parvus (Breck and Jenkins 1997, Jones seed species, not merely to differences in the and Longland 1999). We live-trapped rodents density of a single seed species. That is, the on 21 June 1998 to confirm the existence of actual type of patch (monospecific seed patches rodents on our study blocks (see next section). versus patches with seeds of multiple species) We caught 38 individuals representing 5 species might influence harvest rates and residual seed in a total of 200 traps. The relative abundances densities. The residual seeds not harvested of each species in terms of percentage of total from a patch may, in some cases, act as a chan- individuals captured were D. merriami (71.1), nel of recruitment for a plant population. Thus, D. microps (10.5), M. pallidus (2.6), P. longi- we also present our study as an example of the membris (7.9), and P. parvus (7.9). Although potential need to consider density-dependent there were also granivorous ants and birds at foraging in studies and models of the popula- the study site, most of the seed harvesting that 2005] RODENTS AND RICEGRASS 323 occurred during the seed-tray experiment (see higher overall seed density also always con- below) could be attributed to rodents because tained 2 seed species. the seeds were covered with sand and not In each seed tray we placed a 1-cm layer of accessible to birds and ants (Longland et al. sand that had been cleaned of all debris. We 2001). then sprinkled the seeds on this sand layer and covered the seeds with another 1-cm layer Seed-tray Experiment of sand to prevent harvesting by birds and We measured harvesting of seeds of Ory- ants. Trays were left out in the field for approx- zopsis and the other plant species by deter- imately 30 nights, allowing ample time for mining the number of seeds removed from rodents to find and forage in all trays. We then trays containing a known number of seeds. collected the trays and counted the number of Seed-tray experiments have been widely used seeds remaining in each tray. This seed-tray for more than a decade to measure seed har- experiment was conducted from 16 July 1998 vest by heteromyid rodents. Rodents readily to 13 August 1998 (run 1) and again from 17 enter seed trays to forage, particularly if the August 1998 to 19 September 1998 (run 2). trays are filled with a natural substrate (e.g., The experiment was conducted twice in the sand). On several occasions we visually observed same summer because it was suspected that rodents foraging in our seed trays. Seed-tray the depletion of naturally occurring seeds might experiments will overestimate absolute rates affect the intensity of seed removal from the of seed harvest if rodents “learn” to use the trays. trays as cues for foraging. However, our pri- For each station we recorded 4 variables: mary interest was in comparing harvest in the number of Oryzopsis seeds remaining in monospecific seed patches (Oryzopsis only) their monospecific tray (NORYmono), the num- with mixed-species seed patches (Oryzopsis ber of species X seeds remaining in their mono- and a 2nd species) and not in measuring ab- specific tray (NXmono), and the number of Ory- solute rates of harvest. zopsis and species X seeds remaining in the We established 3 blocks at the study site; mixed-species tray (NORYmix and NXmix, re- blocks were separated by about 300 m. Each spectively). We added 0.5 to the raw data to block consisted of 4 rows of 12 stations spaced make zero values non-zero (<1% of the values 20 m apart. The spacing between adjacent rows in the entire data set were zero) and then log- was 80 m. At each station we placed 3 seed trays transformed the data to achieve normality (Sokal spaced 1 m apart. These trays were small alu- and Rohlf 1995). The transformation succeeded minum pans (diameter 22.5 cm, depth 5.5 cm) in producing a more normal distribution al- containing seeds and sand. Together the 3 trays though it was still slightly left-skewed because represented the following treatments: (1) 100 about 25% of the values represented ≤20 sur- seeds of Oryzopsis without species X, (2) 100 viving seeds and 50% of the values represented seeds of species X without Oryzopsis, (3) 100 ≥75 surviving seeds. seeds of Oryzopsis with species X, and (4) 100 We were primarily interested in testing seeds of species X with Oryzopsis, where X whether the proportions of residual seeds of refers to one of the 6 species previously listed. Oryzopsis (and the other species) were differ- The first 2 treatments are represented by mono- ent in the monospecific and mixed-species specific seed trays. We refer to the 3rd and 4th seed trays. However, we also tested for differ- treatments as the mixed-species seed tray; that ences between the 2 runs of the seed-tray is, the mixed-species tray represents 2 treat- experiment and between the plant species. We ments. Within each row, each pairing of Ory- conducted a split-plot ANOVA, in which Run zopsis with another species was represented and Species X were treated as categorical vari- twice at randomly chosen stations and so each ables, with 2 and 6 levels respectively. Each pairing was represented 8 times in each block. station contained only 1 level of each variable; A total of 3 blocks yielded a sample size of 24 thus we had a split-plot design with Run and for each pairing. Note that with this experi- Species X as between-plot factors. A separate mental design we were not attempting to dis- preliminary ANOVA did not reveal a block tinguish the effects of seed density from the effect; thus it was not included. The within- effects of number of seed species (1 or 2) on plot factor was Type of Seed Patch with the harvest rates. That is, the treatment with a following treatments: monospecific patch of 324 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 1. Results of the ANOVA testing for an effect of Type of Seed Patch, Run, and Species X on the number of residual seeds of Oryzopsis and Species X. Source SS DF MS FP Type of Seed Patch 37.6 3 12.5 42.2 < 0.001 Type of Seed Patch ⋅ Run 3.5 3 1.2 4.0 0.008 Type of Seed Patch ⋅ Species X 73.9 15 4.9 16.6 < 0.001 Type of Seed Patch ⋅ Run ⋅ Species X 26.4 15 1.8 5.9 < 0.001 Error 245.6 828 0.3 — —

Oryzopsis, monospecific patch of species X, (Table 1). Because NXmono, NXmix, NORYmono, and mixed-species patch containing Oryzopsis and NORYmix were significantly different, fur- and species X. The ANOVA provided a test of ther tests to elucidate the differences were the effect of Type of Seed Patch on the num- warranted. Combining data for both runs, the ber of residual seeds (df = 4 – 1). This was ratio of ln(NXmono):ln(NXmix) was significantly essentially a test of whether log-transformed >1.0 (ratio = 1.048, F12,276 = 4.5, P < 0.001) values of NORYmono, NORYmix, NXmono, and as was the ratio of ln(NORYmono):ln(NORYmix) NXmix differed, but with no distinction made (ratio = 1.073, F12,276 = 4.3, P < 0.001). How- among the 6 species represented by X. The ever, the ANOVA also revealed a significant ANOVA also tested for an interaction between interaction between Type of Seed Patch and Type of Seed Patch and Run [df = (4 – 1) ⋅ (2 – the 2 runs of the seed-tray experiment as well 1) = 3]. In addition, the interaction between as an interaction between type of patch and Type of Seed Patch and Species X was tested the 6 species represented by X (Table 1). by the ANOVA [df = (4 – 1) ⋅ (6 – 1) = 15]. Because of these interactions, we did not com- This was essentially a test of whether the bine data from the 2 runs or any of the seed number of residual seeds of the 7 species species in subsequent analyses. The propor- (Oryzopsis and the 6 species X) differed and tion of residual seeds was lower during run 2 whether the differences were related to being than run 1 for all species (Fig. 1). In addition, in a monospecific versus mixed-species patch. some species (e.g., Penstemon and Stanleya) Finally, the ANOVA also tested the interaction tended to have greater residual seed numbers of Type of Seed Patch ⋅ Run ⋅ Species X [df = ⋅ ⋅ than the other species (Fig. 1). (4 – 1) (2 – 1) (6 – 1) = 15]. Paired t tests were conducted to further The relative effect of rodents on Oryzop- elucidate these differences between species, sis seeds in monospecific and mixed-species type of patch, and the 2 runs of the seed-tray seed patches was measured as the ratio of experiment. For each run and each species, we NORYmono to NORYmix. Similarly, the effect tested H0: ln(NXmono) – ln(NXmix) = 0 against of rodents on seeds of species X (without the alternative hypothesis H : ln(NX ) – regard to the exact identity of X) in monospe- 1 mono ln(NX ) > 0. For all species, the proportion cific and mixed-species seed patches was mea- mix of residual seeds was significantly greater in sured as the ratio of NX to NX . A ratio mono mix the monospecific seed trays than in the mixed- significantly different from 1.0 indicates that species seed trays for at least 1 run of the proportions of residual seeds in monospecific seed-tray experiment, typically for both runs and mixed-species patches were different. We also tested for differences between ln(NX ) (Table 2). We also tested for a difference in the mono residual number of Oryzopsis seeds in the and ln(NXmix), separately for each species X, using paired t tests. The monospecific and monospecific seed trays and when paired with mixed-species seed trays at each station formed each of the other 6 species in the mixed- a pair. species seed trays. We found only 2 instances of significant differences. After run 2 of the RESULTS seed-tray experiment, the residual number of Oryzopsis seeds was greater in monospecific The type of seed patch clearly had a signifi- seed trays than in trays also containing Astra- cant effect on residual seed numbers (F3,828 = galus (mean difference = 0.533, sx– = 0.162, N 42.2, P < 0.001) as revealed by the ANOVA = 24, t = 3.28, P = 0.0016). The same result 2005] RODENTS AND RICEGRASS 325

Fig. 1. Mean number of residual seeds in the monospecific and mixed-species seed trays for each of the 7 plant species used in this study. Names of plant species are abbreviated as the first 3 letters of the genus name. Numbers 1 and 2 along the x-axis refer to runs 1 and 2 of the seed-tray experiment. Note that the number of residual seeds was always greater during run 1 and always greater in the monospecific than in the mixed-species seed trays. Results for Oryzopsis are for its pairings with all other species (N = 144 for each bar). Error bars represent +1 s.

emerged when Oryzopsis was paired with Pani- in initial overall seed density. Researchers often cum during run 2 (mean difference = 0.727, sx– use seed trays to study foraging behavior = 0.188, N = 24, t = 3.88, P = 0.0008). How- (Brown 1988, Brown et al. 1988, 1992, Valone ever, when residual numbers of Oryzopsis seeds and Brown 1989, Mitchell and Brown 1990, were pooled across all 6 other species, the Kotler et al. 1993, Hughes et al. 1995, Meyer larger sample size provided a more powerful and Valone 1999, Mohr et al. 2003). Our defin- test, and significant differences between mono- ition of density-dependent foraging and our specific and mixed-species patches were found use of the seed-tray experiment do not allow for run 1 (mean difference = 0.078, sx– = for any inferences about the behavior of indi- 0.046, N = 144, t = 1.71, P = 0.045) and run 2 vidual rodents. Rather, density-dependent for- (mean difference = 0.221, sx– = 0.067, N = aging is seen as a collective property of the 144, t = 3.32, P = 0.0006). community of granivorous rodents. The 2 types of seed patches also differed in composition (1 DISCUSSION versus 2 seed species), and thus differences in residual seed proportions may also have As predicted, the type of seed patch (mono- emerged from foraging behavior (e.g., assess- specific or mixed-species) influenced the ment of patch quality based on composition) number of residual seeds that remained after not due to seed density. rodents foraged within the patches. For each We wish to direct attention to the potential plant species, the number of residual seeds effect of seed foraging by rodents on plant was lower in the mixed-species seed patches population dynamics. Thus, instead of deci- than in the monospecific seed patches (Fig. 1). phering the intricacies of foraging behavior, These differences are consistent with density- we were primarily interested in the way in dependent foraging given that the monospe- which the initial species composition and seed cific and mixed-species seed patches differed density within a seed patch affect the final 326 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 2. Results of the paired t tests for each plant species and each of the 2 runs of the seed-tray experiment. Difference in no. residual seeds in 1 Species Run monospecific and mixed seed trays sx– tP Astragalus 1 5.7 0.043 2.16 0.021 2 9.1 0.110 2.51 0.010 Lupinus 1 2.6 0.149 1.91 0.034 2 8.5 0.129 2.55 0.009 Panicum 1 4.8 0.126 2.54 0.009 2 1.7 0.277 1.86 0.038 Penstemon 1 3.2 0.023 1.95 0.032 2 5.0 0.057 1.62 0.059 Sphaeralcea 1 6.0 0.035 2.18 0.018 2 12.2 0.091 3.11 0.003 Stanleya 1 1.3 0.018 0.84 0.205 2 6.3 0.050 1.79 0.043

1 Values shown are the mean (NXmono – NXmix) paired at each station; t tests were applied to ln-transformed data (df = 24 for each test). Standard errors are for the transformed data.

proportion of residual seeds. Presumably, resid- 1993). Oryzopsis is a highly preferred seed ual seeds may germinate in the spring if con- with an average mass of 3.7–4.4 mg and high ditions are appropriate. Seed patches contain- carbohydrate content, whereas the average ing only 1 species tended to have a greater mass of Penstemon, a highly avoided seed, is number of residual seeds than did patches 0.9–1.1 mg. Seed size is widely thought to containing seeds of 2 plant species. Thus, it is affect competition among seedlings (Harper possible that germination of seedlings from 1977, Rees and Westoby 1997); perhaps, the the former type of patch is more probable than effect of seed size on seed harvest is another germination from mixed-species patches. If so, basic feature of plant population biology. the 2 types of patches may differ in their poten- In the specific case of Oryzopsis and other tial as sources of recruitment for the plant seeds preferred by rodents, the harvest of seeds population of a given species. may have either positive or negative effects on The composition of a seed patch might not plant population dynamics. Heteromyid rodents only affect the absolute number (or probabil- are known to cache the seeds of many different ity) of recruits but also the spatial patterning species in shallow subsurface scatterhoards of a plant community. The proportion of resid- (Reynolds 1958, Smith and Reichman 1984, ual Oryzopsis seeds in the mixed-species McAuliffe 1990, Longland 1995). Caching of patches varied depending upon which other Indian ricegrass seeds has been documented species was present. For example, during late (McAdoo et al. 1983, Young et al. 1983, Breck summer (after run 2 of the seed-tray experi- and Jenkins 1997, Pyare and Longland 2000, ment) there were fewer Oryzopsis seeds in Longland et al. 2001) and may actually have a patches with Panicum seeds than in patches net positive effect on Indian ricegrass popula- with Stanleya seeds. Thus, differences between tions when seedlings emerge and establish species might affect the physical structure of from the caches (Longland et al. 2001). Alter- the plant community; we might expect to find natively, harvest may also be followed by adult Oryzopsis individuals paired with Stan- immediate or later consumption of seeds after leya more so than with a plant species whose recovery from caches. seeds are preferred by the rodents. Indeed, of Our study demonstrates that the harvest of the 7 plant species in this study, heteromyid Indian ricegrass seeds depends upon the den- rodents have distinct and consistent prefer- sity of seeds in the patch as well as the pres- ences for some seeds and avoidance of others ence of seeds of other species. The presence (Veech 2001). Seed preference may, in part, be of a 2nd seed species elevated overall seed due to seed size and the nutritional content of density such that harvest of ricegrass seeds the seeds (Lockard and Lockard 1971, Reich- was increased, perhaps due to density-depen- man 1977, Kelrick et al. 1986, Henderson 1990, dent foraging by heteromyid rodents. Such Podolsky and Price 1990, Jenkins and Ascanio knowledge might be useful in attempts to 2005] RODENTS AND RICEGRASS 327 restore degraded rangeland. Indian ricegrass BROWN, J.S., Y. AREL, Z. ABRAMSKY, AND B.P. KOTLER. 1992. is valued as forage for livestock (Robertson Patch use by gerbils (Gerbillus allenbyi) in sandy and rocky habitats. Journal of Mammalogy 73:821–829. 1976, Jones 1990, Orodho and Trlica 1990, BROWN, J.S., B.P. KOTLER, R.J. SMITH, AND W. O. W IRTZ. Young et al. 1994, Bich et al. 1995) and is often 1988. The effects of owl predation on the foraging be- used in rangeland restoration (Plummer and havior of heteromyid rodents. Oecologia 76:408–415. Frischknecht 1952, Jones 1990, Young et al. GRANTZ, D.A., D.L. VAUGHN, R. FARBER, B. KIM, M. ZELDIN, T. V ANCUREN, AND R. CAMPBELL. 1998. Seeding native 1994, Grantz et al. 1998, Humphrey and Schupp plants to restore desert farmland and mitigate fugi- 1999, 2002). Our results suggest that the suc- tive dust and PM10. Journal of Environmental Qual- cess of efforts to restore Indian ricegrass may ity 27:1209–1218. depend on which other species are present in HARPER, J.L. 1977. Population biology of plants. Academic the seed bank and the degree to which seeds Press, San Diego, CA. HENDERSON, C.B., K.E. PETERSEN, AND R.A. REDAK. 1988. are heterogeneously distributed in patches. Spatial and temporal patterns in the seed bank and Finally, the results of our study could also vegetation of a desert grassland community. Journal be interpreted as another demonstration of of Ecology 76:717–728. short-term apparent competition (Holt and HENDERSON, C.B. 1990. The influence of seed apparency, nutrient content and chemical defenses on dietary Kotler 1987) among seed species (Veech 2001), preference in Dipodomys ordii. Oecologia 82:333–341. because seed “predation” was greater in the HOLT, R.D., AND B.P. KOTLER. 1987. Short-term apparent mixed-species seed patches. Recall that the competition. American Naturalist 130:412–430. residual numbers of seeds were less in such HUGHES, J.J., D. WARD, AND M.R. PERRIN. 1995. Effects of substrate on foraging decisions by a Namib Desert patches. Short-term apparent competition is gerbil. Journal of Mammalogy 76:638–645. the decreased survival of a prey species when HUMPHREY, L.D., AND E.W. SCHUPP. 1999. Temporal pat- in a patch with a 2nd prey species than when terns of seedling emergence and early survival of alone (Holt and Kotler 1987). It can occur if Great Basin perennial plant species. Great Basin Naturalist 59:35–49. the 2 prey species share a predator species. ______. 2002. Seedling survival from locally and commer- Invoking the concept of apparent competition cially obtained seeds on two semiarid sites. Restora- is not necessary to understand our results; how- tion Ecology 10:88–95. ever, the concept does reemphasize that the fate JENKINS, S.H., AND R. ASCANIO. 1993. A potential nutri- tional basis for resource partitioning by desert of seeds in a patch depends on whether seeds rodents. American Midland Naturalist 130:164–172. of other species are also present in the patch. JONES, A.L., AND W. S. L ONGLAND. 1999. Effects of cattle grazing on salt desert rodent communities. Ameri- ACKNOWLEDGMENTS can Midland Naturalist 141:1–11. JONES, T.A. 1990. A viewpoint on Indian ricegrass research: its present status and future prospects. Journal of We thank Bill Longland, Mary Price, and Range Management 43:52–57. an anonymous reviewer for their comments and KELRICK, M.I., J.A. MACMAHON, R.R. PARMENTER, AND suggestions for improving this manuscript. D.V. SISSON. 1986. Native seed preferences of shrub- steppe rodents, birds and ants: the relationships of seed attributes and seed use. Oecologia 68:327–337. LITERATURE CITED KOTLER, B.P., J.S. BROWN, AND W.A. MITCHELL. 1993. Environmental factors affecting patch use in two ANDERSON, C.J., AND J.A. MACMAHON. 2001. Granivores, species of gerbilline rodents. Journal of Mammalogy exclosures, and seed banks: harvester ants and rodents 74:614–620. in sagebrush-steppe. Journal of Arid Environments LOCKARD, R.B., AND J.S. LOCKARD. 1971. Seed preference 49:343–355. and buried seed retrieval of Dipodomys deserti. Jour- BICH, B.S., J.L. BUTLER, AND C.A. SCHMIDT. 1995. Effects nal of Mammalogy 52:219–221. of differential livestock use on key plant species and LONGLAND, W.S. 1995. Desert rodents in disturbed shrub rodent populations within selected Oryzopsis hymen- communities and their effects on plant recruitment. oides–Hilaria jamesii communities of Glen Canyon Pages 209–215 in B.A. Roundy, E.D. McArthur, J.S. National Recreation Area. Southwestern Naturalist Haley, and D.K. Mann, editors, Proceedings of the 40:281–287. symposium on wildland shrubs and arid land restora- BOWERS, M.A. 1990. Exploitation of seed aggregates by tion. United States Forest Service, General Techni- Merriam’s kangaroo rat: harvesting rates and preda- cal Report INT-GTR-315. tory risk. Ecology 71:2334–2344. LONGLAND, W.S., AND S.L. BATEMAN. 1998. Implications of BRECK, S.W., AND S.H. JENKINS. 1997. Use of an ecotone desert rodent seed preferences for range remediation. to test the effects of soil and desert rodents on the Journal of Range Management 51:679–684. distribution of Indian ricegrass. Ecography 20: LONGLAND, W.S., S.B. VANDER WALL, S.H. JENKINS, S. 253–263. PYARE, AND J.A. VEECH. 2001. Seedling recruitment BROWN, J.S. 1988. Patch use as an indicator of habitat in Indian ricegrass (Oryzopsis hymenoides): are desert preference, predation risk, and competition. Behav- granivores mutualists or predators? Ecology 82: ioral Ecology and Sociobiology 22:37–47. 3131–3148. 328 WESTERN NORTH AMERICAN NATURALIST [Volume 65

MCADOO, J.K., C.C. EVANS, B.A. ROUNDY, J.A. YOUNG, AND REES, M., AND M. WESTOBY. 1997. Game-theoretical evo- R.A. EVANS. 1983. Influence of heteromyid rodents lution of seed mass in multi-species ecological mod- on Oryzopsis hymenoides germination. Journal of els. Oikos 78:116–126. Range Management 36:61–64. REICHMAN, O.J. 1976. Effects of rodents on germination of MCAULIFFE, J.R. 1990. Paloverdes, pocket mice, and bruchid desert annuals. US/IBP Desert Biome Research beetles: interrelationships of seeds, dispersers, and Memorandum 76-20, Utah State University, Logan. seed predators. Southwestern Naturalist 35:329–337. ______. 1977. Optimization of diets through food prefer- MEYER, M.D., AND T.J. V ALONE. 1999. Foraging under ences by heteromyid rodents. Ecology 58:454–457. multiple costs: the importance of predation, ener- REYNOLDS, H.G. 1958. The ecology of the Merriam kanga- getic, and assessment error costs to a desert forager. roo rat (Dipodomys merriami) on the grazing lands of Oikos 87:571–579. southern Arizona. Ecological Monographs 28:111–127. MITCHELL, W.A., AND J.S. BROWN. 1990. Density-depen- ROBERTSON, J.H. 1976. The autecology of Oryzopsis dent harvest rates by optimal foragers. Oikos 57: hymenoides. Mentzelia 2:18–27. 180–190. SMITH, C.C., AND O.J. REICHMAN. 1984. The evolution of MOHR, K., S. VIBE-PETERSEN, L.L. JEPPESEN, M. BILDSOE, food caching by birds and mammals. Annual Review AND H. LEIRS. 2003. Foraging of multimammate of Ecology and Systematics 15:329–351. mice, Mastomys natalensis, under different preda- SOHOLT, L.F. 1973. Consumption of primary production tion pressure: cover, patch-dependent decisions, and by a population of kangaroo rats (Dipodomys merri- density-dependent GUDs. Oikos 100:456–468. ami) in the Mojave Desert. Ecological Monographs NELSON, J.F., AND R.M. CHEW. 1977. Factors affecting 43:357–376. seed reserves in the soil of a Mojave Desert ecosys- SOKAL, R.R., AND F. J . R OHLF. 1995. Biometry. 3rd edition. tem, Rock Valley, Nye County, Nevada. American Freeman Publishing, New York. Midland Naturalist 97:300–320. VALONE, T.J., AND J.S. BROWN. 1989. Measuring patch ORODHO, A.B., AND M.J. TRLICA. 1990. Clipping and long- assessment abilities of desert granivores. Ecology term grazing effects on biomass and carbohydrate 70:1800–1810. reserves of Indian ricegrass. Journal of Range Man- VEECH, J.A. 2000. Predator-mediated interactions among agement 43:52–57. the seeds of desert plants. Oecologia 124:402–407. PLUMMER, A.P., AND N.C. FRISCHKNECHT. 1952. Increasing ______. 2001. The foraging behavior of granivorous rodents field stands of Indian ricegrass. Agronomy Journal and short-term apparent competition among seeds. 44:285–289. Behavioral Ecology 12:467–474. PODOLSKY, R.H., AND M.V. PRICE. 1990. Patch use by Dipod- YOUNG, J.A., R.R. BLANK, W.S. LONGLAND, AND D.E. PALM- omys deserti (Rodentia: Heteromyidae): profitability, QUIST. 1994. Seeding Indian ricegrass in an arid en- preference, and depletion dynamics. Oecologia 83: vironment in the Great Basin. Journal of Range 83–90. Management 47:2–7. PRICE, M.V., AND K.M. HEINZ. 1984. Effects of body size, YOUNG, J.A., R.A. EVANS, AND B.A. ROUNDY. 1983. Quan- seed density, and soil characteristics on rates of seed tity and germinability of Oryzopsis hymenoides seed harvest by heteromyid rodents. Oecologia 61:420–425. in Lahontan sands. Journal of Range Management PRICE, M.V., AND J.W. JOYNER. 1997. What resources are 36:82–86. available to desert granivores: seed rain or soil seed bank? Ecology 78:764–773. Received 2 April 2004 PRICE, M.V., AND O.J. REICHMAN. 1987. Distribution of Accepted 15 November 2004 seeds in Sonoran Desert soils: implications for het- eromyid rodent foraging. Ecology 68:1797–1811. PYARE, S., AND W. S. L ONGLAND. 2000. Seedling-aided cache detection by heteromyid rodents. Oecologia 122: 66–71. Western North American Naturalist 65(3), © 2005, pp. 329–334

NUTRITIONAL CONDITION OF ELK IN ROCKY MOUNTAIN NATIONAL PARK

Louis C. Bender1 and John G. Cook2

ABSTRACT.—We tested the hypothesis that elk in Rocky Mountain National Park (RMNP) were at ecological carrying capacity by determining herd-specific levels of nutritional condition and fecundity. Ingesta-free body fat levels in adult cows that were lactating were 10.6% (s = 1.7; range = 6.2–15.4) and 7.7% (s = 0.5; range = 5.9–10.1) in November 2001 for the Horseshoe and Moraine Park herds, respectively. Cows that were not lactating were able to accrue signifi- cantly more body fat: 14.0% (s = 1.1; range = 7.7–19.3) and 11.5% (s = 0.8; range = 8.6–15.1) for the Horseshoe and Moraine Park herds, respectively. Cow elk lost most of their body fat over winter (April 2002 levels were 3.9% [s = 0.4] and 2.9% [s = 0.4] for the Horseshoe and Moraine Park herds, respectively). Nutritional condition indicated that both Horseshoe Park and Moraine Park elk were well below condition levels elk can achieve on very good–excellent nutrition (i.e., >15% body fat; Cook et al. 2004) and were comparable to other free-ranging elk populations. However, condition levels were higher than those expected at a “food-limited” carrying capacity, and a proportion of elk in each herd were able to achieve condition levels indicative of very good–excellent nutrition. Elk in RMNP are likely regulated and/or limited by a complex combination of density-independent (including significant heterogeneity in forage conditions across RMNP’s landscape) and density-dependent processes, as condition levels contradict a simple density-dependent model of a population at ecological carrying capacity.

Key words: Cervus elaphus, condition, ecological carrying capacity, elk, nutrition.

Elk (Cervus elaphus) in Rocky Mountain 2002, Cook et al. 2004). Nutritional condition National Park (RMNP) were hypothesized to of individuals thus provides a direct collation be at ecological carrying capacity (ECC; Lubow of habitat quality because effects of density- et al. 2002), i.e., a “food-limited” carrying capac- driven resource limitations first involve reduc- ity where decreased per capita forage acquisi- tions in nutrition and subsequently condition tion has resulted in decreased individual and (Mautz 1978, Franzmann 1985). However, large population productivity and increased mortal- herbivores can also show poor condition inde- ity, so that populations are recruiting only pendent of density effects if nutrition is limit- enough new individuals to balance annual ing through density-independent mechanisms; mortality (Caughley 1979). Elk and other large for example, if forage quality is inadequate herbivores respond to increasing density via regardless of elk density (Cook et al. 2004). intrinsic regulatory mechanisms (i.e., density Nutritional condition can also be related dependence), including decreases in individ- directly to adequacy of elk diets to support key ual condition, juvenile fecundity, juvenile sur- life processes. Levels of condition have been vival, adult fecundity, and lastly adult survival, identified that influence basic life-history that are ultimately expressed in population rate- parameters in elk (Cook et al. 2004); for exam- of-increase (Gaillard et al. 2000). Fundamen- ple, cow elk essentially cease to ovulate and tally, habitat conditions affect elk populations thus do not breed when total body fat levels in by influencing energy balance and, ultimately, autumn drop below 6%. Moreover, dietary fat reserves of individual elk (Mautz 1978, quality necessary to achieve specific levels of Franzmann 1985, Cook et al. 2004). In turn, condition in elk has been identified in studies condition of individuals strongly influences with penned elk (Cook et al. 2004). virtually every health, production, and survival The most common cause of dietary deficien- parameter of elk and other ungulates (Clutton- cies is thought to be resource limitations due to Brock et al. 1982, Verme and Ullrey 1984, competition at high elk densities because of neg- Adams et al. 1995, Keech et al. 2000, Cook ative feedback in per capita resource capture

1U.S. Geological Survey, New Mexico Cooperative Fish and Wildlife Research Unit, Box 30003 MSC 4901, Las Cruces, NM 88003. 2National Council for Air and Stream Improvement, Forest and Range Sciences Lab, 1401 Gekeler, LaGrande, OR 97850.

329 330 WESTERN NORTH AMERICAN NATURALIST [Volume 65 associated with increased population densities vations above timberline are dominated by or shifts in plant species composition brought alpine tundra and bare rock. about by excessive herbivory (e.g., density Wildlife in RMNP includes a diverse fauna effects; Irwin et al. 1994, Riggs et al. 2000). dominated by large mammals, i.e., elk, Rocky Elk populations experiencing resource limita- Mountain bighorn sheep (Ovis canadensis), tions from density effects show lower condi- mule deer (Odocoileus hemionus), moose (Alces tion than populations not experiencing density alces), black bear (Ursus americanus), moun- effects (Clutton-Brock et al. 1982, Cook 2002) tain lion (Felis concolor), lynx (Lynx canaden- because the former suffer restricted nutrition. sis), and coyote (Canis latrans). To test the hypothesis that elk in RMNP were Elk wintering in eastern RMNP are split at ECC, we therefore determined nutritional between 2 wintering populations: the Horse- condition (ingesta-free body fat) of elk as a col- shoe Park and Moraine Park herds (Lubow et al. lation of habitat quality and related condition 2002). Elk densities in Moraine Park average to the adequacy of the elk nutritional environ- approximately 3 times higher than in Horse- ment. Further, we determined fecundity of adult shoe Park; peak densities in certain portions of elk. We hypothesized that if elk in RMNP the winter range can exceed 90 elk ⋅ km–2 were at ECC, they should exhibit low condi- (Singer et al. 2002). Vegetation impacts are also tion consistent with diets of very low quality greater in Moraine Park than in Horseshoe Park and decreased fecundity. Moreover, survival of (Singer et al. 2002). Despite these differences, adult elk would be affected if a population the herds are often treated as a single popula- were at ECC (Gaillard et al. 2000). tion for modeling, and discussions of elk-ECC in RMNP consider the elk as a single popula- STUDY AREA tion (Lubow et al. 2002, Singer et al. 2002). Overall, elk densities were >30 elk ⋅ km–2 on Rocky Mountain National Park is a 108-km2 7% of RMNP’s winter ranges, and <1–29 elk biosphere reserve located in the Rocky Moun- ⋅ km–2 on the remaining 93% (Singer et al. tain Front Range of north central Colorado. 2002). Bull:cow ratios averaged 22 bulls per Topography in RMNP was shaped by glacia- 100 cows in RMNP (Lubow et al. 2002). tion and consists of high mountainous peaks Our data represent a one-time look at elk interspersed with small subalpine meadows condition and, consequently, nutrition in (parks), lakes, streams, glaciers, and alpine tun- RMNP. Generality of our results is dependent dra at higher elevations. Elevations range from upon generality of spring, summer, autumn, 2440 m to 4345 m at Longs Peak. The Conti- and winter conditions experienced by elk from nental Divide bisects RMNP, creating differ- April 2001 to April 2002. Comparisons of ing climatic patterns to the east and west. monthly mean temperature and total precipi- Eastern RMNP is drier, with annual precipita- tation deviations with long-term means for tion averaging 35.1 cm at Estes Park. Western Estes Park indicated that neither summer– RMNP is more mesic, with precipitation aver- autumn conditions (mean temperature devia- aging 50.8 cm at Grand Lake. Seventy-five tion = +1.04°C [95% CI = –0.23–1.69]; mean percent of the precipitation falls from April to precipitation deviation = –0.20 cm [95% CI = September. Mean daily high temperatures –2.31–1.96]) nor winter (mean temperature range from 3.6°C in January to 25.7°C in July deviation = –2.52°C [95% CI = –5.26–0.23]; at Estes Park. mean precipitation deviation = +0.61 cm Vegetation at RMNP includes more than 700 [95% CI = –0.56–1.78]) conditions differed species of plants. Lower slopes and valleys are from long-term averages (National Climate Data composed of forests of lodgepole (Pinus con- Center archived data). Thus, our data should torta) and ponderosa pine (P. ponderosa), blue be indicative of mean conditions for elk in spruce (Picea pungens), Douglas-fir (Pseudo- RMNP. tsuga menziesii), juniper ( Juniperus spp.), and aspen (Populus tremuloides) interspersed with MATERIALS AND METHODS bunchgrass and sedge-dominated herbaceous meadows. At higher elevations, subalpine forests Elk Capture of Engelmann spruce (P. engelmannii) and sub- We captured 59 cow elk >1.5 years of age alpine fir (Abies lasiocarpa) predominate. Ele- (range = 2.5–12.5), 14 from the Moraine Park 2005] ELK NUTRITIONAL CONDITION IN RMNP 331

Table 1. Total percent ingesta-free body fat (s) of cow elk from the Horseshoe Park and Moraine Park herds, Rocky Mountain National Park, November 2001 and April 2002.

______Horseshoe Park ______Moraine Park Class November April November April Nonlactating 14.0 (1.1)A1 11.5 (0.8)B Lactating 10.6 (1.7)B 7.7 (0.5)C All 3.9 (0.4)D 2.9 (0.4)D

1Means sharing a letter do not differ (P > 0.05). and 15 from the Horseshoe Park herds in cow in November by presence/absence of milk November 2001, and 15 from each herd in in the udder (Bender et al. 2002). We com- April 2002. We captured elk by ground-dart- puted variances around proportions pregnant ing using carfentanil citrate and xylazine and proportions lactating using the normal hydrochloride (1.5 mg carfentanil citrate + approximation (Zar 1996) and compared pro- 300 mg xylazine per elk). Immobilized elk portions pregnant in November and April for were given antibiotics, vitamin E/selenium, each herd using Fischer’s exact test (Zar vitamin B, and an 8-way Clostridium bactrain. 1996). Following processing, the immobilants were reversed with 150 mg of naltrexone + 1000 RESULTS mg of tolazoline per elk. Elk were aged using Nutritional Condition tooth eruption and wear (Quimby and Gaab and Fecundity 1957) and were temporarily marked with an oil-base paint to avoid recapture of the same Ingesta-free body fat differed between sites individuals. and by lactation status (F5,53 = 46.80; P < 0.001). In November elk had more body fat Nutritional Condition than in April for either site (Table 1). Elk that and Fecundity were lactating in November had less fat than cows that were not lactating in either herd. We estimated ingesta-free body fat of elk at Both lactating and nonlactating cows in Horse- each capture using a live animal index, which shoe Park had greater fat levels than in Moraine combined subcutaneous fat depth at the rump Park in November (Table 1). Population-level measured by a large-animal ultrasound with a (lactating and nonlactating elk combined) body body condition score (rLIVINDEX; Cook et fat levels in November were also higher for al. 2001). When ultrasonography was not pos- Horseshoe Park (x– = 12.8%, s– = 0.98, range sible, we used a body condition score (rBCS; x = 6.2–19.3) than Moraine Park (x– = 9.7%, s– Cook et al. 2001). The rBCS involved classify- x = 0.68, range = 5.9–15.1; sx– = 2.59, P = ing fat and muscle catabolism along the sacral 0.015). Fat levels of cows did not differ be- ridge, ilium, ishium, and sacro-sciatic liga- tween herds in April (Table 1). ment into condition classes (Cook 2000). Both Proportion of pregnant females did not dif- 2 methods are strong predictors (r = 0.86–0.90) fer between females captured in November and of total ingesta-free body fat in elk (Cook et al. April in either Horseshoe Park (Fischer’s exact 2001). test P = 0.402) or Moraine Park (Fischer’s We used 2-way ANOVA (Zar 1996) to com- exact test P = 0.275). Proportions were pooled pare fat levels among classes of cows (lactating, for overall rates of 0.86 (sx– = 0.06; 25/29) and nonlactating) and seasons (November, April), 0.63 (sx– = 0.09; 19/30) for Horseshoe and and Student’s 2-tailed t test (Zar 1996) to com- Moraine Parks, respectively. pare body fat between Horseshoe Park and Moraine Park elk in November for both lacta- DISCUSSION tion classes pooled. We assessed pregnancy in November using ultrasonography and in April Lactating cow elk in RMNP exhibited con- by rectal palpation and blood progesterone dition levels indicative of either marginal (Weber et al. 1982, Bingham et al. 1990). We (Horseshoe Park) or poor (Moraine Park) qual- determined lactation status of each captured ity summer–autumn diets (Cook et al. 2004). 332 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Body fat in late autumn averaged 7.7% in et al. 2004), these data indicate that summer Moraine Park and 10.6% in Horseshoe Park. forage conditions used by elk in RMNP varied Marginal diet quality (2.40–2.75 kcal of digest- markedly. While differences in density between ible energy per gram of forage [kcal ⋅ g–1 DE], elk in Horseshoe and Moraine Parks may explain allowing accretion of 8%–12% body fat) may some of the range in fat levels for nonmigra- influence reproduction and survival through tory individuals, it is likely that variations in enhanced probability of winter mortality, de- microclimate, topography, and soils across layed breeding, reduced fecundity, and delayed RMNP’s landscape (Arthur and Fahey 1993, puberty. Poor diet quality (dietary qualities of Hessl et al. 1996, Kalkhan and Stohlgren 2000) <2.40 kcal ⋅ g–1 DE, allowing accretion of also influenced elk condition. That is, some <8% body fat) can markedly affect reproduc- elk probably occupied areas of unusually high tion and reduce survival probabilities (Cook et forage quality and quantity (e.g., high-eleva- al. 2004). Thus, conditions indicated that nu- tion riparian meadows), while other elk occupied tritional deficiencies should exert a moderate summering areas supporting poor forage con- (Horseshoe Park) to strong (Moraine Park) ditions (e.g., remaining in Moraine or Horse- limiting effect on elk productivity in RMNP, shoe Parks throughout the year). This suggests primarily through reduced pregnancy rates, an important density-independent influence on delayed puberty, some increase in overwinter elk productivity, driven by differential range mortality depending upon weather severity, use and thus exposure to forage differing sub- and delayed breeding (Cook et al. 2004), par- stantially in quality. Further, because diet qual- ticularly in the Moraine Park herd. Fecundity ity needs to be maintained throughout the data from both populations (Horseshoe Park = summer–autumn period to achieve these high 86% pregnancy; Moraine Park = 63% preg- levels of condition, an elk range near ECC nancy) supported these assertions. Differences would be unable to provide this level of dietary in fat levels between elk from Horseshoe and quality due to deterioration of range conditions Moraine Parks likely reflect differences in qual- associated with overutilization (Irwin et al. 1994, ity of elk summer ranges (see below) and elk Riggs et al. 2000). densities, which were approximately 3 times Adult survival is the last demographic higher in Moraine Park; ≤90 elk ⋅ km–2 com- affected by resource limitations, but it should pared to ≤29 elk ⋅ km–2 (Singer et al. 2002). decline when a population faces severe resource Fat levels of elk in RMNP also showed that limitations as when at ECC (Gaillard et al. a proportion of cows in both herds were able 2000). Lubow et al. (2002) documented an adult to achieve very good–excellent condition (5/14 cow survival rate of 0.93 in RMNP, the 2nd and 1/15 cows achieved body fat levels >15% highest survival rate published for adult cows, in November for Horseshoe and Moraine Park behind only the 0.97 documented by Ballard herds, respectively). Fat levels in late Novem- et al. (2000) for unhunted elk in Arizona. Thus, ber reached as high as 19.3% for nonlactating adult survival appears unaffected by density in cows in Horseshoe Park, the highest fat level RMNP, further indicating that while certainly yet recorded for free-ranging elk (Cook et al. resource stressed, elk are likely below ECC in 2002), and a lactating elk reached 15.4% in RMNP. Horseshoe Park. In Moraine Park, nonlactators (maximum = 15.1%) and lactators (maximum MANAGEMENT IMPLICATIONS = 10.1%) were unable to reach levels observed in Horseshoe. The higher levels (15%+) were Past discussions of ECC for elk in RMNP indicative of very good to excellent nutrition addressed winter ranges and minimized the (≥2.85 kcal ⋅ g–1 DE; Cook et al. 2004). More- influences of summer–autumn range condi- over, the variation in fat levels of elk in RMNP tions (Hobbs et al. 1982, Lubow et al. 2002). in autumn was also the highest yet recorded However, the literature clearly shows that for free-ranging elk (Cook et al. 2002). This was summer range conditions have considerable true even within lactation status categories; fat influences on pregnancy rates, calf growth, levels of lactating cows ranged from 5.9% to age at puberty, fat accretion of cows, and abil- 15.4%. Because fat levels of lactating cows in ity of elk to survive over winter, as a function autumn are strongly related to forage quality of body fat in adults and body size of calves consumed in summer and early autumn (Cook (Clutton-Brock et al. 1982, Cook 2002, Cook 2005] ELK NUTRITIONAL CONDITION IN RMNP 333 et al. 2004). Ecologically, it can be argued that Condition data, however, demonstrated that winter ranges are simply a place to stay where these herds used foraging habitats of signifi- harsh winter conditions are minimized and thus cantly differing quality, and thus they should rate of condition loss is minimized (Mautz 1978). be treated as distinct populations when assess- A definition of carrying capacity for these con- ing demographics, given the fundamental in- ditions is ambiguous, because a good winter fluence of nutrition on elk survival and produc- range is one that reduces the rate of condition tivity (Clutton-Brock et al. 1982, Cook 2002). loss, while a poor winter range has a relatively higher rate of condition loss. In both situa- ACKNOWLEDGMENTS tions, elk cannot maintain condition, and thus any estimate of “carrying capacity” would be We thank Rocky Mountain National Park, negative. From a practical perspective, the the U.S. Geological Survey, and the National “carrying capacity” of winter range, or the Council for Air and Stream Improvement for number of elk that can survive winter on a funding this project. The New Mexico Agri- given piece of ground, is a function of winter culture Experiment Station provided addi- forage, winter weather, late-autumn fat levels tional support for this work. Dr. Terry Terrell of adults, and calf size (Mautz 1978, Clutton- of RMNP provided logistical and other support Brock et al. 1982, Cook 2002). Winter range without which this project would not have “carrying capacity” is thus higher if adult cows been possible. R. Cook and B. Krueger pro- are fat and consequently calves are large at the vided exceptional field assistance. M. Bender, beginning of winter (Mautz 1978). Condition J. Boren, B. Krueger, S. Smallidge, J. Rachlow, data from RMNP show that both Horseshoe and 2 anonymous reviewers provided helpful Park and Moraine Park herds lose most of suggestions for improving this manuscript. their accumulated fat over winter, although post-winter fat levels remain above levels LITERATURE CITED associated with starvation mortality (~2% body fat; Cook et al. 2004), a pattern in fat catabo- ADAMS, L.G., J. SINGER, AND B.W. DALE. 1995. Caribou calf mortality in Denali National Park, Alaska. Jour- lism similar to other elk herds for which sea- nal of Wildlife Management 59:584–594. sonal condition data are available (Cook et al. ARTHUR, M.A., AND T.J. FAHEY. 1993. Controls on soil solu- 2002). This fat catabolism reflects forage-qual- tion chemistry in a sub-alpine forest in north-central ity data (Hobbs et al. 1982) that indicate elk in Colorado. Soil Science Society of America Journal RMNP would be unable to meet maintenance 57:1122–1130. requirements on winter ranges regardless of BALLARD, W.B., H.A. WHITLOW, B.F. WAKELING, R.L. BROWN, J.C. DEVOS, JR., AND M.C. WALLACE.2000. population densities. Thus, the importance of Survival of female elk in northern Arizona. Journal body fat accretion while on summer range is of Wildlife Management 64:500–504. an undeniably important aspect of the nutri- BENDER, L.C., E. CARLSON, S.M. SCHMITT, AND J.B. HAU- tional and population ecology of elk in RMNP. FLER. 2002. Production and survival of elk (Cervus elaphus) calves in Michigan. American Midland Nat- Limiting evaluations to winter range relations, uralist 148:163–171. as has traditionally been done, limits insight BINGHAM, C.M., P.R. WILSON, A.S. DAVIES. 1990. Real-time into elk-habitat relations and elk population ultrasonography for pregnancy diagnosis and estima- status in RMNP. tion of fetal age in farmed red deer. Veterinary Record Condition data also indicate that elk from 125:102. CAUGHLEY, G. 1979. What is this thing called carrying the Horseshoe Park and Moraine Park herds capacity? Pages 2–8 in M.S. Boyce and L.D. Hay- experienced very dissimilar foraging habitats den-Wing, editors, North American elk: ecology, be- and that significant variation existed within haviour, and management. University of Wyoming, each herd in terms of the quality of foraging Laramie. habitats that individuals exploited. A proportion CLUTTON-BROCK, T.H., F.E. GUINNESS, AND S.D. ALBON. 1982. Red deer: behavior and ecology of two sexes. of elk from both herds acquired good–excel- University of Chicago Press, Chicago, IL. lent nutrition and thus exploited habitats well COOK, J.G. 2002. Nutrition and food. Pages 259–349 in above forage-quality and -quantity levels asso- D.E. Toweill and J.W. Thomas, editors, North Amer- ciated with any definition of a range at ECC. ican elk: ecology and management. 2nd edition. Recent assessments of elk-habitat relations in Smithsonian Institution Press, Washington, DC. COOK, J.G., L.C. BENDER, R.C. COOK, P.B. HALL, AND L.L. RMNP treated the Horseshoe Park and Moraine IRWIN. 2002. Nutritional influences on northwestern Park herds as a single entity (Lubow et al. 2002). elk herds: wild elk capture and nutritional condition 334 WESTERN NORTH AMERICAN NATURALIST [Volume 65

assessment. Progress report, National Council for KEECH, M.A., R.T. BOWYER, J.M. VER HOEF, R.D. BOERTJE, Air and Stream Improvement, LaGrande, OR. B.W. DALE, AND T.R. S TEPHENSON. 2000. Life-his- COOK, J.G., B.K. JOHNSON, R.C. COOK, R.A. RIGGS, T. DEL- tory consequences of maternal condition in Alaskan CURTO, L.D. BRYANT, AND L.L. IRWIN. 2004. Effects moose. Journal of Wildlife Management 64:450–462. of summer–autumn nutrition and parturition date on LUBOW, B.C., F.J. SINGER, T.L. JOHNSON, AND D.C. BOWDEN. reproduction and survival of elk. Wildlife Mono- 2002. Dynamics of interacting elk populations with- graphs 155:1–61. in and adjacent to Rocky Mountain National Park. COOK, R.C. 2000. Studies of body condition and repro- Journal of Wildlife Management 66:757–775. ductive physiology in Rocky Mountain elk. Master’s MAUTZ, W.W. 1978. Sledding on a brushy hillside: the fat thesis, University of Idaho, Moscow. cycle in deer. Wildlife Society Bulletin 6:88–90. COOK, R.C., J.G. COOK, D.L. MURRAY, P. ZAGER, B.K. JOHN- QUIMBY, D.C., AND J.E. GAAB. 1957. Mandibular dentition SON, AND M.W. GRATSON. 2001. Development of pre- as an age indicator in Rocky Mountain elk. Journal dictive models of nutritional condition for Rocky of Wildlife Management 21:435–451. Mountain elk. Journal of Wildlife Management 65: RIGGS, R.A., A.R. TIEDEMANN, J.G. COOK, T.M. BALLARD, 973–987. P. J . E DGERTON, M. VAVRA, W.C. KREUGER, ET AL. FRANZMANN, A.W. 1985. Assessment of nutritional status. 2000. Modification of mixed-conifer forests by rumi- Pages 239–260 in R.J. Hudson and R.G. White, edi- nant herbivores in the Blue Mountains Ecological tors, Bioenergetics of wild herbivores. CRC, Boca Province. U.S. Forest Service, Research Paper PNW- Raton, FL. RP-527. GAILLARD, J.-M., M. FESTA-BIANCHET, N.G. YOCCOZ, A. SINGER, F.J., L.C. ZEIGENFUSS, B. LUBOW, AND M.J. ROCK. LOISON, AND C. TOIGO. 2000. Temporal variation in 2002. Ecological evaluation of potential overabun- fitness components and population dynamics of large dance of ungulates in U.S. National Parks: a case herbivores. Annual Review of Ecology and System- study. Pages 205–248 in F. J. Singer and L.C. Zeigen- atics 31:367–393. fuss, compilers, Ecological evaluation of the abun- HESSL, A.E., P.J. WEISBERG, AND W.L. BAKER. 1996. Spa- dance and effects of elk herbivory in Rocky Moun- tial variability of radial growth in the forest-tundra tain National Park, Colorado, 1994–1999. Open File ecotone of Rocky Mountain National Park, Colorado. Report 02-208, U.S. Geological Survey, Midconti- Bulletin of the Torrey Botanical Club 123:206–212. nent Ecological Science Center, Fort Collins, CO. HOBBS, N.T., D.L. BAKER, J.E. ELLIS, D.M. SWIFT, AND VERME, L.J., AND D.E. ULLREY. 1984. Physiology and nu- R.A. GREEN. 1982. Energy- and nitrogen-based esti- trition. Pages 91–118 in L.K. Halls, editor, White- mates of elk winter-range carrying capacity. Journal tailed deer: ecology and management. Stackpole of Wildlife Management 46:12–21. Books, Harrisburg, PA. IRWIN, L.L., J.G. COOK, R.A. RIGGS, AND J.M. SKOVLIN. WEBER, B.J., M.L. WOLFE, AND G.C. WHITE. 1982. Use of 1994. Effects of long-term grazing by big game and serum progesterone levels to detect pregnancy in livestock in the Blue Mountains Forest Ecosystems. elk. Journal of Wildlife Management 46:835–838. U.S. Forest Service, General Technical Report PNW- ZAR, J.H. 1996. Biostatistical analysis. Prentice Hall, GTR-325. Upper Saddle River, NJ. KALKHAN, M.A., AND T.J. S TOHLGREN. 2000. Using multi- scale sampling and spatial cross-correlation to inves- Received 27 January 2004 tigate patterns of plant species richness. Environ- Accepted 15 November 2004 mental Monitoring and Assessment 64:591–605. Western North American Naturalist 65(3), © 2005, pp. 335–344

ARCHAEOLOGICAL RECORD OF NATIVE FISHES OF THE LOWER COLORADO RIVER: HOW TO IDENTIFY THEIR REMAINS

Kenneth W. Gobalet1, Thomas A. Wake2, and Kalie L. Hardin1

ABSTRACT.—Archaeological sites in the Salton Basin of southeastern California and along the lower Colorado River provided opportunities to determine which fish species were present prior to extirpations, environmental degradation, and the recession of Lake Cahuilla. These remains also represent the fishes exploited by Native Americans. Bonytail (Gila elegans), razorback sucker (Xyrauchen texanus), Colorado pikeminnow (Ptychocheilus lucius), striped mullet (Mugil cephalus), and machete (Elops affinis) have been recovered from 117 sites in the Salton Basin, once filled by the Col- orado River forming Lake Cahuilla. Bonytail and razorback sucker comprise nearly 99% of the remains. Along the lower Colorado River itself, fragmentary elements of bonytail, razorback sucker, Colorado pikeminnow, and roundtail chub (G. robusta) have been recovered, documenting a disappearing native fish fauna. Anatomical details are described that per- mit identification of diagnostic materials commonly recovered during archaeological excavations.

Key words: bonytail, Gila elegans, razorback sucker, Xyrauchen texanus, Colorado pikeminnow, Ptychocheilus lucius, roundtail chub, Gila robusta, zooarchaeology, Salton Basin, Lake Cahuilla, lower Colorado River, Native American fish- eries.

The lower Colorado River is the portion of (1961), Stanford and Ward (1986c), and Mueller the river below Lee’s Ferry (Stanford and Ward and Marsh (2002) listed between 9 and 12 1986a). Lee’s Ferry is located just above the species (but slightly different lists) that are Grand Canyon and below Lake Powell. The restricted to the main channel. The issue of flow of the river has been significantly altered which species were present in the prehistoric with the construction of hundreds of reser- lower Colorado River is further complicated voirs (Stanford and Ward 1986b) as well as by by taxonomic problems regarding the Gila disruptive forces associated with rapid urban robusta complex (Douglas et al. 2001). Rinne growth (Dolan et al. 1974, Mueller and Marsh (1976) recognized at least 4 forms present in 2002). These environmental changes have been the lower Colorado River basin in addition to so dramatic that Mueller and Marsh (2002:2) humpback chub (G. cypha) that are restricted have called the lower Colorado River “one of to the Grand Canyon. Remains of humpback the few rivers in the world with an entirely in- chub were identified from caves below and in troduced fish fauna.” Fish surveys of the lower the Grand Canyon (Miller 1955, Miller and Colorado River basin have been different in Smith 1984), raising questions regarding its focus and create uncertainties regarding which prehistoric range. species reside in the main channel, an impor- Archaeological excavations are useful in tant consideration for conservation and restor- establishing which fish species were prehis- ation efforts. torically present in freshwater drainages (Gob- Moyle (2002) listed only 5 native fishes from alet 1990a, 1990b) and are now possibly the the California portion of the Colorado River only resources we have to the past to deter- (Table 1). Two of the native species, bonytail mine which species were present in any given (Gila elegans) and Colorado pikeminnow (Pty- locality where baseline surveys are incomplete chocheilus lucius), are extirpated in California. or lacking. Environmental data derived from The razorback sucker (Xyrauchen texanus) is the archaeological record thus provide a con- at risk of extinction, and only the striped mul- trol for conservation and habitat restoration let (Mugil cephalus), a marine species that efforts. Fortunately, hundreds of archaeologi- enters freshwater to feed, is in reasonable cal sites exist along the Colorado River and health (Moyle 2002). Minckley (1979), Miller within the Salton Basin.

1Department of Biology, California State University, Bakersfield, CA 93311. 2Zooarchaeology Laboratory, University of California, Los Angeles, CA 90024.

335 336 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Lake Cahuilla, a massive lake 185 km by 56 RESULTS km by 91 m deep (Hubbs and Miller 1948, Wilke 1978), formed on at least 5 separate Salton Basin and occasions in the Salton Basin of southeastern Colorado River Sites California when the Colorado River periodi- Razorback sucker, bonytail, Colorado pike- cally changed its course (Waters 1983; Fig. 1). minnow, striped mullet, and machete remains Nearly 99% of the 17,000 fish remains identi- have been identified at the 22 unreported sites fied to species from 96 archaeological sites in in the Salton Basin when considered collec- the Salton Basin were bonytail or razorback tively (Table 2). More than 98% of these 4869 sucker (Gobalet 1992, 1994, Gobalet and Wake remains identified to species are from razor- 2000). Remaining elements were from Col- back sucker (73.6%) and bonytail (24.9%). Razor- orado pikeminnow, striped mullet, machete back sucker, bonytail, Colorado pikeminnow, (Elops affinis), and possibly desert pupfish and roundtail chub were all represented at (Cyprinodon macularius; Gobalet and Wake IMP-7911 on the Colorado River (Table 3). 2000). Because Stanford and Ward (1986c) and Minckley (1979) reported roundtail chub (G. Distinguishing Between robusta) and flannelmouth sucker (Catostomus Bonytail and Razorback latipinnis) from the main channel of the Col- Sucker Remains orado River, it is logical that each would have Although numerous skeletal elements can been present in Lake Cahuilla along with the be used to distinguish bonytail from razorback tiny woundfin (Plagopterus argentissimus) and sucker material, vertebrae are most likely to Gila topminnow (Peociliopsis occidentalis). If be encountered, as are pharyngeals and unique they were in the local waters, one could sur- interneurals of razorback sucker. Diagnostic mise that they would be in Native American elements not considered include dentary, middens as well. This study was undertaken to anguloarticular, maxilla, quadrate, hyomandib- determine if additional species were present ula, palatine, basioccipital, vomer, cleithrum, in the lower Colorado River prehistorically as coracoid, plural rib, and dorsal elements of the reflected by archaeological remains from 22 axial skeleton associated with the Weberian recent excavations on the lower Colorado River apparatus. These bones are rarely complete and and in the Salton Basin, and to provide ana- fragmentary remains require experience to tomical characters used in making the deter- recognize. minations. Precaudal vertebrae bear a neural arch and spine but no hemal arch or spine (Fig. 2). Cau- METHODS AND MATERIALS dal vertebrae have both neural and hemal Comparative specimens and archaeological arches and spines (Fig. 3). Precaudal vertebrae materials used in this study are listed under of bonytail can be distinguished from those of Materials Examined. Names of fishes follow razorback sucker by the presence of a narrow Nelson et al. (2004) except Siphates bicolor strut interconnecting the parapophysis found (tui chub), which follows Moyle (2002) and on the ventral portion of the lateral surface of Smith et al. (2002). the centrum with the base of the neural spine Characters described below for vertebrae (Fig. 2). The strut projects lateral to the edge anterior to the caudal peduncle are general of the outer rim of the ends of the centra. ones that distinguish minnows from suckers. Parapophyses (the bases to which the ribs In the Salton Basin and along the lower Col- attach to precaudal vertebrae) are rarely found orado River they are useful because diagnostic in place in archaeological materials, and the elements suggest that a single cyprinid (bony- strut interconnects the neural arch with the tail) and a single sucker (razorback sucker) dorsal boundary of the recess into which the dominated the fauna. Another large cyprinid, cone-shaped parapophysis fits. In razorback Colorado pikeminnow, is easily distinguishable sucker there occasionally may be a strut in the from bonytail (see below), and all elements are recess dorsal to the parapophysis recess, but too large to be from diminutive woundfin, the reduced strut does not extend beyond the another cyprinid. Skeletal features that distin- lateral perimeter of the centrum. guish bonytail from roundtail chub are subtle Caudal vertebrae (anterior to the caudal (see below). peduncle) of bonytail have a posterolateral 2005] ARCHAEOLOGICAL FISH REMAINS FROM THE LOWER COLORADO RIVER 337

TABLE 1. Native fishes of the lower Colorado River. Miller (1961) documented fishes from the lower Colorado and Gila Rivers near Yuma, AZ; Moyle (2002) the California portion of the Colorado River; Minckely (1979), Stanford and Ward (1986c), and Mueller and Marsh (2002) the main channel. “E” indicates that the species is extirpated from the main channel in California. Miller Minckley Stanford and Mueller andMoyle Species Common name (1961) (1979) Ward (1986c) Marsh (2002) (2002)

Gila cypha humpback chub X X G. elegans bonytail X X X X E G. robusta roundtail chub X X X Plagopterus argentissimus woundfin X X X X Ptychocheilus lucius Colorado pikeminnow X X X X E Rhinichthys osculus speckled dace X Catostomus latipinnis flannelmouth sucker X X X X Xyrauchen texanus razorback sucker X X X X X Cyprinodon macularius desert pupfish X X X X E Poeciliopsis occidentalis Sonoran topminnow X X X X Elops affinis machete X X X Mugil cephalus striped mullet X X X X X

Fig. 1. Lake Cahuilla at its maximum extent in southern California over 500 years ago. 338 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Table 2. Fish remains from sites in the Salton Basin by number of elements identified. Razorback Striped Colorado Site sucker Bonytail mullet pikeminnow Machete Ocotillo Wells 996 141 — 1 — IMP-7750 1772 821 — — 2 IMP-8209 111 12 16 1 — IMP-3214 28 9 — 3 — RIV-64 75 12 1 — — RIV-1221 46 5 — — — RIV-1177 19 4 — — — RIV-1176 35 20 11 — — RIV-2936 215 9 — 1 — RIV-3013 2500 1235 44 1 4 RIV-3659/H 4 1 1 — — RIV-5774 — 1 — — — RIV-5771 135 20 20 — — RIV-6225 150 80 8 2 — RIV-6190 34 42 3 — — RIV-6353 654 231 22 — — RIV-6357 4 — 1 — — RIV-6484 1 2 — — — RIV-6376 18 4 — — — Salton City/Niland Landfill 3 47 — 2 — SDI-2317/2318/H 24 2 — — — 96 sites* 6334 10,714 151 117 11

TOTAL 13,134 13,410 274 128 16

*Gobalet and Wake (2000)

TABLE 3. Fish remains identified from IMP-791 on the Fig. 5 of Miller and Smith 1984). As a conse- Colorado River. quence, bonytail caudal peduncular vertebrae TaxonElement Count are easy to spot and discriminate from Colo- rado pikeminnow and razorback sucker, in CATOSTOMIDAE 186 Razorback sucker 102 which the spines are more obliquely oriented. CYPRINIDAE 1 Roundtail chub caudal peduncular vertebrae Gila sp. 167 are also more obliquely oriented than those of Bonytail 9 bonytail. Photographs by Miller and Smith Roundtail chub 2 Colorado pikeminnow 8 (1984: Fig. 5) of tail skeletons of G. robusta, G. elegans, and G. cypha demonstrate that expe- rience and a large comparative collection are necessary to discriminate among members of process on the ventral portion of the centrum the Gila robusta complex. (Fig. 3). This process is lacking in razorback Pikeminnow vertebrae are not likely to be sucker. At the transition point between the confused with any other cyprinid. Colorado bonytail precaudal and caudal vertebrae, the pikeminnow are the largest North American posteroventral processes may be poorly devel- cyprinid, and their precaudal vertebrae tend oped and this character is equivocal. Indica- to be short and wide relative to the diameter tions that the processes have broken off would and somewhat dorsoventrally compressed (Fig. support an identification of bonytail. The strut 5). All species of Ptychocheilus (P. lucius, P. on the precaudal vertebrae and the poster- grandis, P. oregonensis, and fossil materials) oventral process on caudal vertebrae are features have a thin midline ridge in the recess on the that distinguish all cyprinids from catostomids. dorsal surface of the centrum below the neural In bonytail and humpback chub, caudal pe- arch of most vertebrae. duncular centra are elongate and their neural Macroscopic fish teeth found in the Salton and hemal spines lie nearly in parallel with Basin will be pharyngeal teeth from bonytail, the long axis of the vertebral column (Fig. 4; razorback sucker, Colorado pikeminnow, or see also Fig. 1 in Gehlbach and Miller 1961 and razorback sucker. The mandibles of these fishes 2005] ARCHAEOLOGICAL FISH REMAINS FROM THE LOWER COLORADO RIVER 339

Fig. 2A, Ventrolateral view of post-Weberian (precaudal) vertebrae 11 and 12 of Gila elegans (ASU 16387) (anterior is to the left); B, ventrolateral view of post-Weberian (precaudal) vertebrae 11 and 12 of Xyrauchen texanus (ASU 13760).

Fig. 3A, Lateral view of post-Weberian (caudal) vertebrae 25 and 26 of Gila elegans (ASU 16387, 280 mm TL) (ante- rior is to the left); B, lateral view of post-Weberian (caudal) vertebrae 28 and 29 of Xyrauchen texanus (ASU 13760). 340 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 4. Lateral view of the caudal peduncular skeleton of Gila elegans (ASU 16387). Dorsal is up and anterior is to the left.

Fig. 5A, Lateral view of 14th precaudal vertebra of Ptychocheilus grandis (KWG 578, 485 mm SL) (anterior is to the left); B, dorsal view of the centrum. are edentate. Striped mullet dentaries and pre- and pointed (Miller 1955: Plate IV). By contrast, maxillae are edged with serrations not recog- those of bonytail are robust, generally blunt or nizable as teeth, and machete teeth are micro- flattened from wear, and thicker at the middle scopic, on virtually all bones lining the mouth than at either end (Fig. 6). Razorback sucker and pharynx, and have the feel of fine sand- teeth are truncate and spatulate, and they have paper. Pikeminnow teeth are slender, conical, a narrow base; the pharyngeals contain dozens 2005] ARCHAEOLOGICAL FISH REMAINS FROM THE LOWER COLORADO RIVER 341

Fig. 6. Dorsolateral view of right pharyngeal of Gila ele- Fig. 7. Ventrolateral view of midsection of the right pha- gans (ASU 16387, 280 mm TL). Anterior is to the right. ryngeal of Xyrauchen texanus (ASU 13760). Anterior is to the right.

Fig. 8. Lateral view of the anterior portion of the postcranial skeleton of Xyrauchen texanus (ASU 14881). Anterior is to the left. of narrow teeth that resemble a comb (Fig. 7). Bonytail pharyngeal bear teeth in 2 rows James (1994) used pharyngeals to discriminate of 4 or 5 inner teeth and 2 small outer teeth among several catostomids with archaeological (Fig. 6; Minckley 1973, Miller 1955: Plate III). materials. In most archaeological materials the There may be supernumerary teeth in the outer teeth are missing and a row of circular or oval (smaller) row (Gobalet 1992) and the tooth bases hollow tooth bases can be identified on a deli- are circular. Individual bonytail teeth and pha- cate, fragmentary bone. The pharyngeal teeth ryngeal fragments are common in Salton Basin of razorback sucker are extremely rare even middens. when 1/16-inch-mesh screens are used during Exaggerated interneurals (predorsals) imme- excavations. diately behind the head are a unique razorback 342 WESTERN NORTH AMERICAN NATURALIST [Volume 65

ABC

Fig. 9A, Lateral view of the first interneural (predorsal) of Xyrauchen texanus from archaeological site IMP-7750 (anterior is to the left and dorsal is up); B, ventral view; C, anterior view.

sucker feature and are the structural ele- bonytail, striped mullet, Colorado squawfish, ments within the “hump” (Fig. 8). The cranial- and machete remains when compared with most interneural is thick and elongate, and is the 21 sites reported here in the Salton Basin. the most distinctive razorback sucker feature The Salton Basin displayed a rather depauper- found in the archaeological or paleontological ate assemblage of fishes (Table 2). In virtually record (Fig. 9; Miller 1955: Plate II). Other all of these new sites, razorback sucker are the fishes have interneurals, but they are thin and most frequently encountered. In only 3 sites laminar. Interneurals 2–6 of the razorback previously studied (RIV-1179, RIV-4754, and sucker more closely resemble those of other IMP-5204), large samples dominated by bony- suckers. The 1st interneural of ASU 13760, a tail skew the frequency data (Gobalet and Wake specimen approximately 365 mm in standard 2000). The comparative scarcity of Colorado length, measures 30 mm high (dorsal–ventral) pikeminnow, with only 128 of a total of nearly by 32 mm long (anterior–posterior) by 11 mm 27,000 elements now identified to species in wide (medial–lateral). The lateral surfaces of the basin (0.47%), is below expectation consid- the 1st interneural possess dorsoventral ridg- ering the Native American preference for this ing and a thick buttress at the midpoint (Fig. species (Castetter and Bell 1951). Rarity in the 9A). The ventral surface of the interneural archaeological record may reflect scarcity of bears condylar surfaces with which the robust the largest native North American minnow in Weberian apparatus parapophyses and plural Lake Cahuilla or an avoidance behavior of the ribs articulate (Figs. 9B, C). Massive interneu- fish weirs. These weirs were noted by Tre- rals have been a razorback sucker feature ganza (1945) and Wilke (1980) and were illus- since at least the early Pliocene (Hoetker and trated and discussed by Gobalet and Wake Gobalet 1999). (2000). The percentage of bonytail and razorback DISCUSSION sucker remains in samples from the southwest shore of Lake Cahuilla (IMP-7750 and IMP- Fishes in the Salton Basin 3214) is the same as previously found in 44 sites Ninety-six sites previously reported by excavated on the Salton Sea Test Base (Gobalet Gobalet and Wake (2000) have quite similar and Wake 2000). Approximately 68% of identi- species representation of razorback sucker, fied remains from IMP-7750 and IMP-3214 are 2005] ARCHAEOLOGICAL FISH REMAINS FROM THE LOWER COLORADO RIVER 343 razorback sucker; and 31% are bonytail. At 44 G. cypha: UMMZ 179577-5, UMMZ 178667; sites on the Salton Sea Test Base, percentages G. robusta: CAS 25851, unnumbered specimen were approximately 68% and 32% for more from S.R. James; Xyrauchen texanus: ASU than 3800 elements (Gobalet and Wake 2000). 13760, ASU 14881, CAS 25860, CAS 26235, This may indicate a curiously similar fre- CAS 66231, LACM 43613-1; Ptychocheilus quency of these species in the Lake Cahuilla lucius: CAS 66191, CAS 66217; P. grandis: region through time. LACM 377277-4, KWG 539, KWG 549, KWG 578, KWG 594; P. oregonensis: KWG 347, Fishes at the Colorado KWG 454; Catostomus latipinnis: KWG 3 un- River Site numbered specimens; C. discobolus: KWG Remains from IMP-7911 on the Colorado unnumbered specimen; C. macrocheilus: KWG River 30 km downstream of Blythe, California, 550; Mugil cephalus: LACM 35486-4, KWG are representative of what the Colorado River 247, KWG 360; Elops affinis: KWG 205, KWG fauna was like prior to 120 years ago when in- 294; Tilapia mossambica: KWG unnumbered troductions of exotic fishes began. The expected specimen; Cynoscion xanthulus: KWG 370. razorback sucker, bonytail, and Colorado pike- Fish remains for this study were provided minnow were present, and these data suggest by Phil Hines (Ocotillo Wells Land Acquisition that roundtail chub were residents of the Col- Project of the State of California Department orado River main channel as reported by of Parks and Recreation), Gary Hurd (CA-IMP- Miller and Smith (1984), Minckley (1979), and 3214/H Imperial County), Joan Oxendine Mueller and Marsh (2002), but not Miller (Niland Landfill, Imperial County), Jamie Cle- (1961), Stanford and Ward (1986c), or Moyle land (IMP-7911/H), Jay van Werlhof (IMP- (2002). Castetter and Bell (1951) did not list 8209), Joan Brown (CA-RIV-6225), Jerry Schae- them in the diet of Native Americans, which is fer (IMP-7750), Bruce Love (RIV-64, -1221, apparently inaccurate. James (1994) discrimi- -1176, -1177, -2936, -3013, -3659/H, -5774, nated between bonytail and roundtail chubs -6190, -6357, -6484), James Brock (RIV-6376), from Pueblo Grande on the Salt River in and Joan Schneider (“GARRA” site, Anza Bor- Phoenix, Arizona, where they were likely con- rego State Park, San Diego County, SDI-2317/ sumed. Additional roundtail chub material 2318/H). Fish materials were returned to these from sites on the Colorado River evaluated by investigators for curation. different specialists would be welcomed to corroborate these findings at IMP-7911 (Gob- ACKNOWLEDGMENTS alet 2001). Phil Hines, Gary Hurd, Joan Oxendine, CONCLUSIONS Jamie Cleland, Jay van Werlhof, Joan Brown, Jerry Schaefer, Bruce Love, James Brock, and These recent findings further confirm that Joan Schneider financed this work. Alison Will- bonytail and razorback sucker were the domi- ingham completed all the illustrations except nant large-bodied fishes in Lake Cahuilla. Figure 7, which was illustrated by Christina Only a scattering of striped mullet, Colorado Wioch. Terry Hansen, the late Ella Pedroza, pikeminnow, and machete appear in the archae- Kay Schimmel-Gobalet, David Germano, ological record, with no evidence of any ex- Stephen James, David Catania, Jeff Seigel and pected small-bodied species. Roundtail chub Peter Schulz also provided technical help or are tentatively confirmed as a species of the comparative materials. Alex Brown and Barry main channel of the lower Colorado River along Miller assisted with the identifications. with bonytail, Colorado pikeminnow, and razor- back sucker. LITERATURE CITED

CASTETTER, E.F., AND W.H. BELL. 1951. Yuman Indian MATERIALS EXAMINED agriculture, primitive subsistence on the lower Col- orado and Gila Rivers. University of New Mexico Institutional abbreviations are as listed in Press, Albuquerque. Leviton et al. (1985), except KWG indicates DOLAN, R., A. HOWARD, AND A. GALLENSON. 1974. Man’s impact on the Colorado River in the Grand Canyon. the author’s comparative materials stored at American Scientist 62:392–401. California State University, Bakersfield. Gila DOUGLAS, M.E., M.R. DOUGLAS, J.M. LYNCH, AND D.M. elegans: ASU 16387, CAS 66038, CAS 25860; MCELROY. 2001. Use of geometric morphometrics to 344 WESTERN NORTH AMERICAN NATURALIST [Volume 65

differentiate Gila (Cyprinidae) within the upper Col- MINCKLEY, W.L. 1973 Fishes of Arizona. Arizona Game orado Basin. Copeia 2001:389–400. and Fish Department, Phoenix. GEHLBACH, F.R., AND R.R. MILLER. 1961. Fishes from ______. 1979. Aquatic habitats and fishes of the lower archaeological sites in northern New Mexico. South- Colorado River, southwestern United States. Final western Naturalist 6:2–8. report, U.S. Department of the Interior, Bureau of GOBALET, K.W. 1990a. Prehistoric status of freshwater Reclamation, Lower Colorado Region, Boulder City, fishes of the Pajaro-Salinas river system of Califor- NV. Contract 14-06-300-2529. nia. Copeia 1990:690–685. MOYLE, P.B. 2002. Inland fishes of California. Revised and ______. 1990b. Native status of Sacramento perch (Archo- expanded. University of California Press, Berkeley. plites interruptus) in Alameda Creek, Alameda County, MUELLER, G.A., AND P.C. MARSH. 2002. Lost a desert river California: evidence from archaeological site CA- and its native fishes: a historical perspective of the ALA-483. California Fish and Game 76:244–247. lower Colorado River. Information and technology ______. 1992. Colorado River fishes of Lake Cahuilla, report USGS/BRD/ITR-2002-0010, U.S. Government Salton Basin, southern California: a cautionary tale Printing Office, Denver, CO. for zooarchaeologists. Bulletin of the Southern Cali- NELSON, J.J., E.J. CROSSMAN, H. ESPINOSA-PEREZ, L.T. fornia Academy of Sciences 91(2):70–83. FINDLEY, C.R. GILBERT, R.N. LEA, AND J.D. ______. 1994. Additional archaeological evidence for Col- WILLIAMS. 2004. Common and scientific names of orado River fishes in the Salton Basin of southern fishes from the United States, Canada, and Mexico. California. Bulletin of the Southern California Acad- American Fisheries Society Special Publication 29, emy of Sciences 93:38–41. Bethesda, MD. ______. 2001. A critique of faunal analysis; inconsistency RINNE, J.N. 1976. Cyprinid fishes of the genus Gila from among experts in blind tests. Journal of Archaeologi- the lower Colorado River basin. Wasmann Journal of cal Sciences 28:377–386. Biology 34:65–107. GOBALET, K.W., AND T.A. WAKE. 2000. Archaeological and SMITH, G.R., T.E. DOWLING, K.W. GOBALET, T. LUGASKI, paleontological fish remains from the Salton Basin, D.K. SHIOWAZA, AND R.P. EVANS. 2002. Biogeography southern California. Southwestern Naturalist 45: and timing of evolutionary events among Great Basin 514–520. fishes. Pages 175–234 in R. Hershler, D.B. Madsen, HOETKER, G.M., AND K.W. GOBALET. 1999. A fossil razor- and D.R. Currey, editors, Great Basin aquatic sys- back sucker (Pisces: Catostomidae, Xyrauchen tex- tems history. Smithsonian Contributions to the Earth anus) from southern California. Copeia 1999:755–759. Sciences 33. HUBBS, C.L., AND R.R. MILLER. 1948. The zoological evi- STANFORD, J.A., AND J.V. WARD. 1986a. The Colorado River dence: correlation between fish distribution and system. Pages 353–374 in R.B. Davis and K.F. Walker, hydrographic history in the desert basins of western editors, The ecology of river systems. Dr. W. Junk, United States. In: The Great Basin with emphasis on Dordrecht, The Netherlands. glacial and postglacial times. Bulletin of the Univer- ______. 1986b. Reservoirs of the Colorado system. Pages sity of Utah 38(20):17–166. 376–383 in R.B. Davis and K.F. Walker, editors, The JAMES, S.R. 1994. Hohokam hunting and fishing patterns ecology of river systems. Dr. W. Junk, Dordrecht, at Pueblo Grande: results of the archaeolofaunal The Netherlands. analysis. Pages 249–318 in S. Kwiatkowski, editor, ______. 1986c. Fish of the Colorado system. Pages 385– The Pueblo Grande Project Volume 5: Environment 402 in R.B. Davis and K.F. Walker, editors, The ecol- and subsistence. Soil Systems Publications in Archa- ogy of river systems. Dr. W. Junk, Dordrecht, The eology 20, Phoenix, AZ. Netherlands. LEVITON, A.R., R.H. GIBBS, JR., E. HEAL, AND C.E. DAWSON. TREGANZA, A.E. 1945. The ancient stone fish traps of the 1985. Standards in herpetology and ichthyology. Part Coachella Valley, southern California. American Anti- I. Stand symbolic codes for institutional resources quity 10:285–294. collections in herpetology and ichthyology. Copeia WATERS, M.R. 1983. Man and Pleistocene Lake Cahuilla. 1985:802–832. Journal of New World Archaeology 5(3):1–3. MILLER, R.R. 1955. Fish remains from archaeological sites WILKE, P.J. 1978. Late prehistoric human ecology at Lake in the lower Colorado River Basin, Arizona. Papers Cahuilla, Coachella Valley, California. Contributions of the Michigan Academy of Science, Arts, and Let- of the University of California (Berkeley) Archaeo- ters, Vol. 40. 1955. logical Research Facility 38. ______. 1961. Man and the changing fish fauna of the ______. 1980. Prehistoric weir fishing on recessional shore- American Southwest. Papers of the Michigan Acad- lines of Lake Cahuilla, Salton Basin, southeastern emy of Science, Arts, Letters 46:365–404. California. Proceedings of the Desert Fishes Council MILLER, R.R., AND G.R. SMITH. 1984. Fish remains from 11:101–102. Stanton’s Cave, Grand Canyon of the Colorado, Ari- zona, with notes on the taxonomy of Gila cypha. Pages Received 10 November 2003 6–65 in R.C. Euler, editor, Grand Canyon Natural Accepted 22 November 2004 History Association Monograph G. Western North American Naturalist 65(3), © 2005, pp. 345–358

VARIATION IN LEWISIA KELLOGGII (PORTULACACEAE) WITH DESCRIPTION OF A NEW SPECIES ENDEMIC TO IDAHO

Barbara L. Wilson1, Valerie D. Hipkins2, Edna Rey-Vizgirdas3, and Thomas N. Kaye1

ABSTRACT.—Lewisia kelloggii has been understood as a rare plant with a disjunct range in California and Idaho. Examination of herbarium specimens and analysis of isozymes in 6 Idaho and 7 California populations revealed consis- tent differences between plants of the 2 states. Fixed differences in alleles at 2 loci (AAT2 and PGI1) distinguished Idaho from California plants. Genetic identities based on isozymes between Idaho and California populations averaged 0.58, lower than the average for congeneric plant species. Idaho plants were smaller than most California plants, but California plants were variable. The most consistent morphological difference between Idaho and California specimens was the difference in the number of glands on the margins of bracts and sepals. Idaho plants had 0 (–5) pink glands on each margin of these organs, all on teeth near the tips. In California plants these organs had 12–25 glands on each mar- gin, the distal ones elevated on teeth and the proximal ones sessile. We recognize the Idaho plants as a new species, L. sacajaweana, and retain the name L. kelloggii for the California populations.

Key words: Lewisia kelloggii, Lewisia sacajaweana sp. nov., Portulacaceae, taxonomy, isozymes, endemic, Idaho, California.

Lewisia kelloggii K. Brandegee sensu lato is phological traits consistently distinguish them. a small rare plant found on ridgelines in open We performed an isozyme analysis of 7 Cali- areas on excessively drained, coarse-textured, fornia and 6 Idaho populations to assess genetic granitic and volcanic soils. It has been under- variability, compare alleles occurring in differ- stood as having a disjunct range, occurring in ent populations, and measure genetic identity the Sierra Nevada of California (from Plumas (Nei 1973). We selected isozyme analysis for County south to Fresno County) and in Idaho this study because the results can be compared (in Butte, Custer, Elmore, and Valley Counties). with large databases of similar results from Small morphological differences between the other species (Hamrick and Godt 1989) and Idaho and California populations have raised because isozymes had worked well to distin- the possibility that they should be considered guish species in an earlier study of California separate species. L. kelloggii (Foster et al. 1997). We used the Lewisia kelloggii populations in California morphological and isozyme information to and Idaho appear reproductively isolated be- assess the species status of populations from cause they have no mechanism of primary the 2 states. Anticipating results, we refer to the seed dispersal likely to cross the 540 km be- Idaho populations as L. sacajaweana through- tween them (Mathew 1989). Geographic isola- out this paper. tion and consequent reproductive isolation alone are not sufficient to justify treating the METHODS Idaho and California populations as members Morphology of 2 distinct species. Separate species status would be justified if isolation has led to genetic We borrowed L. kelloggii specimens from differentiation expressed as consistent morpho- herbaria at University of California, Berkeley logical differences between the species, fixed (UC and JEPS); California Academy of Sci- differences in the alleles studied in isozyme ence (CAS and DS); and California State Uni- analysis, and low genetic identities. versity, Chico (CHSC). Additional specimens We examined L. kelloggii specimens from were collected in Idaho during 2001 and de- California and Idaho to learn whether mor- posited at Oregon State University (OSC). The

1Institute for Applied Ecology, 563 SW Jefferson Street, Corvallis, OR 97333. 2USDA Forest Service, National Forest Genetic Electrophoresis Laboratory (NFGEL), 2480 Carson Road, Placerville, CA 95667. 3USDA Forest Service, Boise National Forest, 1249 S. Vinnell Way, Suite 200, Boise, ID 83709.

345 346 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 1. Collection locations for Lewisia kelloggii samples used in the isozyme study. N = sample size. State National forest Population Latitude/Longitude N Collector Date collected CA Eldorado Brown Rock 38.66ºN 120.26ºW 32 Robert C. Saich 28-Jun-99 CA Eldorado Pack Saddle Pass 38.76ºN 120.17ºW 32 Robert C. Saich 28-Jun-99 CA Plumas Plumas A 39.75ºN 120.86ºW 28 Molly Hunter 27-Jul-99 CA Plumas Plumas B 39.79ºN 120.90ºW 18 Molly Hunter 27-Jul-99 CA Sierra Shuteye Peak 37.35ºN 119.42ºW 30 Robert C. Saich 28-Jun-00 CA Tahoe Soda Springs #1 39.31ºN 120.43ºW 30 Robert C. Saich 22-Jun-00 CA Tahoe Soda Springs #2 39.31ºN 120.41ºW 30 Robert C. Saich 22-Jun-00 ID Boise Burnt Creek 43.31ºN 115.28ºW 30 Amanda Dabbs 22-Jun-99 ID Boise Greencreek Lake 43.34ºN 115.20ºW 28 Amanda Dabbs 15-Jun-99 ID Boise Miller Mountain 44.08ºN 115.30ºW 30 Amanda Dabbs 07-Jul-99 ID Boise No Name Creek 43.31ºN 115.28ºW 30 Amanda Dabbs 22-Jun-99 ID Boise Road 409 44.37ºN 115.44ºW 30 Amanda Dabbs 17-Jun-99 ID Boise Whitehawk Summit 44.23ºN 115.53ºW 30 Amanda Dabbs 08-Jul-99

herbaria at the Rancho Santa Ana Botanic Isozyme Study Garden (RSA); the Rocky Mountain Herbar- SAMPLING.—Two to 3 leaves per plant were ium, Laramie, Wyoming (RM); and Humboldt collected from each of approximately 30 plants State University (HSC) did not have speci- per population in 7 California and 6 Idaho pop- mens of this plant (acronyms from Holmgren ulations (Table 1). Leaves from each individual et al. 1990). For the purpose of describing the were bagged separately from those of other in- species, we measured or counted plant parts dividuals, and stored and shipped on ice within on all plants for which measurements or counts 2 days of collection to the National Forest were possible. A list of all specimens examined Genetic Electrophoresis Laboratory (NFGEL), is found in the Appendix. where they arrived still cold and alive. Collec- For morphometric analysis, we quantified 7 tion locations were reported in terms of legal morphological traits (Table 2). Specimens in- descriptions (township / range / section) and cluded in this analysis were all those that had converted to latitude/longitude using the pro- petals that dried flat (so that they could be gram TRS2LL (Wefald 2001). Idaho populations measured) and bracts and sepals with margins sampled the entire known range of the species. exposed: 7 of L. kelloggii ssp. kelloggii, includ- California collection localities were chosen to ing 2 of Kellogg s.n.; 8 of L. kelloggii ssp. sample most heavily the central and northern hutchisonii Dempster; and 7 of L. sacajaweana, parts of the range, where both named sub- including 2 of Hitchcock & Muhlick 8690 species grow. One southern population, from (Appendix). The ratio of longest leaf length to Shuteye Peak, was included. Three pairs of widest leaf width was log-transformed, and populations were very close together. The Burnt other values were used untransformed because Creek and No Name Creek populations were their distribution did not differ significantly within 0.6 mile on Red Mountain, Idaho. The from normal. We used discriminant analysis to 2 Soda Springs populations were within 2 miles test for significant differences among Idaho of each other. The 2 populations from the specimens and California specimens identified Plumas National Forest were a few hundred as L. kelloggii ssp. kelloggii and L. kelloggii ssp. feet apart. hutchisonii, to determine which traits were TISSUE PREPARATION.—We refrigerated sam- most useful for distinguishing taxa. We used ples until they could be processed, within 3 principal components analysis to evaluate pat- days of arrival. One 7-mm-diameter leaf disk terns of morphological variation in the speci- per individual was submerged in 100 µL of a mens, including morphological discontinuities 0.1 M Tris-HCl (pH 8.0) extraction buffer, or overlap among taxa, and factor analysis to with 10% (w/v) polyvinylpyrrolidone-40, 10% evaluate the importance of individual traits to sucrose, 0.17% EDTA (Na2 salt), 0.15% dithio- the observed pattern of variation. All 3 analy- threitol, 0.02% ascorbic acid, 0.10% bovine ses were performed using NCSS (Hintz 2001). albumin, 0.05% NAD, 0.035% NADP, and 2005] LEWISIA KELLOGGII TAXONOMY 347

TABLE 2. Variables used in morphometric analysis of Lewisia kelloggii and L. sacajaweana. Factor weights for the first 2 axes of discriminant analysis (DA) and principal components analysis (PCA) for Lewisia. Values for the DA axes are correlations between variables and variates (axes). Values for PCA are factor loadings on axes. * = log transformed. L. kelloggii L. kelloggii L. saca- Canonical Canonical ssp. kelloggii ssp. hutchisonii jaweana variate 1 variate 2 PCA axis 1 PCA axis 2 Variable Units mean (s) mean (s) mean (s)DADA PCA PCA

N 877 Leaf length cm 2.89 (1.09) 5.21 (2.03) 4.51 (1.66) –0.00862 –0.4-634 0.150738 0.901428 Petal length cm 1.69 (0.16) 2.62 (0.43) 1.58 (0.24) –0.24104 –0.67651 0.823643 0.353622 Sepal length cm 0.86 (0.12) 1.14 (0.18) 0.63 (0.13) –0.27269 –0.32193 0.910429 0.231352 Bract length cm 0.81 (0.16) 1.01 (0.30) 0.68 (0.25) –0.10518 –0.14850 0.671260 0.324558 Glands on sepals count 14.43 (2.15) 18.12 (2.59) 2.14 (2.12) –0.58909 0.07020 0.879224 –0.271780 Glands on bracts count 18.43 (2.78) 19.12 (5.05) 0.43 (1.13) –0.47703 0.38120 0.830819 –0.273720 Leaf length/width ratio* — 1.50 (0.31) 1.56 (0.40) 2.05 (0.27) 0.13455 –0.17284 –0.576400 0.675336

0.005% pyridoxal-5-phosphate (USDA Forest del 1989). We are unaware of a chromosome Service 2000). Samples were then frozen at count for L. kelloggii (Moldenke 1973, Mathew –70ºC. On the day of electrophoresis, samples 1989, Dempster 1993, Goldblatt 2001). One were thawed and ground and the extracts diploid locus each was scored for ADH, FEST, absorbed onto 3-mm-wide wicks prepared from and PGM1. Two loci (i.e., a pair of homoeolo- Whatman 3MM chromatography paper. gous loci) were scored for G6PDH, GOT2, ELECTROPHORESIS.—Methods of electro- IDH1, LAP2, MDH1, MDH2, MDH4, PGI2, phoresis followed the general methodology of PGM2, TPI1, TPI2, UGPP1, UGPP2, 6PGD1, Conkle et al. (1982), with some modifications and 6PGD2. PGI1 was also scored and used to (USDA Forest Service 2000). All enzymes were distinguish populations but was not included resolved on 11% starch gels. We used a lithium in statistical analysis. For enzymes scored as borate electrode buffer (pH 8.3) with a Tris pairs of loci, an isozyme band pattern compris- citrate gel buffer (pH 8.3; Conkle et al. 1982) ing a single band was considered to represent to resolve alcohol dehydrogenase (ADH), fluo- 2 homoeologous loci. For analysis as an allote- rescent esterase (FEST), leucine aminopepti- traploid, we assumed that 1 locus of each pair dase (LAP), phosphoglucomutase (PGM), and was invariant and assigned all uncommon alle- phosphoglucose isomerase (PGI). We used a les to the other unless the observed band com- sodium borate electrode buffer (pH 8.0) with a binations or intensities suggested otherwise. Tris citrate gel buffer (pH 8.8; Conkle et al. Assuming that the plants were allotetra- 1982) to resolve glucose-6-phosphate dehydro- ploid, we analyzed 33 loci using Popgene, ver- genase (G6PDH), glutamate-oxaloacetate tran- sion 1.21 (Yeh et al. 1997). A locus was con- saminase (GOT), triosephosphate isomerase sidered polymorphic if an alternate allele (TPI), and uridine diphosphoglucose pyrophos- occurred even once. We calculated unbiased phorylase (UGPP). A morpholine citrate elec- genetic distances (Nei 1978), expected hetero- trode and gel buffer (pH 6.1; USDA Forest zygosity (Nei 1973), and gene flow [Nm (the Service 2000) was used to resolve isocitrate effective number of migrants per year) = 0.25(1 dehydrogenase (IDH), phosphogluconate dehy- – Fst)/Fst; (Slatkin and Barton 1989)]. The fixa- drogenase (6PGD), and malate dehydrogenase tion indices for populations (F) were calcu- (MDH). Enzyme stain recipes follow USDA lated in Popgene (Yeh et al. 1997) following Forest Service (2000). Ten percent of individu- Hartl and Clark (1989), but F-statistics for the als were run and scored twice. hierarchy of regions within the species (Fpt), ISOZYME INTERPRETATION.—We inferred populations within the species (Fst), populations genetic interpretations directly from isozyme within regions (Fsp), and individuals within phenotypes based on knowledge of the gener- the species (Fit), regions (Fip), and populations ally conserved enzyme substructure, compart- (Fis) were calculated by the method of Weir mentalization, and isozyme number in higher (1990). The 2 methods produced slightly dif- plants (Gottlieb 1981, 1982,Weeden and Wen- ferent values for F. Dendrograms based on 348 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 1. Lewisia sacajaweana. A–D, petal tips; E, habit; F, flower, with location of ovary behind sepal indicated; G, flower, cut open; H, flowers after anthesis. Note that withered petals remain in flower, sepals expand around growing ovary, and peduncle shrinks. Scale bars = 1 mm. unbiased genetic distances (Nei 1978) were sule back to or near the ground (Fig. 1). Petal generated using UPGMA. tip shape is variable and petals are often more or less damaged or misshapen (Fig. 1). Idaho RESULTS plants had a smaller range of variation than California plants (Table 2). Idaho plants had Morphology small petals like Lewisia kelloggii ssp. kellog- The Idaho plants are small, succulent, gii, but they tended to have proportionately scapose plants with white flowers (Figs. 1, 2). narrower leaves than either California sub- The peduncle is relatively narrow and elon- species. The most consistent difference between gate during flowering but becomes shorter the plants of the 2 states was in number of and thicker after flowering, bringing the cap- teeth and/or glands on the margins of the 2005] LEWISIA KELLOGGII TAXONOMY 349

Fig. 2. Flower parts of Lewisia sacajaweana. A, pistil (note bend in stigmas); B, section of stigma; C and D, anthers; E, seeds; F, bract with hyaline margins; G, flower base showing sepal; H, sepal tip with teeth and gland-tipped mucro.

bracts and sepals (Table 3). Idaho plants usu- of L. kelloggii ssp. kelloggii, and 2 because their ally lacked pink glands along these margins measurements were mostly intermediate. Num- (though they might have up to 5), whereas bers of glands on sepals and bracts were the California plants had 12–25 pink glands (com- variables most highly correlated with the 1st pare Fig. 3 with Figs. 1E, 1H, and 2H). discriminant axis (r = –0.59 and –0.48, respec- Discriminant analysis of morphological traits tively), which separated Idaho from California indicated that all 3 Lewisia taxa were signifi- specimens (Table 2). Length of leaves and cantly different from each another (P < petals were the 2 variables most highly corre- 0.0001). However, the 2 California subspecies lated with the 2nd discriminant axis (r = –0.41 (L. kelloggii ssp. hutchisonii and L. kelloggii and –0.68, respectively), which distinguished ssp. kelloggii) were similar enough that there the larger L. kelloggii ssp. hutchisonii speci- was a slight chance (P < 0.02) that 4 speci- mens from the smaller L. kelloggii ssp. kellog- mens were misclassified between them, 2 be- gii and L. sacajaweana. When the analysis was cause they combined the large flower size of rerun without using gland number (results not L. kelloggii ssp. hutchisonii with the small leaves shown), only 1 specimen each of L. kelloggii 350 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 3. Selected morphological traits in Lewisia populations in Idaho and California. * = excluding the usually gland-tipped mucro at the tip. Trait Idaho (L. sacajaweana) California (L. kelloggii) Flower placement nestled in rosette nestled in rosette or held above it Peduncle jointed at base jointed at base or above, the segment below base often equal to that above Placement of marginal teeth often only near tip; always extending to near base and/or glands in upper half Marginal teeth on sepals and eglandular (or upper 1–5/ glandular bracts* side with glands) Number of marginal teeth and/or 0 (–9) (5–) 8–25 glands on each side* Petal color white white to pink or lavender Petal number 5 (–7) (5–) 7–9 Petal length 10–20 mm 15–30 mm Stamen number 8 (12) 8–26 Anther color cream to yellow cream, yellow, or pink Style branches 4 (–5) 3–6

ssp. kelloggii and L. kelloggii ssp. hutchisonii Polyploidy were misclassified as L. sacajaweana. Evidence for polyploidy in Lewisia kellog- Principal components analysis of morpho- gii included multiband patterns in 3 pairs of metric data clearly separated L. sacajaweana homoeologous loci: PGI2 (7 populations), PGM2 from L. kelloggii along axis 1, but the Califor- (1 population), and TPI1 (3 populations). We nia specimens identified as L. kelloggii ssp. also observed unbalanced heterozygosity in 10 hutchisonii and L. kelloggii ssp. kelloggii did not form separate clusters; some specimens loci and high levels of heterozygosity, includ- were intermediate (Fig. 4). The 1st axis ing 8 pairs of homoeologous loci in which all accounted for 54% of the morphological varia- individuals of at least 1 population were het- tion, and the first 2 axes together accounted erozygous. However, 3 enzymes (ADH, FEST, for 75%. Factor loadings for this analysis sug- and PGM1) appeared diploid because they gested that the 1st axis was strongly associated exhibited high levels of homozygosity, 2 classes with flower traits (glands on sepals and bracts, of homozygotes occurred in some populations, as well as sepal and petal length), and the 2nd and all heterozygotes appeared balanced. Vari- reflected the length and shape of leaves (Table able numbers of gene copies have been 2). Two sheets for each of 2 collections (Kel- observed before in polyploids (Stebbins 1947) logg s.n. and Hitchcock and Muhlick 8680) and might be expected in a genus character- were included in the analysis. These sheets ized by an aneuploid series of chromosome contained different individual plants. Sheets numbers (Table 4). from the same collection did not cluster to- Evidence about the mode of inheritance in gether, indicating considerable within-popula- homoeologous loci was mixed. The fixed het- tion variation. erozygosity characteristic of polyploids with Lewisia kelloggii ssp. hutchisonii specimens disomic inheritance was observed in at least 1 examined were mostly from the northern part population in each of 7 homoeologous pairs of of the species’ California range (Plumas, Sierra, loci. All populations exhibited fixed heterozy- and Butte Counties) with 1 from the central gosity for 6PGD2. On the other hand, some part of the range (Placer County). Most L. kel- enzymes in some populations gave evidence loggii ssp. kelloggii specimens examined came for tetrasomic inheritance (Soltis and Riese- from the southern part (Mariposa County) and berg 1986). Two different classes of unbalanced central part (Placer and Nevada Counties), with heterozygotes (1112 and 1222) were observed only 1 from the north part (Plumas County) of in 8 populations for 6 loci. In 5 loci that had the range, where L. kelloggii ssp. hutchisonii other evidence of polyploidy, 8 populations ex- predominates. hibited 2 alternate homozygous conditions. 2005] LEWISIA KELLOGGII TAXONOMY 351

in Idaho and (rarely) allele 1. In MDH2, Idaho individuals had alleles 1, 2, and occasionally 6. Plants from northern and central California had alleles 3, 7, and rarely 4, but the southern Shuteye Peak population had 2, 7, and rarely 4. In TPI1, all Idaho individuals had allele 1 and a few were heterozygotes with 1 and 2, while California populations nearly all had allele 4, none had allele 2, and allele 1 was rare. Twelve alleles at 8 pairs of homoeologous loci were unique to Idaho, and 29 alleles at 14 pairs of homoeologous loci were unique to California. The mean genetic identity between California and Idaho populations was 0.58. When these genetic identities were expressed diagrammatically, the populations fell easily into 2 groups, 1 from California and 1 from Idaho (Fig. 4). Geographic structuring of isozyme variation also existed within states. Intrastate populations were highly differentiated, with Fst of 0.43 in California and 0.62 in Idaho (Table 6). Genetic identity among California populations varied from 0.69 to 0.99, and within Idaho varied from 0.76 to 0.99. Populations within 2 miles of each other were similar (0.965 for Plumas A and B and 0.998 for Soda Springs 1 and 2 in California; 0.992 for Burnt Creek and No Name Creek in Idaho). Inferred gene flow was very low, espe- cially among Idaho populations (Nm = 0.324 in California, 0.155 in Idaho.) Fig. 3. Flower of Lewisia kelloggii after anthesis. Note Samples from the Plumas National Forest toothed bracts and sepals. (Table 1) came from populations previously identified as L. kelloggii ssp. hutchisonii. Genetic identities of these samples with other north- Genetic Variation and ern California populations averaged 0.873 (range Differentiation 0.835–0.909). Lewisia kelloggii was highly variable, with The California population from Shuteye 85% of the loci polymorphic, averaging more Peak, located over 100 km south of the other than 3 alleles per locus (Table 5). In L. kellog- populations included in this analysis, was par- gii populations, 39%–58% of the loci were ticularly distinct. Genetic identities between polymorphic in each population, but in Idaho, the Shuteye Peak population and other Cali- 5 of the 6 populations had less than 20% poly- fornia populations were low, averaging 0.73. morphic loci. Of the 42 alleles detected in this population, 48% were widespread (occurring in both Cali- Genetic variation was strongly structured fornia and Idaho), 33% were shared with other by geography. About half the isozyme varia- California populations, 7% were shared only tion detected in this study was variation be- with Idaho populations, and 12% were unique. tween states (Fst = 0.525; Table 6). Fixed dif- ferences between states were detected in 1 pair DISCUSSION of homeologous loci (AAT-2) and in the PGI1 locus. Nearly fixed differences were detected in Distinctions Between Idaho and 3 pairs of homoeologous loci. In 6PGD1, Idaho California Populations samples always had allele 2, with variants 4 The Lewisia kelloggii specimens from Idaho and (rarely) 1, while California plants never can be distinguished from all the varied popu- had allele 2, but had 3 alleles never observed lations of L. kelloggii from California. The 352 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 4. Principal components analysis (components 1 and 2) of 7 morphological traits scored for Lewisia kelloggii ssp. kelloggii, L. kelloggii ssp. hutchisonii, and L. sacajaweana.

most consistent morphological trait separating 1.00 (Crawford 1990). The Idaho plants have them is the number of glands on the bracts not previously been recognized as a species. and sepals, the most strongly weighted canon- However, the Idaho populations are amply ical variates in our discriminant analysis and distinct from the California plants and should with factor weights exceeding 0.8 in principal be recognized as a separate species. components analysis. In L. kelloggii these organs Lewisia brachycalyx A. Gray, L. kelloggii, are fringed with teeth bearing many (12–25) and L. sacajaweana share the traits of solitary glands, but in L. sacajaweana they typically flowers having the 2 bracts so close below the lack glands, except 1 at the very tip. This trait sepals that they appear to be 2 more sepals. can be difficult to assess in dried specimens All 3 species belong in the Lewisia section because the bracts and sepals tend to roll up Brachycalyx (Mathew 1989). Lewisia brachy- longitudinally, concealing the margins. The 2 calyx has a disjunct distribution extending from species also tend to differ in size of flower Baja California to Arizona, and perhaps also parts (smaller in L. sacajaweana); sepal length New Mexico and southern Utah (Davidson was the most strongly weighted factor for 2000). Lewisia sacajaweana resembles L. bra- principal components analysis axis 1, and petal chycalyx in that both have narrower leaves length was almost as heavily weighted (Table than L. kelloggii and both typically lack glands 2). In addition, L. sacajaweana had propor- on the edges of the bracts and sepals. How- tionally narrower leaves than L. kelloggii. ever, L. sacajaweana has blunt to notched leaf Lewisia sacajaweana and L. kelloggii are tips like L. kelloggii and unlike the tapered also clearly distinguished by isozymes. Fixed tips of L. brachycalyx. differences in 2 enzyme systems differentiate We name the small bitterroot from Idaho them. Genetic identities between Idaho and Lewisia sacajaweana in honor of Sacajawea California populations average 0.58. In general, (alternate spelling Sacagawea), the Shoshone plant populations within the same species (and woman who participated in the Lewis and subspecies) have genetic identities greater than Clark Expedition, traveling through the limited 0.90, and populations of different congeneric range of L. sacajaweana 2 centuries ago. Bitter- species have genetic identities (Nei 1973) root was valued by numerous tribes in the Rocky averaging 0.68, though varying from 0.25 to Mountain region for food and medicinal uses. 2005] LEWISIA KELLOGGII TAXONOMY 353

TABLE 4. Published chromosome numbers of Lewisia. * = recently moved to a different genus: Cistanthe tweedyi (Hershkovitz 1990). Chromosome number Species Reference 2n = 20 L. brachycalyx G. Engelmann ex A. Gray M. Daker in Elliott 1966 2n = 22 L. longipetala (Piper) Clay Dempster 1993 2n = about 24 L. congdonii (Rydberg) S. Clay M. Johnson in Mathew 1989 2n = 28 L. cantelovii J. T. Howell Hohn 1975 L. cotyledon (S. Watson) B. L. Robinson Hohn 1975, M. Johnson in Mathew 1989 L. leeana (T. C. Porter) B. L. Robinson Hohn 1975, M. Johnson in Mathew 1989 L. rediviva Pursh M. Johnson in Mathew 1989 2n = 30 L. columbiana (T. J. Howell ex A. Gray) B. L. Robinson Hohn 1975 2n = about 56 L. nevadensis (A. Gray) B. L. Robinson M. Johnson in Mathew 1989 2n = about 66 L. pygmaea (A. Gray) B. L. Robinson Weins and Halleck 1962 2n = 92 L. tweedyi (A. Gray) B. L. Robinson* Kruckeberg 1957, Hohn 1975

Sacajawea harvested various food plants for A low, scapose, succulent, glabrous perennial the Corps of Discovery, probably including roots herb with a taproot, 3–7 cm tall. (All measure- of L. rediviva, and she may well have known ments taken from dried specimens.) Taproot this obscure species. single or often with 2 main branches, the fleshy portion 3–8 mm wide and 4–10 cm long; sur- Description of face of root reddish brown or brown, cortex Lewisia sacajaweana white, surface of stele pale yellow to pink or orange, especially toward the top. Caudex very Lewisia sacajaweana B.L. Wilson and E. Rey- short, 1.5–5 cm wide, subterranean. Leaves in Vizgirdas sp. nov. (Fig. 4) a rosette, ascending, entire, with stomata on both sides, often dying and rolling up at or TYPE: USA: IDAHO: Boise County: Boise before anthesis; the outermost (oldest) leaves National Forest, Pilot Peak, on slopes east and of the year papery and 1.3–3 cm long, 3–5 mm west of road 380, at intersection with spur wide, rounded at tip, mucronate, sometimes road to Pilot Peak Lookout, west of lookout, fleshy and pink distally; the inner (younger) T07N R06E S01, 43°57.81′N, 115°41.8′W, ele- leaves succulent, (1.9) 4.8–8 cm long and (3.5) vation 3276 m. 13 July 2002. J. J. Schenk and 4–7 mm wide, dull green to reddish brown Edna Vizgirdas 527. (Holotype: ID; isotypes, (but with the lower 2–4 cm typically whitish), CAS, MO, OSC). narrowly oblanceolate or spatulate, very grad- ually tapering to the petiole, which shrinks Herba pusilla; perennis, scaposa, succulenta, glabra, and becomes wrinkled when dry; the leaf sur- radice palari. Folia rosulata, integra spathulata 4.8–8 cm face covered with a cuticle 1.5 µm thick longa, brunneola vel olivacea apice rotundato aut emar- topped with waxy ridges and flakes which may ginato, mucronato. Scapus articulatus prope basin, 15–30 mm longus sub anthesi. Bracteae 2, subulatae, 5.5–8 mm give the appearance of minute pubescence; longae, proxime infra sepala, sepalis similes sed sepalis leaf tips rounded and slightly notched. Scape dimidia parte angustiores. Sepala 2, rosea, plerumque jointed at the base but not disarticulating, the brunneola vel olivacea, anguste ovata, 5–8 mm longa, 1.75– portion above the joint 15–30 mm long and 3 mm lata, mucrone roseo, glandifero, et dentibus 0–3 (–7) 1.0–1.6 mm wide at anthesis, but shrinking to in quoque marginem eglandulatis vel raro glande rosea. 5–7 mm long and 1.7–2.0 mm wide after anthe- Petala alba, 5 (–7), 10–20 mm longa, integra vel dentibus paucis, apice rotundato, obtuso AUT emarginato, mucrone sis and pulling the flower back to the ground. roseo saepe. Stamina 8 (12), 314 mm longa, antheris 1–1.5 Bracts 2, lanceolate, awl-shaped, 5.5–8 mm mm longis, flavis. Pistillum stigmatibus 4 (–5), albis, 3–5 mm long and 0.9–1.6 mm wide at half length, longis. Semina 1.3–1.6 mm × 1.4–2.0 × 1 mm, testa nigra, located immediately below the sepals and sim- nitida, minute tuberculata. ilar to them in color and length but about half Planta rara in solo sterili granitico montium in Idaho. A Lewisia kelloggii sepalis et bractis integris vel den- as wide, with scarious margins 0.3 mm wide tibus eglandulatis distinguenda. near the base and tapering in width upwards; A Lewisia brachycalyx foliis spathulatis distinguenda. tipped by a usually glandular mucro and with 354 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 5. Genetic variation in Lewisia kelloggii populations: n = average number of samples per locus, P = percent polymorphic loci, A = average number of alleles per locus, Ae = effective number of alleles per locus (Kimura and Crow 1964), Ho = observed heterozygosity, He = expected heterozygosity, SW = Shannon’s information index (Lewon- tin 1972). Standard deviation in parentheses. Forest: Population n PA AeHoHeSW Total 370 85 3.36 (1.60) 1.72 (0.57) 0.06 (0.07) 0.35 (0.22) 0.61 (0.39) California (L. kelloggii) 196 82 2.85 (1.37) 1.56 (0.63) 0.09 (0.13) 0.28 (0.23) 0.49 (0.40) Eldorado: Brown Rock 32 52 1.76 (0.90) 1.39 (0.52) 0.11 (0.18) 0.20 (0.24) 0.32 (0.38) Eldorado: Pack Saddle Pass 32 58 1.94 (1.00) 1.45 (0.62) 0.13 (0.20) 0.22 (0.25) 0.35 (0.41) Plumas: Plumas A 27 39 1.64 (0.93) 1.27 (0.49) 0.04 (0.07) 0.14 (0.22) 0.23 (0.35) Plumas: Plumas B 18 42 1.58 (0.79) 1.28 (0.46) 0.08 (0.15) 0.15 (0.22) 0.24 (0.34) Sierra: Shuteye Peak 30 45 1.61 (0.75) 1.18 (0.30) 0.07 (0.13) 0.12 (0.17) 0.20 (0.27) Tahoe: Soda Springs 1 30 48 1.67 (0.82) 1.28 (0.49) 0.10 (0.19) 0.14 (0.21) 0.24 (0.34) Tahoe: Soda Springs 2 30 39 1.58 (0.83) 1.26 (0.45) 0.08 (0.16) 0.14 (0.21) 0.22 (0.34) Idaho (L. sacajaweana) 174 58 1.88 (0.93) 1.26 (0.40) 0.02 (0.05) 0.15 (0.20) 0.24 (0.31) Boise: Burnt Creek 30 12 1.12 (0.33) 1.04 (0.14) 0.02 (0.08) 0.03 (0.09) 0.04 (0.14) Boise: Greencreek Lake 27 48 1.70 (0.85) 1.29 (0.53) 0.07 (0.14) 0.14 (0.22) 0.24 (0.34) Boise: Miller Mountain 30 18 1.18 (0.39) 1.07 (0.18) 0.01 (0.01) 0.05 (0.12) 0.08 (0.18) Boise: No Name Creek 30 15 1.15 (0.36) 1.08 (0.24) 0.02 (0.06) 0.05 (0.13) 0.07 (0.19) Boise: Road 409 29 18 1.21 (0.48) 1.09 (0.23) 0.03 (0.07) 0.06 (0.14) 0.09 (0.21) Boise: Whitehawk Summit 30 9 1.09 (0.29) 1.04 (0.16) 0.01 (0.04) 0.02 (0.09) 0.04 (0.13)

TABLE 6. F-statistics (fixation indices) for Lewisia kel- covering the capsule. Stamens 8 (–12), in 2 loggii for a 3-level sampling hierarchy (individuals within (–3) series that differ in length, 3–14 mm long, populations within states within total), assuming that the plants are allotetraploids with disomic inheritance. the anthers pale yellow, 1–1.5 mm long. Ovary superior, pink, 2–3 mm long at anthesis; undi- Comparison F vided style white or pink, topped by 4 (–5) individual within population Fip = 0.483 white style branches each 3–5 mm long; style individual within state Fis = 0.755 branches minutely hairy and apparently stig- individual within total Fit = 0.884 matic their entire length, at anthesis spreading population within state Fps = 0.526 horizontally and bending horizontally at nearly population within total Fpt = 0.775 90°, 0.5–1 mm from the tip, forming a swastika- state within total Fst = 0.525 like shape. Capsule often persisting below ground and releasing seeds by decomposition. Seeds thickly disk-shaped, 1.3–1.6 × 1.4–2.0 × 1 mm, shiny black, the surface cells swelling out- 0 (–5) teeth on each side in the upper half, ward between the anticlinal walls, producing a these teeth eglandular or less often tipped finely tuberculate surface. with a pink gland. Sepals 2, ovate-lanceolate, 5–8 mm long and 1.75–3 mm wide, sometimes pink but usually dull green or brown and Key to Selected Lewisia becoming pink in the upper half with age; section Brachycalyx sepals tipped by a usually glandular mucro 1. Bracts more than 2, or distinctly separated from and with 0–3 (–9) teeth on each side in the the 2 sepals ...... other sections upper half, these teeth eglandular or less often 1. Bracts 2 and located immediately below the sepals, so sepals apparently 4 ...... 2 tipped with a pink gland; sepal base fitting 2. Leaves oblanceolate, the tips tapered; flow- tightly around the growing capsule. Petals ers 3–6 cm in diameter, sepals and bracts white, 5 (–7), entire or with a few widely and entire) ...... Lewisia brachycalyx irregularly spaced teeth, which may be pink 2. Leaves spatulate, the tips rounded to emar- ginate; flowers usually 2–3 cm in diameter; and gland-tipped, near the tip; petals 10–20 sepals and bracts entire or toothed) ...... 3 mm long and 1.5–5 mm wide, widest near the 3. Teeth on each side of the sepals and tip (or near the center in unusually small petals), bracts 0–5 (–7), usually lacking pink the tip rounded, obtuse, or emarginate, often glands, located in only upper half ...... Lewisia sacajaweana with a tiny mucro which may be pink. With- 3. Teeth on each side of sepals and bracts ered petals remain in the flower after anthesis, (5–) 8–25, glandular, the teeth and/or 2005] LEWISIA KELLOGGII TAXONOMY 355

Fig. 5. Similarities among Lewisia kelloggii populations, based on Nei’s (1978) unbiased genetic distances.

glands extending well below the middle lar in size to those at the center of the range ...... Lewisia kelloggii but may have more flower parts. The southern 4. Longest leaves usually >4.5 cm (–10 cm) long, >1 cm wide; petals plants have been named L. yosemitana (Jep- 2 or >2 cm long; range Placer son 1923) and are distinguished from L. kel- County and north ...... loggii because L. yosemitana has 16–26 sta- ...... L. kelloggii ssp. hutchisonii mens, versus 10–15 for L. kelloggii, but that 4. Longest leaves usually <4.5 cm long, <1 cm wide; petals usually distinction did not win wide acceptance in this <2 cm long; throughout range of morphologically variable species. In our mor- the species ...... phometric analysis, plants from Yosemite ...... L. kelloggii ssp. kelloggii National Park cluster with other L. kelloggii from farther north (Fig. 4), but the analysis did Variation and Taxonomy not include counts of flower parts because Within California “Lewisia is fiendishly hard to describe ade- quately from pressed material. . . . The num- Distinguishing Lewisia sacajaweana from ber and shade of petals, stamens, and stigmas L. kelloggii is complicated by variation among defies the most careful dissection” [letter from L. kelloggii populations. The morphological Lauramay Dempster to Paul Hutchison, 2 variation has been noticed and treated taxo- March 1989, in a fragment packet on Hutchison nomically. Lewisia kelloggii was published based and Bacigalupi 8105 (JEPS)]. Isoyzme analysis on a specimen from Placer County, California suggests that the southern populations may be (Brandegee 1894), near the center of the plant’s differentiated from their more northern rela- California range. The holotype remains at CAS tives. The 1 southern population included in (Howell 1949) and an isotype is at UC (Appen- the isozyme study, from Shuteye Peak south of dix). Plants growing farther south in California, Yosemite, has 3 alleles found elsewhere only particularly in Yosemite National Park, are simi- in the Idaho populations plus 5 unique alleles. 356 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Its genetic identities with other California pop- 4:86–91. ulations average 0.71 (range 0.66–0.74), lower CONKLE, M.T., P.D. HODGSKISS, L.B. NUNNALLY, AND S.C. HUNTER, 1982. Starch gel electrophoresis of conifer than average for populations of different sub- seeds: a laboratory manual. General Technical Report species (Crawford 1990). PSW-64, U.S. Department of Agriculture, Forest Ser- Plants twice the size of typical L. kelloggii vice, Pacific Southwest Forest and Range Experiment were described as L. kelloggii ssp. hutchisonii Station, Berkeley, CA. 18 pp. CRAWFORD, D.J. 1990. Plant molecular systematics: macro- from a single specimen collected on Saddle- molecular approaches. John Wiley & Sons, New York. back Mountain in Sierra County, near the north 388 pp. edge of the species’ California range (Dempster DAVIDSON, B.L. 2000. Lewisias. Timber Press, Portland, OR. 1996). The 2 populations sampled from the DEMPSTER, L.T. 1993. Lewisia. Pages 900–903 in James C. Plumas National Forest came from populations Hickman, editor, The Jepson manual: higher plants of California. University of California Press, Berke- previously identified as L. kelloggii ssp. hutch- ley. 1400 pp. isonii (Janeway 1998), and inspection of speci- ______. 1996. A new subspecies of Lewisia (Portulaca- mens at CHSC supports this identification. ceae) in California. Madroño 43:415–416. Genetic identities with other northern Cali- ELLIOTT, R.C. 1966. The genus Lewisia. Bulletin of the Alpine Garden Society 34:1–76. fornia populations average 0.873. In the con- FOSTER, M., E. CARROLL, AND V. D. H IPKINS. 1997. Saw- text of the highly differentiated California pop- toothed lewisia: to be or not to be. Fremontia 25(1): ulations, these plants did not exhibit isozyme 15–19. patterns distinct from the typical populations GOLDBLATT, P., EDITOR. (website accessed 30 August 2001). Index to Plant Chromosome Numbers (IPCN). Mis- (Fig. 5). When Dempster (1996) described L. souri Botanical Garden website: http://mobot.mobot. kelloggii ssp. hutchisonii, she commented on org/W3T/search/ipcn.html. the lack of intermediates between the holotype, GOTTLIEB, L.D. 1981. Electrophoretic evidence and plant the only plant of this taxon she had seen, and populations. Progress in Phytochemistry 7:1–46. L. kelloggii ssp. kelloggii. Collections at CHSC ______. 1982. Conservation and duplication of isozymes in plants. Science 216:373–380. fill the gap between the 2 taxa, morphologi- HAMRICK, J.L., AND M.J. GODT. 1989. Allozyme diversity cally and geographically (Appendix), and prin- in plant species. Pages 43–63 in A.H.D. Brown, M.T. cipal component analysis showed that some Clegg, A.L. Kahler, and B.S. Weir, editors, Plant pop- specimens are intermediate (Fig. 4). Discrimi- ulation genetics, breeding and germplasm resources. Sinauer, Sunderland, MA. nant analysis suggests that petal length could HARTL, D.L., AND A.G. CLARK. 1989. Principles of popula- be useful in distinguishing the California taxa tion genetics. 2nd edition. Sinauer Associates, Sunder- (L. kelloggii ssp. hutchisonii has longer petals). land, MA. 542 pp. HERSHKOVITZ, MARK A. 1990. Nomenclatural changes in Portulacaceae. Phytologia 68:267–270. ACKNOWLEDGMENTS HINTZ, J. 2001. NCSS and PASS. Number Cruncher Sta- tistical Systems, Kaysville, UT. Website: http://www. The project was initiated due to collections ncss.com. made by Wayne Owen and Greg Lind. The HOHN, J.E. 1975. Biosystematic studies of the genus project was managed by Chris Frisbee and Lewisia, section Cotyledon (Portulacaceae). Unpub- lished doctoral dissertation, University of Washing- continued by Teresa Prendusi, both of the ton, Seattle. USDA Forest Service and funded by the Boise HOLMGREN, P.K., N.H. HOLMGREN, AND L.C. BARNETT. National Forest. We thank Suellen Carroll, 1990. Index herbariorum. Part I: The herbaria of the Patricia Guge, and Randy T. Meyer at the world. 8th edition. New York Botanical Garden National Forest Genetic Electrophoresis Lab- Press, New York. 693 pp. HOWELL, J.T. 1949. Plant types in the Herbarium of the oratory for technical support; Amanda Dabbs, California Academy of Sciences. II. Wasmann Col- Molly Hunter, and Robert C. Saich for tissue lector 7:222–230. collection; John Schenk, Kay Beall, and David JANEWAY, L.P. 1998. Lewisia kelloggii var. hutchisonii plant Potter for collecting specimens in Idaho for occurrence discovery record. In species files, Feather River Ranger District, Plumas National Forest, Oro- the morphological study; and Bruce Bartholo- ville, CA. mew at CAS, Barbara Ertter at UC, and Law- JEPSON, W.L. 1923. A manual of the flowering plants of rence Janeway at CHSC for loans of speci- California. University of California, Berkeley. 1238 pp. mens. KIMURA, M., AND J.F. CROW. 1964. The number of alleles that can be maintained in a finite population. Genet- ics 49:725–738. LITERATURE CITED KRUCKEBERG, A.R. 1957. Documented chromosome num- bers of plants. Madroño 14:111–112. BRANDEGEE, K. 1894. Studies in Portulacaceae. Proceed- LEWONTIN, R.C. 1972. The apportionment of human di- ings of the California Academy of Science, Series 2, versity. Evolutionary Biology 6:381–398. 2005] LEWISIA KELLOGGII TAXONOMY 357

MATHEW, B. 1989. The genus Lewisia. Timber Press, Port- USDA FOREST SERVICE. 2000. National Forest Genetic land, OR. Electrophoresis Laboratory standard operating proce- MOLDENKE, A.R. 1973. A contribution to a chromosome dures. NFGEL, USDA Forest Service, Camino, CA. atlas of the California flora. Technical Report 73-22, WEEDEN, N.F., AND J.F. WENDEL. 1989. Genetics of plant University of California, Santa Cruz. isozymes. Pages 46–72 in D.E. Soltis and P.S. Soltis, NEI, M. 1973. Analysis of gene diversity in subdivided editors, Isozymes in plant biology. Dioscorides Press, populations. Proceedings of the National Academy Portland, OR. of Science USA 70:3321–3323 WEFALD, M. (accessed August 2001) TRS2LL. Online. ______. 1978. Estimation of average heterozygosity and Available http://www.crl.com/~wefald/trs2ll.html. genetic distance from a small number of individuals. WEINS, D., AND D.K. HALLECK. 1962. Chromosome num- Genetics 89:583–590. bers in Rocky Mountain plants. Botaniska Notiser SLATKIN, M., AND N.H. BARTON. 1989. A comparison of 115:455–464. three indirect methods for estimating average levels WEIR, B.S. 1990. Genetic data analysis. Sinauer Associ- of gene flow. Evolution 43:1349–1368. ates, Sunderland, MA. SOLTIS, D.E., AND L.H. RIESEBERG. 1986. Autopolyploidy YEH, F.C., R.-C. YANG, AND T. B OYLE. 1997. Popgene, ver- in Tolmiea menziesii (Saxifragaceae): genetic insights sion 1.20. University of Alberta, Edmonton, Alberta, from enzymes electrophoresis. American Journal of Canada. Botany 73:310–318. STEBBINS, G. LEDYARD, JR. 1947. Types of polyploids: their Received 8 July 2003 classification and significance. Advances in Genetics Accepted 29 December 2004 1:403–429.

Appendix on the following page. 358 WESTERN NORTH AMERICAN NATURALIST [Volume 65

APPENDIX Emigrant Pass, 6350 feet, 17 June 1973, Heckard & Stebbins 3444* (JEPS); Plumas Co., Big Meadows, 1880, Austin Taxonomic Citations s.n.* (UC); USFS road 22N84X on the north side of Onion Lewisia kelloggii K. Brandegee, Proc. Calif. Acad. Sci. Valley at its junction with 22N43Y 0.8 mile east of La Ser. II. 4: 1494; Oreobroma kelloggii (K. Brandegee) Rydb., Porte–Quincy Rd., ca. 1 mile north of Pilot Peak, on the N. Am. Fl. 21: 326. 1932. CA: Sierra Nevada, Camp Yuba south edge of the road, 6750 feet, 8 August 1998, Oswald (Cisco), 27 June 1870, Kellogg s.n. (HT: CAS; IT: UC). & Pires 9460* (CHSC); Plumas/Sierra Co. line, in the Lewisia yosemitana Jepson, Man. Fl. Pl. Calif. 352. 1923; center of the Pacific Crest Trail, on Bunker Hill Ridge, Oreobroma yosemitanum (Jepson) Rydb., N. Am. Fl. 21: about 0.5 mile (air) southwest of Pilot Peak, T22N R10E 326. 1932 [not Lewisia rediviva var. yosemitana K. Brande- S09 SW1/4, 6600 feet, 7 July 1994, Ahart 7467* (CHSC); gee = L. disepala Rydb.]. CA: Mariposa County, Yosemite, Sierra Co., on the north side of Henness Pass Road, at El Capitan, Jepson 4357 (HT: JEPS). Keystone Gap, east of Keystone Mountain, about 1.5 miles Lewisia kelloggii ssp. hutchisonii Dempster, Madroño northeast of Middlewaters, about 11 miles (air) northeast 43: 415. 1996. CA: Sierra Co., Saddleback Mountain, ca. 9 of Allegheny, T19N R12E S06 SE1/4, 6600 feet, 1 July miles north of Downieville, July 1932, Hutchison & Baci- 1994, Ahart 7446* (CHSC); Saddleback Mountain, forestry galupi 8105 (HT: JEPS; IT: CAS). road ca. 9 miles north of Downieville, west of summit of junction with a side road to the northwest, on north-facing Specimens Examined slopes within 100 feet from road, 1.8 miles north of side (* used in morphometric analysis) road to Excelsior Mine, 6000 feet, July 1982, Hutchison & Bacigalupi 8105** (CAS, JEPS); North Sierra Buttes Trail, Lewisia kelloggii ssp. kelloggii. California: Eldorado Co., ca. 1 mile south of Packer Saddle trailhead, 250 m, 27 Cody Summit Ridge, southwest of Strawberry, T10N R16E June 1990, Patterson 1958 (JEPS). S01, 7900 feet, 7 July 1971, Stebbins 8039 (CAS); Mariposa Co., on El Capitan, Yosemite Valley, 28 June 1917, Buck & Lewisia sacajaweana. Idaho: Boise Co., Miller Mountain McCauley s.n. (UC); El Capitan Trail, near type locality, Site #2, Lowman Ranger District, Boise Nat’l Forest, 31 May 1940, Howell 15551* (CAS); between Snow Creek 44°08′40.18″N, 115°30′45.62″W, 7560 feet, 11 July 2002, and Mt. Watkins Ridge, 1 June 1940, Howell 15574 (CAS); Potter & Beall s.n. (OSC); Miller Mountain, near transects Gin Flat (2 miles east of), Crane Flat, 6300 feet, 30 May at site 3. Lowman Ranger District, Boise Nat’l Forest. 1924, Jepson 10514* (JEPS); Sierra Nevada, Yosemite Nat’l 44°08′40.905″N, 115°30′45.361″W, 7650 feet, 11 July 2002, Park, Horse Ridge, 9500 feet, 6 July 1941, Mason 12495 Potter & Beall s.n. (OSC); Miller Mountain, site 9, Low- (JEPS, UC); on the top and slopes of a gravelly ridge near man Ranger District, Boise Nat’l Forest, 44°08′41.073″N, El Capitan, Yosemite, 4 July 1922, Michaels s.n.* (CAS); 115°30′45.477″W, 7525 feet, 11 July 2002, Potter & Beall Summit El Capitan, Yosemite National Park, 7640 feet, 21 s.n.* (OSC); Boise Nat’l Forest, Clear Creek Summit, on June 1936, Sharsmith 2154 (UC); Yosemite National Park, road 510, 100 feet east of the county line, 44°13.94′, Mt. Watkins, 10921 feet, July 1916, Sierra Club Members 115°31.28′, 2362 m, 13 July 2002, Schenk & Rey-Vizgirdas HMH 9071, (UC); ridge top of Sentinel Dome, above 525* (OSC); Boise Nat’l Forest, Scott Mt. road 555BC, 1.5 Yosemite Valley, 28 June 1949, Webber s.n., (CAS); Nevada miles west of intersection with road 555, 44°10.43′, Co., Tahoe Nat’l Forest, Castle Peak, 9000 feet, 20 July 115°42.62′, 2310 m, 13 July 2002, Schenk & Rey-Vizgirdas 1932, Smith 2422* (CAS); Placer Co., Camp Yuba (Cisco), 526* (OSC); Boise Nat’l Forest. Pilot Peak, on slopes east Sierra Nevada, 27 June 1870, [Kellogg s.n.]* (CAS); Camp and west of road 380, at intersection with spur road to Yuba (Cisco), Sierra Nevada, 27 June 1870, Kellogg s.n.* Pilot Peak Lookout, west of lookout. T07N R06E S01, (UC); Plumas Co., Sierra Nevada, west shoulder of Mt. 43°57.81′, 115°41.8′, 3276 m, 13 July 2002, Schenk & Rey- Elwell, trail to Mt. Elwell, Lakes Basin, 5 August 1974, Vizgirdas 527* (CAS, ID, MO, OSC); Custer Co., Challis Williams & McPherson 74-P-14* (CAS); no county, Ameri- Nat’l Forest, Bench Creek Trail, west of Hwy 21, about 2 can Valley, May 1877, Austin s.n. (UC); locality data prob- miles west of trailhead, on north side of trail, north of Bull ably in error, Siskiyou Mountains: Cook and Green Pass, Trout Lake, 44°19.95′, 115°15.74′, 13 July 2002, Schenk & July 1976, Roderick s.n., (JEPS). Rey-Vizgirdas 517 (OSC); Elmore Co., ca. 4 miles north of Pine, Boise Nat’l Forest, 4 June 1944, Hitchcock & Muh- Lewisia kelloggii ssp. hutchisonii. California: Butte Co., lick 8690** (CAS, UC); Valley Co., Boise Nat’l Forest, area of saddle between Coon Hollow and Chips Creek, Whitehawk Mt. Summit, 150 feet north of outhouse, near jeep trail, T25N R05E S10 SW1/4, 6300 feet, 22 July 44°17.5′, 115°31.89′, 2549 m, 13 July 2002, Schenk & Viz- 1988, Janeway & Schlising 3047* (CHSC); Placer Co., girdas 520* (OSC). Summit of Big Valley Bluff, about 7 air miles southeast of Western North American Naturalist 65(3), © 2005, pp. 359–364

POLLINATION NEEDS OF ARROWLEAF BALSAMROOT, BALSAMORHIZA SAGITTATA (HELIANTHEAE: ASTERACEAE)

James H. Cane1

ABSTRACT.—Arrowleaf balsamroot, Balsamorhiza sagittata (Pursh) Nutt, is a common, sometimes dominant, long- lived forb that flowers early in spring from the foothills to upper-montane areas of the northern Rocky Mountains and Intermountain West. Public land managers desire its seed for rangeland rehabilitation. Through manual pollination field trials, the species was found to have a mixed pollination system. It is primarily xenogamous (46% of ovules yielded plump achenes) but partially self-compatible (31% of achenes were plump). Unvisited flower heads formed virtually no mature achenes; only plump achenes contained seeds with endosperm. Freely visited flower heads in 2 populations pro- duced as many achenes as manual outcross pollinations of flower heads, suggesting that seed production was not polli- nator limited. Two species of Osmia bees rely mostly on Balsamorhiza and its close relative, Wyethia, for pollen. At least 165 females per hectare will need to be stocked to achieve thorough flower visitation in cultivated seed production fields.

Key words: Engelmanniinae, Osmia, Apiformes, Apoidea, bees, seed set, self-incompatibility, pollinator limitation.

The balsamroots (Balsamorhiza, 14 spp.) and Farming seed crops often requires pollinator mule’s ears (Wyethia, 14 spp.) together form a supplementation. To evaluate pollination needs, monophyletic clade within the subtribe Engel- a plant species’ breeding biology must first be manniinae [largely equivalent to the former understood, but there are no published accounts Ecliptinae (Heliantheae: Asteraceae); Robinson for any species of Balsamorhiza, Wyethia, or 1981, Urbatsch and Jansen 1995, Clevinger any other species of their subtribe except and Panero 2000, Moore and Bohs 2003]. Echinacea angustifolia (Leuszler et al. 1996). A They are restricted to western North America, cavity-nesting vernal solitary bee, Osmia cali- where they are widespread and often abundant, fornica, can be common at capitula of Balsa- ranging from valleys and foothills to subalpine morhiza; museum label data and pollen con- habitats. Most members of their subtribe stitution of larval provisions reveal it to be a bloom in summer, but species of Balsamorhiza specialist on the Asteraceae (Rust 1974, Torchio and Wyethia are unusual: their large taproots 1989). It occurs throughout the western USA, enable them to put forth large flower heads (= north of the warm deserts and south of Can- capitula) in early spring. At this time their ada (Rust 1974), thus largely matching the young foliage and capitula are preferred for- geographic range of B. sagittata. This study’s 2 age of deer, elk, and both domestic and big- objectives were (1) to characterize the breed- horn sheep (Burrell 1982, Wikeem and Pitt ing biology of B. sagittata to understand its 1992). Local populations can be extensive, relative dependence on pollinators; and (2) to dense, and persistent, with cohorts of plants estimate stocking densities for the native bee persisting for as many as 40 years (Treshow O. californica to achieve adequate floral visita- and Harper 1974). As a consequence of the tion for commercial seed production. ecological prevalence and forage utility of bal- samroots, particularly B. sagittata, they have MATERIALS AND METHODS long been advocated for use in rangeland Pollination Treatments revegetation and rehabilitation. Wildland seed production is erratic and prohibitively expen- My assistants and I chose and tagged 25 sive to harvest, however, prompting a call for plants of B. sagittata at 2 separate populations agricultural production of B. sagittata seed. near Logan, Cache Co., Utah, USA (Fig. 1). We

1USDA-ARS Pollinating Insect Research Unit, Utah State University, Logan, UT 84322-5310.

359 360 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 1. Arrowleaf balsamroot, B. sagittata, in flower. Inset: female O. californica foraging at flower of B. sagittata.

tagged 4 capitula on each plant just prior to pollinate capitula, a donor capitulum that was anthesis; 3 were enclosed in drawstring bags shedding pollen was gently but thoroughly made of white fine mesh “no-see-um” netting, rubbed against the open florets of the recipi- 2 of which were used for manual pollinations. ent capitulum. After each pollination event, Once florets began to dehisce pollen, the same recipient capitula were rebagged. 2 capitula of each plant were manually polli- We applied 4 pollination treatments in the nated every other day for 10 days. To manually field: autogamy (unassisted autopollination), 2005] POLLINATION OF BALSAMORHIZA SAGITTATA 361 geitonogamy (manual transfer of self-pollen), film). Viability of 100 X-rayed seeds was xenogamy (manual transfer of outcross pollen), checked by the tetrazolium test (Grabe 1970). and free-visitation (no bag). One capitulum Germination was attempted using reported remained bagged throughout bloom to test for protocols (Young and Evans 1979), but proved autogamy. Geitonogamous pollination involved unsatisfactory. rubbing the recipient capitulum with an extra Many capitula in the autogamy treatment untagged blooming capitulum from the same produced no plump seed, complicating statis- plant. Donor capitula for xenogamy were tical comparison. I first compared autogamy clipped from plants growing >100 m distant. and geitonogamy for the proportion of capitula Manually pollinated capitula were thus polli- bearing >1 versus no plump achenes, using a nated every other day from the onset of bloom G-test with Williamson’s correction (Sokal and until the last central florets closed. Freely vis- Rohlf 1995). General linear model ANOVA tests ited capitula were tagged but remained un- were then used to compare the 3 pollination bagged and accessible to pollinators, serving as treatments (excluding autogamy) for total ach- a positive control for our manual pollinations ene production, sum of plump achenes, and while also revealing natural seed production. the proportion of achenes that were plump. A The technique’s efficacy for manually trans- randomized complete block design used plants ferring pollen was assessed using a pollen sur- as blocks. I square root transformed achene rogate. A light dusting of fluorescent powder counts, rendering homogeneous variances for was applied by brush to open florets of 4 capit- all 3 variables (Levene’s test, P > 0.6). Where ula. Each of these capitula was then rubbed treatment differences were significant (P ≤ against a 2nd recipient in the manner used in 0.05), I compared treatments by Ryan-Enot- the field. We then illuminated the 4 recipient Gabriel-Welch (REGW) a posteriori tests (SAS capitula by ultraviolet light and viewed them Institute 1989). Degrees of freedom are given microscopically. In this trial, 92% of 101 recip- in subscript brackets for ANOVA tests. ient florets picked up some fluorescent pow- der from donor capitula (range of 73%–100% Activity of Osmia transfer per capitulum). californica Bees A nesting shelter with overwintered nests of Seed Production Osmia californica Cresson, a release box, and After flowering ceased, bags were removed. 4 drilled wooden nesting blocks was placed at We protected the 4 capitula of each plant from the edge of several hectares of blooming B. vertebrate seed predators by inserting each sagittata (and budded B. macrophylla and into a stiff cylinder made of coarse plastic mesh. Wyethia amplexicaulis Nutt.). Once nesting These are marketed to protect young conifer had commenced, nest entrance traffic was saplings used for reforestation (Forestry Sup- filmed for 45 minutes at midday. This video pliers Inc., Jackson, MS). The top and bottom was later transcribed for durations of 14 pollen of each tube were drawn closed with a wire. foraging trips, each of which ends when a re- Each mesh tube was supported by a stake. turning female first enters her nest hole head Once achenes were mature, but before they first, regurgitates nectar, then walks out and were shed, capitula were individually bagged, backs into her nest to unload pollen (which clipped, and returned to the laboratory. After differs from stray hole visits, nest partition drying for 10 days, achenes were harvested. manufacture, etc.). Concurrently, 21 females Visibly plump achenes and shrunken achenes were timed and followed as they each visited a (Fig. 2 inset) were sorted and tallied for each sequence of 5 B. sagittata capitula that were capitulum. Reproductive potentials of the visu- seen to be dehiscing pollen. ally scored plump and shrunken achenes were evaluated in 3 ways: (1) seed mass, (2) endo- RESULTS AND DISCUSSION sperm content, and (3) viability staining. Sub- samples of 5 plump and 5 shrunken achenes Achene size proved to be a useful indicator were taken from 8 treatment plants, weighed, of viability. From 91 capitula, we obtained 6739 and compared by a t test. Endosperm content achenes, 67% of which were plump. Achenes was visualized by X rays (HP 4380N Faxitron, scored as plump (Fig. 2 inset) were 5-fold 25 KV, 30 seconds, medium-grain industrial heavier than shrunken achenes (groups of 10 362 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 2. Four pollination treatments compared for the sum of plump achenes produced per capitulum of B. sagittata. Bars followed by different letters are statistically different from one another (P ≤ 0.05). Means and 95% confidence inter- vals are presented as their back-transformed values (Sokal and Rohlf 1995). Numbers of capitula are given in the column to the right of the graph. Inset: image of 1 plump (filled) and 2 shrunken (empty) achenes.

– achenes, x = 75 mg vs. 15 mg; t[14] = 7.0, P < Total achene production (combining plump 0.0001). Endosperm absorbs X rays; it was and shrunken achenes) is an estimate of ovule readily discerned as clear unexposed areas in number for individual capitula. For the 3 treat- the radiograph negatives of achenes. Endosperm ments other than autogamy, total achene pro- was evident in 78% of visibly plump achenes duction per capitula differed among plants (n = 132), whereas shrunken achenes lacked (F[24,66] = 2.4, P < 0.008) but not between endosperm (69 of 70 achenes). For the sub- pollination treatments (x– = 73–79 achenes; samples of 10 achenes which were X-rayed F[2,66] = 0.3, P < 0.7). Hence, there was no and then tested using tetrazolium staining for systematic size bias for ovule number in viability, 64 of 67 achenes with apparent endo- assignment of treatments to individual capit- sperm were scored as live, while all 33 ach- ula within plants. enes lacking apparent endosperm were scored Production of plump achenes varied with as dead. treatment as well as maternal plant. The num- Autogamy treatments of B. sagittata capitula bers of plump achenes produced differed both rarely produced any plump achenes compared among plants (F[24,66] = 2.5, P < 0.005) and with capitula from geitonogamous pollination among the 3 treatments (excluding autogamy; ≥ (13% vs. 75% of capitula with 1 achene; n = F[2,66] = 3.9, P < 0.03) with no significant 47 capitula; Gadj = 19, P < 0.0001). Of the 24 interaction (Fig. 2). Manual pollination using capitula in the autogamy treatment, 18 had pollen from the maternal plant yielded signifi- only shrunken achenes, and the remaining 6 cantly fewer plump achenes than either xeno- produced a sum of only 62 plump achenes gamy or the freely visited treatments. Xenogamy (range 1–39). Autogamy yields little if any nat- and freely visited treatments resulted in the ural achene set in B. sagittata (Fig. 2). maximum set of plump achenes per capitula, 2005] POLLINATION OF BALSAMORHIZA SAGITTATA 363 and were nearly identical (Fig. 2). When ex- mated commercial seed production is 100 ± 25 pressed as proportions, plump achene produc- lbs ⋅ acre–1 (= 112 kg ⋅ ha–1; Stevens et al. tion differed among both plants (F[24,66] = 2.9, 1996). We found there to be 133 achenes per P < 0.0013) and the 3 treatments (F[2,66] = gram, which would give an expected harvest 6.4, P < 0.004) with no significant interaction. of 15 million achenes per hectare. Our yield of Capitula receiving self-pollen set proportion- 35 plump achenes per capitulum would there- ately fewer plump achenes (31%) than did xeno- fore require 427,000 full capitula per hectare gamy or open pollination, which were identi- (= 43 ⋅ m–2 or 14 full capitula per plant). This cal in the proportion of ovules producing plump estimate seems reasonable in light of recom- achenes (46%). Evidently, achene production mended planting of 30,000 plants per hectare by B. sagittata was not pollinator limited at the (calculated from Stevens et al. 1996). study sites. Comparable contrasts between The numbers of capitula visited in a female pollination treatments were reported for Echi- bee’s lifetime can be calculated from either nacea angustifolia (Leuszler et al. 1996). foraging and provisioning tempos, or rates of The importance of pollinator visitation for pollen acquisition and caching (Cane et al. 1996). sexual reproduction of species in the Engel- Combined with pollination efficacy estimates, manniinae has been demonstrated only for optimal stocking densities of nonsocial bees Echinacea angustifolia (Leuszler et al. 1996) can be estimated that would maximize crop and now B. sagittata. Autogamy is at most in- production (e.g., Cane et al. 1996, Vicens and frequent among other representatives of the Bosch 2000, Torchio 2003). Females of O. cali- Heliantheae (Sundberg and Stuessy 1990). fornica typically produce 1 offspring daily, each Species of the Engelmanniinae host diverse requiring pollen and nectar acquired during native bees, but few if any other pollinating 25–30 foraging trips (Rust 1974, Torchio 1989). insects, even at a single locale. Bees are un- I found that midday pollen-foraging trips by doubtedly the primary pollinators, although we O. californica in wild patches of B. sagittata were unable to reliably track fates of rings of lasted 8.4 ± 6.8 minutes (median = 5.5 min- maturing (or empty) achenes that resulted from utes, n = 14 trips). At midday, pollen-laden rings of receptive florets being individually females handled an average of 9.6 ± 4.7 capit- visited by a bee. At Carlinville, Illinois, USA, ula per minute (n = 21 bees, 105 capitula), exhaustive multiyear samples yielded 24–48 bee and could be seen patting the florets with their species visiting flowering species of Engel- abdominal venters to acquire pollen. Honey- maniinae (Echinacea purpurea, Ratibita pin- bees (von Frisch 1967) and alkali bees (Cane nata, Silphium perfoliatum, and Verbesina personal observation) both fly at about 23 km ⋅ helianthoides; Robertson 1929). From speci- hr–1, so the comparably sized O. californica men labels at the USDA-ARS Pollinating should need 30 seconds to travel an arbitrary Insect Research Unit in Logan, Utah, 35 species average commute distance of 100 m out and of native, nonparasitic bees had been taken back between nest and meadow. Multiplying from the western U.S. while visiting species of average capitula handling rates by the median Balsamorhiza, although Balsamorhiza has never duration of foraging trips (minus commute time) been the focus of a methodical pollinator sur- and thence by the number of trips to provision vey. I have initiated such a survey and thus far a nest cell, gives an estimated 48 capitula that have found that the cavity-nesting, nonsocial are visited per trip; thus, 1320 capitula would bee, Osmia californica, is always present and be visited daily for 1 nest cell. Each female re- often prevalent at capitula of both B. sagittata portedly produces as many as 30 progeny in and B. macrophylla. Collectively, these obser- the greenhouse (Torchio 1989), but field bees vations illustrate that native bees are abundant probably produce only a third as many, so and key to pollination in this subtribe. each female might visit 13,200 Balsamorhiza Pollinators will be essential for any agricul- capitula in her lifetime. Since we could fully tural production of B. sagittata achenes, an pollinate capitula manually by pollinating them objective of a multiyear federal program to 5 times in 10 days, a female bee might fully produce seed for wildland rehabilitation in the pollinate 2640 capitula (13,200/5) in her life- Intermountain West. It is useful to estimate time. From these measures, I calculate that at the stocking densities of bees that will be least 165 nesting female O. californica would needed to pollinate such seed fields. Esti- be needed to pollinate a single hectare of farmed 364 WESTERN NORTH AMERICAN NATURALIST [Volume 65 arrowleaf balsamroot, comparable to the 250– MOORE, A.J., AND L. BOHS. 2003. An ITS phylogeny of 1100 females per hectare reportedly needed Balsamorhiza and Wyethia (Asteraceae: Heliantheae). American Journal of Botany 90:1653–1660. in several tree fruit and berry crops (Cane et ROBERTSON, C. 1929. Flowers and insects. Science Press al. 1996, Vicens and Bosch 2000, Torchio 2003). Printing Co., Lancaster, PA. 221 pp. Nesting shelters probably can be widely spaced ROBINSON, H. 1981. A revision of the tribal and subtribal in seed fields; nesting females of the closely limits of the Heliantheae (Asteraceae). Smithsonian related, like-sized vernal composite specialist, Contributions to Botany 51. 102 pp. RUST, R.W. 1974. The systematics and biology of the Osmia montana, were seen foraging at a distance genus Osmia, subgenera Osmia, Chalcosmia, and of ≥0.6 km to the nearest blooming suitable Cephalosmia (Hymenoptera: Megachilidae). Wass- floral hosts (Helianthella and Crepis; personal mann Journal of Biology 32:1–93. observation). These rough guidelines will be SAS INSTITUTE. 1989. SAS/STAT user’s guide, version 6. 4th edition. SAS Institute, Cary, NC. 943 pp. useful for native seed growers interested in SOKAL, R.R., AND F. J . R OHLF. 1995. Biometry. 3rd edition. maximizing pollination in commercial fields of W.H. Freeman, New York. 887 pp. this slow-growing perennial wildflower. STEVENS, R., K.R. JORGENSEN, S.A. YOUNG, AND S.B. MON- SEN. 1996. Forb and shrub seed production guide for Utah. Utah State University Extension Publication ACKNOWLEDGMENTS AG501. 52 pp. SUNDBERG, S.D., AND T.F. S TUESSY. 1990. Isolating mecha- Faye Rutishauser, Carole Scoville, Morgan nisms and implications for modes of speciation in Yost, and James McDonald contributed ably to Heliantheae (Compositae). Plant Systematics and all facets of the field and laboratory work. I am Evolution [Supplement 4]:77–97. indebted to Emerenciana Gabilo Hurd (retired TORCHIO, P.F. 1989. In-nest biologies and development of immature stages of three Osmia species (Hymen- botanist, USDA Forest Service, Rocky Moun- optera: Megachilidae). Annals of the Entomological tain Research Station) for expertise in per- Society of America 82:599–615. forming and interpreting the tetrazolium tests. ______. 2003. The development of Osmia lignaria Say Research was part of the Great Basin Native (Hymenoptera: Megachilidae) as a managed pollina- tor of apple and almond crops: a case study. Pages Plant Selection and Increase Project funded 67–84 in K.V. Strickler and J.H. Cane, editors, For through the USDI-BLM Great Basin Restora- non-native crops, whence pollinators of the future? tion Initiative and the USDA-FS Rocky Moun- Thomas Say Publications in Entomology, Entomo- tain Research Station. I am grateful to Vincent logical Society of America, Lanham, MD. Tepedino, Nancy Shaw, and anonymous re- TRESHOW, M., AND K. HARPER. 1974. Longevity of peren- nial forbs and grasses. Oikos 25:93–96. viewers for detailed, constructive comments. URBATSCH, L.E., AND R.K. JANSEN. 1995. Phylogenetic affinities among and within the coneflower genera LITERATURE CITED (Asteraceae, Heliantheae), a chloroplast DNA study. Systematic Botany 20:28–39. BURRELL, G.C. 1982. Winter diets of mule deer in relation VICENS, N., AND J. BOSCH. 2000. Pollinating efficacy of to bitterbrush abundance. Journal of Range Manage- Osmia cornuta and Apis mellifera (Hymenoptera: ment 35:508–510. Megachilidae, Apidae) on ‘Red Delicious’ apple. Envi- CANE, J.H., D. SCHIFFHAUER, AND L.J. KERVIN. 1996. Pol- ronmental Entomology 29:235–240. lination, foraging, and nesting ecology of the leaf- VON FRISCH, K. 1967. The dance language and orientation cutting bee Megachile (Delomegachile) addenda of bees. Harvard University Press, Cambridge, MA. (Hymenoptera: Megachilidae) on cranberry beds. 566 pp. Annals of the Entomological Society of America WIKEEM, B.M., AND M.D. PITT. 1992. Diet of California 89:361–367. bighorn sheep (Ovis canadensis californiana) in British CLEVINGER, J.A., AND J.L. PANERO. 2000. Phylogenetic Columbia: assessing optimal foraging habitat. Cana- analysis of Silphium and subtribe Engelmanniinae dian Field Naturalist 106:327–335. (Asteraceae: Heliantheae) based on ITS and ETS se- YOUNG, J.A., AND R.A. EVANS. 1979. Arrowleaf balsamroot quence data. American Journal of Botany 87:565–572. and mules ears seed germination. Journal of Range GRABE, D.F., EDITOR. 1970. Tetrazolium testing handbook Management 32:71–74. for agricultural seeds. No. 29. Association of Official Seed Analysts; Contribution to the Handbook on Received 9 June 2004 Seed Testing, prepared by the Tetrazolium Testing Accepted 20 December 2004 Committee of the Association of Official Seed Ana- lysts. LEUSZLER, H.K., V.J. TEPEDINO, AND D.G. ALSTON. 1996. Reproductive biology of purple coneflower in south- western North Dakota. Prairie Naturalist 28:91–102. Western North American Naturalist 65(3), © 2005, pp. 365–370

NEW SPECIES OF MENTZELIA (LOASACEAE) AND PHACELIA (HYDROPHYLLACEAE) FROM NEW MEXICO

N. Duane Atwood1 and Stanley L. Welsh1

ABSTRACT.—New species of Mentzelia and Phacelia are described from northwestern New Mexico, USA, as Mentzelia todiltoensis, N. Duane Atwood & Stanley L. Welsh, and Phacelia sivinskii N. D. Atwood, sp. nov. The new Mentzelia is compared to M. humilis based on similarities in seed, fruit, leaf, and flower morphology and to M. memorabalis in stem, leaf, and fruit morphology. Phacelia sivinskii is compared to P. constancei N. D. Atwood on the basis of seed, leaf, and flower morphology.

Key words: Mentzelia, Phacelia, New Mexico, nomenclature, North America, Loasaceae, Hydrophyllaceae.

The new Mentzelia and Phacelia are part of Mentzelia todiltoensis N. D. Atwood & S. L. voucher collections made during the 2004 Welsh, sp. nov. (Fig. 1) field season in conjunction with fieldwork on the genus Phacelia for the North American TYPE here designated: USA. New Mexico: Flora project. Cibola Co., vicinity of I-40/junction of Hwy 6, 4 August 2004, N. D. Atwood & A. Clifford MENTZELIA 30538 (holotype, BRY; isotypes, BRY, ASU, MO, NMC, NY, RM, SJNM); vicinity of I-40/ Initial attempts at identification of the junction of Hwy 6, 28 September 2004, N. D. Mentzelia were made using the early treatment Atwood 30814. Paratypes: USA, New Mexico: of Mentzelia by Darlington (1934), Martin and Bernalillo Co., T10N, R3W, S10NE1/2, Canon- Hutchins (1980), descriptions of related species, cito Navajo Reservation, Gypsum Dome in and the large collection of plants at Brigham Canada de los Apaches W of Day School, 1 July Young University (BRY). Specimens examined 1992, Bill Hevron 1736 (BRY); Santa Fe Co., do not match any herbarium collections studied desert 32 km (20 miles) air distance NE of or fit descriptions of existing taxa in the litera- Interstate 25 at Exit 242 (for Bernalillo); ture. Besides the type of the new Mentzelia, 2 35°27′06″N, 106°13′25″W, T41N, R7E, S7, additional collections, one by N.H. Holmgren 2 August 2003, Noel H. Holmgren et al. 15051 et al. (15051) and an earlier one by Bill Hevron (BRY). (1736) were available for study. Some of the lower leaves on the Hevron collection have a A M. humilis (Gray) Darlington in caulibus elatioribus few short lobes, whereas all other collections foliis caulinorum linearis anguste revolutis ad planis, rare have entire leaves. Mentzelia todiltoensis (Todilto paucilobatis; petalis plus numerosis, brevioribus et angus- stickseed) belongs to section Bartonia, a group tioribus; calyce loborum longioribus; capsulis longioribus; of ca. 40 species with lenticular, mostly winged trichomatis caulinorum et foliorum reflexus; et a M. mem- orabalis N. H. & P. K. Holmgren in caulibus elatioribus et seeds that are horizontally aligned in the cap- robustioribus, foliis caulinorum longioribus; capsulis lon- sule. It is related to the suffrutescent, long- gioribus et latioribus, subcylindricus non crateriformibus, lived perennials of the section, many of which differt. are restricted to specific geological strata. The new Mentzelia is known from the Todilto For- Similar to M. humilis (Gray) Darlington but mation with some overlap on the upper part of differing in having taller stems 2.2–8 dm tall the Morrison Formation. These formations are vs. 2–4 dm tall; narrowly linear revolute to flat members of the San Rafael Group of Middle cauline leaves (rarely with a few lobes) vs. pin- Jurassic age (Scholle 2003). nately lobed leaves; 10 petals vs. 5 petals; longer

1Herbarium, Monte L. Bean Life Science Museum, and Department of Integrative Biology, Brigham Young University, Provo, UT 84602.

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Fig. 1. Mentzelia todiltoensis N. D. Atwood & S. L. Welsh, sp. nov.: A, habit; B, seed; C, leaf; D, flower; E, fruit; F, sta- mens; G, petal. Drawn from holotype collection (N. D. Atwood & A. Clifford 30538 [BRY]). 2005] NEW SPECIES OF MENTZELIA AND PHACELIA 367 calyx segments 6.3–8.2 mm vs. 5 mm; shorter, calyx segments 5, 6.3–8.2 mm long, glochidi- narrower apically acute petals 11–12 mm long ate, spreading to reflexed in fruit; petals 10, × 0.6–1.6 mm wide vs. longer, wider apically yellow, oblanceolate, 11–12 mm long, 0.6–1.6 obtuse petals 12–15 mm long × 2–3 mm wide; mm wide at the middle, base tapering, apex longer capsules 8–12 mm long vs. 7 mm long; acute and barbed; stamens numerous, the outer reflexed to spreading leaf and stem trichomes sinus filaments dilated, the inner shorter; vs. ascending leaf and stem trichomes; and dif- anthers 0.5–0.7 mm long, short-glochidiate, fering from M. memorabalis N. H. & P. K. twisted at anthesis; capsule subcylindrical, Holmgren in having more robust and taller obtuse at the base, 8–12 mm long, 5–6 mm stems to 1 cm thick or more and 2.2–8 dm tall wide, glochidiate; seeds semi-orbicular, hori- vs. 4 mm or less thick and 1.5–4.5 dm tall; sim- zontal in the capsule ca. 28, flattened-lenticu- ilar but longer cauline leaves 5–11.5 cm long lar, 2–2.3 mm long, 1.4–1.6 mm wide, winged, vs. 2–6 cm long; larger and different fruit 8–12 minutely tuberculate or papillate on the body mm long × 5–6 mm thick and subcylindrical and wing, the wing 0.3–0.4 mm wide. vs. 4–6.5 mm long × 3.5–4.5 mm wide and bowl-shaped; reflexed to spreading leaf and Key to Related Species stem trichomes vs. ascending leaf and stem trichomes. 1. Stems tall, 2.2–8 dm long; fruiting capsules 8–12 mm long, 5–6 mm thick, subcylindrical, obtuse Mentzelia todiltoensis also has some rela- at the base; cauline leaves narrowly linear, entire; tionship with M. multiflora which occurs in trichomes of stem and leaf reflexed ...... New Mexico. Both species are tall, robust taxa; ...... M. todiltoensis however, Todilto stickseed is easily distin- — Stems shorter, 1.5–4 dm long; fruiting capsules guished from it by the generally much larger, 4–7 mm long, obpyramidal or bowl-shaped; cau- line leaves pinnately lobed; trichomes of stem longer 2.2–18 dm, and more numerous ridged and leaf ascending ...... 2 stems; almost always simple, entire, narrow 2(1). Capsules narrowly obpyramidal, 7 mm long or cauline leaves; more pointed oblanceolate 11– more, 4–6 mm wide ...... M. humilis 12 mm long petals; smaller 8–12 mm long × — Capsules turbinate, bowl-shaped, 4–6.5 mm long, 5–6 mm wide subcylindric capsules vs. mostly 3.5–4.5 mm thick ...... M. memorabalis shorter 4–8 dm long, smooth stems; broader usually sinuate to pinnate leaves; oblong-oval HABITAT AND DISTRIBUTION.—Apparently obtuse tipped 15–20 mm long petals; and restricted to the Todilto and upper part of the larger 15–20 mm long × 6–8 mm wide urceo- Morrison Formations in Bernalillo, Cibola, late capsules. Both M. humilis and M. memo- Santa Fe, and Socorro Counties, New Mexico. rabilis are more disjunct from populations of Associated species include Ephedra torreyana, M. todiltoensis. Tetradymia filifolia, Cryptantha pustulosa, Dalea frutescens, Selenocarpus lanceolatus, Calylophus Robust, usually multi-stemmed perennial, hartwegii var. filifolius, Tiquilia hispidissima, 2.2–8 dm high; stems 1–18, erect, stout, ridged, Sporolobus neeleyi, Mentzelia pumila, and to 1 cm thick or more, white, leafy, covered with Phacelia sivinskii, from 5600 to 5840 feet ele- minutely reflexed to spreading glochidiate vation. Flowering from late June through Sep- pubescence, with both tapering, spinelike, tember. barbed and capitate heads, eventually exfoliat- ing at least below; cauline leaves entire, green, PHACELIA narrowly linear to narrowly oblanceolate, tightly revolute to flat or subterete, sessile, 5– In 2002 Atwood made an extensive study of 11.5 cm long, 0.5–3.8 mm wide, covered with herbarium specimens annotated as Phacelia white, dense, stout, recurved glochidiate hairs integrifolia from collections on loan from her- with bulbiform and disklike or pustulate base; baria in the Midwest and Southwest. Based on basal leaves weathering, not persistent; flow- this review, it was apparent that several new ers on the upper part of stems and branches in species were present in the 1500 collections corymbosely branched clusters of (1) 2–3, ses- on loan. One of these is P. sivinskii. Early collec- sile to subsessile, subtended by 1 or 2 small tions of Phacelia sivinskii (Sivinski’s phacelia) linear-filiform bracts, opening just before sun- were few in number and were collected in set and remaining open through the night; flower or very early fruit, without mature 368 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 2. Phacelia sivinskii N. D. Atwood & T. Lowery, sp. nov. Drawn from holotype collection (N. D. Atwood 30757 [BRY]). 2005] NEW SPECIES OF MENTZELIA AND PHACELIA 369 seeds for comparison with related taxa. A con- hairs, and with white to light brown silica-like certed effort has been made over the last few grains; leaves lanceolate to oblong, 1–6 cm long, years to secure good material for the type, an 0.5–2 cm wide, irregularly crenate-dentate, effort that finally met with success. densely covered with short, light-colored, stip- itate glands, the basal with petioles 12 mm Phacelia sivinskii N. D. Atwood, P. Knight & long, the upper short petiolate to sessile; inflo- T. Lowery, sp. nov. (Fig. 2) rescence in terminal cymes on the main stem and short lateral branches, somewhat virgate TYPE here designated: USA. New Mexico: with some plants flowering from the base up; Sandoval Co., 6 miles N of San Ysidro on Hwy cymes to 5.5 cm long in fruit, reddish, leafy 44, 35°39′53″N, 106°53′41″W, 27 September bracteate; flowers tubular to tubular-campanu- 2004, N. D. Atwood 30757 (holotype, BRY; iso- late, light violet, (3.7) 4.5–5 mm long, the lobes types, ASU, BRY, CAS, GH, MO, NMC, NY, 1.5–2 mm long, puberulent; stamens and style RM, SJNM, UNM). Paratypes: New Mexico: exserted 5–6 mm, darker violet filaments; Cibola Co., ca. 1 mile N of I-40/Hwy 6 jct, anthers bronze, style divided 3/5 its length, 35°00′18″N, 107°08′89″W, 5 August 2004, N. hirsutulous to the forks; calyx lobes elliptic in D. Atwood & Arnold Clifford 30545; Sandoval flower, 3.3 mm long, 0.8–1.3 mm wide, linear Co., vicinity of San Ysidro, 10 August 1926, to narrowly oblanceolate in fruit, 3.1–3.6 mm Bro. G. Arsene & Bro. Benedict 17617 (GH); just long, 1–1.4 mm wide, stipitate glandular and W of San Ysidro on White Mesa, 35°30′9″N, spreading hirsute; capsule 2.6–2.8 mm long, 106°50′29″W, 1 September 1992, P. Knight & 1.8–2.1 mm wide, short, glandular, and hispidu- T. L owery 4189 (BRY, UNM); 6 miles N of San lous; mature seeds oblong, black, 2.2–2.7 mm Ysidro along Hwy 44, 22 August 1996, N. D. long, 1.1–1.3 mm wide, margins and ridge en- Atwood 21548 (BRY, UNM); ca. 12 miles N tire to corrugated, excavated ventrally, pitted, of San Ysidro on Hwy 550, 35°39′528″N, dorsal surface cross-corrugated. 106°53′69″W, 4 September 2002, N. D. Atwood Phacelia sivinskii is most closely related and 28914; ca. 3 miles due W of San Ysidro, similar to P. constancei Atwood in general habit 35°39′59″N, 106°53′47″W, 3 August 2004, and seed morphology. However, it is easily N. D. Atwood 30523; Bureau of Land Manage- distinguished from this species by the smaller ment lands W of Hwy 544 and ca. 4 miles W seeds, which are less regularly corrugated on of San Ysidro, 35°32′71″N, 106°51′14″W, 3 the ridge and margin of the seeds but more August 2004, N. D. Atwood 30525; 6 miles N distinctly cross-corrugated on the dorsal sur- of San Ysidro on Hwy 44, 35°39′51″N, face, and by the broader and shorter, flat, non- 106°53′44″W, 27 September 2004, N. D. involute leaves. Atwood 30761; 2.5 miles S of San Ysidro, HABITAT AND DISTRIBUTION.—Restricted to thence W on Cabeyon Rd to Gasco, thence 1.6 Todilto gypsum in a scattered juniper-desert miles N to windmill, 35°30′95″N, 106°51′20″W, shrub community. Associated with Juniperus 28 September 2004, N. D. Atwood 30806 and monosperma, Mentzelia pumila, Lepidium mon- 30811; Socorro Co., ca. 20 miles W of Carri- tanum, Chrysothamnus viscidiflorus, Tiquilia zoza on Hwy 380, 33°45′97″N, 106°08′12″W, hispidissima, Selenocarpus lanceolatus, Calylo- 6 September 2002, N. D. Atwood 28989; 19.7 phus hartwegii var. filifolius, Astragalus albu- miles W of Carrizo on Hwy 380, 33°45′96″N, lus, Astragalus kentrophyta var. neomexicana, 106°8′10W″, 22 July 2003, N. D. Atwood & Gaillardia pinnatifida, Erigeron aff. divergens, Blaine Furniss 29678. Eriogonum rotundifolium, and Dalea frutescens. Known from northwestern New Mexico in Similis P. constancei N. D. Atwood in habita et semine Cibola, Sandoval, and Socorro Counties. morphologia sed in seminibus parvioribus et crista et mar- gine corrugata minus regulariter sed cristatis dorsalis lat- eralis distincte, et foliis latioribus brevioribus, panis, non- ACKNOWLEDGMENTS revolutis differt. The authors are indebted to the reviewers Biennial, 2.0–3.7 dm tall; stems solitary to for their constructive reviews of the manu- several, leafy, densely covered with nearly ses- script and to BRY illustrator Leslie Hartman for sile to 3-celled, light-colored capitate glands, the excellent illustrations. The Latin diagnoses some short and longer simple nonglandular were prepared by Stanley L. Welsh. 370 WESTERN NORTH AMERICAN NATURALIST [Volume 65

LITERATURE CITED MARTIN, WILLIAM C., AND CHARLES R. HUTCHINS. 1981. Mentzelia. Pages 1299–1307 in A flora of New Mex- DARLINGTON, JOSEPHINE. 1934. A monograph of the genus ico, Volume 2. Mentzelia. Annals of the Missouri Botanical Garden SCHOLLE, PETER A. 2003. New Mexico Bureau of Geology 21:103–226. and Mineral Resources, geologic map of New Mex- HOLMGREN, NOEL H., AND PATRICIA K. HOLMGREN. 2002. ico, 1:500,000. New Mexico Bureau of Geology and New mentzelias (Loasaceae) from the Intermountain Mineral Resources, Socorro. region of western United States. Systematic Botany Received 29 November 2004 27:747–762. Accepted 3 May 2005 Western North American Naturalist 65(3), © 2005, pp. 371–381

MODELING GLOBAL WARMING SCENARIOS IN GREENBACK CUTTHROAT TROUT (ONCORHYNCHUS CLARKI STOMIAS) STREAMS: IMPLICATIONS FOR SPECIES RECOVERY

Scott J. Cooney1, Alan P. Covich2, Paul M. Lukacs3, Amy L. Harig4, and Kurt D. Fausch3

ABSTRACT.—Changes in global climate may exacerbate other anthropogenic stressors, accelerating the decline in dis- tribution and abundance of rare species throughout the world. We examined the potential effects of a warming climate on the greenback cutthroat trout (Oncorhynchus clarki stomias), a resident salmonid that inhabits headwater streams of the central Rocky Mountains. Greenbacks are outcompeted at lower elevations by nonnative species of trout and cur- rently are restricted to upper-elevation habitats where barriers to upstream migration by nonnatives are or have been established. We used likelihood-based techniques and information theoretics to select models predicting stream temper- ature changes for 10 streams where greenback cutthroat trout have been translocated. These models showed high vari- ability among responses by different streams, indicating the usefulness of a stream-specific approach. We used these models to project changes in stream temperatures based on 2°C and 4°C warming of average air temperatures. In these warming scenarios, spawning is predicted to begin from 2 to 3.3 weeks earlier than would be expected under baseline conditions. Of the 10 streams used in this assessment, 5 currently have less than a 50% chance of translocation success. Warming increased the probability of translocation success in these 5 streams by 11.2% and 21.8% in the 2 scenarios, respectively. Assuming barriers to upstream migration by nonnative competitors maintain their integrity, we conclude that an overall habitat improvement results because greenbacks have been restricted through competition with nonna- tives to suboptimal habitats, which are generally too cold to be highly productive.

Key words: global warming, greenback cutthroat trout, Oncorhynchus clarki stomias, stream temperature modeling, endangered species, resident salmonid.

Global climate change may exert profound of juvenile rainbow trout (Reid et al. 1997). effects on human and natural systems (Scavia The combination of rapid global climate change et al. 2002, Walther et al. 2002). There is wide- combined with existing anthropogenic stres- spread concern that these effects may harm sors will likely present a tangible threat to the efforts to conserve rare and threatened species biodiversity of freshwater fauna (Peterson and (e.g., Houghton 2001, Wlodarska-Kowalczuk Kwak 1999). and Weslawski 2001). Coldwater fishes are The greenback cutthroat trout (Oncorhyn- thought to be particularly vulnerable (e.g., Jager chus clarki stomias; hereafter GCT) is a good et al. 1999, Clark et al. 2001). Warmwater fishes candidate for understanding potential effects replace coldwater and coolwater guilds as water of climate change on a rare, coldwater species temperatures rise in a downstream gradient with high conservation values. Most popula- (Taniguchi et al. 1998). For salmonids in river tions are protected from further encroachment drainages, increased upstream migration in by nonnatives because of barriers to upstream summer and loss of downstream habitat area migration (e.g., dams, waterfalls, etc.). As a re- are widely recognized potential consequences sult, these populations are also geographically of global warming (Meisner 1990, Eaton and isolated from other populations of GCT. Fur- Scheller 1996, Rahel et al. 1996, Jager et al. thermore, some GCT populations have rela- 1999). Moreover, warming water temperatures tively small geographic ranges (e.g., a 2-km appear to dramatically retard protein synthesis reach of stream) and may therefore be highly (a measure of fish health) in the liver and gill susceptible to shifts in abiotic factors such as

1Box 520172, Salt Lake City, UT 84152. 2University of Georgia, Ecology Building, Athens, GA 30602-2202. [email protected] 3Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, CO 80521. 4Trout Unlimited, 1430 Nelson Road, Suite 201-A, Longmont, CO 80501.

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TABLE 1. Translocation success of greenback cutthroat trout sites by location and type of translocation site. Success (as defined in USFWS 1998) has been better in predominantly lake sites (>1 ha) and within Rocky Mountain National Park (RMNP). Data presented here are results of translocation attempts in the South Platte River drainage, Colorado. Potentially Area of stable Stable Unstable translocation populations populations populations Totals Inside RMNP Lakes 9 5 2 16 Streams 2 2 0 4 Outside RMNP Lakes 0 1 1 2 Streams 2 1 6 9

TOTALS 13 9 9

temperature (Kruse et al. 2001). The current lipid reserves to survive winter conditions ranges of most populations are well known, (Harig and Fausch 2002). and range expansion or migration below barri- Here, we examine the potential effects of ers to avoid stressors is not likely as GCT are climate warming on conservation of the GCT displaced by nonnative salmonids (Behnke by assessing the potential effects of stream 1992, Wang and White 1994). warming on GCT populations in 10 transloca- The GCT is 1 of 2 native trout in the tion streams. Given the characteristically cold Arkansas and South Platte River systems and nature of these headwater streams, we hypoth- was once considered extinct (Behnke 1992). The esized that some of these sites may improve as GCT was listed as endangered in 1973 and potential habitat if water warms. Global warm- upgraded to threatened in 1978. Six stable, ing may result in an increase in growth rate historic populations were discovered above and consequently higher overwinter survival natural barriers (e.g., steep cascades) that lim- of YOY GCT. ited upstream migration of nonnative salmonids. The recovery program has consisted primarily METHODS of translocation attempts in streams and lakes Study Sites above such barriers. Locations and results of these translocation projects are described in Water temperatures of 10 GCT transloca- the GCT recovery plan (USFWS 1998) and in tion streams were measured (±0.2°C) a mini- Harig et al. (2000). Success is defined as a mum of once every 96 minutes using either an population that maintains a minimum of 22 Optic StowAway® or TidbiT® thermograph kilograms of GCT per hectare, a minimum of (8 K and 32 K models, Onset Computer Cor- 500 adults (>120 mm total length), and a min- poration, Pocasset, MA) placed in the deepest imum of 2 year classes within a 5-year period pool along the stream segment during a 3-year that are established through natural reproduc- period (data from Harig and Fausch 2002). We tion (USFWS 1998). In the South Platte drain- chose these 10 streams based on similarities of age, 11 of 13 projects that have resulted in stable habitat types, including no substantial lake populations are in Rocky Mountain National habitat. In high-elevation Rocky Mountain Park (RMNP), Colorado, including 9 predomi- streams of this type, hydrology is dominated nantly lake sites (>1 ha lake area; USFWS by snowmelt. The resulting hydrograph is 1998). The percentage of translocation popula- characterized by a peak discharge in the tions in the South Platte drainage considered spring and low base flows during the summer stable was not as high for areas outside of (Hauer et al. 1997). These sites have water RMNP or for sites that were predominantly temperature regimes typical of high-elevation stream sites (Table 1). Failure of predominantly headwater streams (Fig. 1). Most remain at stream sites to support stable populations is 0°C for 5–7 months, and summer temperatures thought to be partially due to the limited num- in some streams do not reach 10°C. Perenni- ber of degree-days available for young-of-the- ally persistent snowpacks and headwater glac- year (YOY) trout to grow and attain sufficient iers as well as rain-on-snow events can have a 2005] WARMING EFFECTS ON GREENBACK CUTTHROAT 373

peratures in 27 high-elevation streams (17 of these were translocation sites of Rio Grande cutthroat trout, O. c. virginalis, a native species with physiological requirements similar to those of GCT, while 10 were GCT streams) in the central Rockies using the data collected by Harig and Fausch (2002) and air temperature data gathered from National Oceanographic and Atmospheric Administration (NOAA) cli- mate stations. Harig and Fausch (2002) col- lected some habitat data directly and some us- Fig. 1. Water temperature in Cony Creek, CO. Water ing data from a geographic information system temperature regime typical of subalpine streams where analysis (see Harig and Fausch 2002 for de- greenback cutthroat trout were translocated. Stream tem- tails). The model is a multiple linear regression peratures remain at or near freezing for 6 months or more that gives mean July water temperature as a and typically have a maximum temperature of about 10°C. These data represent October 1996 to December 1997. function of mean July air temperature, latitude, average pool width, total number of pools, total number of deep pools (>30 cm residual large influence on water temperatures and depth), drainage area, watershed gradient, basin discharge in these systems. As a result of these relief, aspect, main channel length, elevation, factors, these streams are likely to have higher average pool depth, and mean sun arc. interstream temperature variability than streams Harig and Fausch (2002) used mean July in less complex topography. water temperature as representative of the summer growing season for cutthroat trout. Modeling Therefore, we chose a set of a priori candidate Our modeling proceeded in 3 steps. First, models derived from the global model to rep- we used a global model of mean summer resent multiple working hypotheses (Burnham water temperatures in high-elevation streams and Anderson 1998) portraying influences on to determine whether water temperatures could mean July water temperature in high-eleva- accurately be modeled with regional air tem- tion sites. These linear regression models were peratures alone, or whether they were more chosen to determine which of these variables dependent on site-specific physical habitat or combinations of variables most affected variables. This analysis was intended to deter- water temperature in July at each site. mine whether stream temperatures could be We selected best approximating models from more accurately predicted using site-specific the candidate set using likelihood techniques models as opposed to models applied to a and information theoretics (Akaike’s Information region or a set of streams. After establishing Criterion for small samples, AICc; Burnham that need, we developed models based on air and Anderson 1998) to evaluate the influence temperature alone, but specific to each stream. of habitat variables on water temperature. These site-specific models are developed using This analysis is solely intended to elucidate existing water and air temperature data for the importance of some habitat variables and several years at most sites. Site-specific models to determine the relative value of individual reflect the way water temperature responds to stream models. If air temperatures were found air temperature changes at a particular site, to be the most important determinant of stream thus incorporating exposure to the sun, gradi- temperatures, it could be concluded that re- ent, and other site-specific habitat variables gional air temperatures could be applied to that are otherwise impractical to model in numerous streams. If, on the other hand, habi- global climate change projections. We then tat variables (e.g., aspect) were more impor- used these site-specific models to investigate tant, it would indicate that these variables, effects of stream warming on translocation which change from stream to stream within a success, onset of spawning period, and length region or basin, are important to include in a of the growing season for GCT. predictive model of stream temperatures. One GLOBAL STREAM MODEL.—We developed way to do that is to use individual stream models for predicting mean July water tem- models. 374 WESTERN NORTH AMERICAN NATURALIST [Volume 65

INDIVIDUAL STREAM MODELS.—We gathered fixed the upper limit at the maximum observed regional air temperature data for the period water temperature, 2°C above this maximum from NOAA weather stations close to the value, and 4°C above this maximum value. stream site. Given the topographic complexity These models were then objectively tested of the region, proximity (elevation and linear using AIC to determine the strength of evi- distance) of air temperature source to stream dence for each model. This method allows site was considered very important. Thus, we extrapolation based on strengths of evidence generated models for individual streams rather using weighted models. Thus, if an asymptote than applying a regional model. Climate sta- is suggested by the existing data, the modeled tions (n = 10) averaged 183.6 m (s = 168.8, stream maximum will be near that of the ob- median = 133.0) difference in elevation and served stream maximum. If there is no asymp- 24.3 km (s = 30.3, median = 12.4) linear dis- tote suggested by the data, higher maxima tance from streams. These parameters are well models will have more strength of evidence. within the limits of previous studies of this In the latter case, global warming projections type (Stefan and Preud’homme 1993, Webb and will have more of a warming effect on stream Walling 1993, Mohseni et al. 1998, Clark et al. temperature maxima than in the former case. 2001). This method allows extrapolations of global For each stream in the study area, we devel- warming scenarios that do not rise linearly oped nonlinear models predicting weekly (and potentially limitlessly) with air tempera- average stream temperatures from weekly air ture, as in many other studies of this type (e.g., temperatures. Weekly mean temperature values Clark et al. 2001) and take into account are used preferentially (though subjectively) the nonlinear heat storage capacity of water in studies of this type due to practicality and (Mohseni and Stefan 1999). Thus, site-specific for inference to fish physiological health (Eaton models used in this study are actually an aver- et al. 1995, Mohseni et al. 1998, but see Caissie age of 9 different models, weighted based on et al. 2001 for support of the use of daily maxi- their relevance to existing data. The more mum stream temperatures). We used Akaike’s accurate a candidate model is based on its Information Criterion (AIC; Akaike 1973) for AICc score, the more influence it has on the model selection from the following candidate subsequent site-specific model. Other models, models: which may be only marginally less fit, are rep- resented based on their strength of evidence µ α µ (γ*(β – Ta)) –1 Tw = + ( – )*[1 + e ] as well. The resulting site-specific models, (Mohseni et al. 1998) therefore, though based solely on air tempera- ture, can be thought of as representative of the Tw = α*[1 + e(β – (Ta*γ))]–1 (Ratkowsky 1990) other factors (e.g., stream length, stream width, mean pool depth) that are highly spe- α γ βTa cific to the individual stream. Tw = e ( – *( )) (Ratkowsky 1990) EFFECTS OF STREAM WARMING.—We pro- jected water temperature changes for the 10 where Tw = water temperature, Ta = air tem- GCT translocation streams using the weighted perature, α = stream temperature maximum, model averages of individual stream models e = mathematical constant, and β and γ = and based on global warming scenarios of 2° variables determined by the data. and 4°C. These scenarios were based on out- The nonlinear shape of these models results puts of global warming climate models for the from freezing water temperatures at low air central Rocky Mountains (Hauer et al. 1997). temperatures and a vapor pressure deficit We used the model averages to estimate the (causing evaporative cooling) at high air tem- response of several variables to global warm- peratures (Mohseni and Stefan 1999). There- ing. These included number of degree-days fore, the candidate models employed in this (average temperature in Celsius multiplied by analysis have upper asymptotes that limit the the number of days in the growing period, as potential rise of summer water temperatures defined by Harig and Fausch 2002) for growth in global warming scenarios. To account for and survival of GCT YOY cohorts, probabil- this potential limitation in model projections, ity of translocation success (based on a model we employed a method in which we arbitrarily in Harig and Fausch 2002), and expected 1st 2005] WARMING EFFECTS ON GREENBACK CUTTHROAT 375

TABLE 2. AIC analysis of candidate models to determine relevance of certain parameters for inclusion in stream-specific models for Rocky Mountain streams (n = 10). Akaike weights for candidate models indicate strengths of evidence. Higher weights indicate higher strength of evidence for a particular model. Indications are that predictive models used for stream temperatures based solely on air temperature might be misleading, as other parameters appear to carry more relevance in determining stream temperatures at a particular site. RSS = residual sum of squares (error). A priori model Akaike (water temperature as a function of . . .) weight r2 RSS Elevation 0.18 0.22 82.5 Length, depth 0.14 0.37 67.5 Length, latitude 0.11 0.34 70.7 Air temperature 0.10 0.13 93.1 Total # of pools, mean sun arc 0.07 0.28 77.0 Total # pools, width 0.07 0.28 77.1 Latitude 0.07 0.05 100.2 Air temperature, elevation 0.05 0.24 80.6 Air temperature, mean sun arc 0.03 0.17 88.7 Length, gradient, watershed area 0.03 0.35 68.7 Mean sun arc, latitude 0.03 0.14 91.6 Width, depth 0.03 0.13 93.1 Length, elevation, latitude 0.03 0.33 70.7 Width, gradient 0.02 0.09 97.2 Air temperature, drainage relief, # deep pools 0.02 0.30 74.5 Depth, aspect, mean sun arc 0.02 0.30 74.7 Air temperature, elevation, latitude 0.01 0.24 80.6 Aspect, elevation 0.01 0.21 125.3 Aspect, air temperature <0.01 0.28 77.1 Latitude, aspect <0.01 0.07 148.5

spawning period. Criteria exist for some of RESULTS these variables, and we estimated others based on data available. We used the number of The distribution of Akaike weights suggests degree-days in July and August as a surrogate considerable uncertainty in selecting a best for the growing season, selecting 470 degree- approximating model portraying general influ- days in those months based on existing data ences of physical variables on stream tempera- that show most successful translocations (deter- ture (Table 2). The best model included eleva- mined by high population status) above this tion alone (Akaike weight = 0.18). The model range, and unsuccessful (determined by low or including only air temperature had an Akaike no population status) translocations below this weight of 0.10. Relative to this single-variable level (data from Harig et al. 2000). Spawning temperature model, 3 models (all without air was assumed to begin when weekly mean water ° temperature as a parameter) had stronger sup- temperatures first reached 5 C after spring port in the data. All other a priori models with runoff (USFWS 1998). Probability of translo- air temperature as a parameter carried small cation success was determined using a logistic (≤0.05) Akaike weights (Table 2). regression model developed by Harig and Global warming scenarios of 2°C and 4°C Fausch (2002). The model gives the probability of either a high population, low population, or produced different warming in mean July water temperatures between streams (0.70°C no population based on water temperature, ± ° ° ± mean pool width, and total number of deep 0.28, median = 0.89 C, and 1.29 C 0.36, ° pools (>30 cm). These variables were deter- median = 1.50 C, in the 2 scenarios, respec- mined to be the best predictors of translocation tively, n = 10; Fig. 2). The range of mean July success (Harig and Fausch 2002). We calculated water temperature stream warming was the probability of success (high population sta- 0.42°C–1.09°C and 0.85°C–1.77°C, respec- tus) of the streams under the global warming tively, in the 2 scenarios. Table 3 summarizes scenarios, using the assumption that mean pool the stream warming produced by the 2 scenar- width and total number of deep pools would ios, model variances, and 95% confidence remain constant over time. intervals for the projections of 10 streams. 376 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 2. Projections of mean July water temperatures for 10 translocation streams under global warming scenarios. Global warming scenarios of +2°C and +4°C yield heterogeneous warming trends between streams due to the applica- tion of individual stream models. NFBT = North Fork of the Big Thompson River.

The average number of degree-days in July percentage increase was 12.6% for the +2°C and August (the parameter we used as a surro- scenario and 22.7% for the +4°C scenario. gate for growing season) increased by 58.2 (s = 17.1) for the 2°C scenario and 99.2 (s = DISCUSSION 28.2) for the 4°C scenario (Fig. 3). Several streams exceeded the criterion of 470 degree- Results of the analysis on the global model days for suitable growth and survivorship of indicate the value of individual stream model- YOY GCT in the 2°C scenario, and others ing because of the importance of variables that reached it in the 4°C scenario (Fig. 3). Only 1 differ significantly from site to site. An exam- stream (Hourglass Creek) remained below 470 ple of the need for a stream-specific approach degree-days in both scenarios. can be seen in Hourglass Creek, which is sim- Growing seasons were extended for GCT ilar to several of the other streams in terms of in these streams in both global warming sce- mean air temperature, location, elevation, gra- narios. Spawning activity was predicted to dient, aspect, and shading (mean sun arc). begin from 2.0 (s = 1.6) to 3.3 (s = 1.7) weeks Hourglass Creek has historically been very earlier in the 2°C and 4°C scenarios, respec- cold compared with neighboring streams. It is tively. Figure 4 gives an example of the scenar- likely that Hourglass Creek is heavily influ- ios and onset of spawning times for Cony enced by meltwater from persistent snowpack Creek (1 of 10 GCT translocation streams). (stream length = 2.0 km). Without a specific Warmer water temperatures in global warm- model for Hourglass Creek, this critical differ- ing scenarios resulted in higher probabilities ence would likely go undetected, and, conse- of translocation success (Fig. 5). Five streams quently, global warming projections would be would currently have <50% chance of translo- exaggerated in this stream (unless interannu- cation success, and 7 of the 10 would have ally persistent snowpack were to disappear). <75% chance. The average increase for these Therefore, a predictive model of stream tem- streams was 11.2% for the +2°C warming sce- peratures as a result of global warming for nario, and 21.8% for the +4°C scenario, for Hourglass Creek should be more conservative the 5 streams with <50% probability of trans- than models for some other nearby streams location success. In the 7 streams with <75% that may not be as influenced by snowpack. In current chance of translocation success, the this analysis global warming projections for 2005] WARMING EFFECTS ON GREENBACK CUTTHROAT 377

TABLE 3. Mean July water temperatures (Tw), as estimated by stream-specific models, summarized by stream. Also given are recorded mean July air temperatures (Ta), model variances (S2), and 95% confidence intervals for stream-spe- cific model averages (n = number of weekly water temperature averages used to generate model). ° ° ______+2 C scenario______+4 C scenario ______95% CI______95% CI Stream n Ta Tw S 2 Low High Ta Tw S2 Low High Cony 154 14.0 9.4 0.4 8.2 10.7 16.0 9.8 0.6 8.3 11.3 Cottonwood 164 20.7 7.9 0.0 7.5 8.2 22.7 8.6 0.1 7.9 9.2 Fern 155 14.5 9.0 0.7 7.3 10.7 16.5 9.5 1.0 7.5 11.5 Greenhorn 113 14.7 7.9 0.2 7.0 8.9 16.7 8.4 0.4 7.2 9.7 Hourglass 125 17.0 4.8 0.0 4.4 5.1 19.0 4.9 0.0 4.4 5.3 May 55 17.6 8.9 0.3 7.9 9.9 19.6 9.2 0.5 7.8 10.5 NFBT 56 15.1 9.4 1.1 7.3 11.5 17.1 10.3 3.0 6.8 13.8 Roaring 109 15.1 10.3 0.5 8.9 11.8 17.1 10.9 1.1 8.8 13.0 Sheep 49 18.0 8.4 0.2 7.6 9.2 20.0 9.7 0.3 7.6 9.7 West 115 15.1 7.9 0.1 7.5 8.4 17.1 8.3 0.1 7.5 9.0

Hourglass Creek remained on the lower range tion models require specific attention to region- of the projections for all streams, indicating al and site specific factors. the efficacy of the approach. Global warming will likely have mixed Individual stream models may help elimi- effects on GCT. The species has been extir- nate many complexities associated with pro- pated from much of its previous range due to jections of global warming. Regional climatic overharvest, habitat degradation, and the pres- changes are expected to be highly spatially ence of nonnative salmonids (Behnke 1992). heterogeneous (Walther et al. 2002). There- As a result, most GCT populations currently fore, accurate projections of climate change in exist in headwater streams or high-elevation topographically complex regions (such as the lakes, where water temperatures are likely current habitat range of the GCT) are more colder than optimal for GCT growth and difficult than generalized global scenarios reproduction. Harig and Fausch (2002) found (Hauer et al. 1997). Hauer et al. (1997) con- cold water temperatures to be among the fac- clude, “It is unclear whether projected climate tors most closely related to limitation of the change would result in a generalized warming success of translocation sites, likely due to trend throughout the Rocky Mountain region, winterkill of juveniles with insufficient lipid or whether change would be strongly region- reserves (e.g., Hutchings et al. 1999). After alized.” Extrapolating warming scenarios from spawning in the spring, more than a month of atmospheric models to aquatic systems adds a incubation, and emergence, juveniles have further layer of complexity. Limits on extrapo- only a limited time in which to feed, grow, and lation are due in part to the nonlinear heat produce lipid reserves before water tempera- storage capacity of water (Mohseni and Stefan tures drop to near 0°C for the winter. If insuf- 1999) and the complex surface and subsurface ficient reserves are stored to meet the meta- flow paths of water sources prior to entering bolic needs of the juveniles during winter, stream channels. The water temperature of a they may not survive and the population may stream may be influenced by groundwater not persist over time. Therefore, a warming inflows, riparian or topographic shading (slope trend may improve habitat conditions in many and aspect), weather forcing (air temperature, GCT restoration sites, as spring activities are relative humidity, solar radiation, and wind), generally expected to begin earlier (Walther et snowmelt, and anthropogenic effects (Larson al. 2002). and Larson 2001). Thus, single models applied Given that GCT are currently restricted to across regions may have little merit for any cold, unproductive systems, global warming particular site in that region. As GCT are rele- may potentially aid these populations and gated to high-elevation streams and lakes, pro- make more headwater habitat suitable for jections of climatic change from global circula- GCT reintroduction. Before the introduction 378 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 3. Growing seasons of cutthroat trout translocation sites. The number of degree-days in July and August (dd) is used as a surrogate parameter for the growing season. It is estimated from results of translocation attempts that 472 dd (indicated by thick line) are required for adequate growth of cutthroat trout young-of-the-year to persist through the winter.

Fig. 4. Effects of global warming on the projected earliest greenback cutthroat trout spawning events. GCT are assumed to begin spawning when water temperatures first reach 5°C (USFWS 1998). These models represent global warming scenarios based on actual data from January to July 1999 in Cony Creek, CO. Arrows indicate when spawning would be predicted to first occur based on the models. of nonnative trout (ca. 1880s), the historic range for GCT restoration sites in global warming of the GCT extended north into Wyoming and projections. As water temperatures increase, east into the Great Plains (Harig 2000). Thus, the number of degree-days in July and August the range of the GCT would likely extend far increases (Fig. 3), spawning generally begins downstream from most headwater segments it earlier (Fig. 4), and shorter periods are required currently occupies, if not for the presence of for incubation (Hubert et al. 1994). As a result, nonnative salmonids that outcompete GCT. the duration of the growing season increases Several measures of habitat suitability improved and chances of overwinter survival may 2005] WARMING EFFECTS ON GREENBACK CUTTHROAT 379

Fig. 5. Projected probability of translocation success of 10 greenback cutthroat trout populations. Differences exist in projected probability of translocation success under the current thermal regime of 10 translocation sites compared with the regime expected from global warming scenarios.

increase as well (Hauer et al. 1997). These fac- ulations and scour potential spawning habitat tors make long-term viability of populations in (Seegrist and Gard 1972, Pearsons et al. 1992, warmed streams more likely (all else being Latterell et al. 1998, Jager et al. 1999, Clark et equal), assuming nonnative species can con- al. 2001). A significant limitation of the model- tinue to be excluded from these habitats. ing method presented in this paper is that it Whirling disease, however, may be expected does not account for how changes might affect to increase in virulence under these warming groundwater or persistent snowpacks and hence scenarios (Cooney 2002). flow regimes. Our analyses are intended for Concerns over the effects of global climate use only with air temperature changes, all else change on biota are not limited to tempera- being equal. ture. A comprehensive species-specific review Increased air temperature and seasonal of the potential effects of climate change changes in precipitation may lead to increased should include several other aspects. For the intermittency of Rocky Mountain streams in GCT, important aspects of climate change are the summer (Hauer et al. 1997). Increased likely to be temperature, flow regimes, and intermittency, in turn, may lead to water tem- climatic extremes. Although this paper deals perature increases and deoxygenation in re- solely with temperature, flow regimes may be maining pools (Gu et al. 1999), which may be important for the GCT, as many of their habi- detrimental to headwater cutthroat trout pop- tats have very low flows during extended parts ulations. Populations of cutthroat trout iso- of the year. Possible hydrologic responses to lated in headwater reaches are likely to be climate change are extremely variable (Car- highly susceptible to stochastic perturbations penter et al. 1992, Fagre et al. 1997), though (Kruse et al. 2001). This effect may be exacer- earlier spring runoff and lower summer base bated in the case of the GCT, as recolonization flows seem most probable in headwater sys- from downstream is not effectively possible tems (Hauer et al. 1997). Rain-on-snow events for this species. are expected to increase in frequency and in- The definition of stability given in the GCT tensity as global warming occurs (Hauer et al. recovery plan does not include an account of 1997). These events can result in flash floods how these sites may change over time (Young that may extirpate or dramatically reduce pop- and Harig 2001). Climate change can play a 380 WESTERN NORTH AMERICAN NATURALIST [Volume 65 major role in the structural and functional Bruce Rosenlund (U.S. Fish and Wildlife Ser- dynamics of an ecosystem (Meyer et al. 1999), vice), Tom Nesler (Colorado Division of Wild- leading to extinctions, range changes, and life), Jill Baron, LeRoy Poff, Brett Johnson, species invasions (Lodge 1993) for resident David Anderson, Bob Behnke, Andy Holland, stream salmonids (Eaton and Scheller 1996, Nolan Doesken, Ken Burnham, Tom Hobbs Keleher and Rahel 1996, Rahel et al. 1996). (Colorado State University), Mike Hartman, Other abiotic factors associated with global and Mark Losleben (Niwot Ridge C1 weather change, such as hydrologic regimes, acid pre- station) for suggestions, advice, information, cipitation, and seasonality and intensity of pre- and revisions of this manuscript. cipitation events, droughts, and floods, may similarly influence biotic systems (Grimm 1993). LITERATURE CITED Climate change may therefore influence the continued success of GCT populations. AKAIKE, H. 1973. Information theory as an extension of Managers of the GCT have established pop- the maximum likelihood principle. Pages 267–281 in B.N. Petrov and F. Csaki, editors, Second Internation- ulations in diverse habitats that may help al Symposium on Information Theory, Akademiai reduce future uncertainties regarding external Kiado, Budapest. threats such as climate change. Populations BEETON, A.M. 2002. Large freshwater lakes: present state, have been established in many lakes, which trends, and future. Environmental Conservation 29: may provide refugia from persistent low flows 21–38. BEHNKE, R.J. 1992. Native trout of the western United associated with drought, stochastic events such States. American Fisheries Society Monograph 6, as flash floods, and thermal extremes (Beeton Bethesda, MD. 275 pp. 2002). Lakes also provide cover from avian or BOSS, S.M., AND J.S. RICHARDSON. 2002. The effects of mammalian predators (depth) regardless of food and cover on the growth, survival and move- ment of cutthroat trout in coastal streams. Canadian what effects climate change has on riparian Journal of Fisheries and Aquatic Science 59: vegetation, a significant factor in cutthroat trout 1044–1053. survival (Boss and Richardson 2002). Alterna- BURNHAM, K.P., AND D.R. ANDERSON. 1998. Model selec- tively, populations established in fast-moving, tion and inference: a practical theoretic information high-gradient streams may have a refuge from approach. Springer-Verlag, Inc., New York. 353 pp. CAISSIE, D., N. EL-JABI, AND M.G. SATISH. 2001. Model- whirling disease, a malfeasance common in ing of maximum daily water temperatures in a small more stagnant waters. Populations of GCT have stream using air temperatures. Journal of Hydrology been established in Rocky Mountain National 251:119–139. Park, as well as on U.S. Forest Service and pri- CARPENTER, S.R., S.G. FISHER, N.B. GRIMM, AND J.F. KITCHELL. 1992. Global change and freshwater vate land. Most of these sites are open to ecosystems. Annual Review of Ecology and System- catch-and-release angling only, while several atics 23:119–139. are no-fishing areas. Thus, GCT have a poten- CLARK, M.E., K.A. ROSE, D.A. LEVINE, AND W. W. H AR- tial refuge from fishing-related stresses, as well GROVE. 2001. Predicting climate change effects on as intentional restocking of nonnative trout (see Appalachian trout: combining GIS and individual- based modeling. Ecological Applications 11:161–178. Harig et al. 2000 for examples). This variety of COONEY, S.J. 2002. Global warming: implications for the habitat conditions may help GCT adapt to per- recovery of the greenback cutthroat trout. Master’s sistent stressors such as global climate change. thesis, Colorado State University, Fort Collins. As managers continue to establish new popu- EATON, J.G., J.H. MCCORMICK, B.E. GOODNO, D.G. lations, diversity of habitat selection should O’BRIEN, H.G. STEFAN, M. HONDZO, AND R.M. SCHELLER. 1995. A field information-based system remain a priority for these reasons. for estimating fish temperature tolerances. Fisheries 20:10–18. ACKNOWLEDGMENTS EATON, J.G., AND R.M. SCHELLER. 1996. Effects of climate warming on fish thermal habitat in streams of the This project was funded in part by a Sci- United States. Limnology and Oceanography 41: ence To Achieve Results (STAR) grant from 1109–1115. FAGRE, D.B., P.L. COMANOR, J.D. WHITE, F.R. HAUER, AND the U.S. Environmental Protection Agency S.W. RUNNING. 1997. Watershed responses to cli- (Agreement R-827449-01-0) and was addition- mate change at Glacier National Park. Journal of the ally funded by the Colorado Water Resources American Water Resources Association 33:755–765. Research Institute and the College of Natural GRIMM, N.B. 1993. Implications of climate change for stream communities. Pages 293–314 in P. M. Kareiva, Resources at Colorado State University. We J.G. Kingsolver, and R.B. Huey, editors, Biotic inter- extend special thanks to Jessica Higgins for actions and global change. Sinauer Associates, Sun- volunteering on the project. We also thank derland, MA. 2005] WARMING EFFECTS ON GREENBACK CUTTHROAT 381

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MONITORING TEMPORAL CHANGE IN RIPARIAN VEGETATION OF GREAT BASIN NATIONAL PARK

Erik A. Beever1,4, David A. Pyke1, Jeanne C. Chambers2, Fred Landau3, and Stanley D. Smith3

ABSTRACT.—Disturbance in riparian areas of semiarid ecosystems involves complex interactions of pulsed hydrologic flows, herbivory, fire, climatic effects, and anthropogenic influences. We resampled riparian vegetation within ten 10-m × 100-m plots that were initially sampled in 1992 in 4 watersheds of the Snake Range, east central Nevada. Our finding of significantly lower coverage of grasses, forbs, and shrubs within plots in 2001 compared with 1992 was not consistent with the management decision to remove livestock grazing from the watersheds in 1999. Change over time in cover of life-forms or bare ground was not predicted by scat counts within plots in 2001. Cover results were also not well explained by variability between the 2 sampling periods in either density of native herbivores or annual precipitation. In contrast, Engelmann spruce (Picea engelmannii) exhibited reduced abundance at all but the highest-elevation plot in which it occurred in 1992, and the magnitude of change in abundance was strongly predicted by plot elevation. Abundance of white fir (Abies concolor) individuals increased while aspen (Populus tremuloides) individuals decreased at 4 of 5 sites where they were sympatric, and changes in abundance in the 2 species were negatively correlated across those sites. Utility of monitoring data to detect change over time and contribute to adaptive management will vary with sample size, observer bias, use of repeatable or published methods, and precision of measurements, among other factors.

Key words: riparian ecosystems, monitoring, woody vegetation, Great Basin National Park, livestock removal, distur- bance.

Natural disturbance in riparian areas is inti- maintenance of diverse and productive vege- mately tied to the timing, magnitude, frequency, tation that buffers sediment pulses, moderates and duration of stream flows, as well as to the stream temperatures through shading, and geomorphic characteristics of the system (Yount provides habitat for a diversity of wildlife; and and Niemi 1990, Gregory et al. 1991). Anthro- many others (Postel and Carpenter 1997). pogenic disturbances can alter stream flow and Although riparian areas comprise one of geomorphic processes and affect the distribu- the most drastically altered community types tion and composition of riparian plants by over the last 150 years on federal lands in the inducing changes in floodplain characteristics Intermountain West of North America, they (Harris 1986, Auble et al. 1994). Changes in remain the most biologically diverse (Naiman plant communities, in turn, may affect stability et al. 1993, Hann et al. 1997). Their position at of stream channels and flood response. These the interface of aquatic and terrestrial habitats changes also may influence vulnerability to in- brings together diverse geomorphic features, a vasion of exotic plants and the value of riparian consistent supply of water and nutrients, and areas for both wildlife and recreation. In the contrasting landscape elements (Naiman et al. face of natural and anthropogenic disturbances, 1993). As a result of this concentration of re- functioning watersheds are critical for ecologi- sources, as well as increased humidity, higher cal integrity of semiarid regions because they transpiration rate, greater shade, and increased provide numerous ecosystem services, includ- air movement relative to surrounding upland ing (1) a high-quality, dependable supply of habitats, up to 75% of species within semiarid water; (2) moderation of the effects of flooding, mountain ranges may use riparian areas dispro- drought, and climate change; (3) recharge of portionately (Bull 1978, Thomas 1979). Ripar- stream systems and groundwater aquifers; (4) ian areas also act as corridors for dispersal or

1USGS-BRD Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, OR 97331. 2USDA Forest Service, Intermountain Research Station, Reno, NV. 3University of Nevada, Las Vegas. 4Corresponding author: NPS Great Lakes Network, 2800 Lake Shore Dr. E., Suite D, Ashland WI 54806.

382 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 383 migration for many taxa, including carnivores, grazing [1991] and another 2 years after graz- ungulates, birds, bats, and plants (Bull 1978, ing was removed in 1999) and a lack of experi- Gregory et al. 1991). mental controls weaken the ability of managers Free-roaming cattle often concentrate activ- to interpret the impacts of management actions ity in riparian areas because these areas pos- on resources. In the context of analysis and sess abundant shade, water, and nutrient-rich interpretation of our results, we provide moni- forage. Herbivory by native grazers likely toring recommendations for land managers played a less significant role in Great Basin who desire to use monitoring in adaptive man- landscapes during the Pleistocene and early to agement. mid-Holocene than does contemporary live- stock grazing (Mack and Thompson 1982, Gray- METHODS son 1993). Introduction of domestic sheep, cattle, and horses by Anglo-Americans led to In 1992, Smith et al. (1994), as part of a higher grazing intensities, especially in the late larger study, established 10 permanent plots in 1800s and early 1900s (Mack and Thompson 4 watersheds of the Snake Range to address 1982). In many areas grazing by domestic live- hypotheses about change over time in struc- stock can significantly alter characteristics of ture and composition of riparian communities, woody riparian vegetation such as height, den- and about how this change varied among sity, connectedness, habitat complexity, and drainages and sites. Through repeated sam- species composition (Rickard and Cushing pling of these plots over time, researchers 1982, Schulz and Leninger 1990, Green and could “potentially document long-term suc- Kauffman 1995, Jansen and Robertson 2001). cessional processes in the Park” (Smith et al. Nonetheless, many areas exist in the Great 1994:63). The plots were explicitly designed Basin where removal of livestock may not im- for monitoring over time and had been perma- prove ecological integrity because transitions nently marked. to altered ecosystem states (e.g., encroaching We (EAB, DAP, and assistants) performed junipers, areas of widespread invasion by exotic fieldwork in GBNP from 21 July through 20 species, exceeded geomorphic thresholds) have August 2001. Unless stated otherwise, methods prevented the possibility of return to previous described herein pertain to 2001 sampling. In conditions (Archer and Smeins 1991, Laycock addition to garnering all relevant information 1994, Miller and Wigand 1994). from the 1994 report, we worked with collabo- After numerous studies of riparian restora- rators on the previous research before, during, tion and decades of livestock management in and after our 2001 sampling to maximize com- semiarid riparian systems, there remains un- parability between the 2 sampling dates. In certainty about the multiple effects of livestock 2001 our primary goals were to (1) provide a grazing with varying grazing seasons, duration, 2nd set of measurements of the plots, 9 years periodicity (amount of rest), and stocking rate, after the 1st sampling in 1992; (2) implement as well as the short- and long-term consequences standard methods for our sampling and docu- of removing such grazing. This research repre- ment them in sufficient detail to facilitate pre- sents an effort to evaluate short-term variabil- cise comparisons with subsequent sampling; ity in riparian vegetation in relation to removal (3) expand the components sampled within the of cattle grazing from Great Basin National plots to account for recent increased attention Park (GBNP). to taxa such as bryophytes, lichens, and rare Our intent was to compare composition and plants; and (4) determine, to the degree possi- structure of vegetation in 10 permanent plots ble, to what extent observed differences were established in 1992 between 2 sampling dates, consistent with anticipated vegetational changes 1992 and 2001, to see if change had occurred. following removal of cattle grazing from the We also tested whether successional relation- park in 1999. ships observed during 1992 sampling remained Smith et al. (1994) presented 3 types of data evident in 2001. An underlying goal was to from the 10 permanent plots: (1) percent cover assess the degree to which removal of domestic of forbs, grasses (thus excluding Carex and cattle grazing from the park in 1999 affected Juncus), shrubs, and bare ground, as well as woody riparian vegetation. However, constraints species richness of shrubs; (2) frequency dis- of having only 2 sampling points (1 during tributions (histograms) of DBH size classes for 384 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 1. Mean stream gradient, drainage area, and hydrogeomorphology of 4 target watersheds. Gradient and drainage areas were obtained via GIS analyses in ArcInfo. Watershed Mean stream Drainage area Range of elevations Hydrogeomorphic (creek name) gradient (%) (ha) of mainstem (m) units presenta Strawberry 8.7 1921 2080–2774 ACG, AV, AFV, AFD Lehman 10.7 2174 2000–3073 IMV, LOV Baker 11.0 3006 2056–3239 IMV, ABC, LOV, AFD Snake 8.4 5827 1893–3200 IMV, AFV, ACG, TBV aFrom Frissell and Liss (1993). Listed in order of occurrence on mainstem from highest to lowest elevations within GBNP. Some units appear in ≥2 disjunct seg- ments within a drainage. ABC = alluviated canyon, boulder-bedded; ACG = alluviated canyon, gravel- and cobble-bedded; AFD = alluvial fan delta; AFV = alluvial-fan-influenced valley; AV = alluvial valley; IMV = incised moraine-filled valley; LOV = leveed outwash valley; TBV = terrace-bound valley. the most abundant tree species in each plot; tem and resembled the downstream reaches of and (3) relative cover of bare ground, forbs, Snake and Baker Creeks (Table 1). Active grasses, Carex and Juncus, and shrubs (both channel width in midsummer averaged 1–3 m, combined and for individual shrub species). but the channel was significantly braided in These 3 analyses, along with 4 relationships many locations (E. Beever personal observa- the authors observed in their analyses, formed tion). The highest-elevation plots exhibited the foundation for our comparison across sam- traits characteristic of Rosgen’s (1985) “A” clas- pling periods. These 4 relationships were be- sification for stream channels, and lower plots lieved to relate to long-term successional most closely resembled either “A” or “B” processes and included (1) high values of bare streams. Mean precipitation on the east side of ground correlated with reduced vegetative the Snake Range varies from 65.5 cm ⋅ yr–1 at diversity, shrub cover, and tree recruitment; 3182 m elevation, to 33.3 cm ⋅ yr–1 at 2081 m (2) age structuring of Populus individuals re- elevation, to 19.3 cm ⋅ yr–1 at the valley floor lated to site conditions; (3) abbreviated distri- (Garrison, UT; 1518 m elevation; Western Re- bution of P. engelmannii at low elevations, but gional Climate Center online data, Reno, NV). natural succession toward this species at high Although watersheds varied in plant species elevations; (4) apparent competition between composition, upland vegetation bordering ripar- white fir (Abies concolor) and aspen (Populus ian corridors typically transitioned from salt- tremuloides) (Smith et al. 1994). Given the scrub to big sagebrush communities below the removal of livestock, we predicted that bare park boundary, to pinyon juniper–big sage- ground would decrease and tree recruitment, brush (Pinus monophylla–Artemisia tridentata), plant species richness, and cover of shrubs and ponderosa pine (Pinus ponderosa), white-fir– especially grasses would increase across sites. douglas-fir (A. concolor–Pseudotsuga menziesii), mountain mahogany (Cercocarpus spp.), aspen STUDY AREA (P. tremuloides), and Engelmann spruce (P. engelmannii) communities as elevation in- Research was conducted adjacent to streams creased. Soils in the park generally and the in 4 watersheds on the eastern side of the study watersheds in particular derive primarily southern Snake Range in east central Nevada from granitic or limestone parent rock mater- in GBNP. Plots were established along Straw- ial (Blake 1992). Although the Brokit Series berry, Lehman, Baker, and Snake Creeks, be- encompassed only 0.6% of the park area, it has cause roads adjacent to these streams should been assigned to all riparian areas in the park, facilitate resampling by U.S. National Park despite notable spatial heterogeneity in ripar- Service staff over time. The plots ranged in ian vegetation and likely in associated soils elevation from 1948 to 3060 m, but elevations (Smith et al. 1994, Beever personal observa- within these drainages vary from 3968 m at tion). Cattle grazed the area of the park from Wheeler Peak down to the Snake Valley floor the 1860s (Eddleman and Jaindl 1994) until at 1510 m. Stream gradients of all 4 creeks the National Park Service terminated permits were similar. The hydrogeomorphology for the in 1999 due to conflicts with other park uses. upper reaches of 3 of the 4 creeks was that of When using the benchmark of 45% utilization an incised, moraine-filled valley, whereas Straw- of grasses and forbs at the allotment scale, berry Creek was classified as an alluvial sys- Eddleman and Jaindl (1994:41) found that 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 385

Fig. 1. Inset: Location of the Snake Range within the Basin and Range ecoregion (central and northern combined; U.S. EPA 2000) and relative to the western United States. Main map: Location of the 10 permanent plots in 4 target watersheds in the southern half of the Snake Range, east central Nevada. stocking levels were “near the maximum lev- plains of the 4 creeks across a broad range of els in all allotments,” but that use was highest elevations and community types in 1992 (Fig. on slope gradients <15% and within 1.6 km of 1, Table 2). To relocate 1992 plots, we con- water. Consequently, they found that “riparian ducted intensive on-site searches for the plots’ areas [were] overgrazed and many [were] in copper endpoint stakes. Nonetheless, we ex- poor condition (1994:43)” due to historic degra- perienced great difficulty in precisely locating dation as well as current poor distribution and the endpoints of the 1992 plots. Thus, our movement of animals. However, overuse of interpretation of changes in riparian ecosys- riparian areas still occurred even when herd- tem vegetation was partially confounded by ing and salting were used (Eddleman and this and other sources of error (see Beever et Jaindl 1994). Other than domestic cattle, her- al. 2002). We replaced all missing stakes (on n bivores in our target watersheds include prong- = 5 plots) and recorded locations of all stakes horn antelope, mule deer, elk, a few bighorn with a differentially corrected GPS unit, pro- sheep, an occasional mountain goat, domestic viding horizontal precision of ~1.1 m. sheep (at high elevations only), and a diverse Once the 100-m main transect axis was estab- guild of lagomorphs, insects, and granivorous lished, 5-m line-intercept transects were placed rodents. at right angles (angle was sighted with a com- pass) to the main axis, on alternating sides of FIELDWORK the main axis. The first 5-m transect began on the left side of the main axis (looking from 0 Ten 10-m × 100-m plots, each bisected by a toward 100 m), at the 5-m position (Fig. 1). One 100-m transect, were established in the flood- exception to the abovementioned procedure 386 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 2. Summary of abiotic and biotic characteristics for each of 10 permanent plots. Distance of main Elevation axis from active Hydrogeo- Cattle Plot name (m) Community typea channel (m)b morphic unitc defecations Strawberry 1 2213 Betula occidentalis, Rosa 0–8 AV 7 woodsii Strawberry 2 2463 Populus tremuloides, Abies 3–12 AV concolor Strawberry 3 2231 P. tremuloides, A. concolor, 0–9 AV 18 R. woodsii, Salix spp. Snake 4 2475 P. tremuloides, 3–11 AFV 12 Symphoricarpos oreophilus Snake 5 1961 Populus angustifolia, B. 6–19 TBV 22 occidentalis, R. woodsii Baker 6 2404 P. tremuloides, A. concolor, 4–14 AFV 6 R. woodsii, Salix spp. Baker 7 3060 Picea engelmanii 0–15 IMV 49 Lehman 8 2914 P. tremuloides, P. englemanii, 3–17 IMV 17 Pinus flexilis Snake 9 1948 P. angustifolia, B. occidentalis, 4–12 TBV 36 R. woodsii Lehman 10 2691 P. tremuloides, P. englemanii, 6–15 IMV 0 Pseudotsuga menziesii, A. concolor Mean values 2436 18.6 aPer Smith et al. (1994) bValues vary along the 100-m transect due to contrast between linear transect and naturally sinuous stream. cFrom Frissell and Liss (1993). See Table 1 for explanations of abbreviations. was Snake 9, where all 20 transects occurred interceptions were frequently not continuous. on the streamside of the main axis, as in 1992. A gap of >5 cm was required to interrupt a Because the primary goal was measuring veg- continuous interception of a forb, shrub, or etative cover, we did not correct the transect sedge/rush, but the minimum interception re- length (5 m) for slope gradient. quired to record a species’ presence was 1 mm. Along each 5-m transect we recorded basal For overstory sampling, a gap of >20 cm had coverage (at the soil surface), understory to be present within the canopy of a given canopy coverage, and overstory (tree) canopy species to interrupt a continuous interception, coverage. Basal and understory interceptions and a minimum interception of 5 cm was re- in 2001 were recorded to the nearest 1 mm, quired to record a species on a transect. but overstory interceptions could be estimated Within each plot we measured the DBH of only to the nearest 1 cm. Smith et al. (1994) trees at 1.5 m aboveground, rather than mea- generally identified nonwoody plants to life- suring at 1 m aboveground as did Smith et al. form (i.e., grass, forb, and Carex-Juncus). In (1994). Thus, 2001 measurements were 0% to 2001 we identified all plants to genus, and to ~8% larger (depending on tree species and species where possible, using Hickman (1993). DBH, as well as slope gradient) than 1992 For basal measurements we moved items measurements, independent of tree growth. obstructing the view of plant bases to obtain In 1992 Smith et al. (1994) measured DBH to accurate measurements. For understory line the nearest 1 cm by placing a ruler tangential intercepts, grass cover was measured by to the tree trunk, whereas in 2001 we mea- counting individual blades of grass (of each sured to the nearest 0.01 cm with a DBH tape. species) crossing the tape, then multiplying These likely influenced comparisons only mildly, the total number by an average width (0.1–0.4 however, due to the broad width of our DBH cm) of each blade, determined by measuring categories. Greater than half of the tree’s base widths of numerous single blades of each had to be within the plot for the tree to be tal- species. We chose this approach because grass lied or measured. We were unable to identify 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 387 _ Cover by life-form (%) Understory summary data ree data Bare ground data T ree Total Total Bare ground, Litter T species seedlings DBH Bare ground, original Exposed soil cover ______15.3 8.0 4.1 2.9 19.9 10.5 30 42.6 24.31 orb cover, Forb Grass cover, Grass Shrub cover, Shrub Understory Understory Understory F ______. Tree data and bare-ground data for each of 10 permanent plots. . Tree . Cover by life-form and understory summary data, from sampling during 1992 2001, for each of 10 permanent plots. A B 2 2 EAN VALUES ABLE ABLE T T M Strawberry 1Strawberry 2Strawberry 3Snake 4Snake 5Baker 6 7Baker 7 5Lehman 8 4Snake 9Lehman 10Mean values 6 1 4 444 1 2 586 1127 4 5 3.9 44 101 1154 667 811 2049 15 44 327.6 225 23 352 190 1267 48 142 145 683.3 55 36 413 310 55 60 58 71.0 75.3 75.5 76 57.3 75 78 32 70.9 62.0 0.00 83.9 1.52 76.1 4.90 89.0 79.5 88.9 64.5 87.51 1.45 2.17 0.00 94.14 82.92 1.86 0.27 1.42 1.47 5.44 93.22 95.65 96.67 88.72 81.52 76.62 89.29 89.70 Plot name richness + saplings values 1992 definition surface percentage Strawberry 1Strawberry 2Strawberry 3Snake 4 10Snake 5 33Baker 6 17Baker 7Lehman 8 13Snake 9 8.7 11Lehman 10 17.4 34 8.8 8 8 11 13 8 4.8 2 12.3 8 6.5 10.5 3.1 6 6.1 8.6 1 2.1 1.4 3 8.9 1 0.5 28 0.5 3.1 6 11 1.2 32 2.6 0.9 0.7 0.1 24.5 9.7 30 1.1 5.9 12 6.7 0.5 1 18.3 8 52 24.5 36 39 1.7 0.4 37 0.6 4.5 29 32.3 15 51 46 33 29 57 36 26 45.5 19 42 29.08 24.79 49 24.55 22.5 25 29.05 21.75 66 37.98 16.13 11.19 21.89 13.07 35.41 Plot name1992 cover 1992 cover 1992 cover species richnesscover, 1992 (%)cover (%) (%)cover 1992 richnesscover,name1992 species cover 1992 1992 cover cover Plot 388 WESTERN NORTH AMERICAN NATURALIST [Volume 65 to species Juniperus and Salix individuals, ex- diameter of Betula occidentalis canopies. Thus, cept for S. exigua, the only narrow-leaved wil- no DBH comparisons between sampling peri- low in GBNP. In 2001 sampling only, for each ods were made for this species. Smith et al. Betula occidentalis clump, we tallied the num- (1994) measured diameters only to the nearest ber of stems at 1.5 m height, and measured cm; thus, we placed DBH values that fell DBH of the 3 largest stems and 4 randomly between the bounds of adjacent classes in the selected stems, to create frequency histograms lower category (e.g., the 11–20 cm category of distributions of their diameters within a held values from 11.00 cm to 20.99 cm). clump. While measuring DBH values, in 2001 For statistical comparisons between 1992 only, we also tallied the number of cattle defe- and 2001 data, we applied paired t tests, with cations occurring within each plot, counting as each plot paired across years. We tested pur- single defecations instances when animals de- ported relationships (e.g., with elevation, bare fecated while moving. We assumed that these ground) using simple (linear) and multiple lin- tallies reflected intensity of recent livestock ear regressions. For these regressions we ana- grazing. In addition, we took 4 digital photo- lyzed data using the variables (e.g., bare ground, graphs of each plot along the main transect shrub identities) defined in Smith et al. (1994) axis, 1 from each endpoint toward the 50-m for greater comparability and the methods of mark, and 1 from the 50-m mark toward each 2001. To assess effect of livestock grazing on end of the main line. recovery of riparian ecosystem components, we used regressions to test whether number ANALYSIS of cattle defecations detected in our standard- ized surveys significantly predicted the mag- For basal coverage in 2001 sampling, “lit- nitude of change in the [2001/1992] ratio of ter” represented total cover minus cover of cover of each life-form. rock, moss, water, plant bases, trunks, roots, lichens on rock, dead trees, bryophytes, and RESULTS bare ground (defined as exposed soil surfaces). Bare ground was recorded only if the inter- Comparisons of 1992 and 2001 cepted patch was >1 cm long. Smith et al. Data: Bare Ground, Life-forms, (1994) did not distinguish in their field sam- and Shrub Species pling of permanent plots between truly bare When we used the definition adopted by ground (i.e., exposed soil surface) and unvege- Smith et al. (1994), bare ground comprised an tated areas. Rather, they defined bare ground average of 1.33 times more cover in 2001 than as [1 – (forb cover) – (grass cover) – (shrub in 1992 (Table 3). However, truly bare ground, cover) – (Carex-Juncus cover)]. This original defined by exposed soil surface, averaged only definition of bare ground does not reflect the 1.9% across plots (range = 0%–5.4%) in 2001, sum of bare soils plus litter, as litter can also whereas litter averaged 88.7% and was as high occur under vegetation (compare 2001 values as 96.7% of basal cover (Table 3). Whereas in Table 3). Overlapping canopies of different both forb cover and shrub cover in 2001 aver- species frequently occurred; in such cases, we aged 53% of the 1992 cover values, grass cover tallied the full lengths of both species. We ana- in 2001 averaged nearly 70% and was not sig- lyzed relationships applicable to shrubs using nificantly different from 1992 values (Table 3). all species considered shrubs by Hickman Shrub cover in 2001 was >1.88 times higher (1993) and, for direct comparability with initial at all Snake Creek sites than at any site from analyses, using the list of species considered other drainages, which was not true in 1992 shrubs by Smith et al. (1994; the last 17 species (Smith et al. 1994). Snake Creek sites exhib- listed in Table 3). ited particularly high cover of Woods’ rose For DBH sampling in 2001, we defined seed- (Rosa woodsii), skunkbrush (Rhus trilobata), lings as independent tree sprouts noticeable and snowberry (Symphoricarpos oreophilus) in above ground surface, but <0.46 m tall. Sap- 2001. Cover values for all life-forms except lings were 0.46–1.0 m tall. We used the same forbs and all “shrub” species except Salix exigua size classes as did Smith et al. (1994) for com- and Clematis liguisticifolia were significantly paring distribution of DBH values for dominant correlated between the 2 sampling periods tree species, except that we did not measure (Table 3). When considering only the 17 species 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 389

TABLE 3. Value of various parameters, across 10 permanent plots established in 1991 in watersheds associated with Strawberry, Baker, Lehman, and Snake Creeks. Values are from plot measurements (mean ± 1s) taken in 1992 (as in Smith et al. 1994), and in 2001 (Beever and Pyke). For each parameter, N represents the number of permanent plots on which that parameter occurred. The rightmost “probability” column represents the P-value for a paired t test, whereas the other “probability” column represents the P-value of Fischer’s r to z transformation for each correlation. UNLV (1992) USGS (2001) Average ratio Probability Probability Variable value N value N 2001/1992 (P) Correlation (P) Bare ground, 1994 definition 57.30 ± 5.04 10 76.05 ± 2.96 10 1.327 0.0008 0.669 0.032 Truly bare ground — 10 1.86 ± 0.60 10 0.032 <0.0001 –0.671 0.032 Litter — — 88.72 ± 2.10 10 — — — — Forb cover (%) 15.30 ± 3.16 10 8.03 ± 1.45 10 0.525 0.028 0.470 0.18 Grass cover (%) 4.10 ± 1.30 10 2.86 ± 1.02 10 0.698 0.09 0.870 0.0004 Shrub cover (%) 19.90 ± 5.15 10 10.46 ± 3.46 10 0.526 0.008 0.865 0.0005 Species richness of shrubs 4.00 ± 0.83 10 4.90 ± 0.82 10 1.225 0.029 0.911 <0.0001 Species richness of forbs — — 16.80 ± 2.23 10 — — — — Understory cover (G+F+S; %) 42.58 ± 4.76 10 24.31 ± 2.84 10 0.571 0.0007 0.657 0.037 Relative cover, Carex-Juncus (%) 3.28 ± 1.85 4 2.60 ± 1.01 7 0.793 0.57 0.836 0.0014 Relative cover, AMEALN (%) 0.00 ± 0.00 0 0.03 ± 0.02 3 N/A 0.23 — — Relative cover, ARTTRI (%) 0.50 ± 0.39 3 0.62 ± 0.53 3 1.230 0.46 0.991 <0.0001 Relative cover, CHRNAU (%) 0.10 ± 0.10 1 0.05 ± 0.05 1 0.540 0.34 1.000 0.99 Relative cover, CHRVIS (%) 0.10 ± 0.07 2 0.09 ± 0.09 1 0.920 0.91 0.667 0.033 Relative cover, CLELIG (%) 0.30 ± 0.21 2 0.19 ± 0.17 2 0.633 0.61 0.448 0.20 Relative cover, CORSER (%) 0.30 ± 0.21 1 0.02 ± 0.02 2 0.077 0.20 0.781 0.006 Relative cover, EQUSPP (%) 0.50 ± 0.50 1 0.25 ± 0.13 6 0.508 0.58 0.643 0.043 Relative cover, JUNCOM (%) 0.25 ± 0.13 3 0.23 ± 0.16 4 0.904 0.79 0.847 0.001 Relative cover, MAHREP (%) 0.40 ± 0.40 1 0.18 ± 0.15 4 0.448 0.39 0.995 <0.0001 Relative cover, PRUVIR (%) 0.60 ± 0.40 2 — — — — — — Relative cover, RHUTRI (%) 3.25 ± 2.26 2 1.90 ± 1.43 2 0.585 0.17 0.980 <0.0001 Relative cover, ROSWOO (%) 5.75 ± 2.72 6 4.37 ± 1.54 7 0.760 0.42 0.856 0.0007 Relative cover, RUBIDA (%) 0.30 ± 0.30 1 0.12 ± 0.12 1 0.413 0.34 1.000 <0.0001 Relative cover, SALEXI (%) 1.75 ± 1.49 1 0.05 ± 0.05 2 0.029 0.28 0.042 0.91 Relative cover, SALSPP (%) 3.22 ± 2.17 2 2.77 ± 1.50 5 0.858 0.74 0.799 0.004 Relative cover, SARVER (%) 0.02 ± 0.02 1 0.00 ± 0.00 0 0.000 0.34 ** — Relative cover, SYMORE (%) 2.67 ± 1.73 5 1.74 ± 1.31 6 0.653 0.13 0.972 <0.0001

**Correlation could not be assessed due to lack of variance in 2001 data. 390 WESTERN NORTH AMERICAN NATURALIST [Volume 65 identified as shrubs in the 1992 data, species alnifolia (serviceberry), all new in 2001 in 3 richness across plots was significantly higher plots (Table 3). Of the 17 individual shrub in 2001. species graphed in Smith et al.’s (1994) Appen- Although Smith et al. (1994) did not discuss dix 4, only 4 species (Chrysothamnus nauseo- overstory cover, the number of overstory (tree) sus, C. liguisticifolia, Rhus trifolium, and Rubus species occurring across all transects within idaeus) occurred in 2001 solely in all plots in plots in 2001 ranged from 1 to 7 (mean = 3.9) which they were observed in 1992. species. One to 3 more species may have DBH Measurements occurred at middle-elevation plots due to Salix and Juniperus trees that we were not able to The distribution of tree diameters in 2001 identify as separate species. Species richness was biased more heavily toward the smallest of understory plants ranged from 15 to 39 (mean size class than in the 1992 data for both A. = 29.9) species and exhibited more of a bell- concolor and P. engelmannii. The proportion of 2 shaped relationship with elevation (r adj = 0.41, individuals with DBH <2 cm increased from 2 × P = 0.07) than a linear relationship (r adj = 1992 to 2001 at 4 of 5 (10-m 100-m) plots (and 0.07, P = 0.24). remained the same at the 5th) for A. concolor, Cattle defecations in 2001 averaged 18.6 and at 3 of 4 plots for P. engelmannii (Appen- per plot, but ranged from 0 to 49. Number of dix). In contrast, relative frequency of smallest defecations did not linearly predict the (2001/ size class Populus species was not higher in 1992) ratio of cover of bare ground, grasses, 2001 than in 1992; the proportion of individu- forbs, shrubs, or all understory species. This als with DBH <2 cm decreased at both sites remained true whether analyzed in simple for P. angustifolia, and at 3 of 6 sites for P. regressions (P > 0.10 for all regressions) or in tremuloides (with increases at remaining sites multiple linear regressions that accounted for of only 1%, 5%, and 12% absolute increases; the effect of elevation (Pdefecns > 0.15). We Appendix). In addition, the distribution of the performed the latter regressions because both largest-diameter trees migrated 1–2 classes up- cover and species richness (SR) of shrubs in ward for A. concolor at all 4 plots possessing 2001 declined with increasing elevation (cover: the species where both stakes were relocated, 2 F1,9 = 12.1, r = 0.60, P = 0.008; SR: F1,9 = as well as for P. engelmannii and P. tremuloides 23.5, r2 = 0.75, P = 0.001), as in 1992 (Smith at 1 site each (Appendix). In contrast, all larger- et al. 1994). Monotonically decreasing SR with diameter P. engelmannii individuals were lost increasing elevation has been observed in plants, from plot 6, and P. tremuloides appeared to have vertebrates, and insect taxa (Stevens 1992), been totally lost from plot 3. Distributions of and numerous hypotheses have been proposed DBH values remained similar to those observed to explain the mechanism of this relationship in 1992 for Populus tremuloides in plots 4 and (reviewed in Fleishman et al. 1998). 10, P. angustifolia in plot 5, and P. engelmannii We observed 27 differences in presence of in Lehman 8 (Appendix). individual species identified as shrubs by Smith The number of A. concolor individuals in- et al. (1994). Sixteen of those differences creased from 1992 to 2001 at 4 of 5 plots but occurred on plots (n = 5) where we could not decreased by 81% at the remaining mid-eleva- locate both original stakes, whereas only 11 dif- tion site (Appendix). In contrast, the number ferences occurred on plots (n = 5) that were of P. tremuloides individuals decreased from precisely relocated. Five of the 27 differences 1992 to 2001 at 5 of 6 plots; the decrease were apparent losses of shrub species from ranged from 8% to 100% (Appendix). Although plots, whereas the other 22 differences were the number of P. angustifolia individuals in- shrubs that we detected in 2001 that were not creased at plot 9, the number decreased at the detected in 1992. Three of the 5 apparent adjacent site by 73% (Appendix). losses were shrubs represented with ≤1% Revisitation of Successional cover in 1992, and the other 2 were losses of Phenomena Observed in 1992 Salix spp. (willows) from Strawberry 3. Horse- tails (Equisetum spp.) were added at 5 plots, High values of bare ground were suspected and the next most common additions were by Smith et al. (1994) to lead to reduced tree Carex-Juncus, broad-leaved Salix spp., Maho- recruitment, shrub species richness, and shrub nia repens (Oregon grape), and Amelanchier cover. Bare ground did not predict the total 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 391

Fig. 3. Relationship of shrub cover to percent cover of bare ground, defined as exposed soil surface, at 10 perma- nent plots. Life-forms for shrubs followed Hickman (1993). Dotted lines represent 95% CI on slope.

cover dwarfed grass and forb cover (Table 3), shrub cover not surprisingly decreased with increasing amounts of bare ground (original 2 definition) in 2001 (F1,9 = 21.6, r = 0.73, P = 0.002). However, shrub cover increased with Fig. 2. Relationship of species richness of shrubs to per- increasing amounts of exposed soil surface, cent cover of bare ground within 10-m × 100-m perma- 2 although not as sharply (F1,9 = 4.2, r = 0.35, nent plots in 4 watersheds on the east slope of the Snake P = 0.07; Fig. 3). Range. Dotted lines represent 95% CI on slope. A, Only species considered shrubs in 1992 sampling (Smith et al. Second, recruitment of Populus varied among 1994) were regressed against the 1992 definition of bare plots, demonstrated by an L-shaped distribu- ground [1 – (forb cover) – (grass cover) – (shrub cover) – tion of DBH values of P. angustifolia (DBH (Carex-Juncus cover)]; B, life-forms follow Hickman <2 cm were most common) at plot 9 in 1992, (1993) and bare ground represents exposed soil surface. whereas in plots 4 and 5 moderate-sized (DBH 11–20 cm) individuals were most common. On a coarse level, the comparison continued to number of seedlings and saplings in plots in hold during 2001, but results varied across 2001, when defining bare ground either as plots and species. The distribution of P. angus- unvegetated ground or as exposed soil surface tifolia at plot 9 was again heavily biased toward 2 (F1,9 < 0.3, r < 0.03). Using species defined smaller trees, as over 50% of the trees had as shrubs by Smith et al. (1994), we observed DBH <2 cm and 84% of the trees had DBH in 2001 the same inverse relationship between <11 cm (Appendix). The distribution of P. species richness (SR) of shrubs and cover of tremuloides sizes at plot 4 was again bell- 2 unvegetated ground (F1,9 = 8.2, r = 0.51, P (rather than L-) shaped, but the center of the = 0.021; Fig. 2A) as in 1992. Interestingly, distribution had increased such that individu- however, as amount of exposed soil surface als of 11–20 cm, 21–30 cm, and 31–40 cm increased, so did SR of shrubs in 2001, using diameter were all about equally abundant. species identified as shrubs by Hickman (1993; Distribution of P. angustifolia was again not L- 2 F1,9 = 7.2, r = 0.47, P = 0.028; Fig. 2B) or by shaped at plot 5, as 76.3% of P. angustifolia 2 Smith et al. (1994; F1,9 = 4.2, r adj = 0.26, P trees had DBH values >11 cm. However, in = 0.08). In both cases of this relationship to contrast to 1992 results, trees with DBH 21– SR, however, the strength of the relationship 30 cm were twice as abundant as any other size was driven largely by high values of shrub SR class at plot 5 (Appendix). Relative to 1992, at Strawberry 3 and Snake 9 plots. Given that both plots with P. angustifolia exhibited a de- bare ground was defined as the absence of crease in the number of individuals in each of vegetative cover and the result that shrub the 2 smallest DBH size classes. 392 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Third, P. engelmannii was relatively rare at loides individual to the 2001 total at plot 3 to lower elevations in 1992, reached its maximum allow a logarithm, log change in number of A. density between 2650 and 2850 m elevation, concolor individuals in the plot from 1992 to and appeared to be outcompeting A. concolor 2001 was inversely correlated with log change and P. tremuloides at higher elevations (Smith in number of P. t r emuloides individuals in the et al. 1994). Number of P. engelmannii individ- plot where the species were sympatric in 1992 uals decreased from 1992 to 2001 at the 3 low- (r = –0.96, P = 0.007). In contrast, the log of est-elevation plots (2409–2914 m; at all of which the ratio of individuals observed in 2001 ver- we located both stakes) and increased only at sus 1992 was not related to elevation for either the highest-elevation (3060 m) site (Appendix). A. concolor or P. tremuloides (r2 < 0.4, P > 0.25 The log ratio of number of individuals encoun- for each species). tered in 2001 compared with 1992 was strongly and linearly predicted by plot elevation (F1,3 DISCUSSION = 269.2, r2 > 0.99, P = 0.004). At plot 10, where the apparent competition was noted in Disturbance has been defined by researchers 1992, the distribution of DBH values for P. in numerous ways (e.g., White and Pickett 1985, tremuloides migrated to slightly larger DBH Petraitis et al. 1989, Pickett et al. 1989), with values, although the number of individuals definitions varying in terms of their inclusive- dropped by 52% (Appendix). In contrast, dis- ness of spatio-temporal scales as well as ecosys- tribution of A. concolor moved more heavily tem components and processes. In addition to toward smallest-size trees, yet number of indi- intensive use by livestock, riparian areas in the viduals increased by 15%. P. engelmannii, al- Great Basin have been affected during the last though its abundance decreased by 54%, ex- 100 years by impoundments for agriculture, hibited 6 individuals with DBH >41 cm in heavy recreational use, introduction of exotic 2001, compared with none in 1992. At plot 6, plant and animal species, fire exclusion, min- frequency distributions for all 3 remained simi- ing, dams, channelization, insect and disease lar in 2001 to those observed in 1992 (Appen- outbreaks, and by factors that were also the dix). dominant historic disturbances—periodic floods Fourth, A. concolor was believed to be in- and fires, beaver dams, and periodic ungulate vading and competing strongly with P. tremu- browsing. In GBNP the dominant disturbances loides at high elevations (Smith et al. 1994). in riparian systems over the last 2 centuries This supposition was inferred from data in 1992 have included sheep and cattle grazing, mining, from 2 of 10 plots: (1) plot 10 possessed many and recreation. A. concolor seedlings, yet few P. tremuloides Riparian areas comprise landscape elements seedlings and saplings; and (2) at plot 4, there of the northern Intermountain West that have were only a few small A. concolor individuals been particularly altered over the last 2 cen- and very few large trees in the plot. In sam- turies. This alteration has been suggested to pling during 2001, the relationship at plot 10 have arisen primarily because of improper live- remained true, but only among the most im- stock grazing practices (i.e., during summer, for mature individuals; there were 149 A. concolor too great a duration, or in too great a number; seedlings in the plot, compared to 16 P. tremu- Hann et al. 1997). Kauffman and Krueger (1984), loides seedlings (Appendix). However, the plot Trimble and Mendel (1995), and Belsky et al. contained only 1 more A. concolor sapling (13 (1999) reviewed a broad range of impacts of vs. 12) than P. tremuloides saplings. Further- livestock grazing on riparian systems and pro- more, the plot contained 95 P. tremuloides trees vided considerations for management. In simi- older than saplings and seedlings, compared lar fashion Platts (1991) reviewed impacts on to only 25 A. concolor trees with DBH > 0. At instream conditions, focusing particularly on plot 4 in 2001, the distribution of A. concolor fishes. Relevant to our study, for example, ex- DBH values differed strongly from the 1992 cessive livestock grazing may alter riparian eco- distribution. In 2001, 84.4% of the A. concolor systems by accelerating erosion, stream inci- trees in plot 4 occupied the smallest (<2 cm) sion, and siltation; compacting soils and thus size class, in contrast to a unimodal distribution reducing infiltration; widening and shallowing of DBH values, centered on the 11–20 cm class, the streambed; altering timing and volume of in the 1992 data. When we added 1 P. tremu- water flows; and decreasing vigor and biomass 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 393 and altering species composition and diversity some increase in grasses may have occurred of riparian vegetation (Kauffman and Krueger between 1992 and 2001. Increase of grasses 1984, Belsky et al. 1999). after removing grazing would be the most likely Although season, duration, livestock type change if livestock grazing were exerting per- and class, distribution, and stocking rates may sistent influence that did not cause riparian all be manipulated to attempt recovery of ripar- systems to cross ecological thresholds (sensu ian areas (Kauffman and Krueger 1984), most Tausch et al. 1993, Laycock 1994), because diets cases of successful riparian restoration in the of cattle are composed of up to 95% grasses Intermountain West have excluded livestock (Hanley and Hanley 1982). However, compar- for 2 or more years (Hann et al. 1997, Dobkin et isons of life-forms were compromised by the al. 1998, Homyack and Giulano 2002, Krueper fact that we could not exactly replicate the et al. 2003). This period of exclusion often methods used to record interceptions in the facilitates recovery due to improved manage- 1992 sampling. ment in subsequent years. Nonetheless, some Given the sources of error that often occur authors have found that removal of livestock in repeat sampling of plots (e.g., slightly differ- grazing from riparian areas produces either no ent transect locations sampled; see Beever et al. detectable improvement in aspects of riparian 2002), we cannot be confident that all changes condition (Buckhouse et al. 1981) or improve- in presence of individual shrub species reflect ment only after significant time lags (Kondolf true additions or losses to plots. On the other 1993). Furthermore, research in central Nevada hand, assuming that plots were originally placed riparian systems suggests that, at least in some in locations representative of nearby areas, even watersheds, effects of current management for those transects where we could relocate practices (such as grazing management) are only 1 endpoint, measurements should not be overshadowed by residual effects of past (paleo- excessively influenced by small deviations in and historic) climate change on hillslope pro- transect location. The degree of heterogeneity cesses and sediment regimes (Chambers et al. at small spatial scales in plant community char- 1998, Miller et al. 2001, 2004). We sought to acteristics will determine how greatly the im- test whether vegetative characteristics differed precise relocation of monitoring plots will affect across 10 permanently marked sites during 2 results. Nonetheless, using the same suite of periods that had received similar precipitation species defined as shrubs for 1992 sampling, and intensity of other ungulates but differed we did observe an increase of an average of in their grazing (grazed vs. 2 years’ rest from 22.5% greater SR of shrubs (mean = 4.9 vs. 4.0 grazing). species) in 2001 compared with 1992, consis- tent with our prediction of system response to Permanent Plots grazing removal. The apparent addition of wil- Smith et al. (1994:72) reported that riparian low to 3 new plots in 2001 sampling is simi- areas of GBNP “can be considered in fair eco- larly consistent with the fact that cattle in many logical condition,” but that the condition var- riparian areas often heavily utilize willows, as ied among reaches from “near-pristine” to do native ungulates (Singer et al. 1994, Patten “degraded.” They concluded that “the primary 1998, Peinetti et al. 2001). impacts on riparian ecosystems of the Park FOUR RELATIONSHIPS RELATED TO LONG-TERM appear directly related to livestock grazing.” SUCCESSIONAL PROCESSES.—Although extent and These authors proposed several hypotheses to distribution of bare ground can play critical revisit with subsequent sampling. roles in ecosystem function of both riparian COMPARISONS OF 1992 AND 2001 DATA.— corridors and associated uplands, our ability to Our method of sampling appeared to produce detect any change over time in bare ground consistently more conservative estimates of was confounded by 2 main attributes of the cover, as cover of all life-forms and all shrubs 1992 sampling. First, bare ground was defined except Artemisia tridentata was notably lower as the absence of forbs, shrubs, grasses, sedges, in 2001 than in 1992 (Table 3). Although the and rushes, but was not distinguished from lit- logic behind this conclusion is only indirectly ter. Second, line-intercept sampling methods supported by the data, the smaller apparent were not precisely described or referenced decreases in cover of grasses in 2001 (relative to against any published source; consequently, decreases in forbs and shrubs) may mean that we struggled to replicate the methodology used 394 WESTERN NORTH AMERICAN NATURALIST [Volume 65 in 1992. Because soil properties, erosion poten- Specifically, recruitment of Populus individu- tial, and biotic properties often differ dramati- als will be affected not only by survival of ger- cally between areas of exposed soil and litter- minants experiencing browsing by domestic covered ground, we distinguished the 2 in our and native herbivores, but also by the distri- 2001 sampling. bution and suitability of benches of stream Smith et al. (1994) postulated that high levels channels as germination sites. The mainte- of bare ground at low-elevation sites probably nance and magnification of a bell-shaped dis- reflect a substantial grazing impact on vegeta- tribution at plot 5 two years after livestock tion. While we observed even higher amounts removal suggests that the high degree of chan- of bare ground (using the original definition) nel incision within the 100-m plot length may than that observed in 1992, we cannot say with have compromised recruitment of P. angustifo- confidence to what degree this resulted from lia there (see Yount and Niemi 1990). Highly methodological differences in line-intercept divergent recruitment patterns of P. angustifo- sampling or from authentic system response to lia in plots adjacent to each other (note also livestock removal. This difference was not well trends in total individuals at plots 5 and 9; explained by precipitation patterns, as precipi- Appendix) and in the same hydrogeomorpho- tation was 6.8% higher in the 12 months before logic unit are somewhat unexpected and under- 2001 sampling than in 1992 (Fig. 4). Neither score that variability in processes such as re- tree recruitment nor SR of shrubs was consis- cruitment and establishment occurs at numer- tently related to amount of bare ground in 2001, ous spatial scales. although shrub SR was inversely proportional Picea engelmannii occurred rarely at low to elevation. Whereas bare ground is itself a elevations in 1992 and appeared to be outcom- response to disturbances and management peting A. concolor and P. tremuloides at higher actions rather than a direct cause-and-effect elevations (Smith et al. 1994). Under scenarios agent on the vegetation attributes we revis- of climate change, distributions of most species ited, bare ground and vegetation may interact are broadly predicted to move either upslope in feedback loops (e.g., through greater desic- or to more northern latitudes. Although the cation, sheet and rill erosion, and higher wind proportion of individuals in the smallest size speeds; Davenport et al. 1998). In addition to class increased at 3 of 4 P. engelmannii plots, livestock effects, inverse relationships of bare the total number of individuals declined in all ground to shrub SR and tree recruitment could but the highest-elevation plot (Appendix). Ele- also be caused by higher levels of allelopathy vation strongly predicted change in abundance or other interspecific competition among plants, across the 4 plots (r2 > 0.99), providing stronger independent of grazing. support for a climate-related response in P. Reanalysis of the age structure of trees (as engelmannii. Stronger support yet was pro- seen through the distribution of DBH values) vided by comparing walking surveys in 0.2- at Snake 9 versus Snake 4 and Snake 5 yielded mile segments in the 4 watersheds in 2002 results broadly similar to those observed in (Beever unpublished data) to elevational dis- 1992 sampling. The most notable exception was tributions of the 7 species reported by Smith that distributions of tree sizes shifted upward et al. (1994). Whereas the lower end of the to larger size classes, suggesting maturation of elevational distribution did not increase for larger trees without concomitant die-off. Other- Pinus monophylla, P. angustifolia, A. concolor, wise, all 3 cases of Populus species highlighted P. tremuloides, or P. flexilis (except for modest by Smith et al. (1994) demonstrated results increases at 1 site each in P. flexilis and A. con- similar to those of 1992, despite the fact that color), the lower limit of P. engelmannii in- we could not precisely relocate 2 of the 3 plots. creased by 175–200 m in 3 of 4 watersheds. The persistence of this result across plots is Pinus engelmannii in the Snake Range is asso- consistent with the strong relationship of Pop- ciated with higher-elevation habitats that have ulus recruitment to hydrologic regime and geo- shorter growing seasons, deep shade, and cooler morphic constraints (rather than solely to man- microsites (Smith et al. 1994). Thus, reduc- agement effects), common for riparian obligates tions of P. englemannii at lower elevations are such as P. angustifolia (Stromberg and Patten consistent with the trends of both (1) in- 1991, Auble et al. 1994, Chambers et al. 2004). creased temperatures (Mote et al. 2005) and 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 395

Fig. 4. Five-year averages of cumulative monthly precipitation in the periods before the initial (1992) and repeat (2001) sampling at Park Headquarters of GBNP, 2081 m elevation, Snake Range, NV. Also shown is the 56-year average of precipitation. Data source: Western Regional Climate Center online data, Reno, NV.

earlier snowmelt and streamflow (Stewart et ing dead.” These types of elevationally explicit al. 2005) in the Great Basin and across the data sets will prove invaluable for assessing eco- West during the 20th century; and (2) decreased system response to climate change in the future. snow-water equivalent (SWE; measured 1 Although we did not consistently observe March and 1 April) amounts in Baker Creek the aspects of relationships noted by Smith et at elevations of 2505 m, 2805 m, and 2902 m al. (1994) between mature and young individ- during 1942–2001 (G. Baker, GBNP ecologist, uals of A. concolor and P. tremuloides at Lehman April 2005 unpublished report). More specifi- 10 and Snake 4, other 2001 data nonetheless cally, April SWE has decreased by 22%, 26%, suggest an antagonistic relationship between and 15% at those elevations, and March SWE the 2 species. Differences in abundance of has decreased by 20%, 32%, and 31%, as noted smallest size class individuals in 1992 did not in regional-scale, climate-driven trends across translate into differential recruitment into larger much of the West, reported by Mote et al. size classes at those plots (Appendix). However, (2005). The magnitude of shift (175–200 m in the 2 species exhibited opposite directions in 9 years) in the lower-elevation boundary far ex- change in total abundance at all 5 sites, and ceeds the migration expected for trees in the these changes correlated strongly with changes Swiss Alps (8–10 m per decade; Grabherr et al. in the other species but not with elevation. 1994); however, this was the only tree species Across the Intermountain West, P. tremuloides whose distribution exhibited notable upward becomes established quickly in disturbed sites, migration. Furthermore, the bioclimatic enve- particularly after fire, but is replaced over time lope for this species may not have been well by A. concolor or other conifers under fire sup- established at the time of the 1992 sampling, pression. The park is currently moving toward such that the lowest-elevation trees were “stand- reincorporation of fire into the disturbance 396 WESTERN NORTH AMERICAN NATURALIST [Volume 65 regime through active management. Because most lotic systems recovered quite rapidly from we were able to precisely relocate 4 of 5 plots disturbance due to their high flushing rates, having both species, we suggest that this rela- the availability of upstream and downstream tionship reflects a true biological phenomenon refugia for recolonization, and life-history on the landscape rather than a source of error. characteristics of species that allow rapid re- Monitoring a greater number of locations population of affected areas. In contrast, recov- could further clarify this relationship. ery was protracted when disturbances resulted Alternative Explanations for in alterations to the physical habitat (e.g., min- Observed Differences Between ing activity, clear-cut logging, channelization; Sampling Periods Yount and Niemi 1990). Relative to the timing of our 2nd sampling, numerous authors have The fact that tallies of cow defecations within reported significant recovery in 1 or more plots did not predict magnitude of change in parameters of riparian vegetation in similar cover of any life-form suggests either that tal- time frames (<2 years after protection from lies poorly reflected grazing intensity (e.g., if grazing; e.g., Davis 1982, Case and Kauffman the system were flushed with peak flows, or if 1997, Auble and Scott 1998, Dobkin et al. 1998, microsite conditions created variability across Homyack and Giulano 2002). Rates of vegeta- sites in rates of decay of defecations during tion and channel recovery in any given stream the period since grazing removal) or that grazing reach may be strongly affected by factors such effects were overshadowed by hydrogeomorphic as watershed stability, climate, subsurface and clinal constraints on plant composition. For moisture availability, soil organic content, con- example, some soil types or hydrogeomorphic dition and proximity of propagule sources, and units associated with vegetative communities degree of channel incision (Sarr 2002, Cham- may be naturally more vulnerable to grazing bers et al. 2004). and other disturbance than others. Frissell and Relatively rapid recovery in some riparian Liss (1993) found that Strawberry and Snake ecosystems contrasts markedly with the un- Creeks possessed a geomorphology that was inherently more prone to system alteration. In predictable trajectories of recovery in arid and contrast, riparian corridors in Baker and Leh- semiarid upland communities, where produc- man Creeks were extensively armored with tivity is much lower, plant recruitment more boulders and cobbles, providing stability to sporadic, and dynamics are characterized by the system. Depending on the response vari- thresholds, nonlinear recovery, and multistate able, 10 plots may provide insufficient power systems (Tausch et al. 1993, Laycock 1994). to detect disturbance-related relationships Regardless of how disturbance is defined, long- across areas of broad environmental hetero- term data are required to assert recovery with- geneity. in riparian areas, which can provide informa- Another source of change in riparian systems tion on the frequency and rates of change (reviewed by Trombulak and Frissell 2000)— rather than simply point estimates (Gore et al. the presence of dirt roads near sampled reaches 1990). Additionally, ecologists are becoming of streams—may also have confounded our increasingly aware that livestock-grazing dis- analysis of change relative to change in live- turbance must be investigated in concert with stock management. Although dirt roads exist other influences such as precipitation, fire, in all 4 of our target drainages, roads were and fluctuations in density of native herbi- within 0.25 km of the active channel at only vores (Drewa and Havstad 2001). the 2 pairs of low-elevation sites (sites 1, 3, 5, Precipitation during the previous year(s) and 9), a nonrandom subsample of the bio- will clearly affect the magnitude, duration, and physical conditions found across all sites (and timing of stream flows in montane riparian thus inappropriate for analysis of road effects). systems, as well as the productivity and diver- Our sampling represented a single sampling sity of upland vegetation, though likely with event 2 years after cessation of grazing, which different time scales and lags. However, pre- may be insufficient time for vegetative recov- cipitation at none of 3 temporal scales we ery in riparian zones of semiarid ecosystems. investigated strongly supported the vegetative In their thorough review of case studies of differences we observed between sampling recovery, Yount and Niemi (1990) found that periods, and trends were in fact opposite those 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 397 that would be predicted by our results at 2 and there probably have never been >50 ani- temporal scales. On the most proximate level mals in the entire south Snake Range (C. of causation, precipitation in GBNP ranged Baughman personal communication). Up to from 24% to 28% higher (rather than lower) 30–40 elk may occupy drainages near Straw- during the months of sampling (July and berry Creek during summer months, but this August) in 2001 compared with 1992. On a number varied little between 1992 and 2001. slightly longer scale, precipitation occurring in Censusing and population modeling of mule the 12 months before 1992 sampling totaled deer (Odocoileus hemionus) by the Nevada 32.7 cm, 7% lower (rather than higher) than Division of Wildlife became more fine-grained the 34.9 cm of precipitation received during between 1992 and 2001. The data collected for the 12 months before 2001 sampling (Western both sampling dates estimated that mule deer Regional Climate Center, online data, Park populations within a 5-mountain-range area Headquarters weather station at 2082 m; Fig. approximated 18,600 animals in 1992 but only 1). Riparian shrubs and trees depend more on 11,700 animals in 2001. Assuming that the pro- the amount of winter snowpack and subse- portion of animals in the Snake Range relative quent spring runoff and aquifer recharge than to the other 4 ranges was similar, this would on summer precipitation, and so precipitation produce an estimated total of 5800 deer in the from October to April/May would be most criti- Snake Range in 1992. This value is 1.6 times cal for their productivity. Again, precipitation higher than the estimate from mountain range– patterns were counterintuitive to our finding specific census data of 3600 animals in 2001. of lower shrub cover in 2001 than 1992, as Thus, disparities between riparian vegetation precipitation during October–May was 42% data in 2001 and 1992 that were not consistent higher before 2001 than before 1992 sampling. with predictions of vegetation change follow- On relatively longer time scales, precipita- ing livestock removal (e.g., lower shrub cover, tion levels during the 5 years previous to each lower grass cover) do not correspond to fluctu- sampling period were nearly indistinguishable ⋅ –1 ations in native herbivore numbers during that from each other (33.35 cm yr during 1987– period. Furthermore, Trimble and Mendel 1992, vs. 32.99 cm ⋅ yr–1 during 1996–2001) and (1995) suggested that variability in numbers of the 56-year average (33.27 cm ⋅ yr–1; Fig. 4). native herbivores may have more influence on Furthermore, slightly lower precipitation dur- trends in upland rather than riparian commu- ing the latter period may have resulted simply from its larger number of days of missing data nities, whereas cattle often exert greater rela- (3.8 d ⋅ yr–1, compared to 1 d ⋅ yr–1 during 1987– tive pressure in the riparian corridor itself. 1992), though both frequencies are relatively Implications for Future Efforts small. Because vegetation dynamics do not scale linearly with precipitation, it is difficult to Monitoring is an essential element of eco- predict what types of variability in vegetative system management, in that it is intended to parameters we would expect in these systems detect long-term environmental change, pro- without other long-term data sets. However, vide insights to the potential ecological conse- interannual changes in cover of trees and per- quences of the change, and help decision makers ennial shrubs under variable precipitation determine if and how management practices should be comparatively small. should be amended (Noon et al. 1999). It is possible that removal of nonnative her- We sought to address to what degree long- bivores from GBNP was compensated by sub- term monitoring can be used to address hy- sequently higher densities of native herbivores, potheses about plant community relationships thus preventing system recovery. Historic rec- and vegetation change. Also of interest is com- ords of elk (Cervus elaphus) in eastern Nevada paring the percent change over time that a are fragmentary, but we do know that they given method can detect, and how that com- were first introduced to the region in the adja- pares to what percent change is ecologically cent Schell Creek Range in 1932 and were relevant. Our results suggest that the utility of first reported in the southern Snake Range in monitoring will depend on the precision of the 1976 (C. Baughman, Nevada Division of Wild- data, the question being addressed, and the life, personal communication). Elk are rarely short-term variability of the response variable, found in eastside drainages of the Snake Range, among other things. With the types of data we 398 WESTERN NORTH AMERICAN NATURALIST [Volume 65 collected, comparisons that can most robustly cal structuring and organization are particu- and meaningfully be interpreted are changes larly evident in stream networks (Frissell et al. in relative proportions of different life-forms, 1986, Gregory et al. 1991). For example, using shrub and tree densities, size structuring of Bray-Curtis ordination and cluster analysis, trees, and relationships among these. For man- Baker (1989) found that riparian vegetation in agement-based monitoring to be maximally 115 plots in the southern Rocky Mountains effective in filtering out the effects of expected reflected complex interactions of macroscale intrinsic variability or cycles (i.e., noise) from abiotic gradients (e.g., elevation and geology) the effects of human-induced patterns of change with microscale (valley morphology) charac- (i.e., signal), monitoring activities should follow teristics. Although not strictly hierarchical, the several guidelines. Adequate replication within original placement of the 10 permanent plots the domain of interest, in combination with permits analysis to a limited extent within veg- concomitant sampling of “control” or bench- etation associations of the same drainage (n = mark sites, can help clarify indicator dynam- 2 pairs), across different associations within ics. In their assessment of needs for multiscale the same drainage, and across 4 drainages of monitoring of vegetation in the park relative to the Snake Range. changing management and abiotic conditions, Future Research Directions Eddleman and Jaindl (1994) noted that meth- ods should index vegetation attributes at scales Because semiarid ecosystems generally do of 10–15 years to accurately detect true vege- not exhibit succession to climax communities tation change. in the Clementsian sense (Tausch et al. 1993, Repeatability is the single-most important Laycock 1994), research is needed to improve aspect of successful monitoring, but it is elu- our understanding of the conditions under sive because budgets are restricted and vary which transitions between different vegetation greatly over time, and because changes in states occur in diverse communities and the monitoring personnel inevitably lead to ob- inputs of resources (i.e., active restoration server bias. Repeatability in space can be im- treatments) needed to shift ecosystems from proved by (1) placing permanent markers at less desirable states to one of many other pos- ends of plots or transects that cannot be easily sible metastable configurations. For desert detected and removed by the general public streams Fisher (1990) argued that the concept or natural processes (e.g., floods); (2) recording of ecosystem resilience and resistance to dis- plot locations with differentially corrected turbance, rather than succession to a climax GPS or a handheld GPS unit with WAAS (Wide state, better represents system dynamics. Area Augmentation System); (3) using tradi- Determining how ecosystem patterns and tional orienteering techniques to triangulate processes in semiarid regions respond to bulk plot vertices (see Harrelson et al. 1994); and grazing by cattle, horses, and elk constitutes a (4) taking pictures from defined locations. major focus area of future research needs. Few Repeatability in time can be improved by stan- studies exist on how landscape-level patterns dardizing or including covariates in analyses in riparian vegetation affect viability of wild- factors such as sampling date and time, as well life populations. Many research needs for ripar- as atmospheric conditions (e.g., moon phase, ian areas related to scale remain, including (1) weather). Although these temporal conditions effects of homogeneous vs. heterogeneous dis- affect vegetation monitoring in many systems tributions of disturbance, (2) how local distur- only through their effect on phenology, many bances or restoration efforts affect ecosystem animals respond strongly to them. Repeatabil- function and structure in a regional context, ity of techniques used in the field can be and (3) importance of size and location of criti- improved by following published guidelines cal vs. noncritical patches of disturbance at for well-established methods, noting explicitly different spatial scales and temporal frequen- any deviations from the standard method. cies (Gore et al. 1990). Because ecosystem interactions operate with- Given that many of the ecological issues in a hierarchy (Noss 1990), it is critical that related to land use and environmental quality monitoring and evaluation address questions may be ameliorated with effective management and trends at various spatial scales. Hierarchi- of riparian corridors (Naiman et al. 1993), 2005] MONITORING IN MONTANE RIPARIAN ECOSYSTEMS 399 monitoring in managed areas should focus at ter, National Park Service. A. Tiehm of the least partially within riparian zones. Geomor- Northern Nevada Native Plant Society (Reno, phology can strongly affect both floral and fau- NV) provided stellar assistance with plant nal assemblages within riparian areas (Huryn identification. and Wallace 1987, Harris 1988). Consequently, we recommend stratifying by hydrogeomor- LITERATURE CITED phic zones (Frissell and Liss 1993) and domi- nant woody vegetation to capture dominant ARCHER, S., AND F.E. SMEINS. 1991. Ecosystem-level pro- cesses. Pages 109–140 in R.K. Heitschmidt and J.W. gradients in community composition. Other Stuth, editors, Grazing management: an ecological authors have described quantitative yet easily perspective. Timber Press, Portland, OR. implemented methods for monitoring change AUBLE, G.T., J.M. FRIEDMAN, AND M.L. SCOTT. 1994. in riparian vegetation in managed ecosystems Relating riparian vegetation to present and future streamflows. Ecological Applications 4:544–554. that may be useful alternatives to the system AUBLE, G.T., AND M.L. SCOTT. 1998. Fluvial disturbance of permanent plots described in this research. patches and cottonwood recruitment along the upper For example, the 3 sampling methods presented Missouri River, Montana. Wetlands 18:546–556. by Winward (2000) provide practitioners with BAKER, W.L. 1989. Macro- and micro-scale influences on riparian vegetation in western Colorado. Annals of information about extent of various plant com- the Association of American Geographers 79:65–78. munities along the riparian “greenbelt” and BEEVER, E.A., D.A. PYKE, J.E. HERRICK, J. BELNAP, AND across stream sections, as well as in density of J.C. CHAMBERS. 2002. Soil and vegetation changes individual woody species within a 1.83 × 221.3- related to livestock removal at Mojave National Pre- m plot along the greenbelt. Similarly, Herrick serve and Great Basin National Park. NRPP annual report to Great Basin National Park. et al. (2005) describe methods that record the BELSKY, A.J., A. MATZKE, AND S. USELMAN. 1999. Survey channel profile and the shape of the soil surface of livestock influences on stream and riparian eco- in uplands, and cover of individual species systems in the western United States. Journal of Soil along the greenline. Indicators that may be and Water Conservation 54:419–431. BLAKE, E.W. 1992. Soil survey of Great Basin National monitored with these 2 methods include total Park, Nevada (parts of Humboldt National Forest, canopy cover, cover of stabilizing species, total Nevada, South Part Soil Survey). USDA Soil Con- woody cover, and bank angle and width-depth servation Service, Reno, NV. ratios (Herrick et al. 2005). Both frameworks BUCKHOUSE, J.C., J.M. SKOVLIN, AND R.W. KNIGHT. 1981. Streambank erosion and ungulate grazing relation- view change through the lens of inherent site ships. Journal of Range Management 34:339–340. capacity and utilize methods that not only BULL, E.L. 1978. Specialized habitat requirements of birds: characterize plant composition but also index snag management, old growth, and riparian habitat. ecosystem function by analyzing vegetation in Pages 74–82 in R.M. DeGraaf, editor, Proceedings of the workshop on nongame bird habitat management concert with hydromorphology of the adjacent in coniferous forests of the western United States. stream. Ecologists are increasingly beginning General Technical Report PNW-GTR-64, USDA For- to understand the interconnectedness of ripar- est Service, Pacific Northwest Forest and Range Ex- ian and adjacent upland communities (e.g., periment Station, LaGrande, OR. Gregory et al. 1991); future riparian monitor- CASE, R.L., AND J.B. KAUFFMAN. 1997. Wild ungulate in- fluences on the recovery of willows, black cotton- ing should thus integrate these communities. wood and thin-leaf alder following cessation of cattle In these systems such monitoring may be used grazing in northeastern Oregon. Northwest Science as a starting point to define baseline condi- 71:115–126. tions, understand the range of current vari- CHAMBERS, J.C., K. FARLEIGH, R.J. TAUSCH, J.R. MILLER, D. GERMANOSKI, D. MARTIN, AND C. NOWAK. 1998. ability in riparian vegetation parameters, and Understanding long- and short-term changes in veg- detect undesirable short-term changes within etation and geomorphic processes: the key to ripar- reserve areas and adjacent ecosystems. ian restoration. Pages 101–110 in D.F. P otts, editor, Proceedings: Rangeland Management and Water Re- sources, 27–29 May 1998, American Water Resources ACKNOWLEDGMENTS Association and Society for Range Management, Reno, NV. The NRPP program of the National Park CHAMBERS, J.C., R.J. TAUSCH, J.L. KORFMACHER, J.R. Service provided funding for this research. S. MILLER, AND D.G. JEWETT. 2004. Effects of geomor- Shaff and J. Noel assisted with fieldwork in phic processes and hydrologic regimes on riparian vegetation. Pages 196–231 in J.C. Chambers and J.R. 2001. We thank G. Lienkaemper for assistance Miller, editors, Great Basin riparian ecosystems: with Figure 1 and GIS analyses. Logistical ecology, management, and restoration. Island Press, support at GBNP was coordinated by K. Heis- Covelo, CA. 400 WESTERN NORTH AMERICAN NATURALIST [Volume 65

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Environmental Management 30: 516–526. Received 2 March 2003 SCHULZ, T.T., AND W. C . L ENINGER. 1990. Differences in Accepted 6 December 2004 riparian vegetation structure between grazed areas and exclosures. Journal of Range Management 43: 295–299. 402 WESTERN NORTH AMERICAN NATURALIST [Volume 65 vada. Seedlings and saplings are defined in 610000186 210000 25 210000633 621000 41 000000 6 000000 38 000000 35 400000101 000000 0 923000320 100-m plot. Plot # refers to sites in Figure 1. Data from 1992 sampling were collected 100-m plot. Plot # refers to sites in Figure × tremuloides P. POPTRE = opulus angustifolia; P date lings lings DBH 2–10 11–20 21–30 32–40 41–50 51–60 >60 cm individuals POPANG = POPANG a Picea engelmannii; PICENG = . Distribution of tree sizes (cm), by species, at 9 plots in 4 watersheds in Great Basin National Park, Snake Range, eastern Ne . Distribution of tree sizes (cm), by species, at 9 plots in 4 watersheds Great Basin National Park, Abies concolor; Creek (m) species BakerBaker 2405 2405 ABICON ABICON 1992 2001 — 473 — 28 427 516 38 42 59 57 16 40 0 5 0 1 0 0 0 0 540 661 LehmanLehmanSnakeSnake 2914Snake 2914Snake PICENGBaker 1948 PICENG 1992Baker 1948 POPANG 2001 1961 POPANG 1961 1992 — POPANGLehman 2405 2001 POPANG 2405 3 1992 POPTRE — 2001 POPTRE — 2914 10 1992 — 2001 POPTRE 7 — 6 13 — 1992 7 — 44 12 38 — 3 — 40 21 116 89 34 38 484 — 33 19 331 22 58 27 11 203 15 35 136 3 41 92 13 10 62 11 8 18 3 21 78 3 31 4 11 37 5 13 17 6 0 3 2 13 14 9 7 4 0 1 0 3 7 9 0 9 0 1 0 0 3 132 0 108 0 106 0 0 142 341 780 491 93 SnakeStrawberryStrawberryStrawberry 2231Strawberry 2475 2231Baker ABICON 2463 ABICONBaker ABICON 2463 1992Baker ABICON 1992 2001Baker ABICON 1992 3060 — 2001 3060 619 — PICENG 2405 — PICENG 2405 260 1992 PICENG — 2001 — PICENG 8 1992 — 107 — 2001 13 627 5 24 — 276 382 — 6 9 10 73 — 3 55 26Lehman 7Snake 0 21Snake 97 19 15 13Strawberry 2914Strawberry 24 6Strawberry 2475 POPTRE 2231 48 22Strawberry 13 2475 2231 7 6 2001 POPTRE POPTRE 2463 20 POPTRE POPTRE 2463 41 1992 0 1992 0 POPTRE 2001 2001 10 7 POPTRE 3 21 1992 — — 21 2001 0 1 23 0 4 — 7 17 130 — 13 — 0 33 0 — 4 0 5 6 84 14 88 6 0 366 2 247 2 0 0 1 2 7 16 9 175 242 59 12 368 443 2 0 3 31 17 36 29 99 142 6 33 16 0 36 1 0 7 1 0 3 1 0 0 101 564 129 PPENDIX A 6 6 8 8 9 9 5 5 6 6 8 4 3 3 2 2 7 7 6 6 8 4 4 3 3 2 2 ABICON = the text. Values in each cell represent the number of individuals that size class 10-m Values the text. Plot# Elevation Tree Sample # seed- # sap- <2 cm # # trees # trees # trees # trees # trees # trees # trees # of Total a 1010 Lehman Lehman 2691 2691 ABICON ABICON 1992 2001 — 149 — 13 107 164 44 15 11 0 0 0 0 0 162 1010 Lehman Lehman 2691 2691 PICENG PICENG 1992 200110 —10 Lehman Lehman 24 — 2691 2691 7 POPTRE POPTRE 84 1992 2001 33 — 44 16 13 — 38 12 12 26 74 32 20 8 76 23 8 84 0 45 4 13 0 18 1 5 0 3 1 3 200 1 92 0 1 0 0 255 123 by Smith et al. (1994), and 2001 data were collected USGS personnel. Western North American Naturalist 65(3), © 2005, pp. 403–404

COLLECTION OF ASIAN TAPEWORM (BOTHRIOCEPHALUS ACHEILOGNATHI) FROM THE YAMPA RIVER, COLORADO

David Ward1

Key words: Asian tapeworm, Bothriocephalus acheilognathi, humpback chub, roundtail chub, bonytail chub, Colo- rado pikeminnow.

On 20 July 2004 a single Asian tapeworm Asian tapeworm has been identified as 1 of 6 (Bothriocephalus acheilognathi) was collected potential threats to the continued persistence from the intestine of a roundtail chub (Gila ro- of humpback chub (Gila cypha) in Grand busta) in the Yampa River in Dinosaur National Canyon (USFWS 2002) and is considered a Monument in northwestern Colorado. This fish potential reason for documented declines in (274 mm TL) was collected at river mile 24 and adult humpback chub condition in the Little dissected in the field. A single tapeworm was Colorado River (Meretsky et al. 2000). Brouder removed from the intestine and preserved in (1999) found a strong negative correlation be- ethanol. The tapeworm was later identified in tween growth of roundtail chub and Asian tape- the laboratory as B. acheilognathi by its char- worm infestation in the Verde River, Arizona. acteristic arrow-shaped scolex (Poole et al. 1984). Reduced growth as a result of high Asian tape- This is the 1st recorded incidence of Asian worm infestation may increase predation risk tapeworm infecting fish in the Yampa River and decrease survival of endangered cyprinid drainage. fishes. The interaction of slow growth and in- Asian tapeworm is considered one of the creased early life mortality is already considered most dangerous pseudophyllidean cestodes of an important cause of Colorado pikeminnow carp in Europe (Heckman et al. 1987) and can declines in the upper Colorado River basin cause heavy infections in juvenile cyprinids, (Kaeding and Osmundson 1988). especially when spreading into new locations The Yampa River is one of the few large (Hoffman and Schubert 1984). When parasites rivers in the entire Colorado River system that are numerous, marked enlargement of the retains characteristics of its historic hydro- abdomen can occur with severe hemorrhagic graph and has become one of the only places enteritis and intestinal blockage (Hoole and where all of the endangered “big river fishes” Nisan 1994). Asian tapeworm can cause high of the Colorado River can still be found. Once mortality when infecting new host species established, Asian tapeworm will be extremely (Hoffman and Schubert 1984), and parasitized difficult to eradicate, and it is likely to spread carp in hatcheries often cease feeding, become throughout the Yampa and Green River sys- emaciated (Hoole and Nisan 1994), and die tems as it is non-host specific and has an ex- with up to 100% losses (Korting 1975). tremely rapid life cycle, maturing from egg to Asian tapeworm was introduced into North adult in less than 15 days at 25°–30°C (Hoff- America with grass carp imported from China man 1976, Granath and Esch 1983). Habitat to control aquatic vegetation (Hoffman and alteration and predation by introduced fish Shubert 1984) and has since become wide- species are known factors contributing to the spread through bait bucket introductions. It decline of southwestern native fishes, but intro- was first found in the Colorado River in Grand ductions of new parasites such as the Asian Canyon in 1990 (Minckley 1996) and in the tapeworm may also play an important role in San Juan and upper Colorado Rivers in 1994 the continuing decline of native fish popula- (Hauck 1997). tions.

1Arizona Game and Fish, Research Branch, 2221 W. Greenway Road, Phoenix AZ 85023.

403 404 WESTERN NORTH AMERICAN NATURALIST [Volume 65

LITERATURE CITED pseudophyllidean tapeworm, Bothriocephalus achei- lognathi Yamaguti, 1934. Journal of Fish Diseases BROUDER, M.J. 1999. Relationship between length of 17:623–629. roundtail chub and infection intensity of Asian fish KAEDING, L.R., AND D.B. OSMUNDSON. 1988. Interaction tapeworm Bothriocephalus acheilognathi. Journal of of slow growth and increased early-life mortality: an Aquatic Animal Health 11:302–304. hypothesis on the decline of Colorado squawfish in GRANATH, W.O., JR., AND G.W. ESCH. 1983. Temperature the upstream regions of its historic range. Environ- and other factors that regulate the composition and mental Biology of Fishes 22:287–298. infrapopulation densities of Bothriocephalus achei- KORTING, W. 1975. Larval development of Bothriocephalus lognathi (cestoda) in Gambusia affinis (Pices). Jour- sp. (Cestoda: Pseudophyllidea) from carp (Cyprinus nal of Parasitology 69:116–1124. carpio) in Germany. Journal of Fish Biology 7:727–733. HAUCK, A.K. 1997. Aquaculture newsletter. Utah Depart- MERETSKY, V.J., R.A. VALDEZ, M.E. DOUGLAS, M.J. BROUDER, ment of Agriculture, Fish Health Program, Salt Lake O.T. GORMAN, AND P.C. MARSH. 2000. Spatiotempo- City. ral variation in length-weight relationships of endan- HECKMANN, R.A., P.D. GREGER, AND J.E. DEACON. 1987. gered humpback chub: implications for conservation New host records for the Asian fish tapeworm Both- and management. Transactions of the American Fish- riocephalus acheilognathi, in endangered fish species eries Society 129:419–428. from the Virgin River, Utah, Nevada, and Arizona. MINCKLEY, C.O. 1996. Observation on the biology of the Journal of Parasitology 73:226–227. humpback chub in the Colorado River basin 1980– HOFFMAN, G.L. 1976. The Asian tapeworm, Bothriocepha- 1990. Master’s thesis, Northern Arizona University, lus gowkongensis, in the United States and research Flagstaff. needs in fish parasitology. Pages 84–90 in Proceed- POOLE, D., K. RYDER, AND C. ANDREWS. 1984. The control ings of the 1976 fish farming conference, annual con- of Bothriocephalus acheilognathi in grass carp, Cteno- vention of the catfish farmers of Texas. Texas Agri- pharyngodon idella, using Praziquantel. Fisheries cultural and Mechanical University, College Station. Management 15:31–33. HOFFMAN, G.L., AND G. SHUBERT. 1984. Some parasites of USFWS. 2002. Humpback chub (Gila cypha) recovery exotic fishes. Pages 233–261 in W.R. Courtney, Jr., and goals: amendment and supplement to the humpback J.R. Stauffer, Jr., editors, Distribution, biology and chub recovery plan. U.S. Fish and Wildlife Service, management of exotic fishes. Johns Hopkins Univer- Mountain-Prairie Region, Denver, CO. sity Press, Baltimore, MD. HOOLE, D., AND H. NISAN. 1994. Ultrastructural studies on Received 10 August 2004 intestinal response of carp, Cyprinus carpio L., to the Accepted 6 December 2004 Western North American Naturalist 65(3), © 2005, pp. 405–409

WESTWARD EXPANSION OF THE EASTERN PIPISTRELLE (PIPISTRELLUS SUBFLAVUS) IN THE UNITED STATES, INCLUDING NEW RECORDS FROM NEW MEXICO, SOUTH DAKOTA, AND TEXAS

Keith Geluso1, Tony R. Mollhagen1, Joel M. Tigner2, and Michael A. Bogan1

Key words: Pipistrellus subflavus, eastern pipistrelle, westward expansion, distribution, New Mexico, South Dakota, Texas.

The eastern pipistrelle (Pipistrellus subflavus) South Dakota, this study; Nebraska, Benedict occurs in eastern North America, including parts 2004; Wyoming, Bogan and Cryan 2000; Kansas, of Canada, United States, Mexico, Guatemala, Sparks and Choate 2000; Colorado, Fitzgerald and Honduras (Hall 1981). In the United States et al. 1989; New Mexico, this study; and Texas, the known distribution of P. subflavus in 1981 Jones et al. 1993, Yancey et al. 1995, and this extended from the Atlantic coast west to Min- study). nesota, Iowa, Nebraska, Kansas, Oklahoma, and Of the 16 extralimital records from 8 states Texas. Despite published records beyond west- reported herein, records include individuals ern limits in the United States since 1981 (see captured in wooded, riparian habitats in sum- below), recently published distribution maps mer (Yancey et al. 1995, Benedict 2004, this of P. subflavus have not accounted for these study), bats discovered in hibernacula in win- records (e.g., Kunz 1999, Schwartz and Schwartz ter (Bogan and Cryan 2000, this study), and 2001, Kays and Wilson 2002). It is not clear individuals captured on human-made struc- whether omissions were oversights by the tures in spring, late summer, and early autumn authors or assumptions that these records were (Fitzgerald et al. 1994, Jones et al. 1993, Bene- accidental. This study updates the known dis- dict 2004, this study). Both males and females tribution of P. subflavus in the United States have been reported, and lactating females were by amassing published accounts and new rec- documented at 2 locations in Nebraska (Bene- ords since 1981. We also attempt to determine dict 2004). None of the existing data are sug- whether western records represent accidental gestive of animals either in poor health or records, undetected populations, or recent west- roosting in locations atypical for the species. ward expansion. Recent records most likely represent west- The reported distribution of P. subflavus ward expansion of P. subflavus in the United changed little from 1959 to 1981 (Hall and States rather than accidental records or unde- Kelson 1959, Hall 1981). During this period tected populations. Evidence against records the geographic range of this species expanded representing wandering or lost individuals in- from southern Maine to Nova Scotia and from cludes reproductively active females that prob- central Florida to the Florida Keys. Along the ably were summer residents, hibernating indi- western edge of its range, a more modest ex- viduals that probably were winter residents, pansion was noted from western Oklahoma to and the fact that P. subflavus is known to move the Texas Panhandle and from central Iowa to only short distances between summer and northwestern Iowa. More recently, the known winter roosting sites (Fujita and Kunz 1984, range of this bat has expanded significantly Schwartz and Schwartz 2001). We also suspect westward in the United States (Fig. 1). Records that most of these records do not represent now exist beyond the distribution mapped by undetected populations. Although some records Hall (1981) for all states along its western edge may represent previously undetected popula- in the United States (Minnesota, Hazard 1982; tions, past mammalian surveys in some regions

1United States Geological Survey, Arid Lands Field Station, Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131. 2Batworks, Rapid City, SD 57702.

405 406 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Fig. 1. Distribution of the eastern pipistrelle (Pipistrellus subflavus) in North America. Shading represents the distri- bution of P. subflavus published in Hall (1981). The solid black line represents the revised western limits of its range based on the present study. Closed circles represent published records of eastern pipistrelles since 1981 (see text), and open circles represent additional records reported in this study. The westernmost open circle in South Dakota repre- sents 3 records of P. subflavus.

now containing P. subflavus also suggest recent Below we report 6 additional records of P. colonization (e.g., Turner 1974, Schmidly 1977, subflavus in the United States, which repre- Dalquest et al. 1990). We concur with Sparks sent the 1st record in New Mexico, the 1st and Choate (2000) that increases in wooded four records in South Dakota, and the west- corridors along waterways, such as those doc- ernmost record in Texas. umented in the Great Plains (Tomelleri 1984, On 30 September 2003, KG discovered a Johnson 1994), and construction of mines and male P. subflavus roosting under a cement other human-made structures in the region bridge in Union County, New Mexico. The have led to the expansion in distribution of solitary individual was first observed about 3 eastern pipistrelles. The combination of these m from the west wall in the northern section factors probably has enabled P. subflavus to of the bridge (36°54.096′N, 103°00.125′W; inhabit riverine corridors in summer and to NAD83 datum). In KG’s presence, it flew to hibernate in nearby areas in winter. Additional the west wall and was captured by hand surveys of bats along wooded riparian corri- (36°54.096′N, 103°00.131′W). The west end of dors with nearby hibernacula likely will show the bridge is in New Mexico, but most of the P. subflavus more widespread in western parts bridge lies in Oklahoma (the Cimarron Merid- of its range. ian at 103°00.117′W divides the states). State 2005] NOTES 407 highway markers on the ground also confirm The area surrounding the mine consists of a that locations of P. subflavus were in New forest dominated by ponderosa pine (Pinus Mexico. The bridge spans Carrizozo Creek, ponderosa). On 11 January 2004, JMT discov- which flows into the Dry Cimarron River 2 ered another torpid P. subflavus roosting in km downstream. Both waterways contain open this same mine. This individual was observed water and are bordered in areas by cotton- 1.5 m above the floor on a wall in another pas- woods (Populus), saltcedar (Tamarix), and sageway. Both individuals were not disturbed; other trees. The surrounding area consists of thus none was taken as a voucher specimen. rocky mesas containing woodlands of Col- Other bats reported hibernating in the mine orado piñon (Pinus edulis) and one-seeded on the same day included M. septentrionalis, juniper ( Juniperus monosperma). M. thysanodes, M. ciliolabrum, M. lucifugus, Eastern pipistrelles enter hibernacula in and M. volans. autumn, and some studies report them at On 12 January 2004, JMT discovered a tor- hibernacula as early as August and September pid P. subflavus roosting on a wall in an aban- (Fujita and Kunz 1984, Sandel et al. 2001). doned mine approximately 16 km east-north- Because our individual was captured in Sep- east of Hill City, Pennington County (T1S, tember and contained large amounts of sub- R6E, Section 15). This solitary individual was cutaneous fat on its back, sides, and lower observed 1.5 m from the floor in the main pas- abdominal region, this male probably was in sageway and was not disturbed. Other species the vicinity of a hibernaculum. of bats hibernating in the mine on the same Our capture represents the 1st record of P. day included Eptesicus fuscus, M. septentrion- subflavus in New Mexico (Findley et al. 1975, alis, M. thysanodes, and M. ciliolabrum. The Dalquest et al. 1990). The individual was kept mine has a single opening and approximately as a voucher and deposited in the U.S. Geo- 75 m of underground passageways. The tem- logical Survey, Biological Survey Collection at perature profile was similar to the mine de- the Museum of Southwestern Biology (MSB), scribed above, while relative humidities were University of New Mexico, Albuquerque (MSB noticeably lower than at the other mine (JMT #124271). Nearest published records are 260 personal observation). This mine is situated km to the southeast in the Panhandle of Texas adjacent to a creek in a ponderosa pine forest. (Yancey and Jones 1996) and 360 km to the On 14 April 2004, JMT discovered another east in northwestern Oklahoma (Hall 1981, torpid P. subflavus roosting in a shallow dome Caire et al. 1989). We suspect that eastern pip- in an abandoned mine approximately 9 km istrelles inhabit other wooded riverine corri- east of Hill City, Pennington County (T1S, R5E, dors in eastern New Mexico, and surveys along Section 25). The solitary individual was ob- the Dry Cimarron, Canadian, and Pecos Rivers served approximately 6 m from the mine open- may yield additional records for the state. ing. The bat was not disturbed, but voucher On 7 January 2003, JMT discovered a tor- photographs were taken (MSB #124461). pid P. subflavus roosting on a wall in an aban- Ambient temperature outside the mine on this doned mine 6.5 km east-northeast of Hill City, day was –1°C, whereas temperature at the Pennington County, South Dakota (T1S, R5E, height of the ceiling <1 m from the bat was Section 23). The solitary individual was observed 5°C. This individual was not observed during 1.5 m above the floor in a short passageway off an earlier visit to this mine in January 2004. the main horizontal passageway of the mine. Other bats in the mine on 14 April included E. Other species of bats reported hibernating in fuscus and C. townsendii. The area surrounding the mine the same day included Myotis septen- the mine consists of a ponderosa pine forest. trionalis, M. thysanodes, M. ciliolabrum, M. luci- These observations represent the 1st records fugus, M. volans, and Corynorhinus townsendii. of P. subflavus in South Dakota (Turner 1974, The mine has a single opening and approxi- Higgins et al. 2002). Nearest published records mately 1 km of passageways, all of which are are approximately 190 km to the southwest in at the same level. Relative humidity was approx- eastern Wyoming (Bogan and Cryan 2000) and imately 90% throughout the mine due to pres- 275 km to the southeast in north central ence of water, and temperatures ranged from Nebraska (Benedict 2004). All 4 sighting were 2°C near the opening to 7°C in deeper reaches. from mines located within the Black Hills 408 WESTERN NORTH AMERICAN NATURALIST [Volume 65 region of the state. We suspect that eastern preparing Figure 1, Clyde Jones for assistance pipistrelles occur along riverine corridors with literature, and Kenneth Geluso for help- throughout South Dakota, especially in those ful comments on an earlier version of this areas with nearby hibernacula. manuscript. Winter surveys of bats in the Black On 30 April 2003, TRM and MAB captured Hills were funded by the South Dakota Depart- an adult male P. subflavus in ZH Canyon, ca. 9 ment of Game, Fish and Parks, Pierre. miles (14.5 km) west of Valentine, Sierra Vieja, Presidio County, Texas (UTM coordinates LITERATURE CITED 130531885E 3379571N, 1408 m elev.; NAD27 BENEDICT, R.A. 2004. Reproductive activity and distribu- datum). The individual was netted over a small tion of bats in Nebraska. Western North American stream at 2225 hours. ZH canyon is located in Naturalist 64:231–248. the Sierra Vieja, one of a series of small moun- BOGAN, M.A., AND P. M . C RYAN. 2000. Bats of Wyoming. tain ranges east of the Rio Grande in western Pages 71–94 in J.R. Choate, editor, Reflections of Texas. This steep-walled canyon drains north a naturalist: papers honoring Professor Eugene D. Fleharty. Fort Hays Studies, Special Issue 1, Hays, and then eastward. The capture site is located KS. in the east–west part of the canyon, upstream CAIRE, W., J.D. TYLER, B.P. GLASS, AND M.A. MARES. 1989. and past an abandoned U.S. Army facility (Camp Mammals of Oklahoma. University of Oklahoma Holland, which was built in the early 1900s). Press, Norman. DALQUEST, W.W., F.B. STANGL, JR., AND J.K. JONES, JR. 1990. Pools of water occur over a 50-m stretch from Mammalian zoogeography of a Rocky Mountain– the head of a pipeline to where water emerges Great Plains interface in New Mexico, Oklahoma, and from dense riparian vegetation. Water also exists Texas. Special Publications, Museum of Texas Tech up-canyon, but pools are intermittent and University 34:1–78. FINDLEY, J.S., A.H. HARRIS, D.E. WILSON, AND C. JONES. small. Other species of bats captured the same 1975. Mammals of New Mexico. University of New evening were M. velifer, M. volans, M. califor- Mexico Press, Albuquerque. nicus, P. hesperus, E. fuscus, Lasiurus cinereus, FITZGERALD, J.P., C.A. MEANEY, AND D.M. ARMSTRONG. Antrozous pallidus, and Tadarida brasiliensis. 1994. Mammals of Colorado. Denver Museum of Natural History, Denver, and University Press of An additional 8 species also have been cap- Colorado, Niwot. tured in ZH Canyon in the past (Schmidly FITZGERALD, J.P., D. TAYLOR, AND M. PRENDERGAST. 1989. 1991): Mormoops megalophylla, M. yumanen- New records of bats from northeastern Colorado. sis, M. thysanodes, M. ciliolabrum, Lasionyc- Journal of the Colorado–Wyoming Academy of Sci- teris noctivagans, L. blossevillii, Corynorhinus ence 21:22. FUJITA, M.S., AND T.H. KUNZ. 1984. Pipistrellus subflavus. townsendii, and Nyctinomops macrotis. With a Mammalian Species 228:1–6. total of 17 species, this site has one of the most HALL, E.R. 1981. The mammals of North America. 2nd diverse faunas of bats in Texas, as well as in edition. John Wiley & Sons, New York. the United States. HALL, E.R., AND K.R. KELSON. 1959. The mammals of North America. Ronald Press Company, New York. This capture represents the westernmost HAZARD, E.B. 1982. The mammals of Minnesota. Univer- record of P. subflavus in Texas (Schmidly 1991, sity of Minnesota Press, Minneapolis. Yancey et al. 1995). The individual was kept as HIGGINS, K.F., E.D. STUKEL, AND D.C. BACKLUND. 2002. a voucher and deposited in the Museum of Wild mammals of South Dakota. 2nd edition. South Dakota Department of Game, Fish and Parks, Pierre. Texas Tech University (TTU #100,001; tissues, JOHNSON, W.C. 1994. Woodland expansion in the Platte TK #112,773). The nearest published record River, Nebraska: patterns and causes. Ecological is 87 km to the south-southeast in Presidio Monographs 64:45–84. County, Texas (Yancey et al. 1995). Eastern JONES, J.K., JR., R.W. MANNING, F.D. YANCEY II, AND C. JONES. 1993. Records of five species of small mam- pipistrelles captured east of the Pecos River in mals from western Texas. Texas Journal of Science Texas are presently referred to P. s. subflavus; 45:104–105. however, individuals taken west of the Pecos KAYS, R.W., AND D.E. WILSON. 2002. Mammals of North River and in neighboring Coahuila, Mexico, America. Princeton University Press, Princeton, NJ. KUNZ, T.H. 1999. Eastern pipistrelle/ Pipistrellus subflavus. are referred to as P. s. clarus (Schmidly 1991, Pages 114–115 in D.E. Wilson and S. Ruff, editors, Yancey et al. 1995). Based on geographic The Smithsonian book of North American mammals. grounds, we tentatively assign our individual Smithsonian Institution Press, Washington, DC. to P. s. clarus. SANDEL, J.K., G.R. BENATAR, K.M. BURKE, C.W. WALKER, T.E. LACHER, JR., AND R.L. HONEYCUTT. 2001. Use and selection of winter hibernacula by the eastern We thank Doug Backlund and Brad Phillips pipistrelle (Pipistrellus subflavus) in Texas. Journal of for their assistance in the field, Angie Fox for Mammalogy 82:173–178. 2005] NOTES 409

SCHMIDLY, D.J. 1977. The mammals of Trans-Pecos Texas. TURNER, R.W. 1974. Mammals of the Black Hills of South Texas A&M University Press, College Station. Dakota and Wyoming. Miscellaneous Publications of ______. 1991. The bats of Texas. Texas A&M University the Museum of Natural History, University of Kansas Press, College Station. 60:1–178. SCHWARTZ, C.W., AND E.R. SCHWARTZ. 2001. The wild YANCEY, F.C., II, AND C. JONES. 1996. New county records mammals of Missouri. 2nd revised edition. Univer- for ten species of bats (Vespertilionidae and Molossi- sity of Missouri Press, Columbia. dae) from Texas. Texas Journal of Science 48:137–142. SPARKS, D.W., AND J.R. CHOATE. 2000. Distribution, natural YANCEY, F.C., II, C. JONES, AND R.W. MANNING. 1995. The history, conservation status, and biogeography of bats eastern pipistrelle, Pipistrellus subflavus (Chiroptera: in Kansas. Pages 173–228 in J.R. Choate, editor, Vespertilionidae), from the Big Bend region of Texas. Reflections of a naturalist: papers honoring Professor Texas Journal of Science 47:229–231. Eugene D. Fleharty. Fort Hays Studies, Special Issue 1, Hays, KS. Received 15 March 2004 TOMELLERI, J.R. 1984. Dynamics of the woody vegetation Accepted 15 November 2004 along the Arkansas River in western Kansas, 1870– 1983. Master’s thesis, Fort Hays State University, Hays, KS. Western North American Naturalist 65(3), © 2005, pp. 410–414

BLUE TILAPIA (OREOCHROMIS AUREUS) PREDATION ON FISHES IN THE MUDDY RIVER SYSTEM, CLARK COUNTY, NEVADA

G. Gary Scoppettone1, J. Antonio Salgado1, and M. Bridget Nielsen2

Key words: blue tilapia, predation, Muddy River, Moapa dace, Moapa White River springfish.

Blue tilapia (Oreochromis aureus), native to the Warm Springs area (Don Sada, Desert North Africa and the Middle East (Courtenay Research Institute, personal communication). and Robins 1973, Fuller et al. 1999), has been It did not have access to the area, however, introduced around the world as a human food until February 1995 when a 1.5-m-high diver- source, for vegetation control, and as a game sion dam was removed. Within 2 years of dam fish (Costa-Pierce and Riedel 2000). Blue tilapia removal, blue tilapia had invaded 90% of the has been particularly successful in establish- Warm Springs area, and there was a marked ing and spreading in North American waters decline in native fishes (Scoppettone et al. where it has been reported to change fish com- 1998). By February 2001, snorkel surveys indi- munity structure and cause native fish decline cated that native fishes had been virtually (Courtenay and Robins 1973, Fuller et al. 1999). eliminated from sections of the Warm Springs Because of these detrimental effects, it is now area accessible to and inhabited by blue tilapia generally considered an unwelcome introduc- (James Heinrich, Nevada Department of Wild- tion into North American waters (Dill and life, personal communication). Most of the re- Cordone 1997, Fuller et al. 1999). maining population of Moapa dace and Moapa The 1st known introduction of blue tilapia White River springfish occurred in a tributary in Nevada was in the Muddy River (a.k.a. (Refuge Springs outflow) upstream of a natural Moapa River), Clark County, Nevada, and its barrier that had been enhanced to prevent blue arrival was followed by a decline in popula- tilapia movement upstream (Fig. 1). Endemic tions of native fishes (Scoppettone et al. 1998). fish habitat was reduced from about 5.9 km of The Muddy River is a 40-km-long tributary to stream in the Warm Springs area prior to the Colorado River system harboring 4 native tilapia invasion to <600 m (upstream of a bar- fishes, 2 of which are endemic. Moapa dace rier) post-invasion. This development provides (Moapa coriacea) and Moapa White River strong circumstantial evidence that blue tilapia springfish (Crenichthys baileyi moapae) are was responsible for the decline of native fishes known only from the headwaters of the Muddy in the Warm Springs area. River, referred to as the Warm Springs area. In its native habitat blue tilapia is described The river originates from over 20 thermal as a filter-feeder, consuming zooplankton and springs feeding 6 primary tributaries (Fig. 1). phytoplankton as well as aquatic vegetation The native Virgin River chub (Gila seminuda) and some invertebrates (Spataru and Zorn 1978). also occurs in the Warm Springs area but is In the Warm Springs area we observed aquatic considered thermal tolerant with greater abun- vegetation declining after the blue tilapia in- dance downstream, while native speckled dace vasion, following which tilapia persisted in occurs downstream from the Warm Springs robust numbers and native fishes declined. area (Deacon and Bradley 1972, Cross 1976, We hypothesized that after blue tilapia began Scoppettone 1993). to deplete aquatic vegetation, they switched to Blue tilapia was first observed in the Muddy fish consumption, which would be extraordi- River in 1991 immediately downstream from nary since piscivory has not been previously

1Biological Resources Division, U.S. Geological Survey, 1340 Financial Boulevard, Suite 161, Reno, NV 89502. 2U.S. Fish and Wildlife Service, 1340 Financial Boulevard, Reno, NV 89502.

410 2005] NOTES 411

Fig. 1. Map of the Warm Springs area showing the Apcar Spring outflow and the Muddy River. Also shown is the Refuge Spring outflow and tilapia barrier. In bold is the 600 m of stream habitat haboring virtually all remaining Moapa dace and Moapa White River springfish in 2001. Inset shows the Muddy River system in relationship to State of Nevada and Lake Mead. reported for blue tilapia. In this study we Warm Springs. A 0.6-m-high weir (USGS weir) investigate blue tilapia fish predation in the at Warm Springs Road approximated the be- Warm Springs area of the Muddy River. ginning of the Warm Springs area (Fig. 1). The Warm Springs area spring systems and Immediately upstream of the USGS weir, there river channel had been greatly altered and was a 1.5-m-high gabion dam that served to were inhabited by nonnative mosquitofish divert water to the Reid-Gardner Power Plant (Gambusia affinis) and shortfin molly (Poecilia until it was replaced with a no-head diversion mexicana) for decades prior to blue tilapia system in February 1995. (Hubbs and Miller 1948, Hubbs and Deacon We collected blue tilapia from the Apcar 1964, Scoppettone et al. 1998). This was the Spring outflow (n = 161) on 10 December 1998 case for the Apcar Spring outflow and the following rotenone treatment for tilapia eradi- mainstem Muddy River, source locations for cation (Fig. 1). Several weeks prior to treat- fish used in this investigation. The Apcar Spring ment, we minnow-trapped Apcar Spring out- outflow was 1.1 km in length and flowed at flow to capture and relocate native fishes; 34 0.06 m3 ⋅ s–1, half of which was diverted for Moapa dace and several hundred Moapa White municipal and agricultural use at the upstream River springfish were relocated. We also col- end. The stream channel was partially shaded lected blue tilapia (n = 35) along the Muddy by ash (Fraxinus sp.), cottonwood (Populus sp.), River upstream of Warm Springs Road to the nonnative fan palm (Washingtonia filifera), and junction of the north and south forks, on 6 tamarisk (Tamarix sp.). Before blue tilapia in- August 2000 using a 6.3-mm-mesh, 10.1-m- troduction, approximately 90% of the stream long, 1.2-m-wide seine. Captured blue tilapia bottom was covered with the macrophyte Val- were slit with a scalpel ventral to the digestive lisneria. In the Warm Springs area the Muddy tract, fixed in 10% formalin, and stored in 45% River flowed in a deeply incised channel, and ethanol. The Apcar blue tilapia were placed in the predominant riparian vegetation was tama- formalin within 20 minutes of their exposure risk and fan palms. Prior to tilapia entering the to rotenone, and Muddy River blue tilapia were Warm Springs area, Vallisneria carpeted the placed in formalin immediately after seining. main river channel almost 1 km upstream of For each fish we measured standard length 412 WESTERN NORTH AMERICAN NATURALIST [Volume 65

TABLE 1. Items ingested by blue tilapia (Oreochromis aureus) in 2 tributaries of the Warm Springs area by frequency of occurrence (f) and percent by volume.

______Apcar Spring 2/10/98 (n = 128) ______Muddy River 8/16/00 (n = 16) Food item f % volume f % volume Mosquitofish 42 19.42 5 23.75 Shortfin molly 1 0.79 — — Moapa dace 5 1.25 — — Moapa White River springfish 9 2.89 1 3.75 Blue tilapia — — 1 5.63 Unidentified fish 44 19.52 — — Aquatic invertebrates 31 3.28 2 4.69 Terrestrial invertebrates 2 0.80 — — Plant 58 32.97 11 61.56 Digested matter 35 19.07 1 0.62

(SL) and total length (TL) to the nearest mm. though they were judged to represent over 50% Standard length was also taken of prey fishes of the Apcar fish population. retrieved from the gut that were sufficiently In the Muddy River, 16 of 35 blue tilapia intact to obtain an approximate measurement. collected had stomach contents: 33% by vol- Stomach contents were examined and identi- ume of the items consumed were fishes, 75% fied using a dissection microscope. Items con- of which were mosquitofish (24% by volume; sumed were quantified by frequency of occur- Table 1). Moapa White River springfish as prey rence and mean percent by volume (Windell ranged from 17 mm to 19 mm SL. Two young 1971). Invertebrates were categorized as aquatic blue tilapia were part of the prey, accounting or terrestrial and fishes were identified to for 6% by volume of the items ingested. species. For those fishes that had been exten- This study adds predation to the list of sively digested, we used pharyngeal teeth, mechanisms (competition for space, competi- otoliths, and scales for identification. We cor- tion for food, and change in energy flow) by related predator (i.e., blue tilapia) SL with SL which blue tilapia can cause native fish decline of prey fish consumed. Significance of result- (Gu et al. 1997, Moyle 2002). The long gut of ing correlation coefficients was tested using this species is characteristic of herbivory (Costa- Table R in Rohlf and Sokal (1995). Pierce and Riedel 2000), but herbivory does Fish were found in guts of blue tilapia col- not preclude the ability to digest animal pro- lected in the Apcar Spring outflow and the tein (Hofer and Schiemer 1981). Blue tilapia is Muddy River. In the Apcar Spring outflow, fish apparently a successful fish predator, with sev- were the predominant diet by frequency of eral consuming numerous fish, including small occurrence and percent by volume. Of 161 adult Moapa White River springfish and Moapa blue tilapia collected, 128 had food items in dace. We also documented 2 occurrences of the gut. Of these, 101 had consumed a total of cannibalism by the species. 345 fish, accounting for 44% of the volume Blue tilapia adjusts its feeding strategy to consumed. Five had consumed a total of 11 reflect the relative abundance and composition Moapa dace, and 9 had consumed a total of 14 of available food (Gu et al. 1997), and we Moapa White River springfish (Table 1). Mos- found this adjustment may include fish con- quitofish were the predominant fish taken, with sumption. In the Apcar Spring outflow we 163 found in 42 stomachs; a 150-mm-SL blue assume that blue tilapia switched its diet from tilapia had consumed 25 mosquitofish. Mea- Vallisneria, after it was depleted, to fish. When surable fish prey ranged from 11.0 to 38.7 mm blue tilapia were first observed in the Apcar SL, with Moapa dace the longest (Fig. 2). Spring system in May 1997, over 400 were There was a significant (n = 64, r = 0.44, P = counted. At that time much of the stream was 0.01) positive correlation between blue tilapia covered with Vallisneria, and the Moapa dace SL and prey SL. Only 2 of 326 prey fish that population was extensive (>500), similar to could be identified were shortfin molly even what had been counted in previous surveys 2005] NOTES 413

Fig. 2. Predator blue tilapia standard length (SL) in relation to SL of 3 prey species.

(Scoppettone et al. 1992, 1998). In June 1997, Blue tilapia has proven to be similar to seven blue tilapia (140–240 mm fork length) Mozambique tilapia (Oreochromis mossambi- were captured and were full of Vallisneria cus) in dietary plasticity (Maitipe and De Silva (James Heinrich personal communication), sug- 1985) and ability to tolerate a broader range of gesting it was their primary food source. By 9 temperature (Stauffer et al. 1988) than most December 1998, the Apcar outflow was de- tilapia. Since its introduction to the Muddy nuded and the Moapa dace population had River system, it has spread from the warm collapsed from >500 to <70 (James Harvey water of the Muddy to seasonally cool waters personal communication). We collected fish of Lake Mead and the Virgin River (James samples from Apcar Spring outflow at a time Heinrich personal communication). Thus, its when blue tilapia had switched diet but native potential to spread into North American waters fishes had not yet been extirpated. We were is greater than once believed. This study sup- thus able to implicate blue tilapia piscivory as ports the suggestion that blue tilapia has had a a contributor to native fish decline. detrimental effect in North American waters The high number of fish taken in the Apcar and the recommendation that its introduction Spring outflow was not an artifact of rotenone and spread should be discouraged and existing application (i.e., blue tilapia taking dead and populations extirpated whenever possible. dying fish). First, with the application of rotenone, blue tilapia moved immediately to We thank Cynthia Martinez of the U.S. Fish the water surface, gasping for air, with no indi- and Wildlife Service for funding the project. cation of their preying on fish (James Heinrich Specimens were collected by M. Franz, S. personal communication). Second, many of the Goodchild, J. Heinrich, and S. Reinbold. We prey fish were in an advanced stage of diges- also thank Tom Strekal, Walter T. Courtenay, tion, indicating they had been taken before Jr., Kristin Swaim, Misty Johnson, and Mark treatment. Lastly, blue tilapia seined from the Fabes for reviewing the manuscript. Muddy River had also consumed fish, which was surprising since, other than blue tilapia and shortfin mollies, native fish were extremely LITERATURE CITED rare when the Warm Springs area was snorkeled COSTA-PIERCE, B.A., AND R. RIEDEL. 2000. Fisheries ecol- in February 2000 (James Harvey personal com- ogy of the tilapias in subtropical lakes of the United munication). States. Pages 1–20 in B.A. Costa-Pierce and J.E. 414 WESTERN NORTH AMERICAN NATURALIST [Volume 65

Rakocy, editors, Tilapia aquaculture in the Americas. mossambicus (Peters) populations in twelve man- Volume 2. World Aquaculture Society, Baton Rouge, made Sri Lankan lakes. Journal of Fish Biology 26: LA. 49–61. COURTENAY, W.R., JR., AND C.R. ROBINS. 1973. Exotic MOYLE, P.B. 2002. Inland fishes of California. University aquatic organisms in Florida with emphasis on fishes: of California Press, Berkeley. a review and recommendations. Transactions of the ROHLF, F.J., AND R.R. SOKAL. 1995. Statistical tables. 3rd American Fisheries Society 102:1–12. edition. W.H. Freeman and Company, Stony Brook, CROSS, J.N. 1976. Status of the native fish fauna of the NY. Moapa River (Clark County, Nevada). Transactions SCOPPETTONE, G.G. 1993. Interactions between native and of the American Fisheries Society 105:503–524. nonnative fishes of the upper Muddy River, Nevada. DEACON, J.E., AND W. G. B RADLEY. 1972. Ecological distri- Transaction of the American Fisheries Society 122: bution of fishes of Moapa (Muddy) River in Clark 599–608. County, Nevada. Transactions of the American Fish- SCOPPETTONE, G.G., H.L. BURGE, AND P.L. TUTTLE. 1992. eries Society 101:408–419. Life history, abundance, and distribution of Moapa DILL, W.A., AND A.J. CORDONE. 1997. History and status dace (Moapa coriacea). Great Basin Naturalist 52: of introduced fishes in California. Fish Bulletin 178, 216–225. Department of Fish and Game, State of California SCOPPETTONE, G.G., P.H. RISSLER, M.B. NIELSEN, AND Resources Agency, Sacramento. J.E. HARVEY. 1998. The status of Moapa coriacea and FULLER, P.L., L.G. NICO, AND J.D. WILLIAMS. 1999. Non- Gila seminuda and status information on other fishes indigenous fishes introduced into inland waters of of the Muddy River, Clark County, Nevada. South- the United States. American Fisheries Society Spe- western Naturalist 43:115–122. cial Publication 27, Bethesda, MD. SPATARU, P., AND M. ZORN. 1978. Food and feeding habits GU, B., C.L. SCHELSKE, AND M.V. HOYER. 1997. Intrapop- of Tilapia aurea (Steindachner) (Cichlidae) in Lake ulation feeding diversity in blue tilapia: evidence Kinneret (Israel). Aquaculture 13:67–79. from stable-isotope analyses. Ecology 78:2263–2266. STAUFFER, J.R., JR., S.E. BOLTZ, AND J.M. BOLTZ. 1988. Cold HOFER, R., AND F. S CHIEMER. 1981. Proteolytic activity in shock susceptibility of blue tilapia from Susque- the digestive tract of several species of fish with dif- hanna River, Pennsylvania. North American Journal ferent feeding habits. Oecologia 48:342–345. of Fisheries Management 8:329–332. HUBBS, C., AND J.E. DEACON. 1964. Additional introduc- WINDELL, J.T. 1971. Food analysis and rate of digestion. tions of tropical fishes into southern Nevada. South- Pages 215–226 in W.E. Ricker, editor, Methods for western Naturalist 9:249–251. assessment of production in fresh waters. IBP Hand- HUBBS, C.L., AND R.R. MILLER. 1948. Two relict genera of book 3. Blackwell Scientific Publications, Oxford cyprinid fishes from Nevada. University of Michigan and Edinburgh, UK. Museum of Zoology Occasional Papers 507:1–30. MAITIPE, P., AND S.S. DE SILVA. 1985. Switches between Received 3 February 2004 zoophagy, phytophagy, and detritivory of Sarotherodon Accepted 15 November 2004 Western North American Naturalist 65(3), © 2005, pp. 415–416

BOOK REVIEW

Inland Fishes of California. 2002. Peter B. importance of these teeth to some fishes and Moyle; illustrations by Chris Mari van give the beginner some understanding of the Dyck and Joe Tomelleri. University of reasons ichthyologists consider them impor- California Press, Berkeley and Los Ange- tant. I lacked material to test the keys but they les, California. $70.00, cloth; 502 pages should work, even for difficult groups (lam- + xv. ISBN 0-520-22754-9. preys, juvenile salmonids, sculpins). I’m a fan of keys where alternatives in binary couplets The production of “state fish books” has are illustrated as one progresses through the been a growing industry in recent decades and key, but perhaps this isn’t necessary in this rel- some, like this one, are now appearing as re- atively simple fauna. Cautions to users are vised and dressed-up editions. This new edition given in footnotes. is fully justified by massive changes in the Species accounts include identification, tax- California environment, continuing establish- onomy, names, distribution, life history, and ment and spread of nonnative fishes, and in- status. References are numbered in the text creasing knowledge of California fishes in their with author and date at the end of each account. ecosystems. The author and his associates have Gray literature and personal communications done a significant portion of this research, are cited, which I consider useful and appro- especially on nongame species often ignored priate. Distribution maps, most of which are by management agencies. quite adequate, are shaded instead of the dot The book consists of 4 introductory chap- format which many prefer. The maps are small, ters (Distribution Patterns, Ecology, Change, making isolated populations hard to locate since and A Conservation Strategy) followed by some are not circled. In other cases, some Identification and Keys and ~350 pages of localities mentioned in the text, such as the family and species accounts. The introductory original established populations of the intro- chapters are outstanding. Zoogeography and duced wakasagi smelt, are not mapped. Maps ecology of this large, complex region and its include symbols denoting status and habitat; I fishes are clearly discussed with support from learned to cope with these while reading the good maps and nice figures of fish community book but found them cryptic a few weeks later organization, distributional patterns, etc. Were when I went back to a single account. All I still teaching, I’d borrow some of these fig- species are illustrated with excellent drawings, ures to project in lectures. The mismatch of most by C.M. van Dyck. Color plates by J. California’s human population with water avail- Tomelleri are up to the artist’s usual high stan- ability, coupled with other environmental dam- dards; about one-third of the 37 plates are age and the influx of nonnative fishes, requires salmonids, but my favorites are the Lahontan a chapter on change. This litany of replacement redside and the riffle sculpin (common names and loss is followed by a logical justification are used in figure captions, text, and the ex- for conservation and a multi-layered plan for tensive tables in the introductory chapters). aquatic conservation in California. Enough is known about California popula- The introductory material for the keys is tions of most of the 67 native species and 51 in- adequate but brief. Pharyngeal teeth, although troductions to warrant lengthy species accounts. mentioned here and in the species accounts, The longest (chinook salmon) is 11 pages and are not illustrated. A picture of the sharp pha- details the biology and status of evolutionarily ryngeals of a pikeminnow vs. the molariform significant units (ESUs) and distinct spawning ones of a sucker would show the functional runs. Because the author’s stated bias is toward

415 416 WESTERN NORTH AMERICAN NATURALIST [Volume 65 native species, minnows, sculpins and the live- this is a fine book. Aquatic biologists working bearing tule perch, all receive thorough cover- in California must have it, all westerners will age. Details of variation, distribution, and status find it useful, and easterners will benefit from are given for polytypic species such as the tui the contrast of the very different western and chub. Introductions, dispersal, ecological effects, eastern fish faunas. Moyle’s emphasis on con- and control activities are recorded for non- servation extends far beyond the borders of native species. California and deserves to be read everywhere The book, including figures, is well pro- fishes, water, and human populations interact. duced, although I tallied a dozen misspellings of place, person, and organism names. Most of Andrew L. Sheldon the book is accessible to nonprofessionals 16 Bryant St. although lake areas are given in hectares and Crawfordville, FL 32327 no conversion is given. These quibbles aside,