Great Basin Naturalist

Volume 58 Number 3 Article 12

7-1-1998

Full Issue, Vol. 58 No. 3

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VOLUME 58 n2naN 3 JULY 1998

ML BEAN LIFE SCIENCE MUSEUM

BRIGHAM YOUNG university GREAT BASIN naturalist httpwwwlibbyuedunms FAX 8013783733801 378 3733 editor alsistaassistaassistantnt editor richardwbaumannRICHARD W BAUMANN NATHAN M SMITH 290 MLBM 190 MLBM PO box 20200 PO box 26879 brigham young university brigham young university provo UT 84602020084602 0200 provo UT 84602687984602 6879 8013785492801 378 5492 8013786688801 378 6688 emailE mail richardricharclbaumannbyuedubaumannbyuedu emailE mail nathan smithbyuedu

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JAMES C CALLISON JR PAUL C MARSH department of environmental technology center for environmental studies arizona utah valley state college state university tempe AZ 85287 orem UT 84058 JERRY H SCRIVNER BRUCEDBRUCE D ESHELMAN department of biology department of biological sciences university of ricks college wisconsin whitewater whitewater WI 53190 rexburgredburgRexburg ID 83460110083460 1100

JEFFREY J JOHANSEN STANLEY D SMITH department of biology john carroll university department of biology university heights OH 44118 university of nevada las vegas laslasvegaslosvegasvegas NV 89154400489154 4004 BORIS C kondratieff department of entomology colorado state ROBERT C WHITMORE university fort collins CO 80523 division of forestry box 6125 west virginia university Morganmorgantowntown WV 26506612526506 6125

editorial board richard A heckmann chair zoology berranjerran T flinders botany and range science duke S rogers zoology bruce A roundy botany and range science richard R tolman zoology larry L st clair botany and range science H duane smith monte L bean life science museum all are at brigham young university ex officio editorial board members include steven L taylor college of biology and agriculture and richard W baumann editor great basin naturalist the great basin naturalist founded in 1939 is published quarterly by brigham young university unpublished manuscripts that further our biological understanding of the great basin and surrounding areas in western north america are accepted for publication subscriptions annual subscriptions to the great basin naturalist for 1998 are 25 for individual sub- scriscribersbers 30 outside the united states and 50 for institutions the price of single issues is 12 all back issues are in print and available for sale all matters pertaining to subscriptions back issues or other busi- ness should be directed to the editor great basin naturalist 290 MLBM PO box 20200 brigham young university provo UT 84602020084602 0200 scholarly exchanges libraries orotorotberor otherherber organizations interested in obtaining the great basin naturalist through a continuing exchange of scholarly publications should contact the exchange librarian 6385 HBLL PO box 26889 brigham young university provo UT 84602688984602 6889

editorial production staff joanne abel technical editor emailE mail jyaemailbyuedu copyright 0 1998 by brigham young university ISSN 001736140017 3614 official publication date 1 july 1998 6986 98 750 26629 the great basin naturalist PUBLISHED AT PROVO UTAH BY MLM L BEAN LIFE SCIENCE MUSEUM BRIGHAM YOUNG university

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VOLUME 58 31 JULY 1998 no 3

gleatgreat basin naturalist 583 0 1998 appp 199 216

GAP ANALYSIS OF THE vegetation OF THE intermountain semidesertSEMI DESERT ECOREGION

david A stornslstoms1 frank W davisi kenneth L drieseldnese2driese2 kelly M Cassidy 3 and michael P murray4murraya

ABSTRACT A conservation gap analysis was conducted for the intermountain semidesertsemi desert ecoregioneco region to assess the representation eflandoflandof land covelcover types within areas managed primarilypnmai ilyliy for diversitybiobiodiversity objectives mapped distributions of plant communities were summarized by land management status categories the total amount of land permanently pro- tected in the ecoregionecoiegionecoregion is 4 and most types that are characteristic of the regionlegion have 10 of 48 land cover types 20 weiewere found to be particularly vulnerable to potential loss 01or degradation because of low level ofofieofleofiepresentationpresentationrepresentation in bio diversity management areas and the impact of expected land use activities gap analysis data and findings will be useful in providing a regional perspective in project impact assessment and future conservation planning within this ecoregionecoiegioneco region

key words gap analysis land cover land management conservation assessment national vegetation classification system alliance

in recognition of the alarming but largely species noss 1987 franklin 1993 oriansorlans unmeasured conversion and degradation of 1993 while this approach sounds straightfor- native habitat many conservation biologists ward in principle a lack of comprehensive have recommended protecting representative and consistent data on the extent location samples of all natural ecological communities and management of ecological communities as a goal for preserving biological diversity makes it quite challenging to implement fun- eg shelford 1926 committee on the study damentalda questions have often been beyond of plant and animal communities 1950 51 our capacity to answer with any confidence austin and margules 1986 shafer 1990 scott for example how well are community types et al 1993 underlying this coarse filter represented in areas specially managed for the approach is the assumption that protecting preservation of diversitybiodiversitybio ecosystems or habitats will simultaneously scott et al 1993 outlined a gap analysis confer protection on most plant and animal methodology to identify the underrepresented

institute foifolfor computational eaithearth system science university of california santa barbarabalbara CA 93106 2departmentepaitment of botany university of wyoming laramieLa ramieiamie WY 82071 swashmgton3washingtoncwashington cooperative fish and wildlife researchRe seaich unit university of washington box 357980 seattle WA 98195 idaho cooperative fish and wildlife research unit university of idaho moscow ID 83844

199 200 GREAT BASIN naturalist volume 58 plant communities or gaps in the representa- program reviewers zube 1994 dellasala et al tion of biological diversity in areas managed 1996 very little land in the ISD ecoregionecoregion has primarily foiforboibolhorbor longtermlong term maintenance of native been designated for maintenance of biodiver wildlife populations and natural ecosystems sity while potentially conflicting land uses such this approach uses medium scale mapping of as grazing and cultivation are extensive land cover and land management as the only enough undeveloped habitat remains how- practical solution for assessing the conserva- ever for preactiveproactiveproactive conservation action to be tion status of diversitybiodiversitybio across ecological effective thus the ISD ecoregionecoregion makes a regions covering hundreds of thousands of representative case study that could be applied squalsquaree kilometers originating as a pilot study to other regions throughout the western US in idaho scott et al 1993 caicco et al 1995 planning for conservation and ecosystem man- gap analysis has been expanded into a national agement within this ecoregionecoregion is underway by gap analysis program GAP coordinated by the nature conservancy sandy andelman the biological resources division of the USU S personal communication oregon biodiver geological survey formerly the national bio- sity project vickerman 1996 and interior logical serviceSeivice initial published results have columbia basin ecosystem management pro- focused on analyses at the state level for idaho ject a joint effort by the US forest service caicco etalet al 1995 utah edwards et al 1995 and bureau of land management quigley et and wyoming merrill et al 1996 since its al 1996 BLM is considering wilderness pro- inception however GAP has aimed to provide posals in wyoming merrill et al 1996 propos- a national conservation assessment based on als for new wilderness areas in idaho merrill ecological rather than political planning regions et al 1995 and wyoming merrill et al 1996 scott etetalal 1993 and for new national parks wright et al 1994 the objective of this paper is to report the wright and scott 1996 are being discussed A results of the nationnatiorsots s first multistatemultimultistagestate gap regional gap analysis can add valuable infor- analysis of plant communities of the intermoun mation for all of these planning programs taintam semidesertsemi desert ISD ecoregionecoregion fig 1 as currently delineated in the USU S forest service s intermountain semidesertSEMI DESERT ECOMAP program ECOMAP 1993 bailey ECOREGION 1995 ownership and management status of US forest service s national hierarchi- land cover types within the ISD ecoregionecoregion the cal framework of ecological and 2 subregions are summarized poorly units ECOMAP 1993 was adopted for this ecoregionalecoregional gap represented types are identified and the high- analysis division of regional units is est conservation priorities are identified sec- this widely used both by federal agencies and ondarily discuss the ondarily we some ecological and car- nature conservancy the nature conser- totographic issues of this approach to regional issues vancy Ecoecoregionalregional working group 1996 as assessment technical aspects of conservation the basis for resource assessments the frame- regional will be treated in stoms et mapping in work subdivides the earth s surface into suc- al in press although gap analysis as defined cescessivelysively smaller more homogeneous land by scott et al 1993 typically includes verte- units the highest level called the domain is brate species distributions here we report only associated with broad climatic regimes and plant community types gross physiography domains are split into divi- this ecoregionecoregion was selected for the proto- sions based on vegetational affinities provinces type regional gap analysis for both practical are subdivisions of a division corresponding to and conservation reasons from a practical continental weather patterns soil orders and standpoint the ISD ecoregionecoregion was among the potential natural vegetation domains divisions first for which the requisite land cover and and provinces are all categorized at the eco land management mapping were completed regional level in the framework provinces can by individual state level CAPGAP projects addi- be progressively subdivided into subregions tiotionallynally the area provides a suitable testing landscapes and ultimately land units at the ground foifolforooloor demonstrating whether GAP can project planning level the ISD ecoregionecoregion overcome technical challenges associated with used in this gap analysis is a province in the regional mapping that have concerned some ECOMAP hierarchy 199811998 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 201

0 100 200 300 400 500

kilometers

fig I1 shaded relief image of the intermountainIntel mountain semidesertsemi desert ecoregionecoregion and the 2 subregions columbia plateau and wyoming basin

the ISD ecoregionecoregion encompasses approxi- the combination of soils and climate gen- mately 412000 km2 in portions of washing- erates a characteristic vegetation often called ton oregon idaho nevada california utah 11 sagebrush steppe klichKilchkiichlerlerier 1970 dominated wyoming colorado and montana fig 1 by artemisia sppapp or atriplex conferticonfertifoliafolia shad two geographically disjunct subregions make scale with short bunchbunchgrassesgrasses eg festuca up the larger ecoregionecoregion the columbia plateau sppapp pseudoroegneria sppapp the rainrainshadowshadow in the west and the wyoming basin in the effect produced by the cascade sierra nevada east the ISD boundary corresponds closely ranges favors shrub cover and limits tree cover to the limits of kiichkilehKilchkiichlerlerier s 1970 sagebrush to higher elevations mostly conifers and aspen steppe potential natural vegetation type the narrow riparian corridors or sparse pinyon or ISD ecoregionecoregion southern boundary grades into juniper woodland in low lying alkaline areas the intermountain semidesertsemi desert and desert formed in pleistocene lake beds and subject to province which tends to be warmer drier and periodic flooding sagebrush is replaced by with greater topographic relief than the ISD saltbush atriplex and greasewood sarcoba- ecoregionecoregion the cascade and sierra nevada tus communities shrub species are replaced ranges bound the ecoregionecoregion on the west and by perennial grasses where deeper soils occur the northern rocky mountains on the north most relatively level land with adequate water and east supplies has been converted to agriculture 202 GREAT BASIN naturalist volume 58

west 1988 nonnativenormative annual grasses espe- homer et al 1997 cassidy min press although cially cheatcheatgiasscheatgrassgrass bromus tectoriumtectorumtectorum have inin- most state GAP projects used 1990 2 yr vaded the legionregion since the 1870s successfully satellite imagery from the landsatlandsaw thematic convertingconvel ting native steppe communities to exotic mapper TM sensor combined with heldbeldbeidfield grassland west 1988 and dramatically affect- inventories and existing maps of vegetation in ing ecological processes of this vegetation type compiling their land cover data they differed despite the relatively homogeneous appear- in methods and products maps for idaho ance of sagebrush steppe the ecoregionecoregion is caicco et al 1995 and oregon kagan and floristically complex foifor instance there are 8 caicco 1992 used photomterpretationphotointerpretationphotointerpretation tech- species 01or subspecies of artemisia that domi- niques with older lower resolution multispec nate variousvaliousvallous plant communities three juniper trai scanner MSS images and had larger min- and 2 pinyon species occur in different por- imum mapping units than the other states in tions of the ecoiegionecoregionecorexionregion contrast land cover mapping in nevada and utah was done with digital image processing MEHIODSMETHODS rorFORpor A REGIONAL of TM image mosaics homer et al 1997 this GAP ANALYSIS approach generally achieved greater spatial resolution at some expense in classification the fnfirsthirstbirstan st critical issue in mapping land cover detail the other state projects fall somewhere is selecting a classification system that is eco- in between these methods using manual pho logically defensible and yet feasible for map- tointerpretation of higher resolution TM data ping at a regionallegionallonallonai scale with i emoteremote sensing ege g davis et al 1995 driese et al 1997 cas- and limited field information the alliance level sidy in press few maps have been validated of the proposedpioploposed national vegetation classifi- with a formal accuracy assessment except see cation system NVCS federal geographic caicco et al 1995 edwards et al 1995 data committee 1996 was selected as the for this regionalecoecoregional analysis a regional most appropriate schema derived from the land cover map was required but with greater UNESCO system UNESCO 1973 driscoll et spatial and thematic consistency than was con- al 1984 this hierarchical scheme begins with tained in the collection of state level maps structural and broad ecological properties at therefore an innovative technique was devel- higher levels adding flonsticflonfionfloristicsticstie divisions at lower oped to utilize the state GAP maps as training levels alliances aiealeare named by their dominant data and then reclassify satellite data into a canopy species within structural classes based common set of NVCS cover types first all on lifeilfe form and canopy closure proposed land cover classes in the state GAP maps were NVCS standardsstandaids define closed tree canopy converted to alliances as prescribed by the iei e foiestforest as tieetreeatiee cover of 60 100 open NVCS in some cases it was necessary to aggre- tree canopy 01or woodland with 25 60 tree gate to a higher level where dominant species cover shrubland classes with 25 shrub could not be distinguished in related alliances cover and 25 tree cover and herbaceous ege g deciduous riparian forest types pixels of classes with 25 shrub or tree cover an multi temporal satellite imagery from the example afanofanof an alliance in the ISD ecoregionecoregion NOAA advanced very high resolution radi- would be the pinus ponderosa alliance within ometer were then assigned to these cover the rounded ci ownedcrowned temperate or subpolar types using a maximum likelihood classifier needle leaved evergreen open canopy tree some cover types that were either rare or formation because the samesarne dominant species occur in small patches were not classified with also occurss within a closed canopy tree forma- the I1 km2 satellite data but were retained from tion there are 2 P ponderosa alliances distin- the original maps thus the final map had a guished by canopy closure for simplicity we consistent spatial resolution 1 km2 or 100 ha use the teimternisforestforest and woodland in the text pixel size across the entire ISD ecoregionecoregion in place of the closed and open canopy termi- while retaining the best floristicflon sticstie information nology when referring to land cover classes from the original maps stoms et al in press land covelcover was ongoriginallymallymaily mapped inde- although a comprehensive map accuracy pendently loilolfoifor each of the states in the ISD assessment of the regional land cover map has ecoecoregionecoiegionrexionregion kagan and caicco 1992 caicco et not been undertaken the map was compared al 1995 davis et al 1995 driese et al 1997 to a set of randomly distributed 1 km2 field 199811998 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 203 plots compiled nationwide by the USU S forest the majority of the area but subject to eftiextiextractiveactive service zhu et al 1996 seventy eight of uses of either a broad low intensity type or these plots occur within the ISD ecoregionecoregion localized intense type it also confers protec- this small sample size is insufficient for a sta- tion to federally listed endangered and threat- tististicaltical peipelper elassclass assessment but adequate for a ened species throughout the area undesig- preliminary indication of the strengths and nated public lands managed by the USU S forest weaknesses of the land cover map each plot service or the BLM are examples of this status record listed dominant tree andor shrub category species and their relative canopy cover total status 4 lack of legally enforced easement absolute tree cover in classes similar to the or mandate to prevent conversion of natural NVCS definitions of open and closed canopy habitat types to anthropogenic habitat types presence of grasses identified as annuals or allows for intensive use throughout the tract perennials and presence of agriculture based also includes those tracts for which sufficient on species composition and cover each plot was information to establish a higher status is not assigned to one or in some cases to a set of the available privately owned lands except for pri- cover types in the regional land cover map vate conservation group reserves most depart- maps of land stewardship and landmanland man ment of defense tracts and state school lands agementagemcntargement status were also compiled for individ- are included in this category ual state gap analysis projects usually by digi- intersecting the land-s tewardsbipstewardship and man- tizing BLM surface management status maps agement map with the distribution of land maps of special managed areas were compiled cover classes results in tables that summarize from a wide variety of sources see caicco et al the area and percent of total mapped distribu- 1995 and davis et al 1995 for details these tion of each class in different land stewardship maps were combined to createci eateaate a regional map and management categories the percentage GAP uses a scale of 1 4 to denote relative and acreages of cover types in each manage- degree of maintenance of diversitybiodiversitybio for each ment status category and managed by each tract of land A status of I1 denotes the highest steward were quantified caicco et al 1995 most permanent level of maintenance and 4 represents the lowest level of diversitybiodiversitybio RESULTS management as evidenced by legal and insti- land cover and alliances tuttutionalional factors each tract of land is assigned to I1 of the 4 status levels as defined by scott et forty eight land cover classes were mapped al 1993 for the legionregion table 1 including 2 cultural status 1 an area having permanent protec- land use types 5 vegetatednonnonvegetated or sparsely tion from conversion of natural land cover and vegetated types 16 formations or undifferenti- a mandated management plan in operation to ated groups of related alliances and 25 alli- maintain a natural state within which distur- ances formations tend to be relatively scarce bance events of natural type frequency and types that occur in small patches or as linear intensity are allowed to proceed without inter- features for instance the seasonallytem ference or are mimicked through management poraporarilyrily flooded cold deciduous forest forma- included are research natural areas many tion consists of alliances dominated by populus wilderness areas national parks and monu- tremultremuloidesoides P fremonbremonfremontiifremontnfremontiapremontiitn P balsamiferabalsamifera P ments and nature conservancy preserves angustifoliaangustifoha or other riparian tree species at status 2 an area having permanent protec- the regional scale it was not feasible to dis- tion from conversion of natural land cover and criminate between them species of pinyon a mandated management plan in operation to and juniper have overlapping range except maintain a primarily natural state but which juniperuslumJumtumperus occidentoccidentalisoccidentahsoccidentalistalisallsails which has a distinct may receive use or management practices that geographic range and so were grouped into 3 degrade the quality of existing natural commu- more general classes similarlySimilailyally 2 Cercocercocarpuscarpus nities most national wildlife refuges areas classes C ledifoliusledifohuslediledlfolius and C montanus that of critical environmental concern and some occur in the ecoregionecoregion could not be distin- state parks are included in this category guished in the land cover mapping mixes status 3 an area having permanent protec- of canopy species with no clear dominantsdominants tion from conversion of natural land cover for were also mapped at the formation level this 204 GREAT BASIN naturalist volume 58

ta13i&ilalilcalil I1 1 percentagePei centage of mappedofmapped aleaarea ofoflcindland covelcover classes by management status in the intermountain semidesertsemi deseitdesertdeceit ecoccoceoecoiegionccoregionregion formationforFoi mationmatlon names shown in bold italics

status 1 status 2 status 3 status 4 total area of land covelcover class N N km2 ecoregionecoregion rounded crowned temperate or subpolar needle leaved evergreen closed tree canopy pinus confortacontoconfortatortata forestfoifol est 141 41 729 89 2726 07 pinus condeipondeiponderosaofaosa foresthorestfoifol est 00 36 424 540 106 01 pinus ponderosa pseudotsuga menzieinenziesiimenziesnsn forestfoiestbolesthorest 00 04 474 522 1350 03 conical crowned temperate or subpolarsulsuf polar needle leaved evergreen closed tree canopy abiesables species A concolor A grandis 01or A magnified foresthoresttoltoifol est 01or woodland 00 23 514 463 183 01 picea engelengelmanniiengelrnanmiengelmanniamannii andolandor abies lasiocarpalasiocampa forest 01or woodland 59 02 713 225 606 01 pseudotsuga menziemenziesiimenziesiamenzie&nsiisllsli foiestlorestforest 14 12 638 335 3335 08 montane or boreal cold deciduous closed tree canopy populus tremuloidestremultrernuloide&oidesoldes foiestforesthorest 56 44 596 304 1038 03 seasonallytemporarilySeasonallyseasonallyltemporarilyfloodedtemporarily flooded cold deciduous closed tree canopy populusfiremontiilopiduspopidus fremonbremonfremontnfremontetn P balsambalsamiferabalscimiferaifera P angustifolia P treinuloidestreinuloidef alixsalix alnus betula etc 25 119 141 715 1053 03 roundedpounded crowned temperate or subpolar needle leaved evergreen open tree canopy pinyon woodland pinus adulisedulis 01or P monomonophyllamonophijllaphylla 00 01 526 473 332 01 pinyon juniperiinipei woodland pinus adulisedulis 01or P monomonophyllaphylla with Jumhumjuniperusjumperusperuspeyus osteospenaosteosperma orjjorj01 scopulorumticopulorum 111 00 511 377 391 01 juniper woodland juniperus osteospennaosteosperma 01or J scopulorwnscopuloruin 02 38 571 389 6728 16 juniperus ocadentalisoccidentalisoccidentoccidentalistalisallsails woodland 11 20 510 460 17609 43 pinusflexilisbinuspinus flexihs 01or P albialblalfncaulnalbicauliscauliscautis woodland 72 05 446 477 1141 03 pinus confortacontortacontorta woodland 138 72 522 268 373 01 pinusjefireyipinus jeffreiit foiestforest and woodland 00 00 680 320 181 01 pinus ponderosa woodland 01 30 379 590 7599 19 conical crowned temperate or subpolar needle leaved evergreen open tree canopy pseudotsuga inenziesiimenzie&n woodland 09 02 706 283 706 02 cold deciduous open tree canopy populus tremultremuloidesoides woodland 13 19 504 463 1896 05 ouerQuerquercuscuicus garryanagarryana woodland 00 30 137 833 643 02 microphyllous evergreen shrubland arteinisiaarteniisiaArtenitsiaisiaista ttltntrltridentata sspasp vastyanavasevaseyanayana shrublandslnubland 08 26 505 460 24702 60 artemisia tridentata A arbuscula shrublandshishl nalandnbland 06 48 687 260 46047 112 artemisia tntritrldentata shrublandsill ublandobland 11 29 637 323 117263 286 artemisia tripartitetripartitatrip artita shrublandshishl nlilandneiland 00 14 294 691 3494 09 purshia ttltntridentata shrublandshishl ublandobland 00 03 299 698 1071 03

aggieaggregationgationgatlon occurred lorfortor cover classes such as alliance is defined by a subspecies mountain mountain brush in the temperate cold decidudecidua big sagebrush artemisia dentatatritridentatatridentate sspasp vasey ous shrub formation mixed salt desert shrub ana where it could be mapped separately primarily composed of various atnplexatriplex species from other A dentatatritridentatatridentate subspecies and grassland types grasses were divided three land use or land cover types account into drydi y eg pseudoroegnenapseudoroegneria and poa sppapp for 57 of the region artemisia dentatatritridentatatridentate and moist ege g festuca sppapp perennial bunch 29 agriculture 17 and A dentatatritridentatatridentate A grass an annual grassland primarily the exotic arbuscula 11 other significant types include bromus tectoriumtectorumtectorum and artificial seedings of juniperus occidentoccidentalisoccidentalistalis 4 A tridentata sspasp agropyron cristatum or poa pratensispratensis one vastyanavaseyanavaseyana 6 mixed salt desert shrub 6 199811998 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 205

TABLE 1 continued

status I1 status 2 status 3 status 4 total aleaarea of land covelcover class M km2 ecoecoiegionecoregionregion temperate coldcoid deciduous shrubland artemisia cana shrubland 143 09 598 250 532 01 mountain brush shrublandshiublindbland 35 19 493 453 3339 08 Cercocercocarpuscarpus lediledlledifoliusledifohusfolius or C montanus shrublandshiushlubland 10 12 507 472 1136 03 quercus gambellgambehigambeln shrubland 00 01 176 822 379 ol01 seasonallytemporarilySeasonallyseasonallyltemporarilyfloodedtemporarily flooded cold deciduous shrubland 20 100 430 450 2568 06 extremely xeromorphic deciduous subdesertsubdesert shrubland with or without succulents sarcobatus vermiculatus shrubland 08 52 519 421 5996 15 facultatively deciduous extremely xeromorphic subdesertsubdesert shrubland mixed salt desert shrub atriplex sppapp 06 10 662 321 22668 55 dwarf shrubland artemisia nova dwarf shrubland 00 39 669 293 573 01 artemisia arbuscula A nova dwartdwarf shrubland 00 84 765 151 1813 04 artemisia ngidarigidabrigida dwarf shrubland 03 02 382 612 881 02 atriplex gardgardnengardeengardnerinerinerl dwarf shrubland 00 10 795 194 9898 24 temperate or subpolar perennial grassland dry grafigrasigraslgrasslandsand pseudoroegneria agropyron poa 02 43 189 765 21222 52 moist grassland festuca 00 31 78 891 1927 05 temperate or subpolar perennial grassland cultivated agropyron cricrlcnstatum seedings poa pratensispratensis hayfields and conservation reserve program lands 02 07 685 305 8267 20 temperate or subpolar annual grasslands orfordorforb vegetation annual grasses bromus tectorumtectoriumtectorum etc 07 06 505 482 11522 28 nontidalnon tidal temperate or subpolar hydromorphic rooted vegetation marsh and wetland 02 380 72 546 518 01 alpine and subalpine meadows oftheodtheof the higher latitudes alpine tundra 00 00 1000 00 3 01 wet or dry meadow 347 40 431 181 177 01 sparsely vegetated land cover types seasonallytemporarilySeasonally temporarily flooded sand flats 00 02 733 265 2341 06 sparsely vegetated sand dunes 09 264 476 252 851 02 sparsely vegetated boulder gravel cobble talus rock 02 34 649 315 2415 06 cultural land use types and surface water urban or human settlements and mining 1684 04 agricultureAgnculture 64473 157 open water including ponds 2220 05 regional totals including cultural land uses and surface water 090.9og 282.8 49549.5 46946.9 411277

and annual grassland 5 seventeen types were at least partially consistent such as where had mapped distributions of 1000 km2 each the same species were recorded but percent or 0250.25 of the regional area canopy cover in the plot would assign them to the land cover map and forest service field a different formation type than the map did plots showed general agreement thirty one the largest discrepancies tended to be between 40 of the plots were completely consistent grassland and sparse shrub cover in part be- with the land cover map in both structural cause it is difficult with satellite data to dis- and floristic attributes another 17 22 plots criminate accurately the 25 shrub cover 206 GREAT BASIN naturalist volume 58

threshold on a continuous gradient from grass but less formally protected land than the to shrub several state maps hadbad a sagebrush columbia plateau subregion steppe class that was always assigned to an if the status I1 and 2 managed areas are artemisia dentatatntritndentatatridentatatridentate alliance at the regional examined without regard to steward or site level even though in some cases the shrub name but are simply aggregated into disjunct cover might be 25 another 15 19 of the spatial units thelethere are 809 separate sites with plots that disagreed with the map were located a median size of just 252 ha mean size of 1886 within I1 pixel s width J1 km of a landscape ha of these 228 are 100 ha in size and with the correct type according to the plot another 399 are between 100 and 500 ha which could be attributed to a combination of despite the large number of small sites 78 map registration errorerron mixed pixels at eco of the total number they account for only 7 tones and more generally to the fuzzinessfuzzmess of of the area of all status 1 and 2 lands only 26 transitions between alliances absolutely wrong sites are 10000 ha but represent 70 of labels according to the plots were assigned to protected area five managed areas are each 13 17 samples we emphasize that this com- 50000 ha sheldon national antelope range parison is only indicative of the strengths and 220000 ha in northwestern nevada idaho weaknesses of the land cover map but due to national environmental engineering lab hart the small sample size conveys no statistical mountain national antelope range in oregon significance about its accuracy owaheeowyhee river bighorn sheep habitat area of critical environmental concern ACEC man- land stewardship and aged by the bureau of land management in management status idaho and malteurmalheur national wildlife refuge steens mountain ACEC complex in oregon sixty percent of the land in the ISD ecoreacore in gion is publicly owned table 2 the steward gap analysis of with the greatestgleatest holdings is the bureau of land cover classes land management 45445445.445 4 of the total land the profile of management status for each area the USU S forest service and state gov land cover type for the ISD eco einelneinmentsernmentsernments control slightly more than 4 each ecoregionregion is shown in table 1 this table can be summa- tribal lands account for 2.8228 8 of the 28 region rized by categorizing the percentage of total while the USU S fish and wildlife service area of each type within status 1 and 2 man- department of energy of department de- aged areas categories include types not rep- fense bureau of reclamation national park resented in any status 1 or 2 managed area service and county or regionalionallonallonai leg governments types with 1 1 10 10 20 20 50 and make up the remainder of public lands in in 50 the number of land cover types in descending order of private lands includ- area each category for the region and for each sub- a very small of nongovernmen- ing proportion region is shown in table 4 despite the low tal organization holdings constitute nearly 40 level of representation across most types the gigreater than 96 of is eater the ecoregionecoregion is man- representation is an unbiased sample of the aged such that eftiextractiveexti active resource uses are communities of the ISD ecoregionecoregion chi square permitted and biodiversitybio diversity conservation is not 525752.5752 57 43 df P 08490.8490 849 that is the pattern a 3 primary objective status and 4 table 2 of representation across types is not signifi- og only 090.90 9 3648 km2 is designated to be main- cantly different than if sites had been selected tained in its natural state by formal designa- with the intention of achieving equal repre- tion status 1 with an additional 282.82 8 11288 sentationsentation for all cover types km2 managed as status 2 lands fig 2 the TYPES WITH NO representation IN STATUS bureau of land management USU S fish and I1 AND 2 MANAGED AREAS only 2 natural wildlife service department of energy and land cover types aiealeare completely unrepre- state lands constitute the major stewards of sented within the ISD ecoregionecorcgionecoregion according to this protected land this regional pattern of the regional maps pinus jeffrejeffreyijeffreyjyi and alpine small proportions of status I1 and 2 with tundra similarly several cover types are not approximately equal amounts of status 3 and 4 represented in status 1 and 2 lands within I1 of is repeated in both subregions table 3 the the 2 subregions even though they are repre- wyoming basin has slightly more public land sented within the ecoregionecoregion as a whole these 199811998 GAP ANALYSISANALYSIS intermountainINTE OUNTAIN semiS semidesertEMIEMIDESERIDESERIDESERT ECOREGIOECOREGION in 207

TABLE 2 peicentageoflandbymcpercentage of land by managementinagement statusstat us by steward inin the intermountainintermoiInterintermormoimotetainmtain semidesertsemiserrusenrudserou desertClesel t ecoregioneco region status 1 status 2 status 3 status 4 aleaarea aleaarea steward M M Wkm2 N private including NGOs 01 05 01 994 163005 396 countyregionalCounty regional government 00 00 1000 00 2 00 state government 01 74 194 731 19381 47 bureau of land management 05 17 978 00 186663 454 national park service 735 265 00 00 317 01 USU S fish and wildlife serviceselvlee 298 688 14 00 4581 11liii1.11 1 US forestfoiest service 52 02 946 00 16857 41 tribal lands 00 00 00 1000 11488 28 department of energy 00 699 00 301 3441 08 bureau of reclamation 77 20 00 903 1160 03 military reservations corps of engineers 00 02 00 998 2161 05 largelallai ge water bodies 2220 05 ISD ecoregionecoregion total 09 28 495 469 411277 1000

TABLE 3 Peipercentageper centage of land by management status by subregion in the intermountain semidesertsemi desert ecoiegionecoregioneco region does not include watelwater bodies

status 1 status 2 status 3 status 4 aleaarea Subiesubregiongionglon M km2 wyoming basin 06 13 553 428 118942 columbia plateau 10 35 470 485 290617 ISD ecoregionecoregion total 09 28 495 469 409559

TABLE 4 the number of land covelcover classes at various percentagepeipel centage levels of representationrepiesentation in existing managed areas status level I1 and 2 combined does not include open water agropyron cncristastatumtuinturn seedings 01or culturaleuitcultuialulalulai land covetcover types not with with with with with

subregion represented 1 I1 1 10 10 20 20 50 50 total wyoming basin 4 7 14 2 4 0 31 columbia plateau 4 7 20 5 5 1 42 ISD ecoregioneco region total 2 7 26 5 4 0 44

unrepresented types in the columbia plateau the subregions in addition to those listed for include the pinus ponderosa forest and P con the ISD ecoregionecoregion are pseudotsuga menziemenziesiimenztesitmenziesiasiisil torta woodland alliances in the wyoming woodland and A nova in the columbia plateau basin unrepresented types are pinyon juniper and pinusflexilispinusflexths 01or P albialblalbicaulisalbtcauhscaulis woodland and woodland mountain brush Cercocercocarpuscarpus ledi dry perennial grassland in the wyoming basin folius or C montanus and purshia tridentata subregion TYPES WITH 1 I1 IN STATUS I1 AND 2 TYPES WITH 1 10 IN STATUS 1 AND 2 seven alliances or cover types have minimal twenty six types are in this category includ- representation 1 of their mapped extent ing the most widespread ones such as the varivarlvari- within the ISD ecoregionecoregion these include pinus ous juniperusJumperus and artemisia dentatatritrltridentatatridentatetrzdentata types ponderosa pseudotsuga menziemenziesiimenziesiasii forest pinyon sarcobatus vermiculatus and mixed salt desert woodland purshia tridentata quercus gambe shrub dry grassland and annual grassland the hiliiill artemisia rigidabrigida atriplex gardnerigardneri and artemisia ttltntridentata A arbuscula shrubland seasonallyseasonallytemporarilytemporarily flooded sand flats alkali type has proportions by status level that are playa minimally represented types in one of nearly identical to the region as a whole fig 3 208 GREAT BASIN naturalist volume 58

status 12

14 status 3

M axpx status 4 M

M 11 MY

0 100 200 300 400 500

kilometers

fig 2 land management status of the intermountain semidesertsemi desert ecoiecoecoregiondecoiregioneglon levels are defined inm the text

TYPESTYPLS WITH 10 20 IN STATUS 1 AND 2 the P confortacontorta forest alliance is similarly rep- five alliances or cover types have this level of resented in the wyoming basin presentationlerepresentation in the ecoregionecoregion these types TYPES WITH 50 IN STATUS I1 AND 2 are the pinus confortacontortacontorta forest alliance season there are no types in this category in the temporarilyallytemporarilyally flooded cold deciduous iei e ecoregionecoregion only the pinus flexilisflexilis or P albi riparian forest pinyonpryonpmyon juniperjumper woodland arte- caulis woodland type has 67 representation misia cana shrubland and seasonallytemporar in the columbia plateau subregion while the ily flooded cold deciduous shrubland wyoming basin has none TYPESTYPLS WITH 20 50 IN STATUS 1 AND 2 foulfour types are in this category the pinus discussion confortacontortacontorta woodland alliance nontidalnon tidal or sub- polar hydromorphic rooted limitations of regional vegetation iei e gap marsh and wetland wet or dry alpine or sub- analysis alpine meadows and sparsely vegetated sand gap analysis at the state or regional scale is dunes in addition to these types the season subject to limitations pertaining to its basic temporarilyallytemporarilyally flooded cold deciduous forest assumptions and those related to technological and shrubland types have this level of repre- limitations and ecological realities of mapping sentationsentation in the columbia plateau subregion a specific study area we address both forms 199811998 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 209

status 12

status 3

status 4

F 1 othertypesOther types

7

AL idti6t

0 50 100 150 200 250 300 350 400

kilometers

fig 3 land management status of the artemisia tntridentata A arbuscula shrubland type in the intermountainintel mountain semi- desert ecoregionecoregion levels are defined in the text here gap analysis is defined as an expanded quently may be omitted from or underestimated coarse filter approach to conservation scott et in the regional analysis their omission high- al 1993 it provides a baseline assessment of lights the need for complementary linetinefinehinebine filterfliter the distribution and management of biodiver assessments at more local scales to investigate sity elements at a given point in time As such a more complete range of diversitybiodiversitybio in a it attempts to characterize the variability of region As a baseline assessment gap analysis diversitybiodiversitybio across large geographic regions provides little or no information on current with moderately low resolution map informa- conditions or past trends in the community tion this rapid assessment requires the use of where changes in disturbance regime such as satellite remote sensing data supplemented the increase in fire frequency have caused a with a modest amount of field observation and conversion from sagebrush to dense annual any existing land cover maps some plant com- grasses the land cover map depicts the cur- munitiesmunities frequently occur in patches below rent grassland type but the loss of the original the 100 ha minimum mapping unit of the cur- cover type is undocumented impacts from rent mapping phase of gap analysis and conse grazing or other activities that change the 210 GREAT BASIN naturalist volume 58

quality oftheodtheof the cover type but not its classifica- TABLETAULE 5 correspondence of CAP status levels based on tion are not portrayed designation with management categories from the inte- rior columbia basin ecosystem management project A similar limitation of gap analysis is its ICBEMPJCBEMP based on actual and planned land uses on underlying assumption that land management national forest and bureau of land management lands status is determined by the intentions expressed the ICBEMP categories are summarized as follows I1 by the steward in formal designations or agency natural ecological processes 2 non intensive human uses mission statements not the actual or in conservation areas 3 4 low intensity human uses in permit- balance with ecological integrity 5 6 vegetation manip- ted land uses on specific tracts which tend to ulation for resource use 7 8 ecological conditions sig- be more difficult to ascertain for example nificantlynificantly altered by human activities public lands may be inaccessible or otherwise ICBEMP management categories not suitable for intensive resources uses and GAP be de facto wilderness areas GAP normally status level 1 2 3 4 5 6 7 8 assigns these lands to status 3 however be- 1 828 99 464.6 28 00 cause digital map information on site specific 2 604 203 10910.9log 78 07 management is not widely available and future 3 142 08 424.2 792 16 use is uncertain most lands under steward- ship of the department of defense are catego- rized as status 4 except for such dedicated in ways compatible with designated GAP sta- sites as research natural areas because there tus 1 and 2 premise of CAPGAPgae however is is no permanent protection offered for blodi the cae that without the assurance of formal designa- verversityhersitysity management may change with the tion the protection offered in current manage- needs of the national defense or with reassign- ment plans cannot be considered long term ments of base commanders some tracts of such areas currently managed for low intenanten department of defense lands however are sity uses could however be designated with relatively undisturbed compared to some other only minor economic impacts it should be public lands As regional scale data on land noted that the interior columbia basin assess- uses and other threats to biodiversitybio become diversity ment area does not cover the entire ISD widely available more in electronic form in the ecoregionecoregion and management category data future the vulnerability of ofcommunitiescommunities could were compiled for only BLM and USFS lands be more directly assessed by than using land the findings of this comparison of manage- classes management as a surrogate for threats ment classifications cannot necessarily be in the meantime this is the best approximation extended to private or to other public lands to test the validity of this assumption we despite general consensus among ecolo- compared the GAP land status map with a gists and conservation planners that conserva- map of categories of impact of permitted land tion assessments should be conducted over uses on natural ecological processes compiled ecologically and biogeographically meaningful for the interior columbia basin assessment regions there has been no universally accepted area quigley et al 1996 for the geographic system for mapping ecoregionsecoregions suitable for all area of overlap there was very close corre- purposes we chose the ECOMAP mapping of sponspondencedence between the status classifications regions bailey 1995 because it is in wide use based on designation and those based on per- throughout the forest service for ecosystem mitted uses table 5 GAP status levels 1 and management and forms the basis for regional 2 areas were primarily managed for maintain- planning by other groups the nature conser- ing natural ecological processes only 3 of vancy Ecoecoregionalregional working group 1996 it is these lands allowed intensive uses over 80 not clear how different our biological assess- of status 3 lands managed by the BLM and the ment might have been if a different regional- USFS were being managed for a variety of ization had been selected in general cover ecological and human needs most often with types in the 2 subregions hadbad similar manage- high levels of activity and vegetation manipu- ment status suggesting that relatively minor lation roughly 15 of the area in status level boundary adjustments would probably have 3 was also being managed for natural ecologi- little effect on the identification of conserva- cal processes and conservation of representa- tion gaps where atypical plant communities tive or rare diversitybiobiodiversity elements thus 16000 are present only near the boundary of the re- km2 of undesignatedofundesignated public land is managed gion we have not highlighted them as high 199819981 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 211

conservation priority no matter what ecoregionecoregion essary to aggregate to the formationfoieel mationmatlon level scheme one chooses the distribution of some thus the quantitative findings should be con- communities will span more than a single sidered as preliminary indications of potential region there may be biologically important gaps in the coarse filter representation of variation within such communities that is plant communitiescommnmties reflected by regionalecoregionaleco boundaries if one s management implications goal is to capture the full range of biological of the gap analysis variation of a type within special management areas it may be prudent to assess its status with these limitations in mind we draw on across its entire range one such approach is othelother published literature to interpret the raw to assess representation by latitudinal longitu- numbers provided by the analysis on the dinal and elevational variables which have basis of level of representation in status I1 and been found to vary with biotic composition 2 areas the degree to which land cover types and ecological processes mike scott personal are characteristic of the ISD ecoregionecoregion and communication the extent of historic loss or degradation of the land cover map of the ISD ecoregionecoregion habitat or modification of disturbance regime contains several limitations in classification we have tentatively categorized land cover that affect the findings of this analysis to an types by relative priority for conservation unknown degree aside from those related to attention higher priority categories are listed the omission of fine grain patches of commu- inm table 6 states in which more than 20 of nities the greatest source of uncertainty relates the mapped distribution occurs and stewards to canopy closure in assigning vegetation to who manage at least this amount are also formations source maps were not consistent shown in table 6 to alert principal stakeholdersstakeholders in how or whether forest and woodland were of planning and management responsibilities discriminated consequently identification of highest priority types have minimal blodi tree dominated formations in the NVCS hier- versityhersity protection and are vulnerable to archy is probably less reliable than dominant expected land use activities their extent and canopy species information tree dominated management status may be crudely estimated cover types however are minor components at the scale of regional mapping seasonally of the vegetation of the ecoregionecoregion and occur temporarily flooded cold deciduous forest and primarily at the margins the accuracy of the shrubland types generally occur in narrow lin- separation of grassland from shrubland along ear strips adjacent to rivers and streams while the continuous gradient of increasing shrub marshes and meadows tend to be quite small density is also uncertain in the land cover map these patterns make them difficult to map the greatest uncertainty between alliances comprehensively furtherpurtherFurtneinel they contain many occurs among various sagebrush species and different alliances consisting of a variety of subspecies which were not always distin- dominant species and so the status of individ- guished in the source maps to some extent ual riparian alliances is unknown riparian these were identified in the regional land types depend on flood scouring for germina- cover map with elevation data the final point tion which has frequently been prevented by to emphasize is that some cover types could dams noss et al 1995 thus simply allocat- not be meaningfully assigned to an alliance ing nature reserves without other manage- such as where the vegetation has no clear ment actions aimed at maintaining ecological dominant species As an example mountain processes will not preserve them further brush is an aggregate class representing a mix- these 4 types are sensitive to disturbance and ture of deciduous shrub species no species valuable for wildlife habitat native perennial dominates this type and the mix of dominant bunchgrassesbunchgrasses are poorly represented in status species varies between locations so no alliance I1 or 2 lands both types at 5 and have been named for a dominant species was practical in substantially modified by introduced annual other cases the difficulty lies with the NVCS grasses or converted to agriculture three schema where individual alliances are all rare fourths of kileKiAckuehlerkuchlerhlerblerhier s fescuewheatgrass besFesfestucatucal and closely related eg seasonallytemporar pseudoroegneriapseudoroegnena sppapp potential natural vege- ily flooded cold deciduous forest it was nec tation type in eastern washington has been 212 GREAT BASIN naturalist volume 58

TABUTABLI 6 states sheiewheiewhere the most vulnerable land covelcover classes primarily occur 20 of the distribution of the type in status 3 and 4 and stewardsstewaids most lesponsibleresponsible foiforboiboloor thentheutheir management 20 in status 3 and 4 states and stewstewardsaids listed inm descending order otof extent if moiemolemore than one is listed indicates rare type that may be underestimated so other states and stewstewardsstewaidsaids may be involved as mapping is refined

land covelcover class states stewards flrsifiitsiforsi iiiimiiypkioriiyclasslsCLASSES 1 seasonallytempoiseasonallyternporarily ai ilyllyliy flooded cold deciduous forest WY patpvt scasonallytemporarilyseasonallytempoianly flooded cold deciduous shrubland wyldWYIDWY ID BLM patpvt disdrynry grassland pseudoroegneriap&cmcoroegneno agropyronAgropiron poa WA WY OR patpvt moist grassland festuca ORORWAWA patpvt nontidalnon tidal temperate 01or subpolarsub polai hydromorphic lootedrooted vegetation malmarshmai sh and wetland ID OR WA patpvt wet 01or drydi y meadow wyutrWY UT FS patpvt spalsparselyselyseiy vegetated sand dunes WY BLM patpvt slSECONDtondtonoCOND pkior11y11hiority CLASSES artemisia tridentata sspasp vaseianavashoasevasevastyanavaseyanaianatanayana shiushlushiublandshrublandbland ID WY NV BLM patpvt artemisia tridentata A arbuscula shrubland ID NV OR BLM patpvt arterArturartemisianisianisla tridentata shrublandshishl ublandobland WYORWY OR BLM patpvt artemisia tnpartitatripartitetripartitatripartita shrublandshishl ublandobland WA patpvt BLM purshia dentatatritridentatatridentate shrublandshishl ublandobland OR patpvt BLM artemisia cana shrubland OR BLM patpvt sarcobatus venniculatusvermiculatus shrublandshiushlubland WYORWY OR BLM patpvt mixed salt desert shrub atriplex sppapp WYNVWY NV BLM patpvt artemisia nova dwaltdwarf shrublandshishl ublandobland WYORWY OR BLM patpvt artemisia arbarharbusculauscula A nova shrublandshishl ublandobland ID BLM artemisia ngidarigidabrigida dwarf shrublandshishl ublandobland oriOR patpvt BLM Atripatriplexlux gardgardeengardnengardnerinerlnerineyl dwarf shrublandshishl ublandobland WY BLM Seasonallyseasonallytempoiseasonallytemporarilytemporarilyai ilyllyliy flooded sand flats NV BLM patpvt tiiiiii1hirdphird maimymoimyiiiioiury lassesLASSLSCLASSES uniperjumpeijuniperJ woodland juniperus osteospennaosteosperma orior J scopulorum woodland WYwyldWYIDID BLM patpvt juniperus occidentoccidentalisoccidentalistalis woodland OR BLM patpvt populus treinuloidestremuloidestremuloides foiestforestbolest OR WY NV BLM FS patpvt populus treinuloidestremuloidestremuloides woodland WYWYCOCO patpvt FS BLM mountain blushbrush ID patpvt BLM FS Cercocercocarpuscarpus ledifoliusledifohuslediledlfoliuspoliuspollus 01or C inonmontanustanus shrubland WYORWY OR BLM patpvt sparselyspal selyseiy vegetated boulderbouldeidel gigravelavelavei cobble talus rock WY BLM patpvt

converted to other land uses while the wheat ness study areas in wyoming could substantially grassbluegiassgrassbluegrassgrass bluegrass pseudoroegnenapoapseudoroegnerialpoa sppapp type increase the proportion of status 1 for this type has lost 31 of its presettlement extent merrill et al 1996 klopatek etct al 1979 both perennial grass- second priority includes types where their land types are predominantly on privately current diversitybiodiversitybio protection is minimal owned lands dry 77 moist 89 it types are characteristic of the ecoecoregionregion and will take a combination of preservation and they are vulnerable to expected land use activ- active management to maintain adequate rep- ities klopatek et al 1979 reported a 15 loss resentationresen tation of the bunchbunchgrassgrass types sparsely of sagebrush steppe to other land uses largely vegetated sand dunes may also be underesti- agriculture locally the impact on sagebrush mated because dunes beneath sparse vegeta- steppe has been much more severe such as a tion cover are difficult to recognize in satellite substantial conversion ofbigosbigof big sagebrush habitat images management must protect dune form in the snake river plain noss et al 1995 only ing processes to preserve the dune community 1 of the sagebrush steppe has been unaf- and should also recognize that many plants are fected by livestock grazing with 30 being endemic to specific dunes despite a moder- heavily grazed west 1996 the major impact ately high level of representation in status I1 of grazing has been a decrease in perennial and 2 aleasareas this cover type needs a fine filter bunchbunchgrassesgrasses with a corresponding increase in investigation to ensure protection of the indi- woody shrub cover the introduction of bro- vidual plant species it represents BLM wilder mus tectoriumtectorumtectorum has increased fire frequency in 1998 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 213 many locations to the extent that annual grasses wyoming however would contribute very lit- have totally supplanted sagebrush west 1988 tle additional protection for these 4 desert because of the selective grazing pressure on types merrill et al 1996 palatable species even lightly grazed areas can- third priority land cover types aiealeare those not be fully restored to a pristine condition that have low representation in existing blodi west 1996 public agencies have responded versityhersity management areas but do not appear to the removal of native herbs through heavy highly vulnerable from the kinds of activities grazing by seeding large areas with introduced that are most pioploprobablebablebabie also included are types agropyron cristatumcristatum crested wheatwheatgrassgrass which have complex highly variable floristicflonsticstie restoring these degraded or seeded sagebrush composition these types require further study steppe sites would be extremely expensive to assess their conservation status in greater and possibly beyond our current understand- detail perhaps with finer separation of alliances ing west 1996 the artemisia tripartitatripartitetripartita and within the type juniperuslumJumperus occidentoccidentalisoccidentalistalis has purshia dentatatritridentatatridentate alliances are noteworthy doubled in areal extent at least in idaho and because they both have 70 of their mapped oregon where it has replaced sagebrush distributions on private lands in contrast 23 steppe communities as a result of fire suppres- of the A nova type occurs on public lands sionslon miller and rose 1995 and reduced her- the actual management status of A rigidabrigida baceous fuel in the understory from heavy stiff sagebrush dwarf shrubland with 61 in livestock grazing west 1988 given that juni- status 4 is only an estimate it was not mapped per woodlands are expanding into sagebrush in idaho where it is known to occur on small steppe management concern lies more with patches of specific soils that were below the the fire regime than necessarily increasing their resolution of the original idaho land cover representation in designated managed areas map caicco et al 1995 populus tremultremuloidesoides forest and woodland are the xeric cover types including mixed salt also dependent on periodic disturbance moun- desert shrub atriplex gardnerigardneri which was tain brush within the ISD ecoregionecoregion is at the mapped only in the wyoming basin subregion northern limits of its range caicco et al 1995 but does occur in the columbia plateau sar- it is perhaps one of the most complex classes cobatus venniculatusvermiculatus and onallytemporarseasonallytemporarseas in the ecoregionecoregion with a diverse mix of canopy ily flooded sand flats are also in the second shrubs that can vary dramatically between priority category these types tend to be sites this floristicflooflonsticstie complexity makes moun- arranged in distinct gradients of moisture and tain brush a difficult class about which to draw alkalinity in valley bottoms with strong com- meaningful conclusions concerning its protec- petipetitivetive sorting of species stutz 1978 pro- tion status with GAP data so it needs to be poses that rapid evolutionary divergence and examined in greater detail the Cercocercocarpuscarpus hybridization within the atriplex genus may alliance tends to occur on steep rocky out- be occurring in different valleys in wyoming crops which are not prone to development in nevada and utah if true this would argue fact as a fire sensitive species Cercocercocarpuscarpus for protection of many replicates in this ecoreacore has expanded its range since the beginning of gion and in the intermountain semidesertsemi desert fire suppression kagan and caicco 1992 and desert ecoregionecoregion to the south to nurture while not of the highest conservation priority this evolutionary process currently 2 of it should still receive further consideration the mixed salt desert shrub type is in status I1 merrill et al 1996 the sparsely vegetated or 2 lands the seasonallytemporarilyseasonallytemporarilyseasonally temporarily flooded boulder gravel cobble and talus rock is a sand flats or alkali playa type is even less well very general class for many types of essentially represented at 020.2 the A gardnerigardneri and S bare ground little can be concluded about its venniculatusvermiculatus alliances have 1 and 6 repre- diversitybiodiversitybio value except at a more site spe sentationsentation respectively but are not highly vul- cificcefic scale nerable to grazing impacts because of the fourth priority includes types that tend to defense mechanisms of their dominant species be marginal to the ISD ecoregionecoregion these types over 80 of the A gardgardnerineri type was mapped may be of concern but are better assessed inm on public lands primarily under the jurisdic- neighboring regions or across their entire tion of the BLM formally designating the range these types include all conifer forest BLM wilderness study areas in the state of and woodland types except juniper woodlands 214 GREAT BASIN naturalist volume 58 quercus garryanagarryana woodland Q gambehigambeliigambgambelineliibitibitt shrub- the vulnerability of communities over their land and alpine tundra the gap analysis pro- ranges findings from a sample of the commu- jects in idaho and wyoming in combination nity such as a single state could be mislead- provide some of that broader perspective for a ing and generate inefficient conservation action few of the types marginal to the ISD acoreecore generally land cover types had similar man- gion pinus confortacontortacontorta forest and woodland types agement status in the ISD ecoregionecoregion analysis are more characteristic of the northern rocky as they did in the 3 gap analyses published to mountains where they also appear to be well date for idaho caicco et al 1995 utah presentedrepresentedle caicco et al 1995 merrill et al edwards et al 1995 and wyoming merrill 1996 P flexflexilisilis occurs mostly in the wyoming et al 1996 types with low representation basin on sites unsuitable for most human land within individual states were likewise poorly uses even though it is not well protected by represented in the region well represented formal land management designations it is types at the state level were mostly conifer for- not highly vulneiablevulnerable and not a high conserva- est types that occur in yellowstone national tion priority in the ecoregionecoregion merrill et al park and large wilderness areas of central 1996 the picea engelengelmanniiengelmannnengelmanniaengelmmanniiannuannn andor A lasto idaho which are outside the ecoregionecoregion thus carpa forest and woodland type is widespread even if these tree dominated types had low throughout the mountains of idaho and representation in the ISD ecoecoregionregion we felt wyoming where it is well represented they were not a high conservation priority applapproximatelyappi oxioxlmately 40 in each state in status 1 regionally this correspondence of state and and 2 lands caicco et al 1995 merrill et al regional findings in this particular instance is 1996 probably not typical beyond the initial conservation assessment conclusions these findings can be applied in at least 2 additional directions first they can provide a A gap analysis was conducted for the inter- regional perspective when the impacts of spe- mountain semidesertsemi desert ecoregionecoregion using data cific land use proposals are investigated GAP compiled from 9 states despite limitations in data can quantify how rare a community type the data ouioulour gap analysis provides the first is where else it occurs and how well it is rep- systematic assessment across all ownerships of resented in diversitybiodiversitybio management areas the management status of plant communities second the data from GAP can play a signifi- within a multistatemultimultistagestate region forty eight land cant role in followupfollow up conservation planning cover types were mapped at the regional level efforts at a statewide or regional level crowe many of which are at the alliance level of clas- 1996 vickerman 1996 for instance GAP sificationsification twenty types were determined to data such as shown in figure 3 can provide be the highest conservation priorities as they the missing biodiversity dimension in discus- aiealeare especially vulnerable to future losses or sions about alternative wilderness and national degradationdegiadegladation in the absence of formal designa- park proposals wright et al 1994 merrill et tion or active intervention for longtermlong term blodi al 1995 1996 wright and scott 1996 the versityhersity management over 96 of the terres- nature conservancy has already used the trial environment within the region is poten- GAP database from the columbia plateau sub- tially available to intensive human uses for region as a coarse filter to identify candidate resources recreation or urbanization the pro- areas to ensure adequate representation of all portions are similar for the columbia plateau community types because GAP projects are and wyoming basin subregions we urge that now underway in almost every state in the findings regarding individual vegetation types nation data to support other regional analyses from this assessment be carefully validated by and conservation planning will soon be forth legregionalionallonallonai field investigation to better deter- colimcomimcoming mine their true level of representation and actual vulnerability to threats before policy acknowledgments decisions are made and implemented one of the motivations for conducting gap support for this project was provided by the analysis foiforholbol an ecoregionecoregion rather than for politi- gap analysis program of the USGS biological cal jurisdictionsjuns dictions is to reflect more accurately resources division and the IBM corporation 199819981 GAP ANALYSIS intermountain semidesertSEMI DESERT ECOREGION 215

environmental research program we are ECOMAP 1993 national hierarchical frameframeworkwoik of eco- especially grateful to jimmy kagan for help in logical units USDA forest service washington compiling the regional land cover map rex DC 20 appp EDWARDS TC JR CGC G HOMER SDS D BASSETT A FAL- and crawford marion reed bob moseley of CONER RDR D RAMSEY AND DWD W wichtWIGHT 1995 utah the nature conservancy reviewed a draft of gap analysis an environmental information system the land cover map michael bueno devel- final project report 95195 1 utah cooperative fish and oped software to process state GAP land cover wildlife research unit utah state university logan 189 appp maps into a more regional product consistent FEDERAL geographic DATA COMMITTEE vegetation sub- patrick crist blair csuti chris grue collin committee 1996 FGDC vegetation classification homer mike scott and 2 anonymous review- and information standards june 3 1996 duftdraft ers provided helpful advice and comments FGDC secretariat reston VA 35 appp we also thank lori kleifgen and tom kohley FRANKLIN JFJ F 1993 preserving diversitybiobiodiversity species eco- systems or landscapes ecological applications 3 for providing data to the project 202 205 HOMER CGC G RDR D RAMSEY TC EDWARDS JR AND A literature CITED FALCONER 1997 landscape cover type modeling using a multi scene TM mosaic photogrammetric AUSTIN MPM P AND CRC R MARGULES 1986 assessing repre- engineering and remote sensing 635963 59 67 sentativeness pages 45 67 inm MBM B usherushen editor KAGAN J AND S CAICCO 1992 manual of oregon actual wildlife conservation evaluation chapman and hall vegetation idaho cooperative fish and wildlife ltd london researchRe searchseaich unit moscow 190 appp BAILEY RG 1995 description of the ecoiegionsecoregionseco regions of the KLOPATEK JM RJ OLSON CJ EMERSONEMLRSON AND JL united states 2ndand edition revised and expanded JONESS 1979 land use conflicts with natural vege- miscellaneous publication 1391 USDA forest ser- tation in the united states environmental conser- vicevlee washington DC 108 appp with separate map at vation gigi61916 191 199 1 750000017500000 kughlerKOCHLERKUCHLER AWA W 1970 potential natural vegetation map at CAICCO SLS L JMJ M scotSCOTTr B butterfield AND B CSUTICSUTL scale 1 750000017500000 pages 90 91 in the national atlas 1995 A gap analysis of the management status of the oftheofodthethe USAUS A US government printingpi mtmg office wash- vegetation of idaho USA conservation biology ington DC 9498 511 MERRILL EHE H TW KOHLEY MEM E hlrdlndorfherdendorfherdendoreHERD ENDORE WA CASSIDY KMK M in press land covelcover of washington state REINERS KLK L DRIESE RWR W MARRS AND SHS H ANDER- volume 1 in KMK M cassidy CEC E dueouegrue MRM R smith SON 1996 wyoming gap analysis a geographic analy- and KMK M dvornich editors washington state gap sis of bioblobiodiveidiversitysity final report university of wyo- analysis final report washington cooperative fish ming laramie 109 appp and wildlife research unit university of washing- MERRILL T RG WRIGHT AND JM SCOTT 1995 using ton seattle ecological criteria to evaluate wilderness planning COMMITTEE ON THE STUDY OF PLANT AND ANIMAL com- options in idaho environmental management 19 munities 1950 51 nature sanctuaries in the united 815 825 states and canada a preliminary inventory living MILLER RFR F AND JA ROSE 1995 historic expansion of wilderness 15115 1 46 juniperusJumperus occidentoccidentalisoccidentalistalis western juniper in south- CROWE R 1996 use of gap analysis in regional planning eastern oregon great basin naturalist 553755 37 45 in southern california pages 221 238 in JMJ M scott NOSS RER F 1987 from plant communities to landscapes in THT H tear and FE davis editors gap analysis a land- conservation inventories a look at the nature con- scape approach to bio diversity planning american serservancyvancy USA biological conservation 411141 11 37 society for photogrammetry and remote sensing NOSS RER F ETE T LAROE liililIII111 AND JMJ M SCOTT 1995 endan- bethesda MD gered ecosystems of the united states a preliminary DAVIS FWEW PA STINEDMSTINE DM STOMS MIM I1 BORCHERT AND assessment of loss and degradationdegiadegladation biological report ADA D HOLLANDER 1995 gap analysis of the actual 28 national biological service washington DC 58 vegetation of california 1 the southwestern region PP Madmadronorofloroffo 424042 40 78 ORIANS GHG H 1993 endangered at what level ecological DELLASALA DAD A JRJ R strittholt RFR F NOSS AND DMD M applications 32063 206 208 OLSON 1996 A critical role for core reserves in QUIGLEY TM RW HAYNES AND RTRX GRAHAM TECHNI-TFCHNI- managing inland northwest landscapes for natural CAL EDITORS 1996 integrated scientific assessment resources and diversitybiobiodiversity wildlife society bulletin for ecosystem management in the interior columbia 2420924 209 221 basin and portions of the klamath and great basins DRIESE KLK L WA REINERS EHE H MERRILL AND KGK G general technical report PNW GTR 382 USDA GEROW 1997 A digital land cover map of wyoming forest service pacific northwest research station USA a tool for vegetation analysis journal of vege- portland OR 303 appp tation science 8133 146 SCOTT JMJ M ET AL 1993 gap analysis a geographic DRISCOLL RSR S DLD L MERKEL DLD L RADLOFF DED E SNY- approach to protection of biological diversity wild- DER AND JSJ S HAGIHARA 1984 an ecological land life monographs 1231123 1 41 classification framework for the united states mis- SHAFER CLC L 1990 nature reserves island theory and celcellaneous publication 1439 USU S department of conservation practice smithsonianSmith soman institution press agriculture forest service washington DC 56 appp washington DC 189 appp 216 GREAT BASIN naturalist volume 58

SIILLIORDSHELFORD VE EDIIOREDITOR 1926 naturalistnatuialistss guide to the 1996 strategies for maintenance and repair of americas williams and wilkins baltimore MD 761 biotic community diversity on rangelands pages PP 326 346 min RCR C szaloszaro and DW johnston editors slomsSIOMSSTOMs DMD M MJM J BUENO FWEW DAVIS KLK L DRIESE KMK M diversitybiodiversityBio in managed landscapes oxford univer- CASSIDY AND JSJ S KAGAN in press map guided clas sity press new york sificationsilicationsification of regional land covelcover with multi temporal WRIGHT RGR G JGJ G maccracken AND J HALL 1994 an AVHRR data photogrammetric engineering and ecological evaluation of proposed new conservation remote sensing areas in idaho evaluating proposed idaho national SIITIZHCSTUTZ H C 1978 explosive evolution ofperennialpeipel ennia atriplex parks conservation biology 82078 207 216 in western americaamelica gleatgreat basin naturalist memoirs WRIGHT RGR G AND JMJ M SCOTT 1996 evaluating the eco- 2161 168 logical suitability of lands for parks and protected conservancy tlle NATURE CONSErvancyevancy ecorlcionalecorrgional WORKING GROUP areas using gap analysis databases pages 121 130 in 1996 designing a geography of hope guidelines for RG wright and J lemons editorsediedltoistors national parks ecoiegionecoregion based conservation in the nature con- and protected areas their role in environmental pro- servancyseiselser vancsvanesvancy aidard3id3rd draft arlington VA tection blackwell science cambridge MA UNESCO 1973 intelinternationalnational classification and mapping ZHU Z DOD 0 OHLEN RLR L czaplewski AND RER E BURGAN of vegetation series 6 ecology and conservation 1996 alternative method to validate the seasonal land united national educational scientific and cultural cover regions of the conterminous united states organization fansparispans fiancefranceflance 35 appp pages 409 418 in HTH T mowrer RLR L czaplewski VICKERMANVICKLRMAN S 1996 using gap analysis data foiroirolfor statewide and RHR H hamre editors spatial accuracy assessment bioblo diversity planning case studies of applied gap in natural resources and environmental sciences analysis foifolforhorbor planning of land use and biological re- general technical report RM GTR 277 USDA sources pages 195 208 inm JMJ M scott TH tear and forest service rocky mountain forest and range FWEW davis editorsediedltoistors gap analysis a landscape experiment station fort collins CO approach to biodiversity planning american society ZUBE E H EDITOR 1994 peer review panel report of the rhifoifor photogrammetry and remote sensing bethesda national gap analysis program for the national bio- MD logical survey nbsidahoNBS Idaho cooperative fish and wild- weslwestWESI NE 1988 intelintermountainmountain deserts shrub steppes life research unit university of idaho moscow and woodlands pages 210 230 in MGM G barbour and WD billings editors north american tenestnalterrestrial received 17april17 april 1997 vegetation cambridge university presspi ess cambridge accepted 27 september 1997 great basin naturalistnatuiahst583583 0 1998 appp 217 230

NATURAL HISTORY OF A SALINE MOUND ECOSYSTEM

robert R blankl2blank12blankly james A younglyoung1youngbl james D trenti and debra E PalmquPalmquististl1

ABSTRACT along the margins ofplayasolayasofplayas in northwestern nevada a saltsait tolerant plant community occupies mounds that dot a largely unvegetated landscape in this environment we studied soil development and plant soil relationships the mounds averaging 03mm030.3 rn in height are occupied by the shrubs allenrolfea occidentoccidentalisoccidentalistalis iodine bush sarcobatus venniculatusvermiculatus black greasewood and atnplexatriplex lentiflentifonnislentiforrmsonnis sspasp torresitorreyi torrey saltbush distichlis spicatespicata desert salt grass is the only herbaceous plant occupying this community soil salinity decreases with depth in this environment and content ofofaqueousaqueous extractable soluteskolutes is significantly influenced by site specific vegetation content of silt clay and salt in mound surface horizons suggests a chronosequencechionosequencechronochiono sequence of mound formation with the youngest at the barren playa interface and the oldest at the upland vegetation border plant demography and mound soil stratigraphy suggest that a pulse of plant recruitment and mound building occurred during a time of neoneoglacialglacial cooling As a substrate for plant recruitmenti mounds have a limited lifespan because deposition of eolian transported salts and geochemical cycling by plants quickly render them too saline for seed germinationgeigel meationmmation the apparent periodicity of mound formation precludes definitive conclusions regarding those mound characteristics favorable for plant recruitment and survivorship

key words allenrolfea occidentoccidentalisoccidentalistalis atriplex lentiformislentiforrnislentiformis sppapp torresitorreyitorreyi eolian dust sarcobatus vermiculatus

vegetated mounds hummocks or hillocks recruitment on playasolayas may hinge on the for- occur in desert climates worldwide shantz mation of large desiccation cracks these cracks and Pierpleiplerpiemeiselneisel 1940 bendall et al 1990 danin accumulate sediment presumably of low 1991 the origin of these features is generally osmotic potential capture seeds have higher thought to be capture of eolian sediment by available water content for establishing seed- vegetation gile 1966 vasek and lund 1980 lings and begin the process of mound build- thus the term pythogenic hillock batanouny ing another pathway of plant recruitment on and batanouny 1968 plants occupying these saline playasolayas occurs when phreatophytic mounds often have adaptive growth character- species are able to tap into low osmotic poten- istics such as aerial structures and roots and tial groundwater and then begin mound build- runners favoring the capture and stabilization ing neal and motts 1967 assumed in the of eolian materials bendallBendali et al 1990 colo- previous recruitment process is a favorable nizationnization of mounds by cryptogamic organisms establishment phase sufficiently long to allow lends further stability to the soil danin 1991 plant roots to reach the water table this process during the pleistocene the lahontan basin likely hinges on optimal climatic conditions of northwestern nevada consisted of numer- and a high water table jacobson and jankow- ous interconnected lakes russell 1885 at the ski 1989 present another mechanism for plant onset of the holocene these pluvial lakes re- recruitment on saline playasolayas at discharge spots ceded leaving a complex of highly saline fine evaporative concentration establishes dense textured lacustrine sediments intermixed with brine pools crystallization of gypsum in capil- coarser textured less saline deltaic beach lary zones heaves the ground which can then and offshore bar deposits fluviatile sands and be colonized by halophytic plants eoliancolian reworked material offered a favorable research was initiated to understand plant substrate for plant colonization culminating in soil relationships and the history of mound the presently diverse plant community young development in this arid saline environment et al 1986 two basic questions were asked 1 Is mound post pluvial recruitment on the very saline formation a prerequisite to the establishment playa sediments however was problematic and evolution of plant communities 2 con- neal and motts 1967 suggested that plant ververselysely are mounds happenstance a natural

iusV S department of agriculture agricultural research service ecology of temperate desert rangelands unit 920 valley road reno NV 89512 corresponding author

217 218 GREAT BASIN naturalist volume 58

consequence of aerodynamic baffling by vege- tion is dominated by atriplex conferticonfertifoliaconfertzfohafolia and tation in an environment with a high flux of sarcobatus baileyibazleyibaileyy billings 1945 wind trantianspoitedsported material working hypothe- six mounds each supporting A occidentoccidentahsoccidentalisoccidentalistalisallsails ses developed during initial fieldwork postu- S venniculatusverrmculatus A lentiformislentifornmslentiformis sspasp torreiifortefotretorretorreyitorreyaiiyi and lated that the pimprincipalcipal pedogenicpedogemcpedogenicgenie processes D spispicatespicatacata were randomly selected in 1989 opeloperatingatmaatmg were eolian dust capture by vegeta- from each mound we collected soil samples tion to form mounds and that new mounds beneath each individual plant micmicrositemicroliterosite approx- farmfbrmfoifol m in upland positions while mounds closest imately 10 cm deep excluding the surface crust to the barrenbaibal i en playa are ei odmaodmgeroding we also collected composite soil samples from 1 barren mound surfaces to 10 cm 2 the MLIIIODSMETHODS surface 10 cm of lacustrine material beneath the mound centers and 3 interinterdineinterdunemterdunedune sediment the study was conducted in eagle valley immediately adjacent to the mounds 0 10 cm 39SQWN44n ilg1191192wM 64 km east noitheastnortheast of A saturation extract was prepared for each soil reno nevada eagle valley is a small embay- sample USU S salinity laboratory staff 1954 ment of pluvial lake lahontan bounded to the electrical conductivity was measured with a northwest by the truckee range and to the salinity drop tester ion chromatography was southeast by the hot springs mountains the used to quantify na K cl n03 and westeinwestern boundaiyboundaryboundaiydaly of the playa was the termi- s04 2 nus of the tiuckeetruckee rivelriver during pluvial peri- to explore the spatial distribution patterns ods and consists of coarsechaicoai se textuitextureded deltaic and of soluble salts in mound environments we randomly reworkedi ekoiewoi ked eolian sands elevation of the bar- selected 3 mounds in 1990 A grid overlain mounds ren playa surface in the study aleaarea is 1234 in pattern was on the at nodes at maximum lake levels during pluvial cycles of the grid we collected a 767 6 cm diameter of the pleistocene morrisonmornson 1964 water cov core to the depth at which lacustrine sediments ciereded eagle valley to a depth of approximately were encountered or to 30 cm whichever was shallower the surface crust was excluded 100 in presently watelwater ponds on the barren playa surface only during years of heavy samples were placed in bags brought to the laboratory dried and stored until ana- runoff ouioulour principalpimcipal study area is at the east- air lyzed of soluble facili- ern end of the playa sec 26 t22n r26e extraction species was tated by placing 10 g of the homogenized orig- the location is a gradient flomfrom barrenban en flat inal sample in 50 centrifuge tubes adding finehinebine textured saltsait encrusted sediments to a in ml 10 deionizedde water and shaking for I1 h highelhigher coarserser textured and less saline com- ml ionized coaleoal tubes were centrifuged and subsamples plex of reworked beach material eolian sands the tested for electrical conductivity with a salin- and alluvial colluvial material emanating from ity drop tester and for with a glass elec- transitional ph hot springs mountains this area trode other subsamples were diluted with where halophytic plant communities exist on deionized water to appropriate levels for mounds is the focus of this study I1 is fig analyses by the ionlon chromatograph for cl nearby fallenfallonfailon nevada elevation 1209 with in br n03 s04 2 na K mgtmg2 and ca2caa average precipitation of 12.512125 5 1 the pi ecipitation 125 cm yr had boron was determined using the azomethine following precipitation cm duringdm ing the study H colorimetric procedure john et al 1975 period 1988 1989 129 122 1990 for one of the mounds particle size analysis 14514.514 5 1991 83 1992 10410.410 4 1993 14014.014 0 was done as described below the spatial dis- 1994 13.313133 3 133 based on data from monitor tributiontribution of each individual attribute is pre- wells installed throughout the study area the sented in an XYZ contour fill chart facilitated watelwater table is 3 m inm most years mounds by a commercial graphics program aiealealcarearc dominated by allenrofeaallenrolfea occidentalisoccidentahsoccidentoccidentalistalisallsails S in 1990 we described a sequence of 7 soils watson kuntze atriplex lentiformislentiformzslentiformis sspasp tor along a transect encompassing the width of the feni S watson HMH M hall & clements and mounded area from the barren playa surface sarcobatus vermiculatus hook toneytorrey and southeast to the less saline upland interface by the glassgrass distichlis spicatespicata la11 l1L greene transect distance 12 km A backhonbackhoe was young etct al 1986 in the less saline and coarse used to excavate to a depth of approximately textured beach and colluvial deposits legetavegeta 3 in soils were described using established 199811998 PLAYA SOIL 219

amen 37tn 41 iazi5z 0 a

41

117 vr

4 N r

wr

fig 1 landscape photograph of study areas showing mounds occupied by allenrofeaallenrolfea occidentoccidentalisoccidentalistalis for 50 mounds measured the average length was 31 m s 18 average width was 19 s 11 and average height was 03 m protocols soil survey staff 1984 samples of and 60 cm from 4 randomly selected mounds each horizon were returned to the laboratory after transport to the laboratory in sealedscaled glass for further characterization we quantified the vials on ieeicelee the samples were immediately ana- following attributes 1 organic carbon by the lyzed for gravimetric water content and total dichromate digestion procedure nelson and soil water potential decagon scioSC 10 theimothermosheimo sommers 1982 2 particle size distribution couple psychrometer calibration of the psy- after removal of organic matter and soluble chrometerchrometer was facilitated usingnsingansing saturated salt salts gee and bauder 1986 3 saturated solutions of liclhicl 2944294.4294 4 mpa nacl 38038.038 0 paste extraction USU S salinity laboratory staff mpa KCI 217 mpa and kn03 75 1954 with quantification of anions and cationscanions mpa and nacl solutions with potentials of by ionlon chromatography clay sized fractions 323.23 2 mpa and 181.8isls1 8 mpa reserved from particle size analyses were pre- to quantify eolian dust fluxes and chemical pared for and examined by xrayX ray diffraction content we placed marble dust collectors 3 using standard procedures moore and replicates on the barren playa surface approx- reynolds 1989 the very fine sand fraction imately 8 km southwest of the study area the was examined with a petrographic microscope marble dust collectors consisted of approxi- to identify its mineralogy brewer 1976 the mately a 5scmsemcm depth of glass marbles placed in silt sized fraction was isolated by dry sieving 33 x 24 cm teflon coated cake pans placed on of original samples and examined by xrayX ray dif- the soil surface Collectcollectorsoisols were sampled bi- fraction monthly from june 1994 through june 1995 at at approximately imon1 mon intervals in 1991 which time dust weight was recorded A sub- we collected soil samples at depths of 20 40 sample of the dust was dissolved in deionized 220 GREAT BASIN naturalist volume 58

water 1 g sample 25 ml HO and analyzed kak4K are inconsistent among soils and among for cl n03 s04 2 na and K using ion horizons levels of n03 are extraordinarily chromatography and for boron using the azo high in the surface ernstcrusterust of all soils generally methine H colorimetric procedure declining rapidly with depth clay sized mineralogy is similar among the RESULTS soils examined in the coarse textured material soils overlying varved lacustrine materials K satu rated treatments produce reflections corre- except for soil the described on a large spspondingonding to lattice spacings for kaolin mica dune soil 5 soils along have the transect and a poorly crystalline randomly interstrati grossly similar morphology and stratistratigraphstratigraphygraphy fiedfledbled smectite illiteillige with mg2mgtmg12 saturation and even between mound and interwoundintermound ermoundint micro glycol intercalation the randomly interinterstratifiedstratified sites table 1 vesicular surface crusts overly- component expands to 161.6iglg nm with very broad ing soft sandy loam layers are common to all reflections lacustrine sediments are dominated soils hues are 25y in surface layers grading by smectite one unusual xrayX ray trace was for to 5yay in lower layers munsell color system A the ath5th layer of soil 3 the horizon with anom- textural discontinuity exists in all soils exam- alously low table 1 pattern was ined sandy loam surface layers overlie silty ph the completely amorphous save for a very broad clay loam varved lacustrine sediments the maximum centered at 0400.40 nm which is indica- upper several centimeters of the lacustrine tive of opaline silica jones and segnit 1971 unit contain many indurate nodules ranging xrayX ray diffraction was used to examine the from I1 to 5 cm in diameter tubular pores are silt sized mineralogy of soils 1 3 abundant in the finer textured material these and 6 samples were dry sievedsievek from original mater- pores are in places peripherally coated by whawhat ial to conserve soluble A appears to be organic material perhaps old water minerals peak matching algorithm was used root channels the proportion of sand in sur- to detect miner- als face horizons decreases from the barren playa in the samples the principal evaporiteevaporizeevaporite surface to the higher portion of the landscape mineral identified in the silt fraction was at soil 7 silt and clay content correspondingly halite nacinaclnaclnaci which occurred in all soil layers increases in excavated sections of mounds above the lacustrine sediments the only other graded bedding and cross bedding were evi- evaporiteevaporizeevaporite mineral identified was bloeditebloedite dent in the surface coarse textured material na2mgso4na2mgs04 ah4h4h2020 which occurred in layer I1 organic carbon levels are very erratic among of soil 3 other principal minerals in all hori- soil horizons table 1 there is a slight increase zons in decreasing order of abundance were in organic carbon in the lower mottled re- plagioclase feldspar quartz calcite and mica duced horizons organic carbon is highest in gypsum cas04 2h20 was a major mineral the surface crust of soil 7 visual inspection of component in layers 4 and 5 of soil 3 and this layer did not show any evidence of root- the surface horizon of soil 5 both vegetated ing activity but the crust had encased seeds diagnostic peaks for sepiolite ideal and fruits of halophytic species that occupy sii2mg803ooh4oh24sil2mg8o3ooh4oh24 8h20 were found the mounds in the ath5th layer of soil 1 no zeoliteszeolites were saturation paste extracts show the extreme identified in the silt fraction even though salinity of this environment table 1 com- saline playa environments are known to foster plete solubilization of some salts may not have their formation ming and mumpton 1989 occurred for some samples given the soil to mineralogy of the very fine sand fraction water ratios used these systems are dominated was determined by optical methods and quan- by nanay and CFc1ca levels of na 1 and cl as tified using the line count method brewer well as other solutessokoluteslutes generally decline with 1976 samples were washed with water to depth extractable s04 2 values are erratic remove soluble salts the mineralogy of soil among soils and among soil horizons soils on above lacustrine sediments is dominated by the lowest part of the landscape 1 2 3 and 4 plagioclase feldspar and quartz with minor vol- have a secondary bulge in profile s04 2 levels canic glass hornblendes mica and carbonates which is absent in soils 5 6 and 7 levels of much of the lacustrine material consisted of 199819981 PLAYA SOIL 221

diatom tests partially or completely cemented eolian dust by an isotropic material that appears to be silica the bimonthly eolian dust flux on the bar- plant soil relationships ren playa surface averages over 130 g m 2 table 3 the dust is dominantly composed of content of aqueous extractable soluteskolutes the nanad and cl nearly 40 by weight with very varied significantly among collection micrositesmicrosites high levels of water soluble sa 2 kak4K and 2 saline s0s04 fig the most micromicrositessites were un concentration of phytotoxic boron vegetated mounds and the soil n03 areas atop be- averages over 1400 mg kg 1 neath greasewood soil collected in the unvegunpeg statedetated zone adjacent to mounds and the playa discussion material directly beneath the mounds had in general the lowest levels of extractable soluteskolutes mound pedogenesisPedopaedogenesisgenesis among the collection micrositesmicrosites particle size distribution indicates that soil a bacbackhon using backhoekhoe we were able to uncover development began on a surface that was rela- a root system of A occidentoccidentalisoccidentalistalis that emanated tively coarse textured in comparison to the from a mound and extended over 10 m into underlying lacustrine material depositional the unvegetated interspace the directionality fabrics such as cross and graded bedding and of the root systems suggests linkages among the areal extent of the coarse textured veneer mounds although we did not excavate a com- suggest it is a remnant offshore bar likely re- plete root system from one mound to another worked by beach and wind action as the pluvial the diameter of larger roots was over 5 cm lake receded thus mounds are a composite most large diameter roots had over 90 growth of eolian material overlying offshore beach rings the oldest having 120 rings soil water deposits relations data collected in 1991 a wetter than in the lake lahontan basin given geomor- normal year show the extremely negative total phic surface stability the proportion of fines soil water potentials characteristic of this envi- silt and clay increases with time via thesteadythe steady ronment table 2 capture of eolian dust in the soil skeletal frame- soil samples from 3 spatially separated work of sand and gravel sized particles chad- mounds were collected in a grid pattern to wick and davis 1990 in our study the propor- determine the spatial distribution of aqueous tion of fines in mound surface layers increases soluble soluteskolutessolutes canopy coverage of the mounds from the barren playa interface to the sur- by A occidentalisoccidentoccidentalistalis ranged from approximately rounding upland based on the chadwick and 12 fig 3aaa to much less than 12 occupied davis model youngest mounds are closest to fig 3cac spatial distribution of aqueous solu the barren playa which is supported by mound ble soluteskolutes differs considerably among the 3 stratigraphy mounds closest to the barren playa mounds there is a correspondence between show greater relief and have more visual evi- levels of aqueous soluble soluteskolutes and location dence of recent eolian sand deposition more- of plant canopiescanopies for mounds a and b in mound over as expected there is a general increase a the highest electrical conductivity and Kkak1 in mound salinity from the playa to the upland occur beneath S vermiculatus plants for mound because as time increases cumulative addi- c levels of mg2mgt and s0sas04 2 are especially tions of salt rich eolian dust table 4 and high beneath A occidentoccidentalisoccidentalistalis plants on the plant geochemical cycling of salts also increase south side of the mound mound b which has robert 1950 charley and west 1977 expan- the greatest canopy coverage by A occidenoccident sion of vegetated mounds into barren playa talis generally has the lowest solute concen- surfaces is opposite the general conclusion that tration near the top of the mound correspond- playasolayas in western united states have generally ing roughly to a vegetatednonnonvegetated area there is enlarged during the holocene blackwelder also a directional aspect of solute distribution 1931 malek et al 1990 however eagle val- many soluteskolutes are highest in the southwest ley may be unique due to the immense vol- quadrant all mounds coarse sand content ume of coarse textured deltaic sediments gen- shows a gradient from north to south mound erally upwind of the study area prevailing a very fine sand content is highest at the top winter storm winds from the northwest of the mound and silt and clay are highest at the controlling factors of pedopedogenesispaedogenesisgenesis in this mound edges mound a environment are eolian erosion and deposition L grestGREAT BASINZ Znaturalist volume 58CA 00

of U J easily of pyriteS S g vesicular 3 mottles apores of 0 c- y calciumofcalcium 3 0 coatings porosity cloo S 5 thata tubularS 0io 0 68 3 0 i nj bottom 5 t M 0 M w oftnn 3 0 0 mlsdrymrs spicatespicata drybwy crust u 1 tubular 1 1 1 notes 11 I azzaaznamany 5 Is seams blackazack S of25yr g at G u iS i 3 efflorescences S s c iwhen cementation vesicular debris andman when surface 1 field25 1 11distichlis i easily easily OT K U iw S C i W & C r hard bc 2 S concentrated crystals 2 g structure streaks S g S 11-lootlontroot cag coatings c5g granules lif structure structure 3 crust ass vesicles maam IJsaltoehl go o local hardmalm s s jg 5ss1 l 78 of0 aghagg carbonate N pulverize S a nek M coatingsaai 32 porosity softmzee softocee gti55u a3i horizonSSss32 bisbices egee pulverizes pores pyrite nepo pulverizes egetextremely 8gag mye asso decaying kkt3 scg55gypsum slightly surface surface varved stalonsstolons strong varved manamany ssso pyrite gealy aana roots forms platy platy wolaworavery very S t imipii&js0 iiilj8 o & 5 5aaaaa lallplkg a &aaa CO an CO 00 1 t c0ca 00OO 1 1 M 1 inch 01 1 ta 1003 zheahe140 067087027 021emm 0660260860n012 003 044 578 007 017elg 08300 661eez0 005 049 008 001O 011i 002 670770 009 NO cnlfsirl 0 it 0 nd 0 ttl 0 0 0 1 t0 10 2 0000 0 010tyo 0 00 0 000mth 00oi 0 fo 3 CO 1 00 01OI PCO CO 03 t 0 M os10 rock mez 161 238mem000t216 367meg 283 77 38 49 34 76 73 59 460040 34 26 32 149ahm 95 u zoco601201 i 0 00oo 211bwl CO acot 1 10t1 enci CO 3 hodpol K i lt fol T fcot ffiafi oi i rm 3 paste ri cirico 1 soil ca S &i soil ai eagleW 0 0 2 ca t cocio ci IOOT M 2 i 0 coincoio 10 of0 QO 1 1 1 30 0 amp 6.5 111 arm 62 001035 wam mem 65 30 464 20820.8 202meb 204 340ewt aim172 825 349 110 330 127 431 4161 123 165 em 566 t mm 208oocio 1- of0 tn 0 co i i co soil cico cicciz 650 1 I1 000 3c0 i I T behmeh ill i ttl00001 bocoooco M CO rir rl0 ni lo10 saturated 0 2 YD of0 rlclclco vi t U g s S of0 southeast5 5 U southeast3 S 00oo te 3 1 y southmcula 0 1 i I1 i meh mee gme wae 170zge zwe southwest 0 P oo420 0410 ooo600200 620820220 250 9600 550ooo300 280 oohae410i 11 140whe0ti oo650 ehle3410 2550ommeIOCT2490 2360ccoOCO1630 1540 262000r l 000mth 0 oho000 00 cin003860010 00000 ri rl ormlo 10000 ll i dettedetto 10 0 t ethoralo roy tho t i d cl io at ci ri cl 10c001 m 300 u i 000 Sfsflocoa co rnirsirolOco i fnan0t roisoi C co 0 Sm Sm 350emt0 m 12 co g 200 nj t 0I1 ooI1 380emmCO 4000 820220rooo210i I1 660220 so990OS 540oooi 310i 11670870270 oo380 160 1200CM oo1 630 1870 1460 tom 01 3480 2670 2540 amit 2810 2810 3710 ooiool 0 1 000cl 000 00 00 00000 00 ll 0001 1 1 na ottootat1 QO OOCO 0 arsinotto co oi etteto cofcor i t 0 1 i locore 2 800200sf010qoco cl rsino 3 locorl co d S cl g SOIL0 a approximately

1 o0 CO MOO 1 I1 10 nj loos binrim approximately00oa 000 gl01 75 wem flo 85 meg oems 1 ame gem 0 ohmiclay inch mam1 aee lmh MOUNDSOIL 1 bem lem109 854254 215 mel531mraco 504 y 138cotcor111 1630 oyt194 172 468ic A 141 117 00OO nd 160OCO238 370t 155 167 1 c i i 0 1 zitI1 i tat1 i T I1 C co 1001 1 3 G approximatelystolotsfolotr rloalocio 10 sa ai 0 es1 MOUND& distribution S a 0 0 cn co i r t 00oo 00oo t- co f f i D 00OO c 4 OT I1 mazz pen 58 mee 71 58 ooame silt 149 26326.3 301men 304 444 45710 128 00187 263 604204 454 126 nd 00160 680280 549 eyoeyn150 141P csftnlo1 OOIO c 000 W 1 oko0400101 1 at&t l lnicoalnicocht000CO fi 2 nnacolo0010 olo IM 10 SOILSdlo 3 nn1 ca SOIL c3 u 1 3 sizeN 0O t SOIL OO010OlO lo10 03 scotPCOO 00oo sarcobatusydoyoogoo 01 arah goolo I1 c3ca sand 00010grmooolo 25 39 0 coicol 78 75.6 mog anemt 81 emmlrah a 776gle1 628 445 481 633733 830 650 543 624 788OO 756 857 0n680 482 695 691 ctfcaf cl booroooro co coco 10 mt u 00 1010656 ndc 0000 00 c rslti Q t oo ce l-lolooo P 00 zif z 00 0 100 t OPO 00 oif interspace y MOUND vi S 0 i fc SURFACE M coo i ci i M ci 10 yeb 1 ihi om 10 kem coh 1 ehm 044 emm ehm tami hi0.47 cciacci cioclo Z eememm 0cacu a2ritomci042 036 045 062072 08200 043 030n eliezi017 013 021cit 047 h 032 020cit065 cl061081021 064074IM020 045 065cors062082022 0 coltcoircoit cli rt VJ 0 0 ooo 0 ooo 0 1 oo ix ri 00000 stosotsoo bet000met allenrolfea botbho000 00 00 5 z S

PLAYA i allenrolfea I OTI I i VEGETATED hiiiihl 1 COCNCO t 1 00OO QOOS ilii i cl atnomtno lacto 5.2NO ph 74 73 72 73 74 74 79 81 82 82 82 80 78 81lcto83 80 52 80 81 unvegetated 78 79 & C i- t 00oo 00oo 0000oooo 52mbmoo 00oo horizon titta h 00000010- 0 7 tt M ti M tittttit BARRENa UNZ U L 3 by i a ajobjo ajobjo 5 bdbcm bo bjobobc bo a M c u a a c c c c fi c maa m cence s violent caacaz S violent violent violent efferves aclhcl ightSS strong ight strong strong strong strong strong strong strong strong strong strong siacaacaslight slight3 slight g acaononeacce 13 ssaca i EC g 2 ta U bit sa ggs 2 t3 eits gli s pua K SK999K c K S attributes M sakpuks2 fi c fi 4 0 4 0 0 4

ci common common c c c fi c eg S S e Scommon gs fi U U iu U U U fewmew fewgavgaw fewfow few fewgov fewadvguv fewguv absent absent absent absent absent absent absentlu absent S absent S rootsS fl S gs cSSS1 tm 0 fewmokmow i fewmev 1 selected 0 S 0 P SQrt ca csrtcart rt rt c3ca u lelcaiohl v v v c3ca 05oa v 0 v v c3ca v

N M H 01 aqgq andmam N co 652emm 652 co 652 652emm 00682782 652emm 652emm 3 72 72rsicirico62 72 yakynhIOK 72 63 iomaiomc62 725 iraiobraio l 553 553meemem 1 I- munsell & t cem m 10 zoczooOCO s color dry dbdem 00 72 72 80 td 63roicoleol i i i i i 000i i i COi oo i i tltiitit io ici 00 o f liimhiim lma i umm25y 25y 25yhium25y 25y 25y 25yiralna ici25y 25y 25y 25y i 25y 1025y 25y 25y lomkiinlom Kiin 5yay ay iiim ayiiay 5yay iramiodiramio 5yayoi miomuomun iii 5y 5y 5y 0.101 i8 M i 01 descriptions ia nrnciira m cciacci loioioloioco ci oiciobicioii lomIOM ti CINfi

i 1 i ciloltcitcoi011 i 1 in 1 1 CO 127 loo122zobmymoll-157 depth cm c1ca 15 min 25 030 51 64 91 23 560 C91 010020 76 86co n10 025ia 30 01meemre 00 10 91127 015 86122 i0 830 91 823 emm 8 3051 5164 6491 8 2356 5691 127 60662076 7686semm 122157 157 t 1520 2530 soil 00100008 08 A 1 i Q i i oooo30 51 64r tootuo000ooo 23n 566191 20 76 86OM 0 000008 0 8 N 100yez 0 151006mt OOCO122 oi25aqpq 1 c0100 a TABLE N0 horizon i i rm bio bjoajo bc bo 2cglmcgl 2cg2 0 bk1 bk2 i ri 2cgmcg i aq bowmou c1ca c2cari j c1ca bk cc0 c2caci c1ca c2ca by c3cacq2cac n bk a ummerummur CN A u ro UUN A oumUUM jr M A m 19980 PLAYA sollSOIL 223to bo c4ca

pores porosity pores 1 structure tubular i 111114 tubular pyrite III lii5 1 eanseaasmany J porosity tubular i 56 10 tubular S S emzymany g many black vesicular a ag YRoi blocky3 a structure a c 5g s oa S H a ag2g notes Q03 S 3 manya ra s o3 0 aaas fewgov1 s 500 vesicular amnaamzamany c cementation I cementation ga a u a w w iy di di C c c S c mcleomclampores pores pores coatings coatings films likeelmeelmo crust angular s ield25 S blocky 2 bab0 &0 M bolboibab0 5 l rushlikerustlike easily S fi oa o& u easilya easilya S a c c e pores 15 kie 0 3 amoas faces mrs stallsa3go rust mlsdry crystals structure IISstructure sttllsalgo bedding bedding bedding bedding clayohmsoems s crust tubular tubular tubular local surface fineeeza local fine pyrite of pyrite momgom iwhen sj tetped soijijlbcoatings tei S 4 bo C S bazebacoo o o 0 961a tubular303 o gai E S obbooboz pores pulverizes pulverizes pores pulverizes oboo 111 aaigolom alij u u u s1sa ib 3 common S S S 9 i fe 1 tug gypsum 1 1 Q cl T 1 T us3 c r t coatingr r r e i varved graded gradedT graded gradedT surface y f varved rt strong strong iiistrong strongmafew cdeaaasmany amaiamasmany amasamdymany shiny black puffylij siistikelbard aeto M bobc&jobjobd 0 vi siigsirgw S 6 M aad201 0 fi&di&miblS aai l22ia6to &iai ills201illS CO oooo i asicsi i mir oot M i oooococoicocoi oiioli i coomoomoomoo ooi ooniramonira 0.58 emm 0.14 123 0.04 eem 0.08 0.08 007 4.17tot4704.70 0.08 0.03 0.05 058 0.03 851 8522522.52 0110.11 014 020csiasi 030 004 0050.05 008 008 003 417 141 008 003 005 008 003 003 001 airamcloam032 011 014 MCOOOO toii nof- ciram oo 0 ooo 0 oroee 00 toit 00000 ooocs1000io 0000 00 0 t oeh000

i i co r i 00oo ooco icom cor 707.0 locomcsit73 15 12 17 84 boco 60 43 131 34 31io 121 110 i i 141 doti128 40 12712.7 163 51 58 188 463 224 122 23 60gt i i i 4 oq 00 1 K 3 COCOCOI CT it ooydoqydyD 30100010 10 oc1cnc1d paste soil5 S a ofsoilw 0 t o 4 i 1 1 6 a i N 1 2 i of0 oo OS soil i soil l 18 fl17 29 11 69 79 525.2 44 21lt17 260 gc OOOOOTO50 10 09 10 37.4 1 sfcomcocoot mm 1 158 U 374 862 683 523 480omcacf282 I 203 i mm K 2 K 2104 1776 DOOCCO 52 MI oi f OI- iotaiot1 1 s04 E oj M of bocolooocolo rt fi cn of cittuniatunin io saturated2 c1ca0 southeast southeast gl K 3 eastomme 1 aticti 5 south3 yi 0 Q 0 1 330 190 150 130 680780gme 190 i110 110 460wee 730 660 ere330emm 220 6502500 i OOOOOO450 120 zie170 lle lle hee leeiee geme lle 1130 em 2240 3800 4150 1460 00c1ca 10 5550 2520 1360 1 I1 1 T 1 000000 00000i 000000 00000I i i i i clcooitocoI1 I I1 I R ooooii ilototocococo loccolocll i oqool mfl corscorncoos M i f cl I m 1 I1 m 0 ecoSCO otool C T ft loiocoioioco 500 n 1 C ION fi oo0280 io3500 00 4000 CO

80 1 i i 80 330OOOOO170i 110T lee100zee 830met bre230mee 110i oo OOOOO490 720i 640 ele310ezei 190 6102100 450 150 czi mtr1070 2480ooi36703770 00 helehewe4010 1760 cic 00loy coicof4630 2510 1130 1 1 000000cocoi 00000ozzi 000000coioooio1 00000 izi i na nirii i ioi oj ritmit kocloocl T CO CO yi i coor 1 i tit foloi1 z aj nii C scoocoNCO S attsas1 u toloio approximately ott 01 1 1 I approximately 1 approximatelyI i approximatelyI 00OO fi DCO 1 l 1 l 1 101 I1 cu gos cl 10cltdl drocro gt 000 oems 42.4 mem 136 147 116 123 otheg 450 clayohms 669279 237 181 437 10t0387 i 864274 cti298 nd 424 & 665225cec 602202 t 1 C fe 221661 349 464td OS490 CO 10461 h 217H 268 869279 385qooolo d 1 I tor i i i tot t cechcoch i mcoooi i 0 0 & tlclccicalcati cqctcoc N 00OO CO f f ai&i ci&cocot 3 & 510 distributionQ i i 1 CO SOILff t Q 4 col 5.4 9.7 7.5lokotlooot6.8 6 OODT foifod foo800 7 54 97 75 68 1 1 16.0kofl 24.2 49.9 31.4 160 167 oeor29.0 21.6 56.1 499 474 494 314 609 609 560 490 487 663273 517 56.3 orrmw em 242 290 216i 508 silt5 35135.1 563 obr mel561 5 ndeeoc563mee jaj5 ameofl54 mi97 lm75 690 OC OS 00 DDI1 SOIL i tjlol SOIL d100st t1ta w i myn SOIL gconlo lo10 I1 0dfctductdollofMOl lOf toflo gcotdtdlo00dct DUNESOIL c mollofinf 3 c goi r w 1 I1

1 1 sizemanoN I1 0 DUNE l 14 oot too cocootd90 36 35inin101055 44 oi 55 62 w sands 375tloooloi448 185OO nd 614 744 lem768 777 8161 610710 537 473ozy603 CO COIO t 469hem 122nn10co112 283123 01- clodi 1 1 c OOi an 5 i losz Vs J cobicohl M oot001 S clozi 0nti 10n01 too clilclitditloi clooi MOUND M tl a 100 interspace oitl mam interspace LARGE5 3rt 1 CTS H t cl codoCOOO 00 i i i i cototoooct acci CIOHOO d01 CO 11 0.87 mcq U cciloooooieme emm 0cac g Z eel031 030ere 040 058 049 039COCO033 elpelm015 011rir 010 010 Z 057 046ehmzhichi020 047 056052 043ehm 038 0038 ll lee103zeeoootd087 060 046hrcfco038 049 0 colo Q lofmflo OOOOO 1 OOOOOO 0 tattototto00000Q 661 000000 Q 00000 00 ri 00000 s allenrolfea VEGETATED S z 1 VEGETATEDE I T I1 i EI C M VEGETATED r ililii zui cocciDOCCI80 79oslostzyl77 82MOOCM80 80 plottiplocti75 79 7.6 78dotoot 760 iii 70ooloqo80 ph unvegetated 81 76 83 82 82 82 76ot77 77 75 78 81 81 a bofooroof 000000OOOOOO 11 30000000COOOOOOO unvegetatedM boltoolt66ge t t f hotlootl QOOO M tt jl M tl

UN 1 UN I S s 0 bc bjdbcbcri trobotjobo subjo bab0 moderate ssbjo sbcbcfaobcm 0 C sitiosstiou u c G c a Q c c iu m c c a a a c cence xoe violent violent a fi violent violent 5 violents strong strong zoe strong strong strong efferves c strong strong strong strong strong strongcs strong strong strong 1 a g g lemilemlslight ggg5 slightwwslight gg g gg gwslight slight gggggg M

maw gavmaw gov gov mavgav fow maw gov y mod gov gov gavmaw few aadfew few fewCD few t few few fewQ fewQJ few aakfew alvfew fewQJ fewCD few roots5 D D td absent D absent absent td td D absent dl td aj i i ii fi w w oxx t aficfi w t fi 4 t l 0 few fewgov ii fewgov fewmodmok fewemdeow ii fewfow tl p v v v ca v v i v v v v v citahtabtv v v v v oq 3 652emm 652 63 652 fsas axicxi rn 0101100.1011072 72slomfmtm62 62 62 62rlnloio62 72 72 72 82rlloio 652emm 1 81581.5 S I OO 815 815 munsell color 101 irl 00 drynry loilol tor72 829mig totscdtd 81 SS82 73 73 i 00 i 155 i oooo got 1 tl COOO 0 il 1155 lei10yr 0000 0000 0 3 25y 25y 25y 25y 25y 25y 25y 25y 25y 25y mcs 25y 25y bwymcw 5yayuniouninloio 5yayi 5yay 10101010105 toioiotoivio 5yay 5yayi 5yay 5yayi 5yayi loioioio 5yayi 5yayi i 10cnn1010 CICI c1ca cici0ic1 ncqoilolo 1010 10 CIC M c100cloecyon

continued .5 M t- l c1ca L t 5 1 i cl1 i J j i i 112T cD 132co cob abiwoi127 112 depth& cm lOrO oco cccd 25 1 eco otim1 1 1 ios etim 1 64 loroch43 76 ece10I 33 69 99 13 46 86toltoi 1 81 15lorocd i 51 fi i C 51 OT OO u 81112 025CNT hit 76132 10IO COIOCD 99127 00 86112 lmT 1 wem 510 813 1 1 cst tit1 zemp woi127 foo 112 3051lotdooi5164 6481 alblab112 emmi 1 1543 43761 1 132 1 1 10331 33511 51691 6999I1 I1 ca 81 1 lehm1346 46861 2515 00 055 c1 08 1 1 Q 1 1 i 0icti OOO nutimuti td COIODOO30 51 64 81 ololocotd0 25 15ra 43 76 oloocor0 5 10 33 51 69tooibooi99 00008 13 46 86 1 oi lootoo100 a r1 TABLE N0 horizon c ajobjo bc bc T i bcbjo 0 0 mommmomo 2cg1 2cg2 0 ooo mougom M M co mclmol bom bowmoa 002mom boe803 c1ca c2ca u 2cuac u c1ca c2ca c3ca c4ca abt2btCT c1ca c2caM c3ca j 2cacu ji j u u u u u s uu&imm A uuuuci lousloumA UUUM MM N A oicicicnci 224 GREAT BASIN naturalist volume 58

2 2 footoo100- 0 0 0 1 e80 E 15 I i E W 6- 02 1 W i cr I1 40 05 9 ciaci5 i J 20 i cooCUD I1 Q 0- 0 0 1 1 0 remasSOMAS L I I 150 i 10- 36 ki 0 75 E 8 e27 e100 E U 6 W Z 18 R 00 5- 9 W cc 2 r

0 Z 0 0 20- 9 0 15- 05 E E 85 E E 8 2100 W 10 757.5 Z 7 50 5- 0 6.565 cc0 65 M 0 0 0 C IL A CJ c Z0 5 A0 R a p i a 410 c6ca iv i ci livily

fig 2 aqueous extractable soluteskolutes as influenced by collection micmicrositemicroliterosite codes are as follows BARE top of mound with no vegetation PAD surface soil of unvegetated mound interspace PBD lacustrine sediment beneath mound SAVE ALOC ATTOXIFTO and DISP collected beneath S vermiculatusverrmculatus A occidentoccidentahsoccidentalisoccidentalistalisallsails A torresitorretorreyiyi and D spispicatespicatacata respec- tively values aieare means 1 sps

extreme aridity high salinity halophytic vege- particles by salt weathering goudie et al 1970 tation and aeration status of the lower lacus- in addition the high salt content in conjunc- trine sediments erosion and deposition viavla tion with aridity and plant processes leads to wind action are a constant in these salt desert extreme alkalinization such as seen in S ver environments young and evans 1986 the micumiculatuslatus micromicrositessites robertson 1983 the magnitude of eolian transport in the study locally high ph condition enhances the weath- area is immense table 3 moreover deposi- ering of primary minerals via increased solu- tion of dust in obstructions such as plant cano bility of aluminum iron and silicon lough- pies would rapidly increase their salt content nan 1969 to levels too high for future seedling recruit- at present plant factors come into play only ment the situation thus exists where eolian on the mounds themselves one plant pedo materials both build the vegetated mounds and genic aspect is the biogeochemical concentra- are also partially responsible for their demise tion of elements that accelerates mound salin at some later date due to excessive salt accu- ization due to the capture ofeolianof eolian dust alone mumulationlation and eventual plant death As will be the yearly fall of leaves and seeds becomes discussed later we are not sure mound build- incorporated enriching the mound surface ing is contemporaneous with steady salt accu- horizon with organic matter vegetation seems mumulationlation from dust or whether the mound to play a role in the formation of gypsum as building phase requires some different climate only vegetated mounds contain measurable from that present when less saline coarser quantities gypsum formation may be a func- textured eolian dust is more plentiful tion of plant concentration of calcium and sul- the study areaareas s scant precipitation pre- fur in mound soil to such levels that gypsum cludes extensive leaching of soluteskolutes through can precipitate alternatively mound microcli- the soil steady additions of salt rich eolian dust mate may foster the crystallization of gypsum and plant deposition of salts on the soil surface via salt exclusion from ice marion and grant appear to quickly make mounds extremely 1997 saline another factor in the genesis of these soils one of the consequences of extremely high is the extremely reduced nature of the lacus- salt content in soils is the accelerated physical trine sediments as indicated by gley soil col- breakdown of sand sized particles to silt sized ors mottling and the presence of pyrite fes 199819981 PLAYA SOIL 225

TABLE 2 water relations by depth of mounds values are means with standard errors in parentheses n 4

gralgraigravimetricimetnc water coicoleolcontentitentident totetotalil soil watelwater poterpotentialitialfitial date by depth cm by depth cm 20 40 60 20 40 60 mpa 53091 132651326.513 2 6 5 209652096.520 9 6 5 248542485.424 8 5 4 2273722.73722 7 3 7 11232 8322832.28 3 2 2 61091 137601376.013 7 6 0 26513026.513026 5 13 0 2715927.15927 1 5 9 152341523.415 2 3 4 1275112.75112 7 5 1 52085.2085 2 0 8 7891 94519.4519 4 5 1 27610327.610327 6 10 3 23111123 1 11 1 1464314.64314 6 4 3 68l5688568156 8 1 5 63l363136 3 1 3 83091 5014501.45 0 1 4 23910623910.623 9 10 6 2877328.77328 7 7 3 221272212.722 1 2 7 8018801.88 0 1 8 80218.0218 0 2 1 93091 4808480.84 8 0 8 2956729.56729 5 6 7 2907029.07029 0 7 0 1881518 8 1 5 51045.1045 1 0 4 45034.5034 5 0 3

TABLE 3 average bimonthly dust flux from june 1994 through june 1996 and water soluble composition of dust col- lected on the barrenban en playa surface just west of the study area standard errors in parentheses dust flux months gmg M 2 sodium sulfate nitrate potassium boron

g kg 1 dust mg kg 1 dust jul aug 811468114.681 14 6 17144171 44 275827 5 8 704245704 245 21284622128 462 13022321302 232 sep oct 1725172.517 2 5 12027120 27 336033 6 0 884304884 304 16004291600 429 15474011547 401 nov dec 17299172 9 9 19320193 20 9447944.794 4 7 565240565 240 22151402215 140 17121811712 181 jan feb 15966115966.1159 66 1 15046iso150 46 451544515.445 15 4 626 20766292076 629 1592921592 92 mar aarapr 15732815732.8157 32 8 lsiisi15159151 59 41173 293159293893 159 18801591880 159 1414681414 68 may jun 23953723953.7239 53 7 13642136 42 216321 6 3 2315823 158 16903551690 355 1316851316 85

coatings reduced conditions are likely facili- these complex mounds are favorable for the tated by a shallow water table but subdued oxy- recruitment of new species such as atriplex gen diffusion rates through the fine layered confertifoliaconfertifolia haplopappus acradeniaus and sediments may play a role lack of oxygen for Stanstanleybstanleyaleya pinnatepinnatapinnata further geochemicalbiobiogeochemical en- root respiration will retard root growth of many richmentrichment of the mound in na 1 cl kak1K ca2caaca plants marchner 1986 in addition strongly and mg2mgtmg42 from litter fall and eolian dust leads reduced conditions will increase the solubility to eventual death of plants and mound ero- of metals such as fe and mn stamnstumn and mor- sion soil ph and solute content are control- gan 1996 the unusually low ph in the ath5th ling factors in plant distribution in andaridarld envi- layer of vegetated soil 3 may be a consequence ronronmentsments of the western united states gates of changes in aeration status of the soil if this et al 1956 skougard and brotherson 1979 horizon previously contained reduced sulfur there is no evidence to suggest plant suc- minerals such as pyrite its subsequent oxida- cession occurs on mounds at eagle valley playa tion could lead to the low ph observed nord- mounds begin and end with occupation by A strom 1982 occidentoccidentalisoccidentalistalis andor S vertniculatusvermiculatus and occa- siosionallynally by atriplex conferticonfertifoliafolia and atriplex natural history of mounds lentiflentifonnislentiformislentinlentiformisonnis sspasp torresitorreyitorreyi vasek and lund 1980 present a model of mound establishment potentially could have mound evolution on a playa that involves veg- begun sometime in the latest pleistocene as etation succession primary mound establish- pluvial lake lahontan dried mifflin and wheat ment on a playa begins with eolian dust en- 1979 morrison 1991 the mounds however trapmenttrapment by species of kochia which have high are far younger because they lack profile dif- sodium tolerance As mounds enlarge and ferentiation indicative of nearly 10000 yr of accumulate nutrients conditions are favorable pedopedogenesispaedogenesisgenesis for example in a similar playa for the establishment atriplexofatriplexof lentifonnislentiformistentilentilentiftormisformisonnis sspasp margin environment a clay rich differentiated torresitorreyitorreyi which promulgates mound expansion soil horizon formed in less than 3500 yr peter- to a critical size at which time they coalesce son 1980 moreover field research in the lake 226 GREAT BASIN naturalist volume 58 a PLANTS electrical conductivity M POTASSIUM mm 454.5 45 454.5 4 4- 68 4- 20 52 35 35- 35- 17 46 3 3 3 mi K M 40 14 25-25 25 25- 45834 2 2 2- 28 22 16 5 135 05 05-05 10 2 0 0 0 0 05 1 15 2 25 3 35 0 05 1 151.5 2 252.5 3 353.5 0 050.5 1 15 2 25 3 353.5

SODIUM mm SULFATE mm CALCIUM mm 45 45 45 4- 670 4- 48 4- 49 620 43 35 35 35-35 43 570 38 3- 3 37 520 33 31 25- 470 25 28 25 fil 0 25 420 2 KZ 23 2- 370 15- 18 15- 13 320 1 13 270 8 7 05 05 05- 220 3 LJ 1 0- 0 0 0 05 1 15 2 252.5 3 35 0 05 1 15 2 252.5 3 35 0 05 1 15 2 25 3 35 CHLORIDE mm ph MAGNESIUM mm 4 45 454.5 4- 700 4- 9 4- 52 620 47 35 jjjjjj 35- 88 35 540 42 3- 3 460 86 37 2 32 25- m 380 84 wg 2.727 2 2 2- 27 300 22 15- 15 828.2 15- 220 17 1- 1- 140 8 12 05- 05 05 07 60 78 020.2 0 1 0 0 5 1 I1 s 5 05 1 15 2 3 35 0 050.5 151.5 i 2 5 3 5 0 050.5 1 15 2 25 3 35 coarsesandCOARSE SAND VERY FINE SAND SILT CLAY 45 45 45 4- 11 4- 40 4- 68 10 36 62 35 9 35- 35-35 3 3- 32 56 25- 7 25 28 25- 50 6 24 44 2 2 2- 5 20 38 15 4 15 15- 16 3 32 12 26 05 2 05 05- 8 20 0 0- 0 0 05 1 15 2 5 35 0 05 1 151.5 2 25 3 35 6 0 5 i 1 5 2 5 3 3 5

fig 3 spatial distribution ofaqueousof aqueous eftiextiextractableactable attnbutesattributes forfoimol 3 mounds if a portion of a plant canopy intercepted the grid sampling pattern it is listed in the plants panel in the upper lefthandleft hand corner symbols used A occidentoccidentahsoccidentalisoccidentalistalis 1 S veriniculatusvenmculatuh and A torretorreiitorreyitorreyaii axes of graphs aiealealcare in in all panels are oriented north top to south bottom lahontan basin by morrison 1964 shows that in the sierra nevada expanded considerably pedopedogenesispaedogenesisgenesis since the middle holocene pro- curry 1969 the late holocene cool and wet duces an oxidized B horizon periods or neoglacials contributed to the rise the holocene in the western united states in pluvial lakes morrison 1964 heights ofnerofneoof neo has beenbeen marked by profound shifts in climate glacial pluvial lake maximums are uncertain and vegetation patterns antevs 1938 davis but in all likelihood water at times completely 1982 wigand 1987 anderson and smith 1994 covered the eagle valley embayment further the latest holocene has seen extended peri- reducing the potential age of the mounds ods of drought lasting 100 yr stine 1994 neal and motts 1967 believe that most geo- and cooler and wetter periods where glaciers morphic features on and adjacent to playasolayas in 199819981 PLAYA SOIL 227 b PLANTS LECTRICAL conductivity damdsm POTASSIUM mm electrical 45 45- 45 jlA 454.5 4- 4 99 4- 26 35 35 89 35- 23 79 20 3- 3 69 3 17 25- 25 59 25 14 2- 2 49 2 X 151.5 15 39 15 29 8 19 5 05- 0 05 2 0 0 0 05 1 15 2 25 3 35 0 050.5 1 15 2 25 3 353.5 0 05 1 151.5 2 25 3 35 SODIUM mm ULFATE mm ph 45 45 imaim7 454.5 4- 1450 4- 65 4- 896 1300 57 88 30 35 35-35 1150 i X 49 864 3 1000 3- 41 848 25 850 25 25- 832 33 2 700 2 2 816 26 15 550 15 151.5 8 400 17 784 250 9 768 05 05 5.5 loo100

0 i 1 0 1 0 05 1 15 2 2255 3 35 0 05 1 15 2 25 3 35 60 05 I1 151 5 2 25 3 3355

CHLORIDE mm GNESIUMMAGNESIUM mm CALCIUM mm 4 45 45 4- 1420 4- 36 4- 36 1270 g 32 32 35 35 35 gg i 1120 28 28 3- 3 3 970 24 24 25 820 25 2 25- M 20 2- 670 2- 16 2 16 15 520 15- 2 15- 12

370 08 1 220 040.4 4 05 05 05- 70 0 K 0 0 0 0 05 1 15 2 25 3 35 0 05 1 15 2 25262.6 3 3536 0 05 1 15 2 25 3 35

fiefleficfig 3 continued the western united states were formed within effective precipitation may have leachedbeached solu- the last 100 yr a result of a lowered water table ble salts deeper into the soil thereby favoring caused by manmansmangs activities the most recent plant recruitment this scenario is problem- glacial advance in the sierra nevada occurred atic because longtermlong term increases in effective from 1880 to 1908 curry 1969 which corre- precipitation would promulgate playa flood- lates with rings of A occidentoccidentalisoccidentalistalis in the study ing perhaps plant recruitment on the playa area phytogenic hillocks can form and enlarge margin began at the end of the neoneoglacialglacial in this time frame gile 1966 period there would be greater sources of present osmotic potentials of these playa unconsolidated material at the delta of the margins are a magnitude too high for seed ger- truckee river for mound building moreover miminationnation and suggest that large scale plant the neoneoglacialglacial lake may have reduced the salt recruitment may hinge on rare climatic events content of sediments along the playa margin romo and haferkamp 1987 blank et al 1994 do mounds provide benefits for plants or what were those conditions in the past 90 120 are they happenstance simply a result of inin- yr that initiated mound formation present escapable physical processes phreatophytes plant recruitment occurs rarely in small flood such as S venniculatusvenmculatus which domdominantlymantly root caused channels however mound plant demo- inm the undeiunderlyingdundei lying lacustrine material would graphy suggests pulses of large scale recruit- seem not to require mound formation for con- ment if mound initiation began during a neo tinual survival potentially beneficial aspects of glacial cycle then longtermlong term increases in mound formationfoiroirol mationmatlon could include the following 228 GREAT BASIN naturalist volume 58

C mm PLANTS electrical conductivity damdsm POTASSIUM 5 5- 92 24 i i iWi 4 4 84 4 22 76 20 18 3 3 6 8 3- 16 60 eelieels 14 2- 5 2 1.1 2 52 PEAWINNER 12 44 10 36 8 X 28 6

0 0- 1 1 1 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 SODIUM mm SULFATE mm ph 5 530 49 91 4 380 4 43 4- 9 1230 37 8 9 3 1080 3- 31 3 930 87 780 25 86 2 19 858.5 4 0 13 84 330 7 83 180 82 0 7 0 1 2 3 4 5 7 0 1 2 3 4 5 6 7

CHLORIDE mm NITRATE mm boronmmBORON mM 5 5 1030 32 20 4 4- 4 930 272.7 17 830 14 3 730 3- 22 3- 630 171.7 2 2- 5 1 2 8 4 070.7 1- 5 2 23 02 L 01 0 1 1 6 0 1 3 4 5 7 0 2 3 4 5 6 0 2 3 4 5

BROMIDE mm CALCIUM mm MAGNESIUM mm 5 101.0iolo 50 32 090.9og 4- 44 4 282.8 0840.84 38 24 3 0720.72 3- 32 3 og 2 060.6 26 0.48 16 2- RN 048 2 20 2 0360.36 0240.24 14 012 8 0 2 1 0 0 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7

fig 3 continued

1 a seedbed with superior physical character- measured electrical conductivity values of istics and lower salt content favoring the saturation extracts were always below 4 ds recruitment of a host of plant species 2 more m 2 indicating no osmotic limitation for ger- favorable rooting media compared to the dense minationmination of seeds of native plants in the years lacustrine sediments 3 favorable bio meteoameteo of study however plant recruitment was never logicalrorologicaloological properties in portions of the mound seen on the small eolian veneer on the sides of due to aspect ie cooler soil temperatures in mounds possibly because the ventersveneers are too midsummer on the north side of the mound or thin to allow a rooting mantle it appears then warmer temperatures in early spring on the that early in the life history of mounds recruit- south side of the mound ment of plant species was not limited by salin- at present mounds function very poorly as ity because of extreme periodicity of mound seedbeds given the extraordinary levels of salt formation we are witnessing mounds in eagle which would seem to negate beneficial aspect valley at an advanced age when extreme salinity I1 listed above early in the life history of the prevents new plant recruitment As established mounds however they may have been far less plants die the no longer protected mounds saline throughout this study the salt content will erode and new recruitment must await of recent eolian sand deposits on large dune the next rare mound building phase interest- fields and on the lee sides of mounds was ingly soil description sites were revisited in 199811998 PLAYA SOIL 229 july 1997 all soil pits which were not com- GATES DHD H LA STODDART AND CWC W COOK 1956 soil pletely filled in with soil have had extensive as a factor influencing plant distribution on salt deserts of utah ecological monographs 26155155 174 recruitment of plants one pit has very robust 26 GEE GW AND JW BAUDER 1986 particle size analyses S plants of A lentiflentifonnislentiformislentiformisonnis and venniculatusuermiculatus pages 377 382 in A klute editor methods of soils analysis part 1 american society of agronomy acknowledgments madison WI GILE LHL H 1966 coppice dunes and the koturarotura soil soil science society ofamericaof america proceedings 3065730 657 660 we thank Ms kay blakely and Ms clara GOUDIE ASA S RUR U COOKE AND JCJ C DOORNKAMP 1970 pantello of the US bureau of mines for exten- the formation of silt from quartz dune sand by salt sive use of xrayX ray diffractometer and interpre- weathering processes in deserts journal of andaridarld tation of xrayX ray diffraction data thorough environments 21052 105 112 the groundwater review of a draft by jeanne chambers of JACOBSON G AND J JANKOWSKI 1989 dis dr charge processes at a central australianAusti alianallan playplayaa jour- the US forest service is greatly appreciated nal of hydrology 105275105 275 295 we thank the anonymous reviewers for insight- JOHN MKM K HHH H CHUAH AND JHJ H NEUFELD 1975 ful comments and criticisms application of improved azomethine H methods to the determination of boron in soils and plants anal- ytical letters 85598 559 568 CITED literature JONES JBJ B AND ERE R SEGNIT 1971 the nature of opal I1 nomenclature and constituent phases journal of the ANDERSON S paleoclimatic RSR AND SJS J SMITH 1994 inter- geological society of australiaaustrallaofaustralia 185718 57 68 pretationspretations of meadow sediment and pollen stratigra LOUGHNAN FC 1969 chemical weathering of silicate phles from california geology 2272322 723 726 minerals elsevier amsterdam ANTEVS post E 1938 pluvial climatic variation in the MALEK E GEG E mccurdy AND GDG D BINGHAM 1990 southwest american meteorology society bulletin evapotranspiration from the maimalmargingingln and moist playa 1919019 190igo 193 of a closed desert valley journal of hydrology 120 BATANOUNY KHK H AND MHM H BATANOUNY 1968 formation 15 34 1 plants of phytogenic hillocks I forming phytogenic MARION GMG M AND SAS A GRANT 1997 physical chemistry hillocks acta botanica academialacademiae scientiarum hun of geochemical solutions at subzerosubhero temperatures garicaegancargancae 1424314 243 252 pages 349 356 in IKI1 K ishkandarIshkandar et al editors inter- BENDALIBENDALL FE C FLORET E LE FLOC H AND R PONTANIER national symposium on physics chemistry and ecol- 1990 the dynamics ofvegetationof vegetation and sand mobility ogy of seasonally frozen soils special report 971097 10 in and regions of tunisia journal of andaridarld environ- USU S army cold region research and engineering ments 182118 21 32 laboratory hanover NH BILLINGS WWSS 1945 the plant associations of the carson MARSCHNER H 1986 mineral nutrition of higher plants desert region western nevada butler university academic press london botany studies 7897 89 123 MIFFLIN MDM D AND MMM M WHEAT 1979 pluvial lakes and blackwelder E 1931 the lowering of playasolayas by defla- estimated pluvial climates of nevada bulletin 94 tion american journal of science 221140221 140 144 nevada bureau of mines and geology BLANK RRR R JAJ A YOUNG E MARTENS AND DED E PALM- MING DW AND FA MUMPTON 1989 zeoliteszcolitesZeolites in soils QUIST 1994 influence of temperature and osmotic pages 873 911 in JBJ B dixon and SBS B weed editors potential on germination of allenrofeaallenrolfea occidentoccidentalisoccidentalistalis minerals in soil environments soil science society seeds journal of andaridarld environments 2633926 339 347 ofamericaofamerica book series no 1 madison WI BREWER R 1976 fabric and mineral analysis of soils MOORE DMD M AND RCR C REYNOLDS JR 1989 xrayX ray dif- robert E krieger publishing co huntington NY fraction and the identification and analysis of clay 482 appp minerals oxford university press new york CHADWICK 0OAA AND j0jaJ 0 DAVIS 1990 soil forming inter- MORRISON RBR B 1964 lake lahontan geology of the vals caused by eolian sediment pulses in the lahon- southern carson desert nevada US geological tan basin northwestern nevada geology 1824318 243 246 survey professional paper 401 CHARLEY J AND NEN E WEST 1977 plant induced soil 1991 quaternaryQuateinary stratigraphic hydrologic and chemical patterns in some shrub dominated semi- climatic history of the great basin with emphasis desert ecosystems of utah journal of ecology 63 on lakes lahonLabonlahontantan bonneville and tecolatecopa pages 945 963 283 320 in RBR B morrisonmornson editor quaternary non- CURRY RRR R 1969 holocene climatic and glacial history of glacial geology of conterminous USU S the geology of the central sierra nevada california geological north america geologic society of america boul- society ofofamericaamerica special paper 123 der CO DANIN A 1991 plant adaptations in desert dunes journal NEAL JT AND WS MOTTS 1967 recent geomorphic ofariaofaridof and environments 2119321 193 212 changes in playasolayas of western united states journal DAVIS jaj0J 0 1982 bits and pieces the last 35000 years in of geology 7551175 511 524 the lahontan area pages 53 75 in DBD B madeson NELSON DW AND LE SOMMERS 1982 total carbon and JEJ F oconnell editors man and environment in organic carbon and organic matter pages 539 580 the great basin SAE paper no 2 society for amer- in A klute editor methods of soils analysis paipalpartt 1 icanlean archaeology washington DC american society of ofagronomyagronomy madison WI 230 GREAT BASIN naturalist volume 58

NOROSIKOMNORDSTROM DKD K 1982 aqueous pyritepantepynte oxidation and the SOIL SURVEY stafestateSTAFF 1984 procedures for collecting soil consequent foimationformationfoifor mationmatlon of secondary iron minerals samples and methods of analysis for soil survey soil pages 37 56 in JAJ A kittrick DSD S fanning and LRL R survey investigative report 1 USU S department of hossner editors acid sulfate weathering soil sci- agriculture washington DC 68 appp ence society of america special publication 10 STINE S 1994 extreme and persistent droughtdi ought in cali- madison WI fornia and patagonia during mediamediaevaleval time nature piPETERSONiersonlersonILRSON FFFE 1980 holocene desert soil formationfoibol mationmatlon under 369546369 546 549 sodium salt influence in a playa margin environment SIUMMSTUMM W AND JJ MORGAN 1996 aquatic chemistry quaternary researchResealchseaich 1317213 172 186 john wiley & sons new york ROULRIROBERT EC 1950 chemical effects ofsaltof saltsait toleranttoleibolei ant shrubs USU S SALINITY laboratory STAFF 1954 diagnosis and imim- on soils international congress of soil science ath4th provementprovement of saline and alkali soils USU S agriculture amsterdam 14041 404 406 handbook 60 department of agriculture govern- ROHUUSONROBERTSON JH 1983 greasewood sarcobatus vermicavermicu ment printing office washington DC latulatus hook tontorr phytologiaphytologicPhytologia 5430954 309 324 VASEK FC AND LJL J LUND 1980 soil characteristics ROMO JT AND MRM R HAFERKAMPHAFLRKAMP 1987 effects ofosmoticof osmotic associated with a primary plant succession on a potential potassium chloridechloi ide and sodium chloride on mojave desert dry lake ecology 61101361 1013 1018 geigelgerminationmination of gigreasewoodeasewood sarcobatus vermiculatus WIGAND PE 1987 diamond pond harney county ore- creatgleatgreat basin naturalist 4711047 iloiio110 116 gon vegetation history and water table in the eastern RUSSLILRUSSELL ICI1 C 1885 geologic history of lake lahontan oregon desert great basin naturalist 4742747 427 458 USU S geologic suisulsurveyvesvey washington DC YOUNG JAJ A AND RAR A EVANS 1986 erosion and deposition silsllSIIsiiantzsllani7simantzANTz HLH L AND RLR L PIEMEISEL 1940 types ofvegetaof vegeta- of fine sediment from playasolayas journal of andaridarld envi- tion in escalante valley utah as indicators of soil ronmentsronments 1010310 103 115 conditions technical bulletin 713 USU S department YOUNG JAJ A RAR A EVANS BAB A ROUNDY AND JAJ A BROWN Agricultureofagricultureof e washington DC 1986 dynamic landformslandforms and plant communities in SKOUGARD MGM G AND JDJ D BROTbrothersonhersonnERSON 1979 vegeta- a pluvial lake basin great basin naturalist 46146 1 21 tional responselesiesponse to three environmental gradients in the salt playa nealnear goshen utah county utah great received 17 april 19919977 basin naturalist 394439 44 58 accepted 11 september 1997 great basin naturalist 583 C 1998 appp 231 244 WINTER macroinvertebrateMACRO INVERTEBRATE communities IN TWO MONTANE WYOMING STREAMS

christopher A Pennutopennutol2pennuto1212 frank denoyelles jrjrejr11 mark A Conradconiadoconiad3conrad34344 frank A Vertuccivertucci3535 and shalonsharon L dewey6deweye

ABSTRACT Macromacroinvertebratemacroinvertebiateinvertebrate communities were examined on 4 winter dates over a 4 yiyr period in 2 high altitude rocky mountain streamssti earnsearms to document overwinteringoverwintering assemblages potentially expenencingexperiencing spring acid pulses taxa rich- ness values were comparable to other published lists for alpine and montane stream systems despite the fact that most literature reflected summer collections mean benthic density ranged from 1406 to 19734 oiganismsm2organismsm2 and drift rates ranged from 0 to 1740 organismsorganisms100100 m3ma benthic collections showed higher taxa richness than drift collections while the ephemeroptera and plecoptera occurred in greater proportions in drift than in benthos the nemouridaenemoundaeNemouridae pieple- copteracoptera ephemerellidae and heptageniidaeheptagenndae ephemeroptera chironomidae diptera and hydracarinahydracannaHydracannacarinaearlna were the numennumericallycallycaily dominant taxa in benthic collections Grazergrazersciapersgrazerscrapersscrapers and shredderdetntivoishredderdetritivores es weiewelewere always the numerihumerinumen cally dominant functional feeding groups at all sites composing 60 90 of the benthos Piedapledapredatorstoistols constituting approxi- mately 15 of the community occurred in the same relative proportion at all sites on all dates winter macroinvertemacroinvei te brateblate communities in these low orderordelorden montane streamssti earnsearms exhibit high taxonomictaxon ornic richness and benthic densities as great as lower elevation mountain streams in the west

key words community structure winter collections stream insects functional feeding groups wyoming montane habitat

stream ecologists are interested in under- in mountain streams logan 1963 who sam- standing the forces influencing community pled aquatic insects biweekly through the structure and composition however seasonal winter in bridger creek montana found that changes in habitat features might influence trichoptera larvae dominated the benthic taxa the relative importance of forces structuring andrews and minshall 1979 and minshall stream communities eg peckarsky 1983 1981 sampled monthly throughout the year minshall petersen and nimz 1985 wiens and found all common taxa during all seasons 1977 1981 argued that seasonal multisitemultisite but at different abundances communities data were needed to make accurate assess- sampled were dominated by grazer and collec- ments of community structure and resource tor functional feeding groups bruns and min- use because of annual variation in population shall 1986 also sampled through the winter abundances within and among habitats harsh and showed an extreme change in winter niche winter conditions eg extreme cold deep parameters foiroirolfor the predator guild of an insect snowsnowpackpack ice cover or the timing of insect community in the salmon river they sug- life cycles often prevents stream ecologists gested that resource limitation iei e low prey from sampling some communities on a sea- numbers in winter was a factor determining sonal basis mountain streams in particular spatial resource partitioning in this system receive heavy snowfall making most sites in- however these studies all focused on stream accessible during winter months yet winter is reaches at elevations below 3000 m studies at the longest season of the year in mountain alti- elevations exceeding 3000 mrn have been re- tudes retaining snow cover up to 7 mon strictstricteded primarily to the warmer open water few studies have examined macroinverte season dodds and hisaw 1925 blake 1945 brate communities during mid to late winter elgmork and saether 1965 saether 1965 allan

department of systematicsystematics and ecology university of kansas lawtencelawrenceLawience KS 66045 2presentpresent addlessaddress environmental science and policy Proprogramgiam university of southern maine gothamgorham ME 04038 united states forestfoiest serviceSe ivleeivice centennial station centennial WY 82055 niesentpresentprePiepiesentsent address wyoming department of environmental quality watelwater quality division 122 west 25th sheetstreet cheyenne WY 82002 spiesent5presentSpieseatsent address ENSR consulting & engineering 4303 west laporte avenue foilforthollhoit collins CO 80521 kansas applied remote sensing programPi ogram university of kansas lawrenceLawience KS 66045

231 232 GREAT BASIN naturalist volume 58

1975 short and ward 1980 ward and berner stream from west glacier lake LB approxi- 1980 bushnell et al 1982 1986 ward 1986 mately 2 km downstream from WG at an ele- recent documentation of episodic acidifi- vation of 3163 m is located approximately 100 cation in mountain streams of the western USU S m upstream from little brooklyn lake tl is ege g williams and melack 1991 vertucci and located at 3240 m elevation approximately 75 conrad 1994 suggests a need to understand m downstream of the easternmost north car- winter stream communities if we are to assess bon twin lake and within 100 m of tretreelinefreelineeline potential impacts from snowbeltsnowmelt related spring t2ta is approximately 0250.25 km downstream from ph declines winter samples collected imme-imme tlTI at an elevation of 3230 m and 100 m down- diately prior to any potential spring acid pulse stream from the confluence of the eastern and could provide a reference picture of stream western north carbon twin lakes outflow insect communities while reducing temporal fig 1 difficulties associated with comparisons to WG LB and tl are and2nd order streams later times of the year repeated short term whereas t2ta is a ard3rd order stream substrates acid events may have severe cumulative effects at all sites consist of boulder cobble and on stream communities in acid sensitive gravel all sites are within forest habitat domi- streams of the west kratz et al 1994 impacts nated by lodgepole pine pinus confortacontorta and due to episodic pulses of acidity may i educereduce Engelengelmannmarm spruce picea engelmanniaengelmanniiengelmannii scat- stieamwaterstreamstreamwaterwater acid neutralizing capacity influ- tered stands of quaking aspen populus tremuteemu ence fish community stability in small streams loides also occur near LB all sites contain and mobilize metals baker et al 1996 kiffney populations of brook trout salvelinus fonti- and clements 1996 wigington et al 1996 nalis WG LB and t2ta exhibit perennial flow knowledge of winter community structure while tlTI experiences some zones of intermit- might enhance our ability to understand these tent surface flow the streams were sampled episodic spring events our objective was to on 4 winter dates november 1989 february document the winter macromaeromacromvertebratemacroinvertebrateinvertebrate com- 1990 199iggi19911 and 1992 munity structure in high mountain streams in in in sampling design wyoming for a baseline reference in assessing snowbeltsnowmelt driven episodic acidification we all sites except LB were snow covered on estimated winter benthic maeromacromacromvertebratemacroinvertebrateinvertebrate all sampling dates and required tunneling to and drift density taxonomic richness and reach the streams we constructed 3 tunnels functional feeding group abundance for high at each site on each date by digging through elevation streams having extensive snow cover the snow to the stream banks and proceeding laterally until we reached the streams occa- METHODS siosionallynally tunnels opened directly over the stream in such cases we collected samples study area only upstream from the tunnel to reduce sam- two streams were selected for study west pling bias associated with disturbance of the glacier lake creek WGL and north carbon substrate snow depth cm was measured twin lakes outlet NCT WCLWGL is located from the top of each tunnel to the ground within and NCT adjacent to the united states on each date we took 3 surber samples 1 forest service glacier lakes ecosystem exper- sample per tunnel 929 cm2 280 imum mesh if iments site GLEES log106iyw106 15w longitude water was present all stones within the sam- 4122n41022n latitude GLEES was established to pler were brushed to dislodge any organisms collect baseline and experimental data for and the substrate was agitated to a depth of assessing atmospheric deposition effects on approximately 10 cm organisms were pre- sensitive alpine and subalpine ecosystems served in 80 etohcetoh in whirl pac bags in musselman 1994 an upstream and a down february 1991 and 1992 water was frozen or stieamstidamstream station were established on each stream absent in some tunnels at tlTI resulting in 2 such that the upstream station was located and 1 surber collections on those dates within a geologically acid sensitive zone respectively stations WG and LB are located on WGL after completing benthic collections we tlTI and t2ta on NCT fig 1 WG is at an eleva- placed I1 drift net 1 I1 x h X w 100 x 30 x 46 cm tion of 3250 m and approximately 150 m down 280 pmgm mesh midstream in the upstream most 19981 WINTER STREAM communities 233

north arbon twin aak N t1taT

glacier lakes t2ta

wintwin lake letiet 1waw aladgladgiam creek lak 0

WG bi ooklynoaklyn lake

LB I1 krnarn littlelittie brooklyn lake

fig 1 location of 4 sampling sites in the medicine bow national forest of southeast wyoming

opening for a dusk to dawn drift collection ca on each date we collected a single water 12 h tunnels were covered with black plastic sample for chemical analyses water tempera- and tarpscarps to prevent overnight snowfall accu- tures were taken with a hand held thermome- mumulatinglating in holes and to eliminate any possi- ter just prior to sample collection samples bility that starlight or diffuse duskduskdawndawn light- were collected in dark acid washed plastic ing might influence drift patterns stream vol- bottles laboratory filtered gelman 045 tmum ume filtered was estimated from the product glass micromicrofiberfiber filters and split into an acid of velocity cross sectional area and duration preserved oi01010.1 rlui of 606.0go N nitric acid and a of net set average velocity swoffer model preservednonnonpreserved subsample samples were re- 2100 flow meter and depth were based on 6 frigeratedfri and usually analyzed within 48 h of measurements each from the mouth of nets collection all samples were analyzed by the upon placement and retrieval total settimeset time united states forest service water chemistry was recorded when nets were retrieved sam- laboratory in fort collins CO major anions ple drift density no100m3 was calculated and cationscanions were estimated on a dioneldionex 20101 according to allan and russek 1985 ion chromatograph cationscanions were also verified 234 GREAT BASIN naturalist volume 58

with a smith hieftjahieftje 22 atomic absorption 1380138.0 isemisamiscmgscm at LB major cation and anion spectrophotometer conductivity was mea- concentrations varied across years and sites sured with a YSI conductance meter model calcium and magnesium levels were 3 5 times 32 acid neutralizing capacity anoangANQANC and ph greater at LB than at the remaining sites while weiewelewere determined using an ARAS acid rainram anion levels were similar across sites and low- analysis system radiometer est at WG table 2 community analysis community analyses Mmacroinvertebiatesacroinverteb rates were identified to the of the 56 taxa we identified no taxa lowest possible taxonomic unit usually species occurred at all sites on all dates richness was foifor insects except diptera using the following greatest at LB in all years and lowest at tl in taxonomic keys alienallenailen and edmunds 1962 all years appendix three sites WG LB and jensen 1966 smith 1968 edmunds et al 1976 t2ta showed low year to year variation in rich- baumann et al 1977 bermakpennakpermak 1978 szczytko ness values CV 10410.4 989.8gs and 13613.6 and stewart 1979 merritt and cummins 1984 respectively whereas yearly variation in rich- klemm 1985 peckarsky et al 1985 stewart ness at tlTI was higher CV 41141.1 richness and staikstalkstark 1988 and ward and kondratieff ranged from 9 tlTI in 1992 to 41 LB in 1991 1992 also GT baxter university of wyoming all sites contained representatives of the 4 unpublished manuscript some taxa were veriverlveri- major functional groups the grazerscrapergrazer scraper fied by comparison to the kansas biological guild varied most annually CV 63763.7 survey KBS reference collection to which whereas the predator guild varied least CV new records were added functional feeding 25125.1 Grazergrazerscraperscraper and shredderdetriti gioupgroup designations followed tables in merritt vore groups dominated all sites collectors and cummins 1984 were always least abundant fig 2 collectors represent the combined numbers of calleccollec RESULISRESUKIS gathererstortorgatherers and collectorfilterers predators comprised approximately 15 of the commu- data from novemberNovembeibel 1989 samples are nities at all sites on all dates omitted from any comparisons across years diptera composed the greatest proportion due to potentially confounding time effects of the benthos ie no of diptera in benthic however the november 1989 data are illus samplestotalsamples total no in benthic samples in all ti atedabedtratedgrated for completeness years at all sites except that in 1990 at t2ta ephemeroptera highest 3 physicochernicalphysicochemical analysis were fig on average Nemournemouridaeidae plecoptera Baetbaetidaeidae snow depths ranged from no cover at LB ephemeroptera and hydracarinaHydracarina were the in all years to a maximum of 290 cm at WG in other numerical dominantsdominants in the benthos 1990 table 1 generally the 2 higher eleva appendix few taxa were found at all sites on tion sites WG and tlTI had deeper snow cover all dates the most ubiquitous taxa included than the 2 lower elevation sites LB and t2ta plecoptera Sweltsweltzaza lamba capadazapada lansibansi and morning and evening water velocities were Z cinctcinctipesipes ephemeroptera ephemerellaEphemerella typically within 5 cmseccusecemsee of each other table infrequentinfrequens cinygmula sp and baetisbabtis ricaudabicauda 1 the minimum difference recorded was 030.30 3 tus and trichoptera rhyacophila brunnelbrunnea and cmseccusecemsee at t2ta in 1992 the maximum 535.35 3 cmseccusecemsee R ververrulaverdularula appendix seven taxa plumiperlaPlumiperla at WG in 1990 water depth rarely exceeded diversa paraleuctra ververshinavepshinashina arctopsyche 10 cm surface ieeicelee was encountered only at tlTI grandis rhyacophila kellisapelpellisalisa anagapetusAnagapetus sp in 1991 and 1992 although all sites contained lepidostomaLepido stoma sp and oligophlebodes minutesminutusminutus both anchor and frazil iceieelee in varying amounts were collected only from LB trichoptera watelwater temperature ranged from 03 to 18c1 8cac always accounted for 10 of the benthic table 1 community all sites weiewelewere characterized by circumneu-circumneu diptera and ephemeroptera comprised the tral ph values table 2 WG had the lowest greatest proportion of drifting taxa eg no of ph readings while LB always had the highest diptera driftingtotaldrifting total no drifting whereas ph ANC and conductivity values mean con- trichoptera and hydracarinaHydracarina constituted the ductivities ranged from 302 uscmgscmusamusem at tl to least fig 4 proportions of ephemeroptera cc 1998 CDD CR WINTER STREAM communities 235td C

v

1 co 0 coto13coiecoio 10 144 01 01 53 1 100 t2ta 1000 hoe r 1 N 2 of HOO 1011 temperatureu ft S cslasl ca 1992 0 148 na rtna nj tat1 1700 na na y 60 11

en february1 CO PQ 1 010 010 33 04 10 1 1 1 0 LB r CO 1 1 0 0 NZ hamkadepth v v au 0 i iiui i 1 0 ttoITO C 1 P vaellwater or rf WG0 121 61 02 73 02 47 01 04 1 an2500 zottcoto 0 OSN rqaq0n doto fi M 0con- aclformcw 0 0 t i elm014 bouyou149 906tdoooimooton658emm 249 154 035 068078 056 092 124rn & fou iincotmcts 1 m loyIOS 5 except 0 cocit10000 U u ai i present x aticti t 1 D 69 oa tn 01 000moo elb314 699799 299099omm 75 09oooo48 106zemwem hoo 222 98 70 04 12 94 1 100 to 002384OO 1562 S 940 ofocsl160120 l 1 tat2 1 1 01 oi ZN co co 10tooictitofcnot M oxl 1 1 tottto lri 1 CN & a too Sctrct1 r huelbuel 11 M Y A 6 05 aremru 0 010 010 02 10 1991 lem139 1 0 110 01 I nj S TI 1500OC HO y u v v 1 present d- iu & S a rt u february 1 u 1 i 1 j aqcq as measurements P S i I1 OO OO LB 0 17 181 09 37 06 100 00 00 COOOCOOO CO nonec 1 200 toocobooco1135 1035lemmzemm i cnt r N CN 0 1 0 0 oct000 clo lz 3 006 120lmh 671 028 168COOOCOQzhe106 048 ate103 268 1 1 fc otmtI I I1 1 I1 nj i 01OIotot00OO IOI101 I N 11 tat1 toi gt 70 ri 88 18 76 C c i otirofir302 656 422 i 269229 25725.7 t 1997 lemm ZN 4.0 0 co lemb1392 t nin257 WG 0 112 400 06 800 03 127 01 03 allmeh too30mmooco OT co us 01sinnio m82502250 i 40wt N f ol ri m 1 miwam 0000oooo MO oz U cover M Site 0 dazo CO 0 c3ca yearsite tt U site4 iceloogoe ctfcaf A u moalYeargoar y c5ca capacity

h dates formca oo50 70000ooo08 in 00 na 54 15 na g t2ta sym1100 c N e c c tuomuo s sin1 1 bd 5sas CT 12666 CO 1 CO c G 1299 to r s C 8366 2534 0 0 datesmazos 006OCCO 141 047 169amm 183coa090 246 sampling3 OH ooifm10trli fm i 1 orsi CT CO 10 co neutralizing LBm io S E 1 0 i 0 1 be 19900 173 73 06 na 600 05 03 2 1800 zieaie rt OS tat1 oo01 ta COO N C 80ootdmiracofrsicd tactitocti v H 00 11 S OZ w 164 22 36 129 i 3 1380 9385 5235 226 mie276 vi t0 oooocooo14736 coci sampling Dricoti ri & S cor cornirsicocidricotortwrt i a i R 0 in nr ca 1 odd february february acidmlan T QO 0 3 M 46 02 020 ir 14 0 odsodd LB 01 114wahwlm 18 4 u i i H N lom 11 onC fe 0 leolooio tiz 0 3CO ANC sitesgleasS formca moo coicoq mcc VI 000 ape 14 83 11 74atofto06 808208 toi136 I1 05 0WG 69002900 CO ochach001OO I I10 lap 1 ociaoiOOI O N bc 1 N 0 oi00ci IO OZ 4 ge lfp ij 1432 yot g M ricocoooicti1 8535 5107 2499 kot elcimici emm gscm elm012 u l 099 075 095 097 135 155 chemistry ul 1 sampling& g I lmI1 I1 WG 0 S A 0 ooiocsioooo oj 1 DOOD commCOCT COOO 0 is2 69 pee DOODCOCT62 13 39 78 00hee300 136 i 223 2551omma 1776 1008 1 OCOCD cost s3sa d0101co 10 t contIM 1 4 coicoucokcop 00 1 0T 1 OT coicopcoicol 17 tor water c1ca at 610i wel131aez 93 15 83 76 01 08 tat2 i co oi i ooi 10 ozN 1 CO tj 3 C conductivity3 11 oi stream11 en 198900 01 000300OOO ctivchiv 05 87 98oot20 mm898.9 15 84 07P 010 ll 1250 OS coor89 s t1ta iraoobraoo COOT cotcoo ZN L ffiafi L wlazmean ph j 1 m a M S november soS o and m co boetboyti T m G t LB 93 1 90or1 55 06 020 rt 3 i os i oi i N 2 1 p 1 conditions 0 0 1 lootirao rz i Z J 3 conductivity1 magnesium TABLE ammonium c potassium ductivity i 43 calcium chloride 0 fihesodium file sulfate nitrate 0 & uo useamese 0sas os co in S kroemoANC a 0 70 8002000 32 0 1 99 03 05 oz s emam3 200 i aph uoassasa 0WG oiiolt1220 OCOO N s3 aticti cl brnoernoN M 1 odo au stream NM 02 assauscftuwz

fif i a1aa ajobjo winterS 5 G reading3 oj c v ni mean S cm ICU W 5cm S S am A oi amscms 1 T 5 1 u depth A depth& S s single temperature cover TABLE B S parameter i pms g velocity sam s a 2 snow water is & 11 1 1 ice 236 GREAT BASIN naturalist volume 58

80 80 grazerscrapergrazer scraper shredderdetritivore 60 60 0 tat3 40 40 ln W W 0 k 41 20 20 0 S 0 0 0 g

80 80 & predator collectorgatherercollector gatherer 60 60

03 3 40U 40

20 20

0 OMLM &4 441 19 ff ff 24 ti 2 aaiaal site

fig 2 relative percent composition of functional feeding groups in the benthos during winter months in 2 mountain streams fromplom left to right bars reflect samples collected in november 1989 february 1990 1991 and 1992 respectively

90go diptera 90go ephemeroptera 60 j 1 60 0 30 0 20 30 scn 0 0 0 imma 1 90 hydracarinaHydracarinacarlna go plecoptera 0I 0 60 60

gU 30 30

c 0 0 44jlii 2 v rar1 90go trichopteratnchoptera CO 3 60

30

1 w16m wd lelLEI site

fig 3 relative percent composition of major orders in the benthos from left to right bars reflect samples collected inm november 1989 february 1990 1991 and 1992 respectively 199811998 WINTER STREAM communities 237 and plecoptera in drift samples exceeded ben- latefaterate the effects of local hthologygeomorphollithologygeomorphol thic proportions while diptera occurred in agyogy on insect community development these lower proportions in the drift relative to ben- high elevation streams are near the tretreelmetreelinefreelineeline in thos hydracarinaHydracarina and trichoptera were relatively open woodlands where potential approximately equally represented in benthos autochthonous production is expected to be and drift figs 3 4 high offering ample food resources for the the mean number of organisms in the ben- grazerscrapergrazer scraper guild these patterns suggest thos nomanomnom22 ranged from 1500 to 15000 that the RCC predicts well foirolforhoi the glazergrazer organisms fig 5 chironomidae were always scraper guild in high elevation western streams the most numerous sample drift densities further study is warranted on these streams to generally ranged from 100 to 600 organisms correlate grazerscrapergrazer scraper abundance with algal per 100 m3ma and showed no consistent pattern productivity under winter conditions across sites or times fig 6 shredders were the other dominant func- tional guild composed primarily of nemournemounddemoundnemouridid discussion stonestonefliesflies this contrasts with results of short and ward 1980 for a stream of similar alti- unlike other faunistic studies in mountain tude though a summer study in which shred- stream habitats this study examined macro ders constituted a much smaller percentage of invertebrate communities in 2 high elevation the benthos but were still primarily nemournemounddemoundnemouridid streams under winter conditions taxonomic stonestonefliesflies their study site flowed through a richness observed in this study was slightly meadow while our sites were principally higher than summer faunal surveys from other within forested reaches potentially offering western mountain streams ward 1975 1986 higher quantities of allochthonous material for As expected the highest richness values were shredders also our functional guild is a mix found at the lower elevation sites LB and t2ta of shredders and detntivoresdetritivores possibly the also the 3 sites with permanent water flow detritus feeders dominate these sites and the exhibited lower annual variation in richness shredders are of less importance values CVs 15 than tlTI which had no proportions of the major insect orders were flow on 1 of 4 dates community composition similar to many other mountain stream studies was similar to that recorded by kondratieff ege g saether 1965 allan 1975 ward 1975 1994 during a qualitative summer collection 1986 short and ward 1980 minshall 1981 of aquatic macromacroinvertebratesinvertebrates from lakes and even though most studies reflect summer col- streams in the GLEES area he collected 72 lections diptera primarily chironomidae and taxa during that study while this represents ephemeroptera were always the most numer- 16 taxa more than we collected during this ous taxa in our study in general ephemer- study his collections focused on littoral zones optera and plecoptera occurred in greater pro- of lakes and streams and were made during portions in the drift than in the benthos while summer months our samples were all col- the reverse was observed for the remaining lected during winter from streams only and orders indicating that maymayfliesflies and stonestonefliesflies within midstream micromicrohabitatshabitats are more prone to drift than the remaining functional feeding groups in these streams taxa however drifting maymayfliesflies and stonestonefliesflies during winter were compositionally similar to were predominantly early instar Baetbaetidaeidae and yet proportionally different from summer col- Nemournemoundaenemouridaeidae suggesting that these 2 groups lections in other mountain streams and fit well are winter active or more susceptible to pas- with expectations of an expanded river contin- sive drift than the remaining taxa uum concept RCC vannote et al 1980 min- hydracannahydracarinaHydracannacarinaearlnacalina often exceeded plecoptera and shall et al 1985 we found the grazerscrapergrazer scraper trichoptera inm benthic abundance an occur- guild present in higher proportions and calleccollec rence not generally reported because other gathererstortorgatherers in lower proportions than might faunal surveys based primarily on summer be expected for low order eastern woodland collections and focusing on insects have not streams which are expected to be heavily included the hydracannahydracarinaHydracarinaearlnacanna comparisons are shaded by riparian canocanopiespies that limit autoch- difficult to make however failure to include thonous food resources vannote et al 1980 the hydracannahydracarinaHydracarinaearlnacanna in community analyses will however new syntheses of the RCC incorpo overemphasize proportions of remaining 238 GREAT BASIN naturalist volume 58

go diptera 90 epheteropterhemerhemeropteropter

60 60

30 30

0

90 Hydrahydracarinacarinacarlna go plecoptera

60 60

30 30 U 0 11 0 71

90 trichoptera

60

30

0 1 1 vvo mitiPITAmima 52 site

Ffigig 4 relative percent composition ofmajoiof major orders in the drift flomfromplomprom left to right bars reflect samples collected in novemberNovem beibel 1989 february 1990 1991 and 1992 respectively

25 25

20 WG 20 LB

15 han171enn 15 11

cn 10 10

5 5

t3ta 0 nov 89 feb 90 feb 91 feb 92 nov 89 feb 90 feb 91 feb 92 U cns2sa 110 25 25 20 TI 20 tat2

U 15 is

0 10

5 5

0 0 nov89nov 89 febfabsofebso90 febfeb9191 febfeb9292 nov89nov 89 feb90feb 90 febfeb9191 febfeb9292 date fig 5 mean n 3 density of benthic oiganismsorganisms nomanoMnom2no mam22 only 2 and I1 samples were collected for tlTI in 1991 and 1992 respectively enoienolerror baisbalsbars aiealeare s community members most hydracannahydracarinaHydracarinacarlnaearlnacanna are total density of benthic organisms in these pi edatorypredatory as adults or parasitic as larvae pen- streams was very high compared to other moun- nak 1978 and may have significant impacts on tain streams of similar altitude short and maeromacromacroinvertebratemacioinveitebiateinvertebrate numbers drift estimates ward 1980 but comparable to estimates made changed little with or without inclusion of the by minshall 1981 in a lower altitude stream hydlhydracarinaHydracarinaearlna reach however mesh sizes in all our nets 199819981 WINTER STREAM communities 239

LB 3 WG 3 2 111111112 0 0 4t nov89nov 89 febfeb9090 febfeb9191 feb 92 nov 89 feb90feb 90 febfeb9191 Ffebpebb 92 W 0 llllllll T I1 1 3 3 tat2

2 2

0 0 111111190 91 92 nov89nov 89 feb90febpeb 90 febfeb9191 feb 92 nov89nov 89 feb90feb febfeb91 feb date

6 sample drift densitylllllllfor all organisms fig noloom3 were considerably smaller than those used by collins 1988 because the predators are also short and ward 280 anpntm in our study vs 700 released from fish predation constraints umtm in theirs thus the range of sizes captured this study provides a preliminary assess- was greater maximum densities exceeded ment of winter macromacroinvertebrateinvertebrate community 15000 organismorganismsmorganismsm2sm on some dates but were structure inm high elevation streams and sug- usually nearer 5000m2 we expected low gests that winter communities are diverse and organism abundance during our winter sam- numerically abundant though vertucci and pling because egg diapause was a suspected conrad 1994 documented spring acid pulses life history attribute of some community mem- in some glacial melt headwater streams of bers especially within the trichoptera and GLEES winter ph in our sites was circum- ephemeroptera ege g see tables in merritt and neutral indicating that ph depressions do not cummins 1984 the great abundance of small begin until early snowbeltsnowsnowmeltmelt similarly the 2 mm Baetbaetidaeidae ephemeroptera during macromacroinvertebrateinvertebrate community composition november sampling suggests they have a was not indicative of one stressed by acidity short incubation period prior to hatching further studies comparing these communities minshall 1981 also reported the baetidaeBaetidae in different seasons may provide insights to occurred in high abundance during winter the role of seasonal heterogeneity in commu- months in an idaho stream nity ecology density of drifting organisms was not par- although winter stream conditions are harsh ticularlyticularly high relative to summer drift collec- iei e extreme cold reduced flow lack of sun- tions in other high elevation streams allan light there may be less variability in key abi- 1987 because we did not record diel period- otic parameters during this season than at icity in drift it is hard to ascertain whether other times of the year for example stream this proximal cue is important during winter flow and temperature are 2 critical features for in fact under prolonged darkness it is possi- aquatic insect ecology and biology hynes 1970 ble that drift is equally abundant at all hours ward 1989 variation in stream discharge and of day and night extended periods of dark- velocity during winter is minimal because ness may reduce insect susceptibility to pre- cloudbursts and thaws which may lead to rapid dation by visual feeding fishes resulting in discharge increases do not occur temperature high drift densities likewise drift rates might fluctuations are also minimized because there be high if encounters with predatory inverte- are no direct effects from solar radiation as brates increase peckarsky 1980 soluk and streams are snow covered these observations 240 GREAT BASIN naturalist volume 58

suggest that winter may be a time when physi- lotic predator guilds archivarchev farfur hydrobiologie cal habitat features exhibit low temporal het- 106395106 395 419 BUSHNELL J H NMN M BUTLER AND RWR W PENNAK 1982 gensu 1991 JH erogeneity sensu kolasa and rollo and invertebrate communities and dynamics of alpine may influence winter community structure flowagesflowages university of colorado ecological studies likewise the recent documentation of episodic institute ofarcticof arctic and alpine research 3712437 124 132 acidification associated with spring snowbeltsnowsnowmeltmelt BUSHNELL JHJ H SQS Q FOSTER AND BMB M WAHLE 1986 in the west vertucci and conrad 1994 sug- annotated inventory of invertebrate populations of an alpine lake and stream chain in colorado great gests a need for greater understanding of win- basin naturalist 4750047 500 511 ter community structure A knowledge of over DODDS GSG S AND FLEL HISAW 1925 ecological studies on wintering communities will help us accurately aquatic insects IV altitudinal range and zonation of assess the effects of these episodic events maymayfliesflies stonestonefliesflies and caddiscaddisfliesflies in the colorado rockies ecology 63806 380 390 seasonal of also comparisons community struc- EDMUNDS GFG F JR SLS L JENSEN AND LBL B BERNER 1976 ture and function and a detailed focus on winwin- Maymayfliesflies of north and central america university ter stream dynamics may further our under- of minnesota press minneapolis standing of the forces important in structuring ELGMORK K AND OA SAETHER 1965 distribution of invertebrates in a high mountain brook in the col- stream communities orado rocky mountains university of colorado series 31131 1 55 acknowledgments HYNES HBNH B N 1970 the ecology of stream insects annual review of entomology 152515 25 42 we are grateful to E maurer S swaffar JENSEN SLS L 1966 Maymayfliesflies of idaho unpublished mas- ter s thesis university of utah salt lake city 366 S langley turnbaugh and 2 anonymous re- PP viewers for comments on early drafts of this KIFFNEY PM AND WH CLEMENTS 1996 effects of met- manuscript the research was funded in part als on stream macromacroinvertebrateinvertebrate assemblages from by kansas university GRF grant 6363 to E different altitudes ecological applications 64726 472 481 KLEMM 1985 A guide to the freshwater denoyelles a grant in DJ annelida jr and sigma xi aid polychaeta naidisnaidid and tubificid oligochaeta and to C pennuto R musselman and L odeen hirudinea of north america 2ndand edition of the US forest service provided lodging kendallhuntKendall Hunt publishing co dubuque IA and water chemistry analysis respectively KOLASA J AND CDC D ROLLO 1991 the heterogeneity of heterogeneity a glossary pages 1 23 in J kolasa and STAS TA pickett editors ecological heterogeneity literature CITED springer verlag newnewyoikyork kondratieff BCB C 1994 GLEES macromacroinvertebratesinvertebrates ALLAN JDJ D 1975 the distldistributionalibutional ecology and diversity appendix C pages 70 71 in RCR C musselman coor- of benthic insects in cement creekcleekgleekgreek colorado ecol- dinatordinator the glacier lakes ecosystem experiments ogy 56104056 1040 1053 site general technical report RM 249 united 1987 Macromaeromacroinvertebratemaciomveitebrateinvertebrate drift in a rocky moun- states department of agriculture forest service tain stream hydrobiologia 144261144 261 268 fort collins CO ALLAN JDJ D AND E RUSSEK 1985 the quantification of KRATZ KW SD COOPER AND JM MELACK 1994 stream drift canadian jouinaljournal of fisheries and effects of single and repeated experimental acid aquatic sciences 4221042 210 215 pulses on invertebrates in a high altitude sierra ALLEN RKR K AND GEG F EDMUNDS JR 1962 A levisionrevision of nevada stream freshwater biology 3216132 igiigl161 183 the genus ephemerellaEphemerella ephemeroptera ephemerelephemeral LOGAN SMS M 1963 winter observations on bottom organ- lidaelidah V the subgenus drunella in north america isms and trout in bridger creek montana transac- miscellaneous publications of the entomological tions of the american fisheries society 9214092 140 145 society ofAof americamencamenea 31473 147 179 MERRITT RW AND KW CUMMINS 1984 an introduc- ANDREWS DAD A AND GWG W MINSHALL 1979 longitudinal tion to the aquatic insects of north america and2nd and seasonal distribution of benthic invertebrates in edition kendallhuntKendall Hunt publishing co dubuque IA the little lost river idaho american midland nat- 722 appp uralist 102225102 225 236 MINSHALL GWG W 1981 structure and temporal variations BAKER JP elET AL 1996 episodic acidification of small of the benthic macromacroinvertebrateinvertebrate community inhab- streamssti earnsearms in the northeastern united states effects on iting mink creek idaho USA a ard3rd order rocky fish populations ecological applications 64226 422 437 mountain stream journal of freshwater ecology BAUMANN RW AR gaurinGAUFIN AND RE SURDICK 1977 1131 13 26 the stoneniesstonefliesstonstoneeniesenleseulesflies plecoptera of the rocky mountains MINSHALL GWG W KWK W CUMMINS RCR C PETERSON CEC E memoirs of the entomological society of america CUSHINGGUSHING DAD A BRUNS JRJ R SEDELL AND RLR L VAN- 31131 1 208 NOTE 1985 developments in stream ecosystem the- BLAKE IHI1 H 1945 an ecological reconnaissanceleconleeonleconnaissancenaissance in the ory canadian journal of fisheries and aquatic sci- medicine bow mountains ecological monographs ences 42104542 1045 1055 32083 208 242 MINSHALL GWG W RCR C PETERSEN JR AND CYC F NIMZ 1985 BRUNS DA AND GW MINSHALL 1986 seasonal pat- species richness in streams of differentofdifferent size from the terns in species diversity and niche parameters of same drainage basin american naturalist 12516125 16 38 199811998 WINTER STREAM communities 241

MUSSELMAN RCR C 1994 the glacier lakes ecosystem VANNOTE RL GW MINSHALL KW CUMMINS JR experiments site general technical report RM 249 SEDELL AND CEC E CUSHINGGUSHING 1980 the river contin- united states department of agriculture forest uum concept canadian journal of fisheries and service fort collins CO aquatic sciences 3713037 130 137 PECKARSKY BLB L 1980 predator prey interactions between VERTUCCI FA AND MAM A CONRAD 1994 aquatics pages stonestonefliesflies and maymayfliesflies behavioral observations 30 41 in RCR C musselman coordinator the glacier ecology 6193261 932 943 lakes ecosystem experiment site general technical 1983 biotic interactions or abiotic limitations A report RM 249 united states department ofagoofagnof agri model of lotic community structure pages 303 323 culture forest service in TDT D fontaine and SMS M bartell editors dynamics WARD JVJ V 1975 bottom fauna substrate relationships in of lotic ecosystems ann arbor science ann arbor a northern colorado trout stream 1945 and 1974 MI ecology 56142956 1429 1434 PECKARSKY BLB L SIS I1 DODSON AND DJD J CONKLIN 1985 A 1986 altitudinal zonation in a rocky mountain key to the aquatic insects of streams in the vicinity of stream archivarchev furffirafir hydrobiologie supplement 74 the rocky mountain biological lab including chi- 133 199 ronomid larvae from streams and ponds publication 1989 aquatic insect ecology 1 biology and habi- DC 2825a 85 colorado division of wildlifeofwildlife tat john wiley and sons new york 438 appp PENNAK RWR W 1978 freshwaterfresh water invertebrates of the WARD JV AND L BERNER 1980 abundance and altitu- united states and2nd edition john wiley and sons dinal distribution of ephemeroptera in a rocky new york 803 appp mountain stream pages 169 177 in JEJ F flannagan SAETHER 0OAA 1965 chironomids and other invertebrates and KEK E marshall editors advances in ephemerop- from north boulder creek colorado university of tera biology plenum publishing co new york colorado series 315631 56 114 WARD JV AND BC kondratieff 1992 an illustrated SHORT RAR A AND JVJ V WARD 1980 macroinvertebratesMacromaero vertebratesinvertebrates of guide to the mountain stream insects of colorado a colorado high mountain stream southwestern university press of colorado niwothiwot naturalist 252325 23 32 WEINS JAJ A 1977 on competition and variable environenviron- SMITH SDS D 1968 the rhyacophila of the salmon river ments american scientist 6565590590 597 drainage of idaho with special reference to larvae 1981 single sample surveys of communities are annals of the entomological society of america 61 the revealed patterns realreanreap american naturalist 655 674 11790 98 SOLUK DAD A AND NCN C COLLINS 1988 synergistic inter- WIGINGTON PJ JR DRD R DEWALLE PS MURDOCH WA actions between fish and stonestonefliesflies facilitation and KRESTERKRESTFR HA SIMONINSl MONIN J VAN SICKLE AND JP interference among stream predators oikosbikos 52 BAKER 1996 episodic acidification of small streams 94 100 in the northeastern united states ionic controls of STEWART KWK W AND BPB P STARK 1988 nymphs of north episodes ecological applications 63896 389 407 american stonstoneflyefly genera plecoptera university of WILLIAMS MW AND JM MELACK 1991 precipitation north texas press denton TX 460 appp chemistry and ioniclonic loading to an alpine basin sierra SZCZYTKO SW AND KW STEWART 1979 the genus nevada water resources research 27156327 1563 1574 isoperla plecoptera of western north america morphologyholomorphologyholo and systematics and a new stonstoneflyefly received 26 june 1997 genus cascadoperlaCascadoperla memoirs of the american accepted 22 october 1997 entomological society 32132381 1 120

the appendix follows on the next 3 pages tl242LID GREAT BASINtz 4Z naturalist volume 58

in 0on D X rar a u based functional group samples p aq Q 11 P P P P P P SD SD SD SD SD SD s11 SD SD SDQ SD CG CG ni cqP 771071 d II 111 c3ca 1 1 S S U U

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each 1S respectivelya 8 0 3 0 0 0 0 1 9 0 0 0 0 0 26 ofS 0 0 0 0 00000 0 0 0 0 0 1 iU a i

number 1992 3 1 0 0 0 0 0 24 1 0 8 0 0 50 41 1 0 0 0 0 7 0 0 2 2

mcm TI total andg i ascraper 0 8 1 0 0 0 0 0 0 0 0 2 0 000080 0 0 0 1 00000 0 0 0 0 3 the 51991

grazerscraper D aremao in 43 grazer 23 10 I1 I1 g 4 9 0 0 0 0 2 0 0 0 8 0 181 86 0 0 0 2 30 5 1 11 site tat1 w S alcafrom site each GS S CO M 5 5 3 0 0 0 0 112 20 0 0 73COOSOO59 23 td 1110000CN 0 0 f 0 0 3leh164 3 32 0 86 0 5 takenadmon under 4 0 i a 1 were oom t V 5 0 0 5 0 1 2 leizel107 13 0 0 0 4800089 ime100 30 52 6510 ID jaj3 LB 0 inh5 0 mel101mew 7 10 3 6 1 td numbers VI

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samples& 1 0 rf 00 1 o 2 3 0 16 0 0 0 121 I 0 0 41 tdoitdo46 32 4 58 53 4 5 0000 10000 0 6 2 6 0 tn22 0 U g thehad I1 aadandaam l i S 4 6 0 0 0 1 7 22 2 16 43 10 00 t 1 0 219 1 58 171 tdooo mocnooi0 5 0 0 20 1 37 0 dates 2 SD

embsonly

sampling 8 0 4 98 25 1 77 gatherer 8 0 0 0 CTS 0 0 0 ooooooofo 0 0 6702700100t 0 0 0 0 6 5 0 0 10 1 N

collectorgatherer 4 respectively 1 v 1 on 0 11 72 0 & 4t000no0 0 0 2 0 c10ioc101 9 0 2 0 0 toyoo90 49 0 0 0 0 1 13 0 0 5 collectorv 0 0 WG locations3 N 0 a 199201 U 11 2MO0 1 0 0 4 23 18 10 0 0 i OS 0 0 0 2100000edem0 0 0 0 5 0 0 0 0 edee1 CG 318andmah

sampling 4 141 32 qootoo 00 1 0 1 g e 4 1 0 2 5 0 0 174 0 mootoo791 0 0 30 I 758 0 00000 100 0 0 8 1991 1 predator 11 4 at 1990amme

0 i 1 1 P s abundance3 g perlid3 february 5 198400 3 dabilisdebilis 3 celeodid chloroperlid4

S infrequentinfrequens 2 perlodid 1 quinquepunctatequinquepunctata S I 3 S chloro e 13 u S a a 0i shina S s perlgoaz coloradensis vershinavepshina coloradensis andnannam divera metsa 1 signata modestus 1 benthic cummins I signata 5 ag e si Q H 0 ivluaver besametsa 1g a ajqj o velox S lamba ua& u os PERLIDAE obamba sp s 0 hasuakcaysihaysi CL 1989 u besa maa m sesas110S ipes & IDAE merella tersoniassasp cys perla i paraleptophlebia esta g eutrabaassQ i11111 0 cinctipes g petersolipetersoni unidentified 11111 a chloroperlidae unidentified ephemerellidae leptophlebiidae naka asss doddsi ephemerella S & sssa plumiperla i siphlonuridae and megarcys paraleutra cinctt Q serratella perlodidae isoperla fulvabulva kogotus walliasuwallia nemouridae drunella aj sweltza capadazapada malenka ameletus LEUTRIDAE prostia acapnia pe cultus Megar prestia capnia ephemeroptera appendix 3 CAPNIIDAE Plumi Paral NEMOUR Ephe P gilslllllllaililljs CHLORO S TH november plecopteraA Su jl & 1 i 11 diltD S E Z I merritt nj i 1 1 illi u elijl05 ebabda I I l S 41 i taxaharm u il 2 U S 5 d&pgfsntcs 1998 WINTER STREAM communitiesC c4ca

3 w w functional group CG GS GSbtlGS CG Q Q Q 11 P P P P GS GS GS 5SD SD GS CG SD GS S 00oo 00oo 0 00oo 0 S 0 usoono e

COO 1 00 i 00 i 1 CO roo 1 1 1 18 44 3 130zee 177 i 10 13I1 rotlreCO zil 0 0 8 1 1 0 0 0 0 T 2MOO0 0 000008 0 0 moh 1460 1 tat0 rl

i i in 1 37 711 26 10 coecoo 12M irCO 5 0 otooco0 CM 3 3 0 0 0 0 0 0 0 oc121 0 2 000ooo 0scioriociori600 loriioriloci tat2

1 15 10 i 1 imii 457 49510111i 0 0 54 15 1 110 94 in oiini OT 0 0 0 0 CTS 1 0000 00oo681 9 0 0 t tinebioroior td

030000 DO 76 37 10O 10 in 0000. 1 0 108 0 tocio f i 85 0 18i 31 f1276 0 tocitcof-ecoco 000 0 0 0 00oo 0 0 0 co 2 0l 000 2154mt rlr c1ca 1 N

0tcoOCO3 0 0 0 001oa1 1 0 0 00 o1 000 0 0 0 6 0000OOO0 0 146ahm00000 0 0 too 1 toe T

1 zinoin0zim5 2NO0 0 0moothOCOOO3 0 0 0 0 0 0 0 7 0 0 0 che21 0 0 00 tedzed000 108600000N 01 1 1 TIT 0 20 10 omo 4 0 4 0 1 00c 0 ocotfo0 6 0000 0 0 0 0 0OHO1 0 764 101 0 0 ot ii t0t000

OCO 83 050119i 1 131 0 00 0 0 0OCOOi 4 0 0 0 0 0 0 47 OOO0 0 0 720ngaca 4 0 2 1 00 f c1 tottto000 tbolmoolm u site c5ca

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oo i 69os ci CNOI O as i co to tat1 40088 102web csercsor10I1 27 osoco tmima m 00 leb 0 2CNOIOi CN 0 9 1 3 CO26 4 0 9oskco0 28c1ca oiM 1 5 5 LB 1020 i 00 011

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1 I1 COO i clrcir CICO dad ID i 1 t 1 eco83 0 i110I 100 cli111 olecoleo 40 in 00 OOOcotatt 1 2 i 2 3 6dtd6 0 0 6 0 1il 1 35c0ca ocollococl680eme 23 22 4 doo000i 1 000101 rl dot 10domini

COCO 10 ta 2 139armwem050 67 56 DO M vi253 co 0 0 001en m000 6 0 6 0 0 52 0 0 0 ocloci1 2 24 0 I1 in 3960orl Nt0 i 000 M OT CO

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Q losa8 minutesminutus 0u s s i s maculosemaculosa grandis pelfisa stripesatripes appspp macu continuedg appspp sp sp omm 1. omm &s 1 1 5 la bicaudatusIs lai as sp 0 taital PSYCHIDAE sp stoma atl 1 11 coloradensis mosasoma 0 111 tricaudatus oligophlebodes ll retlepidostomatidae i agapetus S brunnelbrunnea glossosomatidae brachycentridae III i ceratopogonidae hydropsychidae yg ii neothremma rhithrogena ag rhyacophila lepidostoma rhyacophilidae verdulaverrula rii dicosmoecus s arctopsyche heptageniidaeliiiti glossocomaglossosoma cinygmula anagapetus ecclisomyia jus hydrofrilidae umnephilidae lu mesi 2i micrasema raylea pl chironomidae lus ai 1 alii agraylea 5 babtisbaetis Glosso Lepido UENOIDAE APPENDIXz BAETIDAE plii m2riri3 tipulidae M DIXIDAE sllll118138 trichoptera HYDRO Anlogglqi Ag ll8c3ypk3B g tihitlsiglsjtR RSRiR gu g alj lla tai gamso irinsriiaiainin gimso diptera gib ffiafi p i M affiaffa IRin p hih ffiafislj rib 0 3 aopoq taxaharm 21 1 Q grestGREAT BASINtz naturalist

a

functionals group0 P CG CG CG C & u u u e

OOI01I CNI co CNIOcstcnt47i O 2 2 22 15moco1 ohleoble oi 0 moto1 32 M 0 6 172i 0 n rlr l

9CT CO 0 12r 1 1 muao ocil 0 23CICOOIOO4buat0OIOO695emm05 0 24c1ca 0 tat2CO

1 05 coecop 1 acorocor131 29 001 3 0 C 1 1 mam 3 1100000 618i 0 CO32

1 il i DCOOOO 1 I 1 c1010 111 111 2 9 0 i i 6 3 00488 0 CO31

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10 oi 0 0 0 19I1 0 4 gim1 1 000 II11OOOOO0 0 wid170 0 I 000001 tah I1 I

TIi 0 0 0 0 onecioor1ecioecloOCIO 17t 000 2 0orocio0 10152 0 II11

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ID sitemaza W 17f O 10 00 CO 0 1 0 5 00010050 65D 109zemamm 48 CO33 fo I1 0I1

10 l l i 1 0 mimeMIOO151 mahmar tom M 2minh0 5 2normablmabi0 gel161amz 196ameamm05tcotootool2 41 LB norl0 il r 1

10 0 0trotvo141 0 0 16 37 ofo 6 5 il 333CO 7 CO

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co 2 26 ys 000ooo0 0 0 0 Noooioio0 58000 00485 leq106mem 26M ttetto 0i 1 10

T I1 1 OOO0 38 40 0 0000 0 0 4 2n0000co heo4660 co26

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lentise 0 corpulentis 1 corpu continued asp & sp co sp 1 maamam a a a u sp

X heterlimnius limnodrilus cleptelmis sphaerium RICHNESS 5 carina hygrot dytiscidaedyticidae pelecypoda APPENDIX M ELMIDAE ezra miscellaneous coleoptera oligochaeta hydracarina piP i collembola turbellaria ostracoda biB i mollusca ilmi Hydra taxahamahamm 1taxahama Q 0 s boffi P great basin naturalist 583 0 1998 appp 245 249

RANGE OF THE BROWN HEADED COWBIRD IN COLORADO PAST AND PRESENT

jameson F chacelchabelchace1chacey and alexanderAlexan deider cruzl

ABSTRACT the historic range of the bison bison bison on the great plains has been well documented in colorado the range of bison included both the eastern grasslands and higher elevation ridges and mountain parks up to an eleva- tion of 3900 m based on the commensal relationship of the brood parasitic brown headed cowbird molothrus ater with the bison we suggest that the cowbird had a larger historical elevational range in colorado than previously known and consequently has had a longtermlongiong teimterm host parasite relationship with high elevation breeding songsongbirdsbirds

key words brown headed cowbird molothrus ater bison bison bison range expansion colorado

the brown headed cowbird molothrus 1993 we suggest that because of their com- ater is a well studied obligate brood parasite mensal relationship cowbirds also occurred at rothstein 1975 friedmann et al 1977 roth- high elevations in colorado until their range stein 1990 robinson et al 1995 cook et al in contracted with the extirpation of bison and press that historically occupied a range similar that they have undergone an elevational range to that of the bison bison bison friedmann re expansion with the introduction of domestic 1929 cowbirds ranged over the great plains livestock in commensal association with bison these our purpose is to demonstrate that 1 the buffalo birds are thought to have foraged ist observations of cowbirds in colorado among the grazed grasslands for insects stirred occurred during the time lapse between extir- up by herd movements friedmann 1929 may- pation of bison from and movement of cattle field 1965 they later expanded their range into higher elevations and 2 the number of with the clearing of forests and introduction of high elevation records of cowbirds increased as domestic livestock mayfield 1965 rothstein the number of cattle in the western counties 1994 in colorado brown headed cowbirds increased implications of longtermlong term host para have undergone a recent elevational range ex- site interactions in colorado s high elevation pansionpansion possibly due to habitat alteration and region are discussed cattle grazing in the high country hanka 1985 similar to cowbirds in the sierra nevada range METHODS rothstein et al 1980 rothstein 1994 the historical range of bison on the great we reviewed records of cowbird parasitism plains is well documented alienallenailen 1877 roe see chace and cruz 1996 and bison distribu- 1970 in addition bison in the rocky moun- tion and determined the timing and abundance tains historically ranged above timberline in of cattle introductions to the colorado counties montana wyoming and colorado fryxell west of the great plains we also reviewed colo- 1926 1928 warren 1927 beidleman 1955 rado agriculture statistics to obtain the number pattie and verbeek 1967 bison once ranged of cattle in each county per year from 1883 to throughout most of colorado west of the great 1985 intermittent years missing colorado plains and at all elevations armstrong 1972 counties east and west of the front range were meaney and van vuren 1993 furthermore analyzed separately with front range counties bison probably were relatively abundant containing 40 grassland habitat designated throughout northwestern colorado south as eastern see fig I1 for delineation of coun- park middle park north park and the front ties cattle numbers were summed per year range armstrong 1972 meaney and van vuren by eastern and western designation although

depiiitrnentidepartment of environmental population and organismic biology university of coloradcoloredcoicoloradoCol orad Bbiderboulderbouldeniderlder CO 80309033480309 0334

245 246 GREAT BASIN naturalist volume 58

SEDGWICK LOGAN LARIMER 0 1 1 WEL MOFFAT 0 j PHILLIPS houtteROUTTE JACKSON

I1 I1 16 1 00 ghiQ hl 6 0 aranoGRAND MORGAN BOULDER L YUMA f nioRIO BLANCO 0 0 ADAMS 0 IL 1 washington 10 0 11er EAR CR GARFIELD I1 I1 a 0 EFFEFIS ARAPAHOE

0 0 0 EAGLE 0 et

0 ELBERT KT PITKIN 9 nouDOU LAS CARSON A PARK 01 telle LINCOLN MESA DELTA CHEYENNE 0 elpasELIAS IITdlaely 0 L 0 L j GUNNISON 0 FREMONT 71 i 1 G I 11 F klomKIOM MONTROS gi r CROWLEY j7 arkansas P

lurayCURIY ousterCUSTER 1 PUEBLO SAN IGUELMIGUEL SAGUAC I1 0 OTERO BENT I1 PROWERS I DO ORES I1 INSZAL 1 N AIM N fimnim J HUERFANO L ALAIMO MINERAL RIOGRANDE 7 m1itezua BACA COSTILLA LASANIMAS LAPLATA ARCHULETA CONEJOS 0

0 50 100 miles i 0 50 100 150 kilometers

fig I1 recent distributionbistidisti ibution of bison bison bison in colorado with emphasis on the region west of the great plains solid elidescircles representrepiesentvent specimen localities open circles representleprelepiesent localities extracted from literature central line delin- eates Coloiacoloradodo counties west of the great plains map and information taken from meaney and van vuren 1993 with permissionpelpei mission of the denverdenvel museumM iseumuseum of natural history cattle are not the only livestock that attract cow- furthermore based on specimens taken fig- birds rothstein et al 1980 they are by far the gins 1933 some herds of bison wintered in the most numerous and probably are a good index mountain parks and migrated into higher ele- of livestock numbers per county in general vations through forested communities during the summer meaney and van vuren 1993 RESULTS extant free ranging bison in forested montane habitat of the henry mountains of utah have meaney and van vuren 1993 recorded all smaller group sizes 2 30 animals and larger known bison in colorado west of specimens in home ranges 52 km2 than bison of the great the great plains from which we calculated that plains van vuren 1983 van vuren and bray of 116 bison specimens 56956.956 9 were collected 1986 meaney and van vuren 1993 in colo- above 2500 m table 1 recent seaichsealchreresearch on rado benedict 1993 personal communication free ranging bison has shown that bison have seasonal elevational movements through open speculates that bison were extirpated from the park ponderosa pine pinus ponderosa pinon juni estes area by 1859 primarily due to the per woodlands P monomonophyllaphylla and juniperuslumJumperus effects of the harsh winter of 1843 44 that scopulorum and across subalpine forest park- winter in combination with market hunting land habitat fuller 1962 van vuren 1983 van may have been the cause of bison decline in vuren and bray 1986 shaw and carter 1990 other parts of the state the last known wild 199819981 COWBIRD RANGE EXPANSION IN COLORADO 247

TABLE 1 elevational distribution ofbisonorbisonof bison specimens in 30m0 22 colorado counties west of the great plains from meaney and van vuren 1993 250025000 M D cattle inin the emteast no of specimens 4 cattlecattie in the t elevation 116 ff in N 20000 3501 13 3001 3500 21 15000 b 2501 3000 32 0 0 2001 2500 36 W 10000 0 gsg 1500 2000 14

5000-

00 bison in colorado were killed in 1897 in park 1875 1900 1925 1950 19197575 22000 county cory 1912 although a few may have YEAR survived until 1904 warren 1906 bison numbers were very low by 1883 when fig 2 number of cattle in eastern and westeinwestern col- cattle were fairly abundant east of the conti- orado 1883 1985 nental divide in colorado 268585 head with considerably fewer in the western counties 56782 head colorado department of agri- adult wllwilsonWilsorss warbler vitwilsoniaVilsonia lusillapupusillapusilldsilla feed- culture colorado agriculture statistics 1883 ing a young cowbird at 3180 m wllWilwilsonsonss war 1985 nearly equal numbers of cattle occurred biers were also reported to be parasitized in in eastern and western counties through the boulder clear creek and summit counties 1920s fig 2 western counties reached their elisabeth ammon unpublished data in present levels of cattle population by 1959 with 1993 94 cowbirds parasitized warbling vireo a peak in 1974 829300 head fig 2 from vireo gilbusgilvus nests ca 3000 m in boulder 1941 the number of cattle in eastern counties county chace unpublished data recently a consistently was double the number west of number of high elevation records of parasitism the plains with a peak in 1973 of 2978800 have been reported in the colorado breeding head fig 2 bird atlas project table 2 colorado breeding records of cowbird parasitism or presence bird atlas unpublished data rarely mention exact elevational localities early naturanaturalistslists in colorado surveyed high eleva- discussion tions and found cowbirds primarily occurring in grasslands and foothills below 2500 m hen- in colorado cowbirds probably had a his- shaw 1875 drew 1885 gale 1893 cooke 1897 tortoricalical geographical temporal and elevational sclater 1912 more recently cowbirds have distribution similar to that of the bison with an been noted at higher elevations keeler wolf upper elevational limit ca 3800 m bison prob- et al 1972 reported parasitism of a yellow ably were numerous enough in the mountains warbler dendroica letechiapepetechiatechia nest in gunnison to support commensal flocks of cowbirds dur- county 2895 m cowbirds were common in ing the avian breeding season As the bison mountain parks and river valleys in 1977 and approached extirpation in the mid 1800s herds 1978 with observations up to 2890 in in park were small and scattered and cowbirds would lake jackson and larimer counties hanka have been mostly restricted to lower elevations 1985 from 1986 to 1989 164 brown headed where cattle were just beginning to show appre- cowbirds were trapped and banded at a feed- ciable numbers in colorado fig 1 cowbirds ing station on mt evans elevation 3260 m likely became associated with cattle in eastern cowbirds were trapped from april to august colorado and began to re expand their range with highest numbers in may mean 29029.0 following the growing cattle herds to the west males outnumbered females 23512.351 lorraine by the turn of the century naturanaturalistslists began to E reiner unpublished data hanka 1985 re- record avian distributions in colorado even ported parasitism of brewer s blackbirds though higher elevations were surveyed drew eupharuseuphagusEuphagus cyanocephalus at 2895 m in north 1885 sclater 1912 cowbirds were found pri- central colorado spencer 1985 reported an marily from grasslands to foothills and mountain 248 GREAT BASIN naturalist volume 58

tabttautTAUITABLE L 2 records cowbirdofcowbirdof parasitism from western high elevation counties from the colorado breeding bird atlas 1987 1994 species years counties willow flycatcher empidonax traitraihitrailiitrachilii 1987 jackson dusky flycatcher empidonax oberholseri 19941995 jackson eagle cordilleran flycatcher empidonax difficilis 1991 teller hermit thrush Catharus guttatusgutgustatustatus 19901994 park mineral warbling vireo vireo gilbusgilvus 1988199319941988 1993 1994 gunnison fremontFipiemontemont montrose virginiass walllerwarblerWd illerliler vertnivoraverrmvora virginiviigimaevirgimaevirginiaevirginiaavirgimaeimahae 1994 teller yellow warbler dendroica letechiapepetechiatechia 1987199319941987 19931994 grand gunnison jackson yellow lumped warbler dendroica coronata 1991 routt macgillvray s warbler oporornisopororms tolmiei 1994 gunnison wilson s warbler wilomawilsonia ausillapupusillasilla 1988 summit gigreeneen tailedfowheetailedtalled towhee pipilo chloruruschlor urus 19911993 routt montrose fox spalsparrowi ow passerella ifiacailiacd 19931994 eagle grand summit song sparrowspal i ow melospiza melinelodiaodid 1995 teller lincoln sparrow melospiza lincolbnlincolnnfincolniilincolnn 1994 park grdygrascraygray headed junco junco hyemalishyemalis 19911993 grand gunnison brewer s Blackbblackbirdnd eupharuseuphagusEuphagus cyanocephalus 1991 gunnison

parks 2500 in henshaw 1875 gale 1893 but more pronounced along the eastern edge cooke 1897 although friedmann 1929 re- of the rocky mountains ported an observation of a female cowbird inm prior to the extirpation of bison in the mid association with horses at 2895 in inm colorado 1800s brown headed cowbirds undoubtedly it was not until 1958 that the total number of bred and parasitized the nests of many song- cattle in colorado loserose above 2 million head bird species in high elevation regions of col- after 1958 cattle numbers remained high and orado it is likely that cowbird numbers at stable in western counties while the number higher elevations declined as bison were extir- of cattle would double in eastern counties by pated and resurged following the introduction 1973 shortly after this time cowbirds were of cattle however now a different pattern of found breeding at high elevations ca 2800 in cowbird parasitism probably exists when cow- keeler wolf et al 1972 hanka 1985 these birds followed nomadic bison herds their para- data suggest that brown headed cowbirds sitic efforts and eggs were dispersed over the occurred at high elevations in colorado until range of seasonal movements of bison herds the extirpation of bison and have recently whereas now cowbird breeding populations regained their former range with introduction are as stationary as the herds of livestock around of domestic livestock which they forage implications of this chang- in colorado the center of bison abundance ing pattern on songbird communities are likely was the eastern grasslands although bison very important where once songbird commu- have been recorded inm high montane areas in nities may have encountered brood parasitism central and northwesternnorthwestein colorado records for only a portion of their breeding season are conspicuously absent from the southwest- now the pressure of parasitism is pronounced ern corner of the state meaney and van vuren throughout their reproductive effort in addition 1993 cowbirds are known from the eastern because of the strong site fidelity of many song portion of the state but little is known about birds greenwood and harvey 1982 holmes their distribution in the west prior to the bison and sherry 1992 parasitism pressure may exist extirpation they probably were located along throughout the lifetime reproductive effort of the majolmajor tributatributariesries to the colorado river many individual birds rothstein 1994 and were associated with western bison herds following cattle introduc- acknowledgments tions western populations of cowbirds may also have re expanded their elevational distri- initial concepts for this paper came through bution however a distributional change has thoughtful discussions with jim benedict we not been well documented in all probability thank lorraine E reiner and elisabeth ammon the elevational range re expansion was bimodal for sharing their unpublished data with us 199811998 COWBIRD RANGE EXPANSION IN COLORADO 249

comments made by CTC P ortega ADA D bene- HOLMES RTR T AND TW SHERRY 1992 site fidelity of migra- dict JBJ B benedict DMD M armstrong H kingery tory warblerswarblers in temperate breeding and neotropical CAC A meaney and 2 anonymous wintering areas implications for population dynamics reviewers on habitat selection and pages earlier drafts conservation 563 575 are greatly appreciated min JMJ M hagan iliIII111 and DWD W johnston editors ecol- ogy and conservation of neotropical migrant land literature CITED birds smithsonianSmith soman institution press washington DC 609 appp ALLEN JA 1877 history of the americanamerlean bison bison KEELER WOLF T V KEELER WOLF AND WA CALDER americamericanusamericanosamencanusanus annual report of the USU S geological and 1972 bird fauna of the vicinity of the rocky moun- geographical surveys of the territories 94439 443 587 tain biological laboratory journal of colorado field ornithology 15 22 ARMSTRONG D M 1972 distribution of mammals in col- 1522 25 orado monograph of the university of kansas muse- MAYFIELD H 1965 the brown headed cowbird with old um of natural history 313 1 415 and new hosts living bird 4134 13 28 MEANEY CAC A AND D VAN VUREN 1993 BEIDLEMAN RGR G 1955 an altitudinal record for bison in recent distribu- northern colorado journal of mammalogy 36 tion of bison in colorado west of the great plains 470 471 proceedings of the denver museum of natural his- tory 3 4 1 10 BENEDICT JBJ B 1993 excavations at bode s draw a series women s work aleaarea in the mountains near estes park PATTIE DLD L AND NAMN A M VERBEEK 1967 alpine mam- colorado research report center for mountain mals of the beartoothBeartooth mountains northwest science archeologyArchearchaeologyology 616 1 42 4111041 iioilo110 117 ROBINSON CHACE JEJ F AND A CRUZ 1996 knowledge of the col- SKS K SIS I1 ROTHSTEIN MCM C BRITTINbrittinghamCHAM LJL J orado host relations of the parasitic brown headed PETIT AND JA grzybowski 1995 ecology and cowbird colorado field ornithologists journal 30 behavior of cowbirds and their impact on host popu- 67 81 lations pages 428 460 inm TE martin and DMD M finch editors COOK T SKS K ROBINSON SIS I1 ROTHSTEIN SGS G SEALY AND ecology and mangementmanagementmangement of neotropical press JNMJ N M SMITH EDITORS in press ecology and mange migratory birds oxford university new york ment ofcowbirds university oftexasof texas press austin 609 appp COOKE WW 1897 the birds of colorado bulletin of the ROE FG 1970 the north american buffalo 2ndand edition press state agriculture collection 37 technical series university oftoiontoof toronto toronto ontario canada 212 1 224 991 appp CORY CBC B 1912 the mammals of illinois and wisconsin ROTHSTEIN SIS I1 1975 an experimental and teleonomicteleonomic publication of the field museum of natural history investigation of avian brood parasitism condor 77 zoology series 1531153 15021 502 250 271 1990 A for DREW FM 1885 on the vertical range of birds in colo- model system coevolution avianavlan brood rado auk 2162 16 parasitism annual review of ecology and systemat- acs FIGGINS JDJ D 1933 the bison of the western area of the ics 2148121 481 508 mississippi basin proceedings of the denver muse- 1994 the cowbird s invasion of the far west his- um of natural history 12416124 16 33 tory cause and consequences experienced by host FRIEDMANN H 1929 the cowbirds a study in the biology species studies in avian biology 1530115 301 315 of social parasitism charles C thomas springfield ROTHSTEIN SIS I1 J VERNER AND E STEVENS 1980 range IL 421 appp expansion and diurnal changes in dispersion of the FRIEDMANN H LFL F KIFF AND SIS I1 ROTHSTEIN 1977 A brown headed cowbird in the sierra nevada auk further contribution to the knowledge of the host 9725397 253 267 relations of the parasitic cowbirds smithsonianSmith soman con- SCLATER WL 1912 A history of the birds of colorado tributions to zoology 2351235 1 75 witherby & co london 576 appp FRYXELL FM 1926 A new high altitude limit for the SHAW J AND TS CARTER 1990 bison movements in rela- american bison journal of mammalogy 71027 102log 109 tion to fire and seasonablyseasonality wildlife society bulletin 18 426 430 1928 the former range of the american bison in 18426 the rocky mountains journal of mammalogy 9 SPENCER RAR A 1985 brown headedbeaded cowbird feeding inci- 129 139 dents journal of colorado field ornithology 193919 39 FULLER WA 1962 the biology and management of the VAN VUREN D 1983 group dynamics and summer home bison of wood buffalo national park wildlife man- range of bison in southern utah journal of mammal- agement bulletin canadian wildlife service series ogy 6432964 329 332 1 16116igi 1 52 VAN VUREN D AND MYM P BRAY 1986 population dynamics GALE D 1893 field notebooks 1883 to 1893 edited by of bison in the henry mountains utah journal of J henderson 1905 mammalogy 6750367 503 511 WARREN E R GREENWOOD PJ AND PH HARVEY 1982 the natal and ER 1906 mammals of colorado colorado col- breeding dispersal ofbirds annual review of ecology lege publications general series 19 science series and systematics 13113 1 21 46225 274 1927 limit HANKA LRL R 1985 recent altitudmalaltitudinal range expansion by altitude of bison journal of mammal- the brown headedbeaded cowbird in colorado western ogy 8608 60 61 birds 1618316 183 184 HENSHAW HWH W 1875 report upon the ornithological col- received 23 december 1996 lections USU S geographical surveys west of the accepted 2277 september 19919977 looth meridian creatgleatgreat basin naturalist 583 0 1998 appp 250 264 CHEMICAL AND biological characteristics OF DESERT ROCK POOLS IN intermittent STREAMS OF CAPITOL REEF NATIONAL PARK UTAH

jill S baroni toben lafrancois2LaFrancois2 and boris C kondratieff 2

AISSIKAC r chemical vaivalvariabilitylability and biological communities of rock pools found in small desert drainage basins of capitol reef national park weiewelewere characterized over 8 mon in 1994 neither flooding drying nor the presence or absence of surrounding vegetated wetlands had a great effect on chemical composition which was very dilute and fluc- tuated somewhat in lesiesresponseponse to lainiainrain events neither flooding noinolnor drying affected the composition of biological commu- nities in the pools summer stormsstoistol ins affected only a few drainagesdi ainages at a time and only a few study pools of significant vol- ume dried completely during the hot dry summer this suggests that only a portion of the Waterwaterpocketpocket fold aquatic community is evelever disturbed at a time leaving undisturbed areas as a source of recovery pools bordered by vegetated wetlands always supported greater numbers of species throughout the year than those bordered only by bedrock but thetiletiie samesarne taxa weiwelweree found in both vegetated and bedrockbedibedl ock pools the rock pool fauna in capitol reef national park appealappear to be lesilieresilientnt to climatic variabilityvaival lability

key words desert rock pools aquatic invertebrates aquatic chemistry disturbance capitol reef national park utah

aquatic environments in the and colorado these pools grades from obligate wetland plateau aiealeare extremely important resources foiforeblbelhorbor species such as typha latifolialatifolia cattail salix the maintenance of desert ecosystems many sppapp willows phragmites australis reed and aquatic risouiresouiresourcescesees are ephemeral characterized carex sppapp sedges to upland species common by spatial and temporal discontinuities in flow in surrounding desert shrub pinyon juniper grimm and fisher 1992 ephemeral streams and slickrockslickrock communities spence and hen- may flow after storms and snowsnowbeltsnowmeltmelt but sur- derson 1993 spence and henderson 1993 face water rapidly becomes confined to pools found an increase in the number and abun- as the running water evaporates or is tran- dance of nonnativenormative species associated with spired poffardpoffandpoff and ward 1989 pools where cattle grazing had previously the watelwaterpocketWaterpocket fold is a 62 X 1251 25 km occurred suggesting that these systems are 100 X 2 mi ridge of exposed navajo sand- vulnerable to such disturbance stone that lunsruns the length of capitol reef limited information has been collected on national park utah fig 1 the waterpocketWaterpocket desert rock pools along the Waterwaterpocketpocket fold fold contains many small drainages cut laterally in capitol reef national park previous inves- across its width due to water erosion these tigations have addressed questions regarding small drainages presentrepresentle an extreme example the role of disturbance by flooding on aquatic of ephemeral streams cut directly into sand- organisms haefner and lindahl 1988 1991 stone bedlockbedrock these drainages function as similar systems of the colorado plateau have streams only a few days each year stream flow received more attention including a chemical occurs during and immediately after rainram or characterization of rock pools in northern ari- snowbeltsnowsnowmeltmelt between precipitation events water zona van verbekehaverbekeHa 1990 biological charac- resides in lockloekrockroek pools many of which are large terizations of temporary pools near moab utah enough that they rarely dry out pools are of 2 dodson 1987 and ecosystem scale studies in moiphologiesmorphologiesmorphologies those cut directly into sandstone sycamore creek arizona gray and fisher with no surrounding vegetation and those with 1981 fisher et al 1982 grimm and fisher riparian vegetation borders sandy alluvial 1992 we conducted a 6 mon intensive study deposits that support vegetation also allow to assess the status of physical and biological groundwater storage vegetation surrounding resources as the essential ist step in managing

united statestates geologigeologygeologicalI survey biological resources division natural resource ecology laboratory colorado state university foitfort collins CO 80523 2lela1t1uc11tzptpiitiiicnt of entomologyofentonjology Coloiacoloradodo state university folifoitfort collins CO 80523

250 199819981 CAPITOL REEF ROCK POOLS 251

burr trailtralltrait

U T r L willow tanks 5 capacapw RW

a cottonwood tanks b L b muley tanks 1750 0 1820 1680 1870 1750 n 1890 brirnhal 2100 19801890 1820 addgebddge 2030 351 hallshailshalis cree SCALE erloook 252.5 cm 090.9og km red sitesise C oldoid airstrip c fountaintanksFountainTanks

2100

gil611 gulch 231 scott 1750 miahanamiyahana tanks

2030 45 L 2100 halls creek narrows 2240 2380 SCALE SCALE og 25 cm 3.535 km 2450 252.5 cm 090.9 km 252.5 35

fig 1 map showing location of capitol reef national park and enlargements of the 3 study drainages where both chemical and biological analyses were conducted a cottonwood tanks b muley tanks and c fountain tanks con- tour lines on enlargements are in meters

natural resources stohlgren et al 1995 this over time and spacespaced does the presence of study complemented a larger survey of 460 surrounding vegetation influence water qual- rock pools in 80 major drainages berghoff ity pool volume or ecology how important 1994 we explored temporal and spatial vari- are flooding and drought as disturbances to ability of pools to answer several questions bothwaterboth water quality and aquatic invertebrate how variable is pool chemistry and ecology community composition 252 GREAT BASIN naturalist volume 58

SITE description precipitation and pool volume we placed rain gages near the top and bot- the Waterwaterpocketwatcrpocketwatchpocketpocket fold also known as capi- tom of each drainage and monitored them tol reef is a north south trending monocline weekly each gage was a funnel that drained to of navajo sandstone that extends approxi- a coiled tygoncygon tube connected to a plastic liter mately 112 km north from lake powell in bottle were slight differences in the southern utah fig 1 the Waterwaterpocketpocket fold there amounts collected by each pair of gages but is specifically named for the more than 460 waterwaterpocketspockets or rock pools that have been since we were unable to determine whether differences were due to precipitation variabil- carved by water and scouring action in the to gage efficiency many small west east drainages cut into the ity or catch we used the sandstone drainages are typically 2 km long gage that reported the greatest total precipita- and are made up of a of pools connected tion for the summer to represent rain for each series past with a drainage depression that conducts water drainage experience has suggested it is during and after precipitation events because very difficult to overovercollectcollect precipitation in harsh so the there is no upupwellwellingmg of groundwater in the environments maximum amount navajo sandstone kimball 1988 precipita- recorded is more likely to represent actual rain- fall than is 2 tion is the only source of new water to these a statistical average of gages baron 1992 volume of intensively rock drainages rock pools range in volume from a the studied few liters to 1000 m3ma some vegetated wet- pools was measured weekly by geometrical lands adjacent to pools can have sediment approximation using an algebraic formula for a depths up to 2 m half ellipse and the depth of water was mea- mean annual precipitation ranges from 183 sured with a meter tape mm at fruita capitol reef NP headquarters chemical analyses inm the north to 140 mm near lake powell the samples collected approximately maximum mean july temperature is 33c were every while the minimum mean january temperature other week from I1 pool with surrounding vege- is 8cac spence and henderson 1993 national tation and I1 pool without surrounding vege- oceanic and atmospheric administration 1994 tated wetlands in cottonwood muley and fountain tanks between march and august METHODS 1994 we collected 23 samples from cotton- wood tanks 13 from vegetated and 10 from studies were centered on 5 drainages in the vegetatedununvegetated pools 22 from muley tanks 11 southern part of capitol reef national park from each pool type and 21 from fountain cottonwood muley fountain and miahanamiyahana tanks 11 from vegetated and 10 from unvege tanks and gil scott gulch fig 1 each drain- tatedbated pools water samples were collected in age supported pools with and without sur- 125 ml high density polyethylene HDPE rounding vegetation from which we selected 2 bottles that had been acid washed in 10 aclhclhc1 pools with and 2 pools without vegetation for solution rinsed and stored full of deionized min depth study those with surrounding vege- water prior to sampling for ph and specific tation were classified as either palustrine conductance samples collected for major ion emergent or palustrine scrub shrub wetlands analyses were stored in 250 ml HDPE bottles cowardin et al 1992 bedrock bordered pools that had also been acid washed with the same were classified as lacustrine littoral cowardin procedures because samples could not be re- et al 1992 drainages ranged from broad and frigeratedfri immediately major ion samples were open at muley tanks to long and narrow at preserved with 050.5 ml chloroform keene et cottonwood the headwaters of cottonwood al 1986 samples were filtered in the field tanks originate in a narrow slot canyon we with a nalgene hand pump through whatman made an attempt to select drainages along a GFC filters into baked dark colored borosili- broad length of the waterpocketWaterpocket fold to test cate glass bottles for analysis of dissolved organ- the results of flooding we chose pools from ic carbon water temperature was recorded at among larger more permanent water bodies so the time of sampling that they would have water in them when july specific conductivity and ph of water sam- and august storms were expected in spite of ples were determined weekly using a conduc- this selection objective some pools dried out tivity amber science inc model 604 and ph 199819981 CAPITOL REEF ROCK POOLS 253 meter beckman model 21 for summary sta- between the cottonwood pools through july tistics ph was converted to Hhah1 concentrations and august pools in muley drainage were sep- averaged and then reconverted to ph because arated all summer as no rain event was strong ph values can vary diurnally according to algal enough to cause spillage from the top pools photosynthetic activity and we did not stan- pools in fountain drainage overflowed only dardize sample collection times to account for once in late july chemical analyses after the this ph values should be viewed as approxi- flooding event in fountain were excluded from mate rather than absolute preserved samples the analysis were analyzed for major ions within 3 4 mon biological analyses after sample collection Aliquoaliquotsts were filtered whatman GFC filters for cation analyses we sampled aquatic fauna from macrozoo major ions were analyzed with ion chromatog- plankton to vertebrates weekly from 4 pools in raphy and alkalinity was analyzed with a gran each drainage march through august 1994 titration at the USFS rocky mountain forest additional collections were made in septem- and range experiment station in fort collins ber 1993 and january february and septem- colorado odeen et al 1994 dissolved organ- ber 1994 microfaunamacrofaunaMacrofauna were defined as any ani- ic carbon DOC was analyzed by the USGS mals larger than the mesh size 1 mm2mma of a water resources division in boulder colorado standard dip net based upon previous labora- oceanography international model 700 car- tory identifications we field identified organ- bon analyzer quality of the chemical analyses isms to the lowest practical taxon usually was assessed by calculating the ion percent dif- species and noted their life history stage juve- ference JPDIPD between positively and nega- nile or adult bottle trap and light trap collec- tively charged ions this is an important com- tions were used for specific identification of ponent of being able to interpret results with adult insects A voucher collection of the inver- confidence all but 2 of the samples met 15 tebrate samples has been deposited in the CP gillette museum cutoff criteria for acceptable IPD at ionic of arthropod diversity at colorado state university strengths of greater than 200 lealpalpqlleql these 2 data samples were discarded stensland and semiquantitativesemiS emi quantitative measures of abundance were recorded as a rank based 3 bowersox 1984 odeen et al 1994 eight upon standard dip net sweeps of each pool DOC samples were collected in duplicate the sweeps were taken from different sides of the pool and the they compared within 10 over a range of samples combined in 3 32 mg CL were a single white pan organisms were placed into taxa and ranked 0 comparisons of mean chemical characcharacteris-teriterls no individuals 1 1 10 individuals 2 11 50 tics between the 3 drainages were made using iioilo110 individuals or 3 51 individuals a studentS newman keuls test for studentized three additional sweeps were then taken to insure range the studentized range is the difference consistent monitoring of rare species and any between the largest and smallest treatment taxa found that were not present in the first 3 means divided by an estimate of the standard sweeps were given an abundance rank of 1 error of each single separa- treatment mean organisms were returned to the pool after tion of the means in the rank order influences enumeration and identification the size of the difference required for signifi- common methods for quantitatively sam- cance ferguson 1981 pling the pools were field tested in february of comparison the chemistry of pools adja- and march 1994 these were found to be unre- cent to vegetated wetlands with pools sur- liable and destructive in such small systems it rounded by sandstone was done with a wil- was important to sample nondestructivelynondestructively to coxon matched pairs signed rank test because avoid affecting pool communities through direct the test assumes independence between the 2 removal of pool organisms both a 30 micron groups being compared we used a reduced plankton tow and standard ekman dredge pro- data set connection of the pools during flood- duced variance as large as population means ing events invalidates the assumption of inde- the rock pool organisms do not however fit penpendencedence no vegetated versus unvegetated other characteristics expected of a poisson dis- comparisons were run for cottonwood drain- tributiontribution that would exhibit this variance age since rain events caused observed flow Bhattacharyybhattacharyyaa and johnson 1977 rock pool 254 GREAT BASIN naturalist volume 58

communities cannot be assumed to be inde- period caused flooding defined as overflow pendent of each othelother but are affected by the from the pools maximum measured volumes previous community standard sampling letbmeth-metb ranged from 325 to 800 m3ma for pools bordered ods also were subject to other problems such as by vegetation and 50 to 635 m3ma for pools bor- not accounting for patehpatchpatchinessmess of pool organisms dered by bedrock minimum volumes of 0 150 and escape tactics by most adult beetles and m3ma were measured for pools bordered by vege- hemipterhemipteransans the portable box method dod- tation and 5 150 m3ma for pools bordered by son 1987 of quantification which was found bedrock major flash floods did not occur dur- suitable only for shallow pools of 12121.21 2 m was ing the study period although flooding was ineffective for quantifying the more abundant observed in cottonwood and fountain tanks benthos such as chironomid larvae but not in muley tanks normalized pool vol- analysis pearson cluster and a transformed ume values against maximum measured vol- correlation matrix using 22 species were used ume with time showed that pool volumes to examine the biological structure of rock pool variedcovariedco with rain events for pools with and communities species chosen included all without surrounding vegetation fig 2 there present on a sampling species given day and appeared to be less variation in volume of repiesentrepresentsent the majolmajor functional groups well repie as pools with surrounding vegetation and soils as the most abundant pool fauna pearson cor- presumably because of the effects of evapo relation coefficients among each abun- evajo species transpiration and soil water storage dance for a given period weiwelwere e transformed into pool water temperatures warmed over the a distance measure and the data were then summer from march to mid april lows 4 180c treated as distances in a cluster analysis to 18c in to highs 32 35c in june july and august determine whether or not groups of organisms fig 3 after mid april most pool waters had could be considered randomlynonnonrandomly associated temperatures in the 22 range regardless groups of species that appeared together as 25c of location exposure or whether they were clusters between zero and 030.30 3 were considered bordered by vegetated wetlands nonrandom associations this analysis was per- or bedrock pools were sampled at different formed 3 times using data from the weeks of times of day temperatures 15 march 10 june and 14 july indicated in figure 3 should be interpreted as within a of the effect of disturbance defined as flood- range measured tem- peraperaturestures for any week ing on the number of species present and ratio given because of wide diurnal of juvenile to adult life history stages was eval- variability uated with t tests the effect of pool volume chemical characterization and temperature on biological parameters was examined with pearson correlation coefficients the waters of the rock pools we sampled were dilute with specific conductivities 200 RESULTS jlscmgscm and ph values near 707.0to the ionic ratio of calcium to alkalinity in the pools was similar hydrology to that measured from groundwater wells of the summer of 1994 was unusually dry the navajo sandstone calciumalkalinitycalcium alkalinity of 040.4 even for capitol reef national park total pre- in the pools compared with 030.3 reported from cipitation at cottonwood muley and fountain well samples by kimball 1988 although the tanks was 66166.166 1 27227.227 2 and 310 mm respectively pools were far more dilute ratios of calcium fig 2 according to the 38 yr record analyzed silica 20 and calciumsulfatecalcium sulfate 8 did not by spence and henderson 1993 13 of the compare well to those in groundwater calcium annual precipitation 46 60 mm usually falls silica 5 calciumsulfatecalcium sulfate 2 while silica can as thunderstorms in july and august julian be consumed by diatoms it is more likely that dates 182 243 in 1994 the july and august mineralogical variation in the bedrock and far combined precipitation was 22722 7 505.05 0 and 31931.931 9 less water residence time in the pools account mm at cottonwood muley and fountain tanks for the different chemistries between ground- respectively water and surface water volumes of the 6 intensively studied pools phosphate an essential and often limiting with vegetation increased with rain events al- nutrient was never measured in concentrations though only 5 events over the entire sampling above detection limits nitrate concentrations 199811998 CAPITOL REEF ROCK POOLS 255

0 E NINE E sies 10

cottonwood CZ eveV a co A E CL

E 0 0 A 0 E E

10 0 76 muley 9.9 20 0 E

E 2.2 0 0 0 E C 10 0 fountain aco 1 20 E E j 0 01

s411 1i e S ole date precippreciapreci vegetatedVegetaled rock

fig 2 precipitation bars and normalized against maximum measured volume pool volumes lines for cottonwood muley and fountain tanks drainages during the period of study march august 1994 rainram events that caused flooding are marked with an asterisk flooding was defined as overflow from one pool to another were also low while ammonium was present in in summer wet precipitation from the 2 near- somewhat higher concentrations est national atmospheric deposition program alkalinity and conductivity were similar in sites green river and bryce canyon utah concentration to those reported by fisher and summer volume weighted mean nitrate con- grimm 1983 for an ephemeral desert stream centrationscentrations at these 2 sites were 29129.1 jmollsmoll and conductivity tmoll was similar to that reported and 43443.4 LimoilmolL respectively NADPNTN by van verbekehaverbekeHa 1990 for ephemeral rock 1996 pools nitrate was somewhat lower in concen- sulfate concentrations in cottonwood and tration in the study pools than reported for the muley tanks 21921921.9 u mollmoil and 27127.1 ujnoilnolL ephemeral stream in arizona fisher and respectively were similar to sulfate measured grimm 1983 nitrate concentrations of48of 484.8 656.5gs in precipitation 10710710.7 gmolljllmollgemoll at bryce canyon smollnmoll were much lower than those measured 25125.1 umollgmollgmell at green river sulfate was 256 GREAT BASIN naturalist volume 58

i i i i i i i i 38 34 i A A A A 30 0 A s A 0 A A D 26 A 8 1 0 i 2 1 1 1 2 22 s S ilkelkeik i 3 A 1 A A 2 8 A 0 18 8 A 0CL A E 1 1 14 a 10 A 0 8 6 A A A

I1 i I1i I1 I11 I1 2 i i i 1 1 i i march april may june july august

fig 3 pool temperatures C during the study period circles represent temperatures of pools with vegetated wet- lands triangles are pools surrounded by bedrock

higher in fountain tanks with a mean concen- other with the exception of dissolved organic tration of 38538.5 umollgmellgmoll fountain tanks is the carbon DOC DOC was significantly higher southernmost set of pools for which we ana- 10610610.6 mg CQCL and more variable in muley lyzed chemical composition and closest to tanks than in either of the other 2 drainages P regional industrial centers that are dominant oolooi0010.01 concentrations of DOC averaged 636.3 sources of sulfur oxides in the region eatough and 434.3 for cottonwood and fountain tanks et al 1996 although it is possible that higher respectively sulfate values in fountain tanks are due to there was no discernible seasonal pattern deposition and that deposition certainly con- to solute concentrations with time over the tributes to the solute load of the pools it is summer fig 4 alkalinity and calcium became more likely that a slight change in bedrock more concentrated in vegetated pools of foun- mineralogy is the source of solutessokoluteslutes the high- tain tanks during the summer but a similar est concentrations of alkalinity ca2caa na 1 pattern did not occur in the unvegetated foun- mgtmg2 and cl of all pools sampled were tain tank pools nor in pools of either of the found in fountain tanks and this suggests the other drainages dissolved organic carbon at difference in water quality is due to different muley tanks reached concentrations as high as bedrock composition rather than deposition 13213.2 mg CL possibly because a small rain- fountain tanks soluteskolutes were 2 3 times more storm flushed organic material into pools from concentrated than either cottonwood or muley the surrounding watershed ammonium and tanks table 1 except for the major plant nitrate concentrations were highly variable nutrients potassium nitrate and phosphate through time ranging from below detection the mean ph of fountain tanks 76767.6 was limits to 80 geaueqgeqleq nh4lnhul and 28 leq n03l slightly higher than the ph of cottonwood and there was no significant difference in concen- muley tanks 70707.0 and 737.3 and the difference trationstrations within each drainage between pools was significant between cottonwood and foun- surrounded by rock or vegetation A plot of tain tanks but not between fountain and muley conductance versus normalized pool volume tanks P ooi0010.01 similarly chloride concentra- using all pools exhibits a negative relationship tions were slightly higher for fountain tanks fig 5 drying accounted for only 0290.29 of but significantly different only between foun- the change in measured conductance for the tain and cottonwood tanks P 0030.03 ammo- entire data set but there was variability by nium was lower and less variable in fountain drainage in fountain tanks 68 of conduc- tanks than the other 2 drainages concentra- tance variability was explained by pool drying tions of all soluteskolutes in cottonwood and muley while 30 and 27 were explainable for muley tanks were not significantly different from each and cottonwood tanks respectively 199811998 CAPITOL REEF ROCK POOLS 257

TABLE 1 mean concentrations and standard deviations of major ions from 3 drainages of capitol reef national park utah means with the same letter are not significantly different soluteskolutes are reported as gmelllmollgmoll unless otherwise indicated cottonwood tanksranks muley tankstanoan ks fountain tanistankstaraariks analiteanalyte mean s sig mean s sig mean s sig ph 7004 A 7309730.97 3 0 9 A 7605 BA conductivity acm6cmjscmoem 52534352534.352 5 34 3 A 62141562.141562 1 41 5 A 11484951148114.8 49549549.5 B calcium 1921192.1192 1 15721572157.2157 2 A 2171217917 1 1522152 2 A 5240524.0524 0 27942794279.4279 4 B magnesium 57641257641.257 6 41 2 A 65849465849.465 8 49 4 A 1358135.8135 8 61761 7 B sodium 17413117413.117 4 13 1 A 17417417417.417 4 17 4 A 34813134.813134 8 13 1 B potassium 32253825388532.2532 25 23023023.023 0 A 43538443538.443 5 38 4 A 28115328.115328 1 15 3 A ammonium 22233322233.322 2 33 3 A 33344433344.433 3 44 4 A 551115.51115 5 11 1 B chloride 169113 A 19722619722.619 7 22 6 A 310113 BA nitrate 481294.81294 8 12 9 A 4897489.74 8 9 7 A 65816 5 8 1 A sulfate 21913521913.521 9 13 5 A 271312713.127 1 3 1 A 38515638515.638 5 15 6 B phosphate below A below A below A detection detection detection alkalinity 5028502.8502 8 4360436 0 A 5553555 3 45844584458.4458 4 A 122612268 8 7298729 8 B silica 133l7133371331713 3 1 7 A 8317831.78 3 1 7 A 23318323318.323 3 18 3 B DOC mg CL 63266.3266 3 2 6 A 106951069.510 6 9 5 B 43l743174 3 1 7 A

biological characterization predaceous as larvae but collector gatherers as adults merritt and cummins 1996 in all pools sampled 59 separate macroinmaceoin water bugs notonectidae and corixidae vertebrate and vertebrate taxa were found were common throughout the year crawl- table 2 these included fathead minnows the ing water bug family naucoridae was also found pimephales kromelaspropromelasmelas rafmesquerafinesquerabinRafinesque in the lowest in late summer the feustonneuston complex con- miahanamiyahana pool that terminates close to hall s sisted of water striders AquaaquaticsaquariusaquatiusTius remidisremigis say creek a stream in which this species is com- and microveliaMicmicromeliarovelia tortorquatetorquataquata champion and the mon anuransanusans were represented by the spade- whirligig beetle gyrinus pliciferplicifer foot toad scaphiopus intermontanusintermontanus cope leconte dipteransDipter ans were represented by a single species treefrogfrog arenicolorcolor cope 2 canyon tree hyla areni and of tabanid various common chironomids and other toads woodhouseiwoodho girard and bufo usei bufo a few mosquito species Dragondragonfliesflies and dam and girard fairy punctatuspunctatus baird the shrimp selselfliesflies were common including aeshnameshna sppapp streptocephalus texanus packard tetanus occurred in and Symsympetrumpetrum oftrusumobtrusum hagen table 2 all pools A snail physellaphydellaPhysella sp was observed in most species in the pools are also common all drainages the remainder of the taxa were in other aquatic habitats of the colorado pla- arthropods present in both larval and adult teau small groups of predators dominate the forms communities whose species all appear to be larvae of the caddisflycaddiscaddishlyfly limnephilus talogabaloga either extremely vagile in dispersal and colo- ross were common throughout the winter and nizationnization attributes or adapted to hydrologically spring months and larval activity was observed fluctuating habitats such as the anuransanusans figs even under ice in january the mayfly cal 6aaa c associations changed through the sam- libietisliblibaetisaetis dictuspictus eaton was found as nymphs pling period primarily due to life history phe throughout spring summer and fall nonologieslogies sixty two percent of species found in aquatic beetles were well represented in all the pools were predators and each cluster was pools the diverse assemblage included preda- primarily composed of species considered pre- ceous dytiscid diving beetles ranging in size dacedaceousous thirty four percent of the species from the minute liodessusLio dessus affinusqffinus say to the were herbivorous collectorgathererscollector gatherers and scrap- larger dysticusDysticus sp common hydrophilid water ers while the remainder were collectorfiltercollector filter scavenger beetles included berosus punctatis feeders simus leconte and tropisternusTropisternus ellipticellipticusus the proportion of juveniles in rock pools leconte these water scavenger beetles are decreased throughout spring and summer fig 258 GREAT BASIN naturalist volume 58

a 100 90 160 A 80 A 1 ito11010 i A 0 A A 70 A A A g g 60 A A 9 A 60 10 4 9 400 200 300 A A A 150 Q 200 A loo100 i100 A A a 100 50 6A A 1 A 1 I ft 0 A i I 1 A 1 0 120 35 28 80 4 0 21 A Zr 40 Z 14 7 A 2 L 1 0 fi 8.8 8 A 0 ft ft ft a a ft le ft 3100 2500 11 19001 00 46 1300300 6 8- 700 A A aliaildil 100 ft A A A 0.0g ft 1 5050 80 10 140 170 200 23023 0 so50 80 110 1401 40 170 200 23023 julian day julian day

b 100 90 A 160180igo A & 80BO 1tio11010 i A A A 70 A ft a 60 60 10 A 400 200 300 A A 150 5 200 0 A 0 100 A A w A A A 100 ft silallsii 50 A 0 0 A 120 35 28 80 co A 082121 z 40 ok A Z 14 A 7 0 0 ft ft 11 ft ft ft 3100 2500 1900 0 11 a 1300 8 6 700 100 A A 1 5050 80 110 140 170 200 2302330 500 80 110 140 170 20200 23023 julian day julian day

C 100 loo W 90 160igo1 60 80 0 110 A A A A i 16 8 A a 70 0 a 60 ft i A 60 A 10 2000 200 1600 150 S 1200 100 & cn a A 800 0 X A A 50 A A A 0 1 t f 0 120 35 28 80 A 1M 32121 z 40 z 14 A 7 & 0 ft 9 A 5 0 ft A 3100 2500 1900 1 11 1300 A A A i 6 7700 A A 122125152 a a 1 A 111a 50 80 110 140 170 200 23023 50 so iioilo110 140 170 200 230 julian day julian day

fig 4 chemical dynamics of selected soluteskolutes over time in a cottonwood tanks b muley tanks and c fountain tanks solid cnclescirclesuncles representlepieleplesent pools with surrounding vegetation open triangles are from unvegetated pools values for calcium ca sulfate 804 ammonium nhanh4N nitrate no3n03noa and alkalinity alk are in gealueqlgeql note difference in scale foifolfor ca foifolfor fountain tanks specific conductance cond values are in uscm2gscm2 and dissolved organic carbon DOC val- ues aiealeare in mg CL julian days are numbered days of year since day I1 on january 1 199811998 CAPITOL REEF ROCK POOLS 259

2250225.0

4 fountain rsq068 n13 2000200.0 mauleymmuley rsq030 n12 A cottonwood rsq027 n1na 3 1750175.0

1500150.0

1250125.0

1000100.0

75075.0

50050.0 A

25025.0 A 000.0oo oo 000.0 050.5 101.0lo normalized pool volume

fig 5 relationship of specific conductance iscm2tscm2 with normalized pool volume volume was normalized by divid- ing weekly volumes by the maximum pool volume measured during the study period

7aaa but there was no difference in the propor- compared with pools studied by dodson 1987 tion of juvenile versus adult stages between pre drying numbers of species and juvenile pools with vegetation versus those surrounded to adult ratios were tested against post drying by rock P 05860.586 there were more species parameters directly after the first filling event in pools that were components of vegetated both variables were normalized with square wetlands mean 105ioslos10.5 s 444.4 n 116 than root transformations neither was significantly pools situated in bedrock only mean 727.2 different as a result of drying species num- s 323.2 n 116 although numbers of species bers P 0160.16olg life history stage ratio P declined in both types of pools from spring 0490.49 through summer fig ab7b neither pool vol- ume P 0540.54 nor temperature P 0740.74 discussion affected the number of species present the effect of flooding on species numbers communities found before and after both was not significant either when comparing flooding and drying events were very similar numbers of species within all pools before and suggesting that hydrologic extremes do not after flood events P 0540.54 or when rock constitute much of a stress on community com- bordered pool species numbers were treated position close spatial association of the rock separately from those surrounded by vegeta- pools and high numbers of predators in small tion P 0870.87 data were normalized by systems buffered variations in the community square root transformation to eliminate the structure expected to result from physical dis- potential for autocorrelation we did not use turturbancebance or competition mclachlan 1985 the 2 middle flooding events in cottonwood schneider and frost 1996 summer storms drainage see fig 2 the first and last storms affected only a few drainages at a time and were considered sufficiently separate events to only a few study pools of significant volume satisfy conditions of independence dried completely during the hot dry summer A similar test was performed to examine the this suggests that only a portion of the water responses of pools to drying as a disturbance pocket fold aquatic community is ever dis- such disturbances were relatively infrequent placed at a time leaving undisturbed areas as a 260 GREAT BASIN naturalist volume 58

TABLE 2 species list of macromaeromacroinvertebratemacromvertebrateinvertebrate and verte- vel11daeVELIIDAE brate lockrockroek pool species collected 11 september 1993 to 23 microveliamicromeliaMicrovelia tortorquatatorquatequata champion septemberSeptembeibel 1994 and 25 october 1995 in capitol reef CORIXIDAE national park utah graptocorixagraptoconxa abdominalabdominalisabdominalesis say belostomatidae vertebrata lethocerus americanosamericanusameric anus leidy cyprinidae trichoptera pimephalespirnephales kromelaspropromelasmelas rafinesqueRafinesque llmnephilidaelimnephilidaelimnophilidae anura limnephilus talofa ross scaphiopus intennontanusintermontanusintermontanus cope coleoptera girard bufo punctpunctatusatus baird and GYRINIDAE woodhouseiwoodho girard bufo usei cyrinusgyrinus pliciferplicifer leconte hyla areniaremoremarenicoloraremcolorcolor cope hydrophilidae gastropoda hydrophilushydrophilousHydrophilus triantrtantriangulanstriangularisgularisgulans say physellaphydellaPhysella sp tropisternusTropisternus ellipticellipticusus leconte nematomorpha hydrocharaHydrochara lineatalaneata leconte arthropoda berosus punctatissimus leconte laccobiusLaccobius sp class anostraca dytiscidae packard streptocephalus texaiiustetanustexanus agabus disintegratusdismtegratusdisintegrates crotch class conchostraca agabus lugensaugens leconte eulimnidiaeuhmmdia texana packard agabus tristisaristis aube class nostostraca agabus sentivittatussemivittatus leconte chopstnops longicaudatus thops leconte thantusrhantus guttigutticolliscollis say class arachnida laccophilusLaccophilus maculosus decipiensdeci Hydrachnid piens leconte a stictotarsus stristriatellusatellus class hexapoda leconte liodessusLio dessus affinus say collembola neoclypeodytes discretusdiscretus sharp isotomidae hygrotusHygrotus collatuscolcollanuslatus fall ephemeroptera thermonectusthennonectusThermonectus mannoratusmarmoratusmannmarmmormoratus mannmannoratusmarmmarmoratusoratus BAETIDAEBAETIDAC hope callibaetis dictuspictus eaton uvarus subsubtilinsubtilistilis leconte odonata dytiscus sp AESHNIDAEALSHNIDAE haliplidae aeshnameshna multicolor hagen peltodytesPelto dytes callosuscallocallosumsus leconte aeshnameshna dalmatapalmata hagen dimeradiptera anaxjuniusanaxjumusAnax juniusjumus drury TABANIDAE libellulidae tabanus sp Symsympetrumpetrum obtrusumobtnisum hagen chironomidae libellula saturatesaturatasaturata uhler chironomus sp LESTIDAE polypedilumPolypedilum sp Archilestes grandis archilestes rambur phaenopsectra dyandyarl townes coenagrionidaecolnagrionidaeCOENCOLN AGRIONIDAE phaenopsectra sp enallagma cyathigerum charpentier micropsectra sp argia sp alotanypus sp hemiptera ceratopoconidaeceratopogonidae notonectidae belziabezzia sp kirbyu notonecta kirbyi hungerford CULICIDAE notonecta undulataungulataulata say und anopheles nus mccracken buenga fransiscafransiscanus buenoa margarimargaritaceamargantaceamargantacea torrebuenotorre bueno culex tartarsalismarsalissalis Coquillett naucoridae culisetaCuliseta inorinornataincornatanata williston ambrysusAmbry sus mormon mormon montandon culisetaCuliseta sp GERRIDAE aquarius remidisremigis say

source of recovery many of the species we components of vegetated wetlands supported found were well adapted for rapid recoloniza- greater numbers of species throughout the tion of pools after disturbance having highly year but none of these species occurred only mobile adult stages terrestrial adult mating in pools with vegetated wetlands the lack of and dispersal stages or animal or wind dis distinct species associations in the cluster analy- persed eggs recolonization can also come sis implies that all species occupied a similar from survivors or eggs laid prior to disturbance ecological niche which is likely the result of cushinggushing and gaines 1989 pools that were close ecological association and proximity and 199819981 CAPITOL REEF ROCK POOLS 261

3a PSP S Scapscepsoepscaphiopushippus intelinterintermontanusintermonlanusmontanus QCSS bufoBuso sppapp PS chironomidae P thantusrhantus gutticollisgufficoffisgutticottiscollis C laccophilusLaccophilus maculosus d P stictotarsus shishiatellusstnatellusateliusatellus P liodessusljodessusLiodessus artinusaftinusaffinus P aquarius remidisremigisnsmigis S limniphilusLimniphilus talogabaloga P ceratopogomdaeceratopogonidae F culicidae P agabus spo SCS C hyla areniameniaremarenicoloraremcoloranemanamcolor S phydellaphysellaPhysella spo P notonecta kirbyikirbyu P graptocofixagraptoconxa abdabdominalabdominalisabdominalesminakisis C callibaetiscalfibaefis dictapicta P gyrinus piidplicifw C Hydrachnid a P libellula saturatesaturatasaturata C tropisternusTropisternus elliptic us C bemsusberosusbemous pundatissimuspunctatissimus 00 02 04 06 08 10 12

1 P rimepimaphelaspimephelasPimePimaphelas prokromelaspmmelaspromelasmelas CSQS hyla areniarenioarenioolorarenicolorolorcolor S physellaphydellaPhysella spa C callibaetiscallibaefis dictapicta P aesbnaanaxaeshnalanax spu P libellula satsatusaturatesaturataurata P archilestesArchi lestes grandis P microveliamicromeliaMic rovelia torquatatotquatatorquatetottorquata P graptocorixagraptoconxa abdoabdominalabdominalisabdominalesis C Hydrachnid a P notonecta kirbyikirbyu P aquarius remidisremigis P ceratopogonidaeceratopogomdae C tropisternusTropi sternus elliptic us C laccophilusLaccophilus maculosusmaculdsus d F culicidae P gyrinus pliciferplicifer PS Scapscaphiopushippus intermoritanusmtermontanus CS bufobusobubbbubo spo F streptocephalussfreptocephalus tetanustexanus PF eulimnidaeulimmda texana P tabanus appspp PC chirornmidaechitonomidaechironomidae C berosus punctatissimus P thantusrhantus gutticollisgufficolfisgutticollis C hydrophilusHydrohydrophilousphilus triangulatnangulanstriangulatistisris P bouodessusbodessusUodessus affinus P dytiscus sppapp P thermonectusthenmonThermon717eanonectusectus marmmarmoratusoratus m P stictotarsus stristriatellussfnatellusatellus 00 02 04 06 08 10 12 14

C SC bufoBOO spo SC hyla areniarenicolorcolor C nematomorpha P graptocofikagraptoconxa abdominal is C berosus punctatissimus S phydellaphysellaPhysella appspp P aquarius remidisremigis C callibaetis dictapicta CPQP chironomidae P ceratopogoddaeceratopogonidae P libellula satsaturateuretauratauneta P gyrinus plicifeoliotipliciferplicifer P aeshnaanaxaeshnalanax sppapp C tropisternusTropi sternus ellipticellipticusus P notonecta kirbyikirbyu F culicidae P stictotarsus stnatellus P Liodessus affirms P rhantusthantus gutticollisgutticolfisgutticollis C laccophilusLacco philus maculosus d

1202 04 06 08 1 12 14

fig 6 average linkage cluster analysis for aquatic species collected on a 15 march 1994 b 10 june 1994 and c 29 july 1994 clusters are expressed as normalized root mean square distances species are annotated with functional feed- ing group after merritt and cummins 1996 as follows P predator S scraper C collectorcollectorgatherergatherer and FE filter feeder 262 GREAT BASIN naturalist volume 58

161.6lgig 141.4 a W 0 121.2 101.0iolo 080.8 D 060.6og 040.4 020.2 000.0oo

16 D b W cl 12 7 0 e2ea 8 W E 4 Z 0 march april may june july august

fig 7 characteristics of aquatic organisms in capitol reef rock pools over time a average ratio of juvenile to adult stages and b species numbers circles are numbers in pools with vegetation and triangles are numbers in pools sur- rounded by bedrock

similarity of the rock pools the alternative influenced by the presence or absence of vege- which was not observed would have shown tated wetlands persistent and distinct clusters of species in summary rock pools of capitol reef the rapidity of recovery suggests these sys- national park are populated with a fauna well tems display great resilience a conclusion also adapted to survival in an environment of hydro- reached in a study of maciomacromaeromacromvertebratemacroinvertebrateinvertebrate recov- logic extremes the dilute chemical concentra- ery after flash floods in sycamore creek ari- tions we measured did not vary broadly enough zona grimm and fisher 1989 flood events to pose a salinity problem for aquatic organ- can introduce nutrients and detritus from pre- isms the ability of communities to recover cipitation and upstream as they wash debris after floods and droughts is consistent with a and salts from upstream contributing areas hypothesis posed by hynes 1970 and results creed et al 1996 grimm and fisher 1989 found by others summarized by cushinggushing and hypothesize flood events are necessary to the gaines 1989 that streams with flashy hydrol- maintenance of macromaeromacroinvertebratemacromvertebrateinvertebrate populations ogy should have less abundant and less varied because they refresh the food supply for fast fauna than others cushinggushing and gaines 1989 growing organisms developed a classification scheme for coloniza- there was a chemical response to drying and tion and recolonization characteristics of differ- flooding in the pools although the strength of ent stream types capitol reef rock pools fit well the response varied by solute and pool it under the classification for exoexorheicrheic cold desert appears that nutrients and DOC increased after streams in that the many small streams of the flood events but salts became more concen- Waterwaterpocketpocket fold provide colonization sources trated with drying some chemical constitu- for each other the diversity of stream and ents such as alkalinity increased by an order drainage habitats offers many pathways for fau- of magnitude during the study period concur- nal recovery including downstream drift up- rent with declining pool volume but rapidly stream migration both surface and hyporheichyporheic decreased after a rainram event fig 4 pool chem- refugia in wetlands surrounding some pools as istry was very dilute and was not significantly well as adult and egg survivors of disturbances 199819981 CAPITOL REEF ROCK POOLS 263

acknowledgments sonoran desert stream sycamore creek arizona american midland naturalist 106249106log 249 257 norm sandy borth- GRIMM NJN J AND SGS G FISHER 1989 stability of penphyperiphy thanks to henderson ton and maeromacromacromvertebiatesmacroinvertebratesinvertebrates to disturbance by flash wick kevin berghoff and joel wagner of the floods in a desert stream journal of the northnoi th ameri- national park service for providing logistical can Benthbenthologicalological society 82938 293 307 and financial support for this research eric 1992 responses of arid land streams to changing pirth S and climate pages 211 233 in P firth and SGG fisher allstott brian newkirk louise odeen editorsediedltoistols global climate change and freshwater eco- assisted with the data analysis sandy borth- systems springer verlag newnewyoikyork wick joel wagner and an anonymous reviewer HAEFNER JW AND AMA M LINDAIILLINDAHL 1988 the ecology of provided valuable reviews we thank the small pools in capitol reef national park utah national park resource infor- final leportreport for phase I1 of USDINPS contractConti act service natural PX 1350 7 0259 mation division for the state and park insert 1991 the ecology of small pools in capitol reef on figure 1 this project was funded by the national parkpaikpalk utah final report foifolfor phase II11 of national park service contract CA 126821268 2 USDINPS contract PX 1350 8 0187 HYNES H B N 1970 ecology of waters 9004 HBN the running uni- versity oftoiontoof toronto press toronto ontarioontano canada KEENE WC AAPaaeA A P PSZENNY JNJ N GALLOWAY AND MEM E literature CITED HAWLEY 1986 sea salt corrections and interpreta- tion of constituent ratios in marinemanne precipitation of geophysicalofgeophysical 6647 6658 BARON J 1992 biogeochemistry of a subalpine ecosys- journal research 91d6664791d6 tem loch vale watershed springerspragersprmger verlag new KIMBALL BAB A 1988 geochemistry of water associated york with the navajo sandstone aquiferaquifeibeibel san rafael swell area utah pages 121 133 S and A I1 BERGHOberghofrberghofeBERGHOFFFr K 1994 capitol reef national park wetland in JS mclean AI johnson editors regional aquifer systems of the survey summary report resource management divi- united states aquifers oftheodtheof the western mountain area sionslon capitol reef national parkpaik UT AWRAAVVRA monograph series 14 american watelwater bhattacharyyabharracharyyaBHATTACHARYYA GKG K AND RAR A JOHNSON 1977 statistical bethesda MD concepts and methods john wiley and sons new research associates york mclachlanajmclachlan AJ 1985 what determinesdetel mines the species pre- sent in a rainram poolpooipoop oikosbikos 45145 1 7 COWARDIN LML M V CARTER FC GOLET AND EXE T LAROE MERRITT RW AND KW CUMMINS EDITORS 1996 an 1992 classification of wetlands and deepwater habi- introduction to the aquatic insects of north america tats of the united states united states fish and ard3rd edition kendallhuntKendall Hunt publishing co dubuque wildlife 7931 131 appp service FWSOBS 7931131 IA CREED LFI1 F L E BAND NWN W FOSTER I1 K MORRISON J A LE IK JA NADPNTN 1996 national atmospheric deposition pro- NICHOLSON R S SEMKIN AND D S JEFFRIES 1996 RS DS gram annual data summary precipitation chemistry regulation of nitratemiratemtrate N release from temperate in the united states 1994 natural resource ecology forests a test of the N flushing hypothesis watelwater laboratory colorado state university fort collins resources 32 research 3233373337 3354 CO 256 appp CUSHINGGUSHING C E AND WL GAINES 1989 thoughts on re- CE NATIONAL OCEANIC AND atmospheric administration colonization of endorheicendorheic cold desert spring streams 1994 climatological data utah volume 96 nos journal of the north american benthologicalBenthological society 5 7 ISSN 036455920364 5592 department of commerce 82778 277 287 USA S I1 DODSON SI 1987 animal assemblages in temporary desert ODEEN L R MUSSELMANMUSSLLMAN C REGAN AND M CONRAD rock pools aspects of the ecology of dasyheleaDasyhelea sub 1994 quality controlcontiolqualitycontrolqualityquality assurance program at letteicettei diptera ceratopogonidaeceratopogomdae journal of the north the glacier lakes ecosystem experiments site ggs american Benthbenthologicalological society 6656 65 71 GLEES min the snowy range of wyoming general EATOUGH DJD J M EATOUGH AND NLN L EATOUGH 1996 technical report RM 0000 USDA forest service apportionment of sulfur oxides at Canyoncanyonlandslands dur- rocky mountain forest and range experiment sta- ing the winter of 1990 III111 source apportionment of tion fort collins CO green soxSO to sulfate in the river basin atmospheric POFF NLN L AND JV WARD 1989 implications of stream environment 3029530 295 308 flow variability and predictability for lotic community FERGUSON GA 1981 statistical analysis in psychology structure a regional analysis of stieamflowstrearnflow patterns and education ath5th edition mcgraw hill book co canadian journal of fisheries and aquatic science new york 46180546 1805 1818 FISHER SGS G LJ GRAY NBN B GRIMM AND DED E BUSH 1982 SCHNEIDER DWDWANDTMAND TM FROST 1996 habitat duration temporal succession in a desert stream ecosystem and community structure in temporary ponds jour- following hashflash flooding ecological monographs 52 nal of the north americanamerlean benthologicalBenth ological society 93 110 156415 64 86 FISHER SGS G AND NBN B GRIMM 1983 hydrologic and SPENCESFENCE JRJ R AND NRN R HENDERSONHENDLRSON 1993 tinajaatinaja and hang- material budgets for a small sonoran desert water- ing garden vegetation of capitol reef national park shed during thieethree consecutive cloudburst floods southern utah USA journal of andaridarld environments journal ofariaofaridof and environments 91059 losios105 118 242124 21 36 GRAY LJL J AND SGS G FISHER 1981 post flood recoloniza- STENSLAND GJG J AND VC BOWERSOX 1984 quality assur- tion pathways of macromaeromacroinvertebratesmacroinveiinvertebratestebrates in a lowland ance in acid precipitation monitoring through the use 264 GREAT BASIN naturalist volume 58

of ionlon balance calculations in TRT R johnson and SJS J VAN HAVERBEKE DRD R 1990 physicochemicalphysico chemical characteris- Pankpankalaalaaiadla editorss quality assuiassaiassuranceanceanee of airan pollution tics and ecology of ephemeral rock pools in northern measurements airan pollution control association arizona unpublished master s thesis northern ari- pittsburgh PA zona university flagstaff 98 appp sro1ilgrenS rOHLGREN tjTJJFJY QUINN M RUGGIERO AND GSG S WAG- GONER 1995 status of biotic inventories inm US received 7 april 19919977 national parks biological conservation 719771 97 105 accepted 19 september 1997 great basin naturalist 583 C 1998 appp 265 272

survivorship AND CAUSE SPECIFIC MORTALITY IN FIVE populations OF MULE DEER

vernon C bleichl2bleich12Bleich 12 and timothy J taylorataylor3

ABSTRACT we used retrospective analyses to investigate cause specific mortality and survivorship among 5 popula- tions of mule deer N 168 telemeteredtelemetered animals wintering in the western great basin during 1986 1994 these popu- lations existed under similar environmental conditions but survivorship functions differed among them monthly sur- vival ranged from 09640.9640 964 to 09900.9900 990 and annual survival ranged from 06430.6430 643 to 08840.8840 884 the proportion of deaths attributed to predation and malnutrition or anthropogenic causes did not differ among the 5 populations predation was the leading cause of mortality mountain lions were responsible for approximately 90 of the deer killed by predators no difference existed among these populations in the proportion of telemeteredtelemetered deer that were killed by mountain lions but propor- tiotionallynally more females than males were killed by these large felidsfelias predation by mountain lions is the primary source of mortality and a widespread phenomenon among the populations of mule deer we investigated

key words california felis concolor odocoileus hemionus mule deer modalitymortality nmntainmountain lion predation survivorship

populations of mule deer odocoileus hem- on the physical condition of these large cerbiherbi ionus have been declining in western north vores kucera 1988 taylor 1996 moreover america for many years workman and low the harsh winter of 1992 93 killed many deer 1976 and effects of nutrients competition particularly in northeastern california and predation and climate on these populations northwestern nevada wertz 1996 have been debated among numerous investi- to better understand factors affecting deer gators mule deer are thought to be density populations in the western great basin we in- dependent in their response to resource avail- vestivestigatedgated seasonal distribution habitat selec- ability mccullough 1990 in unpredictable tion cause specific mortality and survivorship environments typical of much of the great in 5 populations of mule deer wintering in basin however it may be difficult to base eastern california and western nevada in this management recommendations on density paper we use retrospective analyses based on dependent responses anticipated to follow pop- telemeteredtelemetered animals white and carrotgarrot 1990 ulation declines mackie et al 1990 what- to compare cause specific mortality among 5 ever factors singularly or in combination reg- mule deer populations that winter in the west- ulate mule deer populations remain open to ern great basin additionally we describe and discussion indeed there is general agreement compare survivorship functions for female that no single cause can be invoked detailed deer in these populations and specific investigations are necessary to evaluate factors that may regulate populations description OF THE STUDY AREA of these important game animals hornocker 1976 knowlton 1976 connolly 1981 our study area is located in mono and inyo recently wertz 1996 expressed concern counties california and douglas county about the dynamics of several mule deer pop- nevada fig 1 deer from the west walker ulatulationsions wintering in the western great basin east walker mono lake and casa diablo win- highway mortality has been a basis for this ter ranges are migratory and display annual concern as have the effects of predation and patterns of movement and range use in spring disease persistent drought has lowered the they make long distance movements some- carrying capacity of deer winter ranges in this times 60 km and spend summers on both general area with resultant negative influences the east and west slopes of the sierra nevada

california department of fish and game 407 W line st bishop CA 93514 21nstitutestatute of arctic biology and department of biology and wildlife university ofofala&kaalaska fairbanks fairbanks AK 99775 abox3boxox 191 june lake CA 93529

265 266 GREAT BASIN naturalist volume 58

WEST WALKER QB NA CA B EAST WALKER NV T MONO LAKElakertlakefty

CASA DIABLO 50 KM 7uau6 7 BISHOP

v 118030118 30 W INYO 37037 0 N MOUNTAINS t

fig 1 location of 5 winter ranges in northeastern california and western nevada mule deer concentrate on these areas from approximately 1 november to 15 may each year

taylor 1988 1991 during autumn deer from occupy an arid region with low and unpre- these populations return to discrete winter dictabledictable precipitation fig 2 similar to that ranges on the western edge of the great basin described by kucera 1988 since 1986 the where they remain from about I1 november to great basin immediately east of the sierra 15 may taylor 1988 1991 deer inhabiting nevada has experienced repeated annual the inyo mountains undergo altitudinal droughts as a result ecological carrying migrations similar to those described by capacity of many winter ranges has declined nicholson et al 1997 but generally do not taylor 1991 migratory populations of mule exhibit the extensive movements made by deer deer can be substantially affected by drought from the other 4 populations currently 4 of conditions on winter ranges despite adequate the populations west walker east walker forage during summer kucera 1988 during mono lake casa diablo are classified as years of low precipitation bitterbrushbitterbrush produc- rocky mountain mule deer 0 h hemionus tion is poor and deer subsist on suboptimal deer occupying the inyo mountains are classi- diets consisting largely of conifers sagebrush fied as inyo mule deer 0 h inyoensis a taxon and blackbrushblackbrush coleogyne ramosissima kucera of questionable validity wallmo 1981 cronin 1988 taylor 1991 and bleich 1995 during winter all 5 populations of deer METHODS occur largely in sagebrush artemisia triden tata steppe or pinyon pine pinus monomonophyllamonophylldphyliaphylla during 1986 1991 we used clover 1956 habitat ranging in elevation from 1500 m to traps a helicopter and linear drive nets 2300 m taylor 1988 1991 VC bleich and D thomas and novak 1991 and a hand held racine unpublished data the primary winter net gun fired from a helicopter krausman et forage for the 4 northern populations is bitter al 1985 to capture mule deer we fitted adult brush purshia sppapp taylor 1988 1991 jyroidJl yr oldoid animals with color coded ear tags although bitterbrushbitterbrush occurs in the inyo moun- and telemetry collars model 500 telonics tains dedecker 1991 specific data on deer inc mesa AZ that incorporated a mortality diets in that range are lacking sensor with a 6 h delay we collared each ani- the sierra nevada creates a formidable mal at its capture site and released it when rain shadow and during winter these deer processing was completed by distributing our 199819981 survivorship AND MORTALITY OF MULE DEER 267

4 we could not ascertain the source of mortality we listed the cause of death as undetermined G tests were used for categorical analyses and a binomial test compared the proportion of 3 deer killed by mountain lions during different D years zar 1984 N we used the kaplan meier 1958 estima- 0 pollock 2 M tor as modified by et al 1989 for t staggered entry of telemeteredtelemetered females into each population and determined survivorship LU A cr A M on a monthly basis to compare survivorship S J functions we used the log rank test cox and 0 oakes 1984 as modified by pollock et al 1989 we calculated the most conservative pollock al 1 chi presented by et 0 square statistic 10 0 10 20 30 1989 to enhance the probability that any dif- survivorship func- teoTEMtemperaturePERJURE C ferencesferences detected between tions were real survivorship was not evaluated on all win- fig 2 climate throughout the study area typically is cold during winter and hot during summer precipitation ter ranges concurrently and deer were not ini- occurs primarily as snowfall during winter but variance in tially collared at the same time of year to min- annual precipitation is high the climograph was devel- imize seasonal effects on mortality in this ret- 1961 1990 from the western oped from data obtained analysis we compared survivorship regional climate center using the mean of monthly mean rospective values of minimum and maximum temperatures for of females from paired populations from the bishop bridgeport bodie and independence california beginning of the ist april during which col- lared deer from each population pair were available to the end of the period for which available for those capture efforts throughout all winter ranges paired monthly data were example studied we minimized potential biases associated with particular populations for we heterogeneous use of those areas by deer we cause specific mortality in the west walker collared male and female deer in the approxi- population during april 1992 january 1995 mate proportion of their occurrence in each and in the inyo mountains population during population each winter we used ground october 1991 december 1994 for this pair based chemical immobilization or a helicopter comparisons of survivorship curves spanned a and net gun to capture and radio collar addi- period of 2 yr and 9 mon from I1 april in year tional deer in each population I1 to 31 december in year 3 using this method in the 4 northern populations we used aer- we compared survivorship over periods of 21 ial and ground telemetry to monitor the status mon for 4 pairs of populations and over 27 of deer at intervals I1 wk thus date of death mon for 5 other pairs to facilitate comparisons could be closely estimated using only aerial we also calculated finite annual and monthly telemetry in the inyo mountains we monitored survivorship for females in each population those deer at approximately 2 wk intervals we restricted our analyses to females because for animals for which we could not ascertain the genders of sexually dimorphic ungulaungulatesungulatedtes the date of death we assumed death occurred may occupy different habitats experience dif- midway between the last known live observa- ferent risks of natural mortality bleich et al tion and the date on which a mortality signal 1997 and respond differently to the threat of was first received predation bleich in press we attempted to determine the cause of we collected data for a minimum of 24 mon mortality for every deer that died for animals in the casa diablo population and a maximum killed by predators we used the criteria of of 39 mon in the inyo mountains although shaw 1983 and woolsey 1985 to identify the investigations did not all run concurrently the species of predator in all but one instance these 5 populations occupy similar habitats in nutritional status was indexed by condition of close proximity to each other they were marrow in long bones cheatum 1949 when exposed to similar climatic regimes table 1 268 GREAT BASIN naturalist volume 58

TABLE 1 correlation matrices for climatological data obtained 1961 1990 from the western regional climate center foiformol bishop bridgeport bodie and independence california these stations are all located on or near the winter ranges investigated herein average monthly maximum temperature bishop bodie bridgeport independence bishop 1000 0988 0995 1000 bodie 0996 1000 0995 0987 bridgeport 0996 0997 1000 0995 independence 0999 0997 0995 1000 bishop bodie bridgeport independence average monthly minimum temperature

average monthlymonthlyanthly precipitation bishop bodie bridgeport independence bishop 10001.0001 000ooo 09360.9360 936 0972 0996 bodie 1000 0934 0935 bridgeport 1000 0979 independence 1000

and several of the investigations were ongoing no evidence of malnutrition among animals simultaneously thus we assumed that quali- killed by predators or among those dying of tative differences among these winter ranges anthropogenic causes were minimal predation accounted for 70 of the known causes of death for females on each winter RESULTS range fig 3 the proportion of deaths attrib- uted to predation did not differ among these we radio collared 168 adult mule deer 27 populations G 59875.987 df 4 FP 02000.200 males 141 females and monitored them for when human induced mortality and malnutri- 21 39 mon 2829 telemetry months table 2 tion were pooled for males sample sizes we determined the proximate source of mor- were too small to allow a comparison among tality for 76 of the females 41 of 54 and populations 85 of males 11 of 13 that died among of 34 female mule deer killed by predators females confirmed causes of death ranged mountain lions accounted for 91 of the from 57 in the inyo mountains to 100 in deaths fig 4 no difference existed among the east walker population among the 41 mor the 5 populations in the proportion of females talitiestalities of females for which the cause of death killed by mountain lions G 29792.979 df 4 P is known 83 were attributed to predation 05610.561 overall the proportion of female 484.8 were human induced and 12212.2 were deer whose deaths were attributable to preda- due to malnutrition in the northernmost pop- tion by mountain lions 31 of 41 was signifi- ulation west walker 3 of 10 mortalitiesmortalities result- cantly greater than the proportion of males ing from predation occurred during or immedi- killed by these large felidsfelias 4 of 11 G 57515.751 ately after the severe winter of 1992 93 and df 1 P 00160.016 7 of 10 occurred during or following the survivorship functions of female deer dif- mild winter of 1993 94 FP 0100.10olo among fered significantly for 3 of 10 pairwise compar- males that died predation by mountain lions isons table 3 survivorship for the west accounted for 36 and hunting for 64 of the walker population differed from the mono 11 mortalitiesmortalities for which the cause of death lake inyo mountains and east walker popu- was determined the source of mortality for 2 lations and was marginally nonsignificant for males could not be ascertained we detected the casa diablo population the finite survival 199819981 survivorship AND MORTALITY OF MULE DEER 269

TABLE 2 sample sizes and estimates of monthly and annual survivorship for west walker WW casa diablo CD east walker EW mono lake ML and inyo mountains IM mule deer populations inyo and mono counties cali- fornia and douglas county nevada 1986 1994 winter deer telemetry monthly annual rangel N months N survivorship STs survivorship sv WW 48 823 0964 00040.004 0643 00100.010 CD 27 469 09850.985 0004 08370.837 00140.014 EW 23 428 09900.990 00040.004 08840.884 00140.014 ML 23 512 09790.979 00060.006 07770.777 00180.018 IM 20 597 09730.973 00080.008 07170.717 00220.022 ciueluelusiveinclusiveclusive dates of each investigation were WW apolapoiapril 1992 january 1995 CD january 1986 deceradecemberDecern ber 1987 EW marchmaichmalch 1988 june 1990 ML maichmarchmalchmaleh 1988 june 1990 IM october 1991 decemberDecembeibel 1994 rate among these populations ranged from there was a difference in survivorship func- about 0750.75 in the east walker population to tions between 3 of 10 pairs of populations that about 0300.30 in the west walker population we compared table 3 and the results were which had the highest proportion of mortality but marginally nonsignificant for a ath4th pair caused by malnutrition among these popula- small samples possibly influenced our ability tions monthly survival estimates ranged from to detect differences pollock et al 1989 be- 09640.964 to 09900.990 and annual survival estimates tween other population pairs but the magni- ranged from 06430.643 to 08840.884 table 2 too few tude of differences between 6 pairs when males were marked to allow a meaningful esti- compared to the remaining 4 suggests sample mate of survivorship for males occurring in size was not problematic table 3 these find- these populations ings were somewhat unexpected given the physical climatological vegetational and fau- discussion nal similarities among the winter ranges we examined and may be attributable to the high predation was the most common cause of proportion of mortality from malnutrition in mortality among 5 mule deer populations that the west walker population during the winter winter east of the sierra nevada fig 3 of 1992 93 that winter was especially severe human induced mortality and malnutrition in northeastern california wertz 1996 varied among these populations based on our in none of our study populations are histor- analyses we conclude that sources of mortal- ical demography and habitat quality adequately ity were similar among these winter ranges for known to begin to factor out the relative roles the periods we studied deaths of female deer of nutrition predation and climate as factors resulting from human activities were recorded influencing the dynamics of these populations only in the west walker and casa diablo pop- additionally the effects of these factors on ulationsulations death resulting from malnutrition survival of young I1 yr old were not investi- was restricted to the west walker and mono gated with the exception of the mono lake lake populations and accounted for 25 and and west walker populations the absence of 21 of the mortality in those populations animals dying of malnutrition suggests that respectively malnutrition overall 98gs989.8 was mortality from predation generally was not however not an important cause of death compensatory many female deer collected among deer killed by carnivorescarnivores mountain from the west walker winter range were in lions were the most common predator and no poor physical condition following the winter differences existed in the proportion of female of 1992 93 taylor 1996 and some animals in deer killed by mountain lions among the 5 that population may have been predisposed to populations we investigated fig 4 our find- death by predation during our investigation ings are consistent with previous ones that nevertheless only 3 of 10 animals killed by mule deer are important prey of mountain predators in the west walker population died lions throughout western north america that winter but 7 of 10 were killed during the hornocker 1976 russell 1978 proportionally mild winter of 1993 94 despite the deaths of more telemeteredtelemetered females than males were 2 females from malnutrition in the mono lake killed suggesting that females may be more population individuals there were in much vulnerable to predation by mountain lions better condition than were west walker females 270 GREAT BASIN naturalist volume 58

7 8 4 14 8 6 6 4 10 8 loo100 loo100

80 80

60 60

40 jaUPREDPREDATIONlonION 40 cimountainMOUNTAINCI LION jraanthropogenicoanthropogenic OTHERMOTHER PREDATOR OMALmalnutrit11NUTRITIONN omalnutrition I1 20 20 05011 0 0 0 CD ML EW WW IM CD ML EW WW IM DEER population DEER population

fig 3 proportion of moitahtiesofmortalities N 41 of femaleoffemale deeldeer fig 4 pi oportionopproportionortionortlon of predation on female deer attrib- that can be attributed to predationpiedation anthropogenic causes uted to mountain lions and other predatorspiedators in each of 5 and malnutritionmalnutimalnati itionaition in each ofot 5 deer populations inhabiting deeldeer populations studied in eastern california and west- easteleasternn californiacalifoicalifor nia and westelwesternn nevada 1986 1994 num- ern nevada 1986 1994 numbers above each bar repre- bers above each baibar aieare total mortalitiesmortalities fromhiomblom known sent total mortality attributed to predators for each popu- causes toifortor each population CD casa diablo EW lation CD casa diablo EW east walker ML east waikelwalkerwaiker ML mono lake WW west waikelwailenwalker and mono lake WWWIN west walker and IM inyo moun- IM inyo mountains tains

during 1992 93 taylor 1991 body condition predationmaywarrantpredation may warrant special considera- of mono lake females during theperiodthe period they tion as a factor in the dynamics of mule deer were under study approached that of the west occupying unpredictable environments indeed walker population during 1994 a year when investigations in boreal systems have sug- no animals died of malnutrition none of the gested that predation by wolves canis lupus animals killed by predators exhibited evidence and bears ursus sppapp can preclude recovery of depleted fat reserves upon examination of of large mammal populations that have become femur marrow if malnutrition was an impor- depressed by a single source or a combination tant factor disposingprepredisposing individuals to death of several sources of mortality gasaway et al by other causes we would have expected to 1983 1992 van ballenberghebollenbergheBallenberghe 1987 based on find evidence of such among victims of preda- observations in the sierra nevada wehausen tion or human induced mortality this was not 1996 suggested that predation by mountain the case lions has substantially influenced the popula- the role of predation in regulating popula- tion dynamics of mountain sheep in part of the tions of large mammals remains open to western great basin removal of several moun- debate skogland 1991 and predation as a tain lions was necessary to preclude the extir- factor potentially regulating deer populations pation of one population of these specialized has not been widely accepted connolly 1981 ungulaungulatesungulatedtes bleich et al 1991 and that popula- for example the effects of mountain lion pre- tion of mountain sheep is sympatric with the dation have been described as unimportant casa diablo deer population for part of the janz and hatter 1986 and conversely as hav- year taylor 1991 ing strong local effects mcnay and voller 1995 given the similarities in cause specific on deer occurring in the same geographic mortality and the importance of predationofpredation as a area these large felidsfelias were responsible for cause of death among the populations we stud- most mortality of adult female deer in each of ied the potential for predation to regulate deer the populations we investigated although we populations might be reconsidered and further noted few adults killed by coyotes canis investigated particularly for migratory deer latranslalatranotrans these caniascanids can have important inhabiting the arid unpredictable ecosystems effects on deer population dynamics espe- typical of the western great basin in such sys- cially through their influence on fawn survival tems predation clearly is an important source knowlton 1976 bowyer 1987 of mortality and may assume greater importance 199811998 survivorship AND MORTALITY OF MULE DEER 271

TABLE 3 pairwisepanpau wise comparisonscompansons of survivorship functions for west walker WW casa diablo CD east walker EW mono lake ML and inyo mountains IM mule deer populations inyo and mono counties california and douglas county nevada 1986 1994 chi square statistics are shown above the diagonal probabilities that survivorship functions did not differ are shown below the diagonal for all companionscomparisonscompansonscompansons degrees of freedomoffreedom 1 chi square values population WW EW ML CD IM WW 7611 4235 2458 4977 EW 001 0388 0326 0231 ML 005 050 0248 0130 CD 010 050 050 0012 IM 005 050 050 090 probability that survivorship did not differ

in population limitation than in more mesicmeslemesie university of california davis awarded to VC environments where the effects of climate are bleich and CDFG contract FG 1230 awarded more tempered and more predictable to TJ taylor this research was funded by in highly variable systems density indepen sportsmen and sportswomensportswomansportswomen of california dent events iei e droughts and harsh winterss through their purchases of hunting licenses occur unpredictably mackie et al 1990 and and deer tags the fish and game advisory can result in unanticipated population declines committee of inyo and mono counties and that confound conservation strategies nonethe- the sacramento safari club this is a contri- less density dependence would continue to bution from the CDFG deer herd manage- operate mccullough 1990 in such systems ment plan implementation program and is and could indirectly affect predation rates professional paper 002 from the eastern sierra mccullough 1979 only through carefully center for applied population ecology designed longtermlong term investigations however will it be possible to reach meaningful conclu- literature CITED sions regarding effects of predation and other sources of mortality on populations of migra- BLEICHBLEICPI VC in press mountain sheep and coyotes pat- tory deer occupying great basin ecosystems terns of predator evasion in a mountainmonnmoun tain ungulate journal of Marnmamammalogylogy acknowledgments BLEICH VC RT BOWYER AND JD WEHAUSEN 1997 sexual seglesegiesegregationgationgatlon in mountain sheep sourcesresourcesle 01or we thank TE blankinship WE clark predation wildlife monographs 1341134 1 50 clarkjrclarkjhJH BLEICH VC CDD HARGIS JAJ A KEAY AND JDJ D WEHAUSEN davis DAD A jessup ERE R loft DRD R racine 1991 interagency coordination and the restoration TL russi RJ schaefer RA teagle RD of wildlife populations pages 277 284 in J edel- thomas and numerous others for assistance brock and S carpenter editors natural areas and with capturing and collaring mule deer and yosemite prospects for the future USU S national C LBL chetkiewiczChetcheskiewiczkiewicz BM pierce D racine park service denver service center denver CO BOWYER RT 1987 coyote group relative to preda- and R thomas for help several size recovering tion on mule deer mammalia 5151551 sis515 526 deer carcasses RWR W anthes served as pilot CHEATUM E L 1949 bone marrow as an index of malnu- during most telemetry nightsflights with occasional trition new york state conservationist 3193 19 22 assistance from L goehring and R morgan CLOVER M 1956 single gate deer trap california fish all of the california department of fish and and game 4219942 199 201 CONNOLLY GEG E 1981 limiting factors and population game CDFG services division SRS R air regulation pages 245 285 in OC wallmo editor dejesus the late J D dondone landells and B K mule and black tailed deer of north america uni- novak piloted the helicopter during capture versity of nebraska press lincoln operations we thank BM pierce for assis- cox DRD R AND D OAKES 1984 analysis of survival data tance with graphics and RXR bowyer MWM W chapman and hall inc new york oehler sr J D wehausen and KRR whitten CRONIN MCM AND VC BLEICHBLEICIL 1995 mitochondrial DNA JD among populations and subspecies of mule for helpful comments on the manuscript prep- variation deer in california california fish and game 814581 45 54 aration of this paper was supported by a cali- DEDECKER A 1991 shrubs and floweringflowelclowel ing plants pages fornia resources agency fellowship from the 108 241 in CAA hall jr editor natural history of 272 GREAT BASIN naturalist volume 58

the white inyo range eastern california univer- associated with migration journal of mammalogy sity of california presspi ess berkeley 7848378 483 504 GASAWAY WC RDR D BOERTJEBOERTJL DVD V GRANGAARD DGD G POLLOCK KHK H SRS R winterstein CMC M BUNCK AND PD kelleykelleyhouseKELLLY HOUSE ROR 0 stephenson AND DGD G LARSEN CURTIS 1989 survival analysis in telemetry studies 1992 the loleioleioieroleroie of predation in limiting moose at low the staggered entry design journal of wildlifeofwildlife man- densities in alaska and yukon and implications for agement 53753 7 15 conservation wildlife monographs 1201120 1 59 RUSSELL KRK R 1978 mountain lion pages 207 225 in JLJ L GASAWAY WC RO stephenson JL DAVIS PK SHEP- schmidt and DLD L gilbert editors big game of north HLRDHERD AND OE0 E BURRIS 1983 interrelationships of america ecology and management stackpole books wolves prey and man inm interior alaska wildlife harrisburgHarns burg PA monographs 84184 1 50 SHAW HGH G 1983 mountain lion field guide arizona game HORNOCKERHORNOCKLR MGM G 1976 the possible influences of the and fish department special report 919 1 27 mountain lion on mule deeldeer populations pages SKOGLAND T 1991 what are the effects of predators on 107 109 in GW workmanwolkman and JB low editors large ungulate populations oikosbikos 6140161 401 411 mule deeldeer decline in the west a symposium col- TAYLOR TJ 1988 migration and seasonal habitats of the lege of natural resources utah state university casa diablo deer herd california department of logan fish and game bishop JANZ DW AND IWLW HATHATTERreraer 1986 A rationale for wolf 1991 ecology and productivity of two interstate control in the management of the vancouver island deeldeer herds in the eastern sierra nevada east predatorpi edatoi ungulate system british columbia ministry walker and mono lake deer herd study california of the environment wildlife bulletin B 45145 1 35 department of fish and game bishop KAPLAN ELE L AND P melerMEIERMLIER 1958 parametricnonparametricnonparametncNon sur- 1996 condition and reproductive performance of vivorship estimation fromgiomglom incomplete observations female mule deer in the central sierra nevada cali- journal of the amerleanamerican statistical association fornia fish and game 821228912282 122 132 5345753 457 481 THOMAS RDR D AND BKB K NOVAK 1991 helicopter drive KNOWLIONKNOWLTON FFFE 1976 potential influence of coyotes on netting techniques for mule deer capture on great mule deeldeer populations pages 111 118 in GWG W work- basin ranges california fish and game 7719477 194 200 man and JBJ B low editors mule deeldeer decline in the VAN ballenberghebollenbergheBALLEN BERGHE V 1987 effects of predation on moose west a symposium college of natural resources numbers a review of recent north american studies utah state university logan swedish wildlife research supplement 14311 431 460 KRAUSMAN PR JJ HERVERT AND LL ORDWAY 1985 WALLMO 0OCC 1981 mule deer and black tailed deer dis- capturing deer and mountain sheep with a net gun tributiontribution and habitats pages 1 25 in 0OCC wallmo wildlife society bulletin 137113 71 73 editor mule and black tailed deer of north america kuceraKUCLRA TE 1988 ecology and population dynamics of university of nebraska press lincoln mulemidemude deer in the eastern sienaslenasierra nevada california WEHAUSEN JDJ D 1996 effects of mountain lion predation unpublished doctoraldoctoiallallai dissertation university of on bighorn sheep in the sierra nevada and granite california berkeley mountains of california wildlife society bulletin mackleMACKIEMACKIL RJR J KLK L HAMLIN DED F PAC GLG L DUSEK AND 2447124 471 479 AKA K WOOD 1990 compensation in free ranging WERTZ P 1996 deer hunt forecast a mixed bag for 96 deer populations transactions of the north ameri- tracks california department of fish and game can wildlife and natural resources conference 133 5 5551855 518 526 WHITE GCG C AND RAR A GARROTT 1990 analysis of wildlife mccullough DRD R 1979 the george reserve deer radio tracking data academic press inc san diego herd university of michigan press ann arbor CA 1990 detecting density dependence filtering the WOOLSEY NGN G 1985 coyote field guide arizona game baby from the bathbathwaterbathwateiwater transactions of the north and fish department special report 151lsiisi15 1 39 american wildlife and natuialnatural resources confer- WORKMAN GWG W AND JBJ B low EDITORS 1976 mule deer ence 5553455 534 543 decline in the west a symposium college of nat- mcnay RSR S AND JMJ M VOLLER 1995 mortality causes ural resources utah state university logan and survivalsuisul vivalvivai estimates for adult female columbian ZAR JHJ H 1984 statisticalbiostatisticalBio analysis prentice hall engle- black tailed deer journaljoul nalnai of wildlife management wood cliffs NJ 5913859 138 146 NICHOLSON MCM C RTR T BOWYER AND JGJ G KIE 1997 habi- received 20 march 1997 tat selection and survival of mule deer tradeoffs accepted 23 january 1998 great basin naturalist 583 0 1998 appp 273 281

persistence OF SUBALPINE FOREST MEADOW ECOTONES IN THE GUNNISON BASIN COLORADO

andrew J Schauerschauerl2schauer1212 brian K wadeiwadel and john B Sowesowell13Sowellsowe1113111313

ABSTRACT forests of the southern rocky mountains are punctuated by persistent meadows called parks that are dominated by grasses and forbs in an attempt to elucidate the maintenance of subalpine parks in the gunnison basin col- orado soil texture and tree morphology differences along 60gom m transects spanning the forest park ecotone were studied in 6 representative parks seedling survivorship percent seed germination and soil moisture available to plants were also studied along one of the transects inm willow park soil analyses revealed 40 more silt and significantly less sand and clay in all 6 parks P 00010 ooi001 which supports the traditional hypothesis that edaphic factors are involved in restricting estab- lishmentlishment of trees in parks in willow park moisture available to plants in soils at field capacity varied significantly across the ecotone P 00110.0110 alioil011 with 54 more water in forest than in park soils measures of growth rate obtained from tree height dahabbdbhdbb and age were significantly higher nearer the ecotone P 000100.001ooi001 the coefficient of variation of annual ring width was significantly higher in forestfoiest than in ecotone trees P 0002 these results suggest that stress of mature engelmann spruce picea engelmanniiengelengelmanniamannii and lodgepole pine pinus concontorcontortdcontortacontortedtortatd is an unlikely explanation of park maintenance P engelman miniinil percent seed germination and seedling survivorship were significantly higher in the forest than in the park P 00010.0010 ooi001 this may be largely due to the more severe seedling microclimate observed in the park results indicate that limited seedling establishment is primarily responsible for maintenance of subalpine parks in the gunnison basin

key words park subalpine meadow forest meadow ecotonesecotones picea engelmanniiengelengelmanniamannii soil texture seedling establishment seed germination soil moisture gunnison basin colorado

montane and subalpine forests of the south- doering and reider 1992 woodward et al ern rocky mountains are punctuated with 1995 herbivoreHerbherbivoryivory klikoff 1965 noble and meadows dominated by grasses and forbs and shepperd 1973 vale 1981 cantor and whit- varying amounts of sage artemisia sppapp willow ham 1989 and seedling competition with her- salix sppapp and sedge carex sppapp locally baceous vegetation robbinsbobbins 1918 peet 1988 these treeless areas are called parks and range coates et al 1991 comeau et al 1993 burton from I1 ha to thousands of hectares in size in and bazzalbazzaz 1995 may be more prevalent in colorado parks form ecotonesecotones with ponderosa meadows than in neighboring forests adverse pine pinus ponderosa forests in the montane climatic conditions such as more extreme tem- zone and mainly lodgepole pine pinus con peraperatureture fluctuations may also limit seedling torta colorado blue spruce picea pungentpunpungensgens establishment in parks pearson 1913 kuramoto and engelmann spruce picea engelmanniiengelmanniaengelmannii and bliss 1970 franklin et al 1971 taylor forests in the subalpine zone 1990 1995 lynch 1995 woodward et al explanations for the presence of parks are 1995 however if these were the only factors numerous but many are not supported by involved tree invasion into parks would be empirical evidence severe disturbances such expected as a result of enhanced seedling sur- as fires and logging may allow the initial for- vival in the more mesic environment near the mation of parks daubenmire 1943 kuramoto ecotone daubenmire 1943 and bliss 1970 koterba and habeck 1971 vale A commonly cited factor for the maintenance 1981 lynch 1995 once established they of forest meadow ecotonesecotones is soil texture may be maintained by a number of biotic and robbinsbobbins and dodds 1908 pearson 1913 abiotic factors that may prevent the survival of dunnewald 1930 ives 1942 daubenmire mature trees but more frequently cited is the 1943 peet 1981 veblen and lorenz 1986 prevention of seedling establishment klikoff doering and reider 1992 unlike other pro- 1965 moir 1967 dunwiddie 1977 taylor 1990 posed explanations which include factors that

lbiologyibiologyabiology department westeinwestern state college cunnisongunnison CO 81231 prerentpresent address departmentdepar tmentament of biological sciences universityuniver sitygity of denver denver CO 80208 3correspondingoi responding author

273 274 GREAT BASIN naturalist volume 58 are moderated at the ecotone soil texture is gunnison basin fig 1 table 1 two transects not readily modified by the forest thus soil spanning the forest park ecotone were estab- texture differences between forest and park lished in each park transects were located in may be capable of preventing tree encroach- more pristine areas away from obvious distur- ment daubenmire 1943 concluded that coniconlconi- bance and human activities these 60gom m tran- fers of the rocky mountain region are adversely sects were oriented perpendicular to the eco- affected by some factor associated with finehinebine tone boundary and extended 30 m into the for- textured compact or poorly drained soils fine est and 30 m into the park sampling occurred textured soil may impede root elongation pre- at the ecotone 0 m and at 15 ra and 30 m into venting the seedling root from reaching sub- both the forest and park we randomly chose 3 surface moisture in a timely fashion dauben- soil sampling sites along a 30 m line oriented mire 1943 patten 1963 fine textured soil may parallel to the ecotone at each of these dis- also retain soil moisture at higher tensions thus tances similarly we chose 3 trees at 0 m 15 m decreasing soil moisture available to plants and 30 m into the forest to obtain tree growth patten 1963 however excessive drainage due measurements for stress analysis one transect to coarse textured soil has been suggested by in willow park was utilized to acquire data on pearson 1913 as a limiting factor in arizona seed germination survivorship of 3 yr old P parks engelmanniiengelmanniaengelmannii seedlings seedling microclimate parks are frequent at 2700 3500 m elevation regimes and moisture available to plants in within the gunnison basin colorado park eco soils at field capacity tones with P confortaconcontortatorta forests and FP engelengelmanniiengelmanniaengelmanrwimannii forests are most common but quaking aspen tree morphology populus tremultremuloidesoides also appear regularly reduced tree growth or stunting was used throughout the basin the purpose of our to measure relative tree stress tree growth study was to elucidate the persistence of parks parameters of 3 randomly selected trees were in the gunnison basin by examining suggested measured along the transects in all 6 parks at explanations of park maintenance the ist ob- the ecotone 0 m and at 15 m and 30 ra into jective was to ascertain whether established the forest the diameter at breast height dahdbh trees at coniferous forest park ecoecotonestones are and height of each tree were measured and stressed compared with trees in the forest each tree was cored at breast height using a interior such stress would suggest that limit- swedish increment borer oriented perpendic- ing factors are operating on mature trees and ular to the slope cores were treated and ana- such factors may limit tree advance into parks lyzed according to fritts 1976 yielding tree stress would not be expected if parks are pri- age and average annual ring width stunting marily the result of inhibited seedling estab- was discerned by lower heightageheightage dbhagedbhage lishmentlishment the and2nd objective was to document and heightdbhheight dahdbh ratios or narrower age adjusted P engelengelmanengelmanniiengelmanmiengelmanniamanniimi seed germination rates and seed- average annual ring widths increased tree ling survivorship across the forest park eco- stress may also be indicated by a higher coeffi- tone inhibited germination and reduced sur- cient of variation resulting from greater sensi- vivorship would be expected if limited tree tivity to climatic variation the coefficient of establishment is maintaining parks the ard3rd variation standard deviation divided by the objective was to document soil texture and mean of tree ring width was calculated using water holding characteristics across coniferous the age adjusted average annual ring widths forest park ecoecotonestones the presence of soil tex for the last 10 yr 1983 1992 for each growth ture gradients across park boundaries would parameter dependent variable we used a support the contention that edaphic factors nested ANOVA transects nested within parks have a role in maintaining paipalparksks in the gunni- to test the null hypothesis that location along son basin the transect proximity to the ecotone has no effect on tree growth MATERIALS AND METHODS seedling establishment study sites to document the influence of the park en- we selected 6 parks to represent the diver- vironmentvironment on seed germination and establish- sity of coniferous forest park ecoecotonestones in the ment we located three 40 m rows oriented 199811998 SUBALPINE FOREST MEADOW ECOTONES 275

TABLE 1 descriptive summary of the 6 representative parks in the gunnison basin coloradocolcoi 01 ado latitude and elevation size soil parent dominant forest park longitude m ha material species big willow asnaan3814n 10720w 3450 160 basaltsbabasalessalts tuffs volcanic picea engelengelmanengelmanniiengelmanmiengelmanniamanniimi conglomerates blue asan io652w10652w 3328 370 ash flow tuffs picea engelengelmanengelmanmiengelmanniiengelmanniamanniimi porphyry SSQN 10621w 3280 15 granitesgragoranitesnites picea engelengelmanengelmanmiengelmanniiengelmanniamanniimi and pinus confortacontortacontorta taylor 3850n 10635w 2938 4110 glacial and outwash pinus confortacontorta deposits union 3847n 10633w 2987 800 granitesgragoranitesnites pinus confortacontortacontorta willow 3804n38004n logwloew10655w 3475 60 andesitesandesites welded tuffs picea engelengelmanengelmanniiengelmanmiengelmanniamanniimi

sanarsanae seeds received 160 ml of water upon sowing COLOMDO 0 and an equal amount twice a week for 3 wk CRESTED germination and survivorship were noted BUTTE 0 taylor park weekly until 9 october 1994 and again from U ionlon 24 july to 23 september 1995 A chi square parkperk P- analysis was used to test the null hypothesis T that there were no differences in seed germi- S M nation rates across the ecotone boundary GUNNISON BW M R- orp aryyry ar seedling survivorship was monitored using mionmaon 3 yr old nursery grown P engelmanniaengelmanniiengelmannii seedlings paw lawyer nursery inc on 9 june 1994 we planted seedlings every 0250.25 m along the same 40 m rows unless obstructions such as rocks were present seedlings received 160 ml of

big819 willow water approximately equal to 20 mm of pre- parkperk blue park cipitation twice a week for 3 wk to facilitate willow park establishment seedling survivorship was noted takeLAKE CITY rpdspdspring creekC k 0 weekly until 9 october 1994 and on 16 july fmpassck 4 V and 23 september 1995 A chi square analysis SAN JUAN MTS was used to test the null hypothesis that there are no differences in seedling survival across fig 1 location of the 6 representative parks within the the ecotone boundary gunnison basin colorado differences in seedling microclimatesmicro climates and potential causes of seedling mortality were assessed by logging weekly maximum and min- parallel to the ecotone in willow park at 30 m imum temperatures 20 cm below the surface into the forest at the ecotone 0 m and at 30 at the soil surface and 2 cm above the surface m into the park at imI1 m intervals along the at the ecotone 0 m and 30 m into both the rows we established 050.5os X 10 m seedbed grids forest and park in willow park from 9 june divided into 50 equal 100 cm2 sections to through 9 october 1994 precipitation was also facilitate the sowing and subsequent locating measured weekly at 30 m into the park during and monitoring of seeds on 9 june 1994 25 P this period engelmanniiengelengelmanniamannii seeds were sown into the first 25 by germinating 72 P engelmanniiengelengelmanniamannii seeds and available sections if rocks or surface roots growing them in a greenhouse utilizing soils prevented a seed from being sown in a partic- collected in willow park we ascertained the ular section we utilized an alternate section influence of forest ecotone and park soils on 276 GREAT BASIN naturalist volume 58 root elongation and thus the potential for tionseions across the ecotone P 00050.005 P 00010.001 seedlings to reach subsurface moisture soils and P 00050.005 respectively therefore taylor were collected to 30 cm depth at the ecotone and union park data were excluded from fur- 0 m and 30 m into both the forest and park ther analyses and the consistent trends ob- the 252.595gs X 20 cm tubes with seeds sown at 5 served in the P engelmanniiengelmanniaengelmannii dominated eco mm depth were watered daily we harvested tones are reported below shoots and roots of 15 wk old seedlings and P engelmanniiengelengelmanniamannii at the ecotone had a signifi- after measuring their lengths dried them at cantly higher heightageheightage ratio P 00010.001 and 70c70 C root lengths and dry weight rootshootroot shoot dbhage ratio P 00010.001 indicating more ratios were analyzed using a one way ANOVA growth per year fig 2 the heightdbh ratios showed that trees at the ecotone had grown soil analyses more in girth than in height relative to trees in soil samples were obtained from a 2iemgemcm the forest interior P 00010.001 fig 2 trees at diameter core of soil extending from the sur- the ecotone had a significantly lower coefficient face to 30 cm depth along both transects in all of variation of tree ring width P 00020.002 in- 6 parks the core excluded the 0 horizon dicatingdicating less year to year variation in growth soil texture analysis was conducted for each increment fig 2 core using the hydrometer method day 1965 seedling establishment hydrometer readings were recorded at 050.5os 1 2 4 8 15 30 60 120 240 480 min to con- at all 3 locations forest ecotone and park struct soil particle size distribution curves and in willow park no germination of sown seeds differences in percent sand silt and clay among was noted in the 1994 growing season germi- locations along the transect were analyzed nation did occur in the 1995 growing season using a nested ANOVA transects nested within and was significantly higher in the forest parks 46 than in the ecotone 28 and park 5 moisture available to plants in soil at field P 00010.001 of the seeds that did germinate capacity was measured for 3 randomly selected total seedling survivorship at the end of the soil samples collected at the ecotone 0 m and season 23 september 1995 was 18 32 30 m into both the park and forest in willow and 42 along the forest ecotone and park park using a 15isls1.5 mpa ceramic plate extractor transects respectively fig 3 these seeds soilmoistureSoilmoisture equipment corporation we tested in vitro in 1994 had a 93 germination measured soil water content at 00100.010 00330.033 rate 050.5os and 151.5isls mpa soil moisture available to survivorship of planted 3 yr old P engel plants was calculated utilizing the difference mannii seedlings was significantly higher in between water content at field capacity and at the forest 50 and at the ecotone 52 than the permanent wilting point these values are in the park 8 after 15 mon P 00010.001 fig most closely correlated to water contents at 4 while the primary cause of mortality 00330.033 and 15isls1.5 mpa respectively peters 1965 appeared to be desiccation during the 1994 banister 1986 differences in soil moisture growing season 73 of seedlings in the forest available to plants among locations were ana- 55 at the ecotone and 0 in the park experi- lyzed using a one way ANOVA enced herbivoreherbherbivoryivory removal of leader shoots during the winter accounted for most of the RESULTS observed herbivoreherbivoryherbivory seedling microclimate during the 1994 morphology tree growing season was more severe in the park two of the 6 parks studied taylor park and than the forest maximum and minimum soil union park were surrounded by seraiseral P con temperatures at 20 cm depth were similar torta forest tree morphology along the P con across the ecotone however at the soil sur- torta transects often exhibited exceptions to face and at 2 cm above the surface seedlings the consistent trends observed in the P engel in the park were consistently exposed to colder mannii forests surrounding the other 4 parks nights and warmer days compared to seed- heightageHeigh tage dbhagedbhage and heightdbh ratios lings within the forest fig 5 precipitation when all 6 parks were included indicated sig- exhibited a pattern typical of the gunnison nificantnificant interactions between parks and loca basin with a relatively dry june followed by 199811998 SUBALPINE FOREST MEADOW ECOTONES 277

03 30 m in forest 150 15 rn in forest ecotone M 125 02 forest too100 M 24 july cohort t 11 aug 01 hl cohort 75 0 d 0 26 aug cohort A 50 00 061ogi06 1 25 M C 05 t 04 VU 0 E 24 july 1 1 lg 26 ug 23 sept 03 0 loo100 0 c 0 1 ecotone 02 DW 75 Q i 0 01 D 0 0 00 4 10 0 t 25 I1 M1 E 08 0 06 E 3 4 july 11 aug 26 kug 23 s6ptsapt 50 2 04- z 5 park 1 020 25

00 000 0 04 1 24 july 11 aug 26 aug 23 sept

RD 03 fig 3 number of seeds germinated and survivorship of ththoseose seedlings in willow park 3 cohorts for Q 0 in the account 0 z6za those seeds germinated to U that prior 24 july 1995 between 02 24 july and 11 august 1995 and between 11 august and D E IS 26 august 1995 g 01 C

00 taylor union big porphyry willow blue park park wilowwillow park park park park 10-lood 00 forestfonest ecotone 2 Heigh VL fig heightagetage ratio dbhage ratio heightdbh ratio park and coefficient of variation of tree ring width of trees near 80- 0 the forest park ecotone in pinus confortacontortacontorta dominated CL and picea engelmanniiengelengelmanniamannii dominateddommated tretreelineselines bars indicate ie standard errors n 6 0L goo 0 60- increased precipitation brought by afternoon cn 40 thunderstorms in july and august 11 P engelmanniiengelengelmanniamannii seedlings grown in forest 20- ecotone and park soils showed no observable differences in growth the mean root length of 0 june july aug sept oct july aug seedlings grown in forest 14114114.1 cm ecotone sept 1994 1995 13713713.7 cm and park 14614614.6 cm soils did not differ significantly P 05340.534 dry weight rootshootroot shoot fig 4 percent survival rate ofaof3 yr old seedlings planted ratios of seedlings grown in forest ecotone and 9 june 1994 along a transect spanning the forest park eco- tone in willow park numbers of seedlings planted in the park soils were 0.67067 0.69ogg and 0.70 067 069 070 respective- forest ecotone and park were 122 145 and 160 respec- ly and did not differ significantly P 07640.764 tively 278 GREAT BASIN naturalist volume 58

60 I1 2 cm above clay siltslit sand soilsoll surface loo100 40

00 8- 20- 4 U CL0 60 0 E 0 0 C 40 20 1

60 U soil surface 20

0 40 S 0- 3 30m30 m 1515mm ecotone 1515mM 30m30 m 111 q 20 forest park U CL 0 fig 6 soil texture along transects spanning the forest E 0 1 park ecotone percentages are the means of 6 parks with 2 I1 transects per park and 3 replications per location n 36

20 discussion 60 forest max 20 cm below c forest minmm soil surface tree morphology data indicated that stress v ecotone max 40 v ecotone minmm of mature trees is an unlikely contributing fac- w park max tor to maintenance of forest park ecotonesecotones in 0 park minmm the gunnison basin trees at the ecotone 20 appear no more stressed possibly even more robust than trees farther into the forest the lower coefficient of variation of tree ring width found in ecotone trees indicates less year to year variation in growth increment suggesting 20 a more uniform and less stressful environment june july august september october fritts 1976 these results indicate that fac- tors limiting seedling establishment con- fig 5 weekly maximum and minimum temperatures at 3 different locations within the seedling s microclimate tribute to the maintenance of parks in the along a tiantransectseetsect spanning the foiestforestbolest park ecotone in wil- gunnison basin which corroborates the con- low paikpark Tempertemperatureatme extremes were recorded weekly clusion of dunwiddie 1977 pertaining to hornfrombormbomm 9 june through 9 october 1994 meadows in wyoming seed germination and seedling survivor- ship of P engelmanniiengelengelmannia soil analyses mannii were restricted in wil- low park which further supports the con- while soils inm all 6 parks were sandy loamscoams tention that parks are maintained by limited soil texture differed significantly P 00010.001 establishment the higher mortality of seedlings across the forest park ecotone forests had a in the park may be due in part to the more mean of 8 more sand 53 less silt and 72 extreme microclimate temperature extremes more clay compared with parks fig 6 mois- play an important role in the survival of P ture available to seedlings in soils at field engelmanniiengelengelmanniamannii seedlings patten 1963 kuramoto capacity also differed significantly FP 00110.011 and bliss 1970 franklin et al 1971 root and across the forest park ecotone there was 54 habeck 1972 noble 1973 moir and huckaby more water available to plants in forest soils at 1994 balisky and burton 1995 taylor 1995 field capacity than in park soils at field capac- woodward et al 1995 and the large diurnal ity fig 7 fluctuations in surface and air temperatures 199819981 SUBALPINE FOREST MEADOW ECOTONES 279

030.3 park locations indicated that the potential for such herbherbivoreherbivoiyherbivoryivory was uniformly high 90 100 across the ecotone removal of P engelengelmanengelmanniiengelmanmtengelmanniamanniimt cotyledons terminal buds by 0 or herbivoresherbivores 0 may limit regeneration noble and shepperd D 020.2 1973 noble and alexander 1977 although the of shoot herbivoryherb in park 0N impact herbivoreivory in willow appears limited considering the observed dam- age of P engelengelmanengelmanmtengelmanniiengelmanniamanniimt seedlings was greatest in the forest where survivorship was highest 01 cantor and whitham 1989 suggest that aspen 0 is excluded from meadows due to below ground herbivoreherbherbivoryivory by pocket gophers below ground herbivoreherbivoryherbivory by rodents as indicated by soil mounds accounted foifolforholbol a small portion of 00 the P engelengelmanengelmanniiengelmanmtengelmanniamanniimt seedling mortality in wil- 30m30 rn 1515mrn ecotone 1515mrn 30 rn low park forest park variation in soil texture across the forest fig 7 moisture available to plants in soil at field capac- park ecoecotonestones supports commonly cited sug- ity for samples collected along the transect spanning the gestionsgestions that edaphic factors help maintain dry forest paikpalkpark ecotone in willow park available moisture is rocky mountain parks daubenmire 1943 the difference between water content at field capacity and watel peet 1988 1994 soils water content at the wilting point bars indicate standard knight fine textured in enoisenolserrors n 15 parks are more favorable for growth of sod forming herbaceous vegetation which may competitively exclude the establishment of tree common to meadows may inhibit tree invasion seedlings stahelinStahehn 1943 however if such hellmers et al 1970 jakubos and romme competition were the primary factor maintain- 1993 during the 1994 growing season tem- ing parks the tretreelinefreelineeline would be expected to peraperaturestures 2 cm above the soil surface in wil- advance into the park where shading from low park fluctuated greatly with a mean weekly ecotone trees inhibits herbaceous vegetation maximum of 43c and a mean weekly mini- daubenmire 1943 park soils may increase mum of 8cac such temperature fluctuation tree seedling mortality by enhancing water alone may prove fatal to P engelmanniiengelengelmanniamannii seed- stress finepine textured soils may slow water infil- lings hellmers et al 1970 noted 0 survival tration and thus increase drought severity of P engelmanniiengelengelmanniamannii seedlings grown in high day knight 1994 daubenmire 1943 suggested 35c350c and low night ac3c30c temperatures in that inhibited root elongation in park soils addition terminal bud formation was inhibited increases susceptibility of tree seedlings to in high day temperatures of 35c hellmers et drought this premise is not supported by our al 1970 which may increase mortality during study where root growth was unaffected by the subsequent winter precipitation and tem- soil texture in willow park park soils at field peraperaturestures for the 1994 and 1995 growing sea- capacity do have less moisture available to sons were near normal at lake city colorado plants thus enhancing the potential for water 36 aerial km west of willow park indicating stress particularly in early summer when pre- that weather data we recorded in 1994 were cipitation is minimal not unusual united states department of factors limiting seedling survival can be commerce 1994 1995 further elucidated by observing the few loca- herbivoreHerbherbivoryivory in parks could potentially limit tions where trees do establish in parks estab- establishment in subalpine meadows however lished trees in willow park are often well away herbivoreherbherbivoryivory alone does not appear to maintain from the ecotone and inevitably associated with the ecotone in willow park although seed willows salix sppapp which may be providing a herbivoreherbherbivoryivory by members of the seed bug family mesicmesiemesle microclimate that facilitates tree estab- lygaeidae was observed in 1994 preliminary lishmentlishment rochefort and peterson 1996 found observations of predation rates of seeds placed tree invasion in subalpine meadows in the in wire mesh containers at forest ecotone and olympic mountains to be associated with 280 GREAT BASIN naturalist volume 58 heath shrub communities that may moderate properties including statistics of measurement and soil temperature and moisture on the other sampling american society of agronomy inc hand the presence of willows may be indica- madison WI DOERINGDOCKING WR AND RGR G REIDER 1992 soils of cinnabar tive of moist soils that could promote seedling park medicine bow mountains wyoming USA survival despite unfavorable soil texture indicators of park origin and persistence arctic and supporting the role of edaphic factors over alpine research 242724 27 39 DUNNEWALD 1930 grass and timber soils distribution climatic factors is the often prolific establish- TJ in the big horn mountains journal of the americanamerlean ment of P engelmanengelmanniiengelmanmiengelengelmanniamanniimi and P confortacontortacontorta observed society of agronomy 2257722 577 586 inm clear cuts near the parks notable is blue DUNWIDDIE PW 1977 recent tree invasion of subalpine faikfarkpaikpark where lecentrecent clear cuts reached the meadows in the wind river mountains wyoming forest park ecotone heiehelehere the ecotone appears arctic and alpine research 93939 393 399 FRANKLIN J F WH MOIBMOIR GWG W DOUGLAS AND C WIBERG to JE be maintained as P confortaconcontortatorta is regenerating 1971 invasion of subalpine meadows by trees min the only in previously forested areas this indi- cascade range washington and oregon arctic and cates that while the climate is suitable for alpine research 32153 215 224 FRITTSFRI ITS HCH C 1976 tree and climate academic press seedling establishment it is the soil or the rings newyoiknew yoriyork 567 appp associated parks vegetation in that maintains HELLMERS H MKM K GENTHE AND F RONCO 1970 tem- forest park ecoecotonestones in the gunnison basin peratureperature affects growth and development of engel- mann spruce forest science 1644716 447 452 IVES RLR L 1942 atypical subalpine environments ecol- acknowledgments ogy 238923 89 96 JAKUBOS B AND WH ROMME 1993 invasion of sub- we thank william H romme and richard alpine meadows by lodgepole pine in yellowstone G reider for thentheir review of the manuscript national park wyoming USA arctic and alpine and helpful comments this research was research 2538225 382 390 KLIKOFF LG 1965 Micromicroenvnonmentalmicroenvironmental influence on funded in part by a biology environmental in thornton research vegetational pattern near timberline in the central crantgigrantant sierra nevada ecological monographs 3518735 ist187 211 KNIGHT DHD H 1994 mountains and plains the ecology of wyoming landscapes yale university press new CITED literature haven CT 338 appp KOTERBA WDANDJRWD AND JR HABECK 1971 grasslands oftheodtheof the BALISKYACBALISKY AC anioanloAND PJ BURTONBUR lonION 1995 root zone soil tem- north fork valley glacier national park montana peratureperature variation associated with micmicrolitemicrositerosite charac canadian journal of botany 49162749 1627 1636 teristics in high elevation forestfoiestbolest openings in the KURAMOTO RT AND LC BLISS 1970 ecology of sub- interior ofbntishof british columbia agriculturalAgncultural and forestfoiest alpine meadows in the olympic mountains wash- meteorology 773177 31 54 ington ecological monographs 4031740 317 347 BANNISILRBANNISTER P 1986 watelwater lelationsrelations and stiessstress pages LYNCH EAE A 1995 origin of a park forest vegetation mosaic 73 143 in PD moolemoore and SBS B chapman editors in the wind river range wyoming unpublished methods in plant ecology and2nd edition blackwell doctoral dissertation university of minnesota minne- scientific publications oxford apolis 86 appp BURTONBUR lonION PJ AND FAEA BAZZAZ 1995 physiologicalecophysiologicalEco MOIR WH 1967 the subalpine tall grass festuca thurbenthurberibenibenl responses of tiectree seedlings invading different patches community of sierra blanca new mexico south- of oldfieldoldoid field vegetation journal of ecology 839983 99 112 western naturalist 1232112 321 328 momMOIR S HUCKABY CANTORCAN OR LF AND TG WIIITHAMWHITHAM 1989 importance of WH AND LSL 1994 displacement ecol- belowgioundbelowgroundbelowground herbivoreheibivoiyherbivoryherbivory pocket gophers may limit ogy of trees near upper timberline international aspen to loeklockrockroek outcrop refugia ecology 7096270 962 970 conference on bear research and management 9 354235 42 COAILSKDCONIEs KD WH EMMINGHAM AND SRS R radosevich NOBLE D L 1973 age of 1991 conifer seedling success and microclimate at DL engelmann spruce seedlings affects ability to withstand low temperature a green- different levels of heibhelbherb and shrub cover in a rhodo house study USDA forest service research note dendron vaccinium menziesia community of south RM 232 rocky mountain forest and range experi- central british columbia canadian journal of forest ment station fort collins CO 4 appp researchResealchseaich 21858 866 NOBLE DLD L AND RRR R ALEXANDER 1977 environmental COMEAUCOMLAU PCPG TFTE BRAUMANDL AND C Y XIE 1993 effects CY factors affecting natural regeneration of engelmann of overtoppingover topping vegetation on light availability and ovel spruce in the central rocky mountains forest sci- growth of glowth engelmann spruce picea engelmanniiengelmanniaengelmannii ence 2342023 420 429 seedlings nalnai of canadian journaljoul forest research 23 NOBLE DL AND WD SHEPPERD 1973 grey headed 2044 2048 gray headed juncos important to first season mor- daubenmireDAUBEN mireMIRL RER F 1943 vegetational zonation in the rocky tality of Engelengelmannmaimmarm spruce journal of forestry 71 mountains botanical review 93259 325 393 763 765 DAY PR 1965 particlePaitpalticleicie fractionation and particle size PATTEN DT 1963 vegetational pattern in relation to analysis pages 545 567 in CAC A black editor methods environments in the madison range montana eco- of soil analysis part 1 physical and mineralogical logical monographs 3337533 375 405 199811998 SUBALPINE FOREST MEADOW ECOTONES 281

PEARSON GA 1913 A meteorological study of parks and STAHELINFAHELIN R 1943 factors influencing the natural restock timbered areas in the western yellow pine forests of ing of high altitude burns by coniferous trees in the arizona and new mexico monthly weather review central rocky mountains ecology 241924 19 30 41161541 1615 1629 TAYLORYLOR AHA H 1990 tree invasion in meadows of lassen PEETFEET RKR K 1981 forest vegetation of the colorado front volcanic national paikpalkpark california professional geog- range vegetatiovegetation 45345 3 75 rapher 4245742 457 470 1988 forests of the rocky mountains pages 1995 forest expansion and climate change in the 64 101 in MGM G barbour and WD billings editors mountain hemlock tsuga mertensianamerten siana zone lassen north american terrestrial vegetation cambridge volcanic national park california USA arctic and university press cambridge alpine research 272079720727 207 216 PETERS DBD B 1965 water availability pages 279 285 in UNITEDNITED STATES department OF COMMERCE 1994 cli- CAC A black editor methods of soil analysis part 1 matmatologicalological data annual summary Coloiacoloradodo 9913 physical and mineralogical properties including sta- 1995 climatological data annual summary col- tistics of measurement and sampling american orado 10013 society of ofagronomyagronomy inc madison WI VALEALE TR 1981 tree invasion of montane meadows in ROBBINS WW 1918 successions of vegetation in boulder oregon american midland naturalist los10561105 61 69 paikparkpalk colorado botanical gazette 6549365 493 525 VEBLENEBLEN TT AND DCD C LORENZLOKENZ 1986 anthropogenic dis- ROBBINS WW AND GS DODDS 1908 distribution of turturbancebance and recovery patterns in montane forests conifers on the mesas university of colorado stud- colorado front range physical Geogiageographyphy 717 1 24 iesles 6316 31 36 WOODWARD A EGE G SCHREINER AND DGD G SILSBEE ROCHEFORT RMR M AND DLD L PETERSON 1996 temporal 1995 climate geography and tree establishment in and spatial distribution of trees in subalpine meadows subalpine meadows of the olympic mountains wash- of mount rainier national park washington USA ington USA arctic and alpine research 272179721727 217 225 arctic and alpine research 285228 52 59 ROOT RAR A AND JRJ R HABECK 1972 A study of high eleva- received 20 january 1997 tional grassland communities in westeinwestern montana accepted 29 september 1997 american midland naturalist 8710987 109log 121 gleatgreat basin naturalist 583 0 1998 appp 282 284

comparison OF THE EPIPROCT STRUCTURE OF TWO CLOSELY RELATED SPECIES SWELTSA FIDELIS BANKS AND S revelstokaREVELSTOKA JEWETT plecoptera chloroperlidaeCHLORO PERLIDAE

jennifer K delkldelkadelk1 mary jane klikiiKilKilgoregorel1 and bill P Starklstarkl2stark12starkly2

S ABSABSTRACTRAur1 the male epiprocts of 2 closely related western nearctic species sweltsa fidelis banks and revel stoka jewett weiewelewere examined using SEM the males of these 2 species have been historicallyhistoncallycaily distinguished by epiepiproctproct measurements the ratio of the length fromblombrom the base to greatest width versus total epiepiproctproct length ranges from 04900.4949 pragragnaum to 0670.670 67 tmum FF 0560.560 56 in S fidelis and 0550.550 55 tmum to 0690.69ogg0 69 tmum Tx 0600.60ogo0 60 in S revelrevelstokastoka similarities in measurement sug- gest that the location of the greatest epiepiproctproct width is not a reliable and consistent character for distinguishing males of these 2 species

key words stonstoneflyefly sweltsaSweltsa epiepiproctproct morphology SEM western north america

sweltsa fidelis banks and S revelrevelstokastoka epiproctEpiproct samples were taken by severing the jewett are similar western nearctic species last 4 5 abdominal segments from male speci- with broadly overlapping geographical ranges mens that had been stored in alcohol samples in the northern rocky mountains and cas- were placed in acetone and cleaned with an cades jewett 1955 noted that only a slight ultrasonic cleaner for I1 min samples were air difference in lateral aspect of epiproctepiproct shape dried placed on double stick copper tape on distinguishes males of the 2 species although SEM stubs coated with gold palladium and females are easily separated by subgenital scanned using an AMRAY model 1810 SEM plate shape surdick 1995 jewett 1955 and the length to the widest point and total length gaufin et al 1972 suggested the S fidelis of the epiproctepiproct were measured using the click epiproctepiproct was about 171.7 times as broad near and drag function of the AMRAY computer the tip as near the base whereas the control software results are presented in epiproctepiproct of S revelrevelstokastoka was less broad near table 2 the tip baumann et al 1977 found the dor- sal aspect of the epiproctepiproct tip of S fidelis to be RESULTS AND discussion almost twice as broad as base in dorsal view and in S revelrevelstokastoka the tip was considered figures 1 4 indicate the close similarity in about the same width as the base surdick epiproctepiproct structure for S fidelis and S revel 1995 abandoned these characters in favor of stoka in dorsum the S fidelis epiproctepiproct fig the location of the greatest epiproctepiproct width as a 1 appears wider than that of S revelrevelstokastoka means of separating males of these species fig 3 but this difference is not supported by the greatest width occurring at 35 length in S measurements the range of widths present in fidelis and at 34 length in S revelrevelstokastoka this S fidelis specimens is 115 177um177gm af5fx 1476147.6 method also proved to be unreliable for distin- umgm which is comparable to the spectrum of guiguishingshing the males of these 2 species widths in S revelrevelstokastoka 81181.1 180 rmm xT 1099109.9 lmurnurmumm MATERIALS AND METHODS the ratio of the length from the base to the point of greatest width versus total length of specimens examined are listed in table 1 epiproctepiproct ranges from 0490.49 lm to 0670.67 rmim afx5f each collection was identified to species by the 0560.56 in S fidelis and from 0550.55 pmgmp m to 0690.69ogg jjjnjojntm examination of associated female specimens Tx 0600.60ogo in S revelrevelstokastoka similarities in

1 biology department mississippi college clinton MS 39058 2addresswaddressidtidicssIdi esscss allaliail lolcolLOI i esponcloncccorrespondence to this authol

282 199811998 comparison OF TWO SPECIES OF SWELTSA 283

TABLE 1 locality data for sweltsafidelissweltsa fidelis banks and S revelrevelstokastoka jewett

sweltsafidelisswells a fidelis sweltsa revelstokarevelstoka IA ID leahilemhi co moose creek blwbaw lost titrailtrallailallali ab1b AB banff nat pk moraine creekcleek pass 23 VII 1979 B stark K stewart 27 vilVII 1972 A gaufingaufm434 6 3 Y R baumann 5 6 5 Y

2aaa mlMT gallatin co hyalite creek hyalite ab2b MT glacier co icebergleeberg lake glacier squaw creek trailhead 24 vilVII 1979 nat pk 21 vilVII 1979 B stark B stark K stewart R baumann IS16 7y7ay K stewart R baumann lc1 d 2 Y

3aaa MT gallatin co portal creek FS 984 ab3b OR clackamasClackamas co still creek 6 mi N big sky 9 VI 1987 B kondratieff campground mt hood 12 vilVII 1979 666dl91yay B stark K stewart 7 65 3 Y 4aaa MT glacier co swift current creek near ab4b OR hood river co salmon rivelriverbivelbiver red rock falls 8 VII 1967 A miner tributary mt hood 13 vilVII 1963 S jewett 4146 1 Y ad4d4d22yay 5aaa MT granite co butte cabin creek ab5b WA pierce co st andrews creek 26 vilVII 1979 M miner 44650y44c 50 mt rainier nat pk 13 VII 1979 B stark K stewartStewaitewalt 16 6 10 Y

6aaa OR benton co parker creek mary s peak road 26 VI 1985 B stark lieilcilolib116 16 Y

7aaa OR lane co 12512 5 mi N blue rivelriver andrews eapexp forestfoiestbolest 6 vilviiVH 1978 B frost 2226 2yay 8aaa WA spokane co deadman creek mt spokane st pk ll11 VI 1991 B stark R baumann 7 6S 449Y

measurements and the broad range present in both species suggest this character is not a consistently reliable means for distinguishing TABLE 2 epiproctEpiproct measurements in pmgm for sweltsa the 2 species fidelis banks and S revelrevelstokastoka jewett LGWTL ricker 1939 and frisonprison 1942 record proct length to the of greatest width epiepiproct point divided by brachypterous males and females of S fidelis total epiproctproct length epi and jewett 1955 describes both long winged site males LGWTL and brachypterous S revelrevelstokastoka adults sur- S fidelis dick 1995 reports that S revelrevelstokastoka com- 1aaa 2 0490 49 0500 50 monly exhibits different degrees of brachyp 2aaa 1 057 tery while S fidelis is usually macropterous aa 2 3a 056 in the present study all S fidelis n 18 4aaa 1 052 males long winged and 10 S revelstokastoka 5aaa 8 0520 52 0670 67 were revel 6aaa 1 056 males n 16 were brachypterous these 7aaa 1 059 reported variations in wing length also bring 8aaa 2 0580.580 58 0600.600ogo60 into question the reliability of this character Tx 056 for distinguishing males of S fidelis and S S revelrevelstokastoka revelrevelstokastoka no synonymy is suggested for IB 2 0570.570 57 0600.600ogo60 ab2b 1 055 these species at the present time because the ab3b 2 060 female subgenital plates are so different but ab4b 3 060ogo0 60 061ogi0 61 distributional records based on isolated male ogg ab5b 8 0560.560 56 0690.690 69 specimens should be considered tentative xT 060 until verified with female specimens 284 GREAT BASIN naturalist volume 58

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figs 1 4 scanning electron micromieromicrographsmicrographygraphs of sweltsa epiprocts 1 S fidelis dorsaldorsai aspect 2 S fidelis lateral aspect 3 S reuelredelrevelrevelstokastoka dorsaldorsai aspect 4 S redelreuelrevelrevelstokastoka lateral aspect

acknowledgments letin of the illinois natural history survey 22 235 355 we thank BC kondratieff colorado state GALTINGAUFIN AR WE RICKER M MINER P MILAM AND RAR A HAYS 1972 the stonestonefliesflies plecoptera of mon- university RW baumann brigham young tana transactions of the american entomological university and CR nelson university of society 98198 1 161 texas for their generous loan of specimens JEWETT SGS G 1955 notes and descriptions concerning this study was supported in part by the western north american stonestonefliesflies plecoptera hughes wasmann journal of biology 1314513 145 155 howard medical institute under- RICKER WE 1939 A preliminary list of stonestonefliesofstonefliesflies pieple- graduate biological sciences education pro- copteracoptera from the vicinity of cultus lake british gram grant 7119553890171195 538901 columbia proceedings oftheodtheof the entomological society of british columbia 351935 19 23 ple- CITED SURDICKSURDILK RFR F 1995 new western nearctic sweltsa pie literature coptera chloroperlidaeChloroperlidae proceedings of the ento- momologicallogical society of washingtonofwashington 9716197 igligi161 177 BAUMANN RW AR GAUFIN AND RW SURDICK 1977 stonestonefliesflies plecoptera of the the rocky mountains received 28 august 1997 of the entomological memoirs american society accepted 27 september 1997 31131 1 208 frisonPRISON TH 1942 studies of north american plecoptera with special reference to the fauna of illinois bul great basin naturalist 583 0 1998 appp 285 288

starvation AND NESTLING EJECTION AS SOURCES OF MORTALITY IN parasitized LAZULI BUNTING NESTS

william B davison 1

key words broodparasitism nestling growth brown headed cowbird molothrus ateraten host parasite interaction

many studies have documented a reduction in this study I1 recorded feeding rates size in host nestling growth and the number of of food items delivered distribution of food fledglings produced from nests of small hosts and growth rates in parasitized and unparaungara parasitized by brown headed cowbirds molo- sitized nests of lazuli buntingsBuntings rasPaspasserinasenna thrus ater nolan 1978 scott 1979 hatch 1983 amoena I1 specifically examined whether bunt- reviewed in may and robinson 1985 marvil ing nestnestlingslings in parasitized nests die due to and cruz 1989 weatherhead 1989 A short starvation or to physical aggression from the incubation period nice 1953 nolan 1978 cowbird nestling lowther 1993 loud begging calls friedmann the primary study area is in western mon- 1929 dearborn 1997 and larger relative tana in missoula county on the western side mouth sizes ortega and cruz 1991 coupled of mount sentinel and mount jumbo these with a rapid growth rate norris 1947 scott mountains are part of the sapphire range and 1979 hatch 1983 lowther 1993 typically are located on the eastern edge of the city of give the cowbird nestling a head start over missoula elevations range from 1070 to 1719 palouse host young As a result the larger cowbird m primary habitat is jalouse prairie consist- nestling gapes higher than most host nestnestlingslings ing of native bunchgrassesbunchgrasses interspersed with which increases the probability of the cowbird shrubs may 1 being fed by host parents smith and mont- fromflom late to august 1995 I monitored 2 parasitized and 16 unparasitized gomerie 1991 teather 1992 leonard and horn nests on mount jumbo and mount sentinel and 1996 thus one potential cause of reduced weighed daily to the nearest 0.10oi01 1 g cowbird and reproductive success in parasitized nests of 01 bunt- ing chicks a pesola scale I1 conducted 2 h small host species could be a disproportionate using behavioral observations of parasitized and un provisioning of food to the young cowbird parasitized nests from a distance of 20 30 resulting in starvation of host nestnestlingslings in how- using a variable power spotting scope to record ever I1 know of only a single study dearborn nestling behavior and the proportion of food 1997 documenting the distribution of food delivered to cowbird andor bunting nestnestlingslings among nestnestlingslings in parasitized nests the size of food items delivered to each nestling addition several studies have in implicated was placed into I1 of 5 categories based upon cowbird nestling behavior ejection as a source the following criteria I1 hard to see 2 of nestling host mortality twomey 1945 dear- equal to bill length 3 just longer than bill 4 born 1996 cowbird nestnestlingslings ejecting host twice bill length 5 more than twice bill young have been video taped once dearborn length volume of food per hour delivered to 1996 and suggested by at least 2 other re- nestnestlingslings was calculated by multiplying the searchers reviewed in dearborn 1996 the number of feeding trips per hour by average extent to which this behavior occurs is not load size observation times were selected to known since most researchers assume miss- ensure that parasitized and unparasitized nests ing host young are taken by predators or re- were observed during the same times of day moved from the nest by parents after starving and under similar weather conditions

1 division1division of biological sciences university of montana missoulaMissoulaouiaould mt59812MT 59812 present addressoidciddiess department ofot zoology 600 lincoln avenue eastern illinois univeisityuniversity charleston IL 61920

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I1 used a mann whitney U test zar 1996 to old mann whitney U test P 0390.390 39 these compare 1 day 3 weights of bunting nestnestlingslings results should be interpreted with caution in parasitizedpaiasitized and unparasitizedunpaiasitized nests 2 aver- since the power of this test is low there was a age nestling weights per nest on day 3 in paiapalapara trend toward cowbird nestnestlingslings 1846 per sitized and unparasitized nests 3 volume of hour receiving a larger volume of food per food peipelper houihour delivered to nestling cowbirds hour than bunting nestnestlingslings 116411.6411 64 per hour and bunbuntingstings and 4 average number of feed- mann whitney U test FP 0060.060 06 ing trips per hour foiforooiool parasitized and unparaungara the relative strength of the provisioning sitized nests A binomial test was performed to stimulus provided by bunting nestnestlingslings did compare the proportion of feeding trips in differ between parasitized and unparasitized which only the cowbird was fed to the propor- nests lazuli bunting eggs in the same nest tion of feeding trips in which just bunbuntingstings usually hatch on the same day greene et al weiwelwere e fed 1996 consequently the degree of develop- the day 3 weight of lazuli bunting nest ment and corresponding height of the gape of lings in paiasitizedparasitized nests n 5 nestnestlingslings was bunting nestnestlingslings between I1 and 4 d of age in significantly lighter than the day 3 weight of unparasitized nests were relatively even lazuli bunting nestnestlingslings in unparasitized nests however I1 observed that at every feeding trip n 16 nestnestlingslings mann whitney U test P to paipalparasitizedasitized nests the gape of the cowbird 0 0009000090.0009 recognizing that withmwithinwiehm nest variavarlavaria- nestling was at least 252.52 5 cm higher than the tion may confound this analysis I1 then aver- gape of the bunting nestlingsnestlings for all 36 ob- aged the day 3 weights for each nest the aver- served feeding trips to parasitized nests dur- age day 3 weight of lazuli bunting nestnestlingslings ing days I1 and 2 at least I1 bunting nestling differed between parasitized and unparasitized could be seen begging but after day 2 of re- nests fT 1841.841 84 g 1151.151 15 s and 4284.284 28 g 03490.3490 349 ceiving less than 20 of the food delivered to respectively mann whitney U test P 0100.100 10 the nest the bunting nestnestlingslings in parasitized small sample size prevents significance how- nests often did not gape when an adult arrived ever each of the 3 d old bunting nestnestlingslings in with food by day 4 both bunting nestnestlingslings in parasitized nests weighed less than the light- I1 parasitized nest died of starvation and were est 3 d old bunting nestnestlingslings in unparasitized found flattened in the bottom of the nest two nests by day 4 all 5 bunting nestnestlingslings in para bunting nestnestlingslings in the and2nd parasitized nest sitized nests were dead A graph of nestling also died of starvation on day 4 the third 4 d mass over time shows a steady decline in weight old bunting nestling was found dead on the of host nestnestlingslings in parasitized nests greene ground below the and2nd parasitized nest etalet al 1996 my observations reveal that gaping and I1 observed 57 feeding trips at 2 parasitized jostling for position by the much larger cow- nests in the ist nest the cowbird hatched the bird nestling often move the bunting nestnestlingslings same day as I1 bunting nestling and the day around inside the nest most of these interac- before the othelother bunting nestling in the and2nd tions appear to be nonaggressive however on nest the cowbird nestling hatched I1 d before 2 occasions I1 witnessed what appeared to be 3 bunting nestnestlingslings all observed feeding trips aggressive head pecking by cowbird nestnestlingslings occurred 1 3 d after hatching of 57 feeding on 4 separate occasions I1 witnessed a single trips observed at 2 parasitized nests 32 of 46 3 d old bunting nestling settle onto the back of resulted in only the cowbird being fed at 1 nest a 4 d old cowbird nestling in every instance binomial test FP 002 and 11 of 11 resulted the cowbird raised up on its legs within 1 3 in only the cowbird being fed at the and2nd nest sec and moved backwards or to the side for binomial test FP 00010.0010 oolooi001 3 12 sec until the bunting nestling was no I1 observed an average of 6756.756 75 s 992 longer touching its back on 2 occasions this feeding trips per houihour foiforboibol 6 unparasitized resulted in the 3 d old bunting nestling lying nests n 87 feeding trips to 18 nestnestlingslings on its side perpendicular to the rim of the nest where bunting nestnestlingslings were 1 3 d old this with its head outside the nest and the rest of did not differ significantly from the average its body directly on the rim in both instances 6146.146 14 s 1861.861 86 feeding trips per hour in 2 par the bunting nestnestlingslings raised their heads and asitized nests n 36 feeding trips to 5 fell back into the nest within 3 5 sec upon nestnestlingslings where bunting nestnestlingslings were 1 3 d returning to this nest the next day I1 found 2 199811998 NOTES 287

bunting nestnestlingslings dead inside the nest and the I1 thank alex badmaevbadyaev paul switzer eric ard3rd bunting nestling lying on the ground bollinger don dearborn and alexander cruz directly below the nest for reviewing earlier versions of this manu- in addition to mortality from inclement script mercedes davison helped with field- weather nestling predation physical aggres- work and erick greene provided financial sion from cowbird chicks and ectoparasites support during my research my results suggest that another cause of re- duced nestling survival in parasitized lazuli literature CITED bunting nests is starvation which results from cowbird nestnestlingslings receiving most of the food CAREY M DED E BURHANS AND DAD A NELSON 1994 field sparrow spizella delivered to parasitized nests this lusillapusillapusilldpusilla in A poole and FE gill while ediedleditorstoistols birds of northth no appears the noi america 103 acad- to be the primary factor responsible emy of natural sciences philadelphia PA and amer- for reduced reproductive success min parasitized icanlean ornithologists union washington DC lazuli bunting nests my observations of nest- DEARBORNamerleanDCD C 1996 video documentation of a brown headed cowbird nestling ling activity also reveal that host young may be ejecting an indigo bunting nestling from the nest condor 98 645 indirectly ejected from the 98645 649 nest as the cowbird 1997 nestling behavior of a bloodbrood paiapalaparasitesite food nestling attempts to maintain its position acquisition and predation risk of brown headed cow- the relative importance of ejection as a birds unpublished doctoraldoctoiallallai dissertation university of missouri columbia source of mortality and the ability of cowbirdcowbirdss FBDMANNFRIEDMANN H 1929 the cowbirds a study inm the biology to host larger eject species than indigo or of social parasitism C thomas springfield IL lazuli buntingsBuntings remains unknown dearborn GREENECREENE E VR MUEHTER AND WB DAVISON 1996 1996 given that nestnestlingslings of many small host lazuli bunting passerina amoena in A poole and starve in parasitized nests mayfield 1977 FE gill editors the birds ofnoithof north americaamenea no 232 academy of natural sciences philadelphia PA payne 1977 nolan 1978 marvil gruz and and gluzcruz american oi mthologistsornithologists union washington DC 1989 ejecting them would seem to do little to HARRISON HHH H 1975 A heldbeldbeidfield guide to birds nests increase cowbird nestling fitness however houghton mifflin co new york many host species nestnestlingslings gain weight nor- HATCH SAS A 1983 nestling growth relationships of bibrownown mally headed cowbirds and dickcissels wilson bulletin field sparrow spizella busilapupusilasila carey et 9566995 669 671 al 1994 common grackle crackle ouisquiscalusqwscalusQuiscaiuscalus qmsculaquisculal LEONARD M AND A HORN 1996 provisioningPioplovisioning rules in peer and bollingerBollmger 1997 prothonotary war- tree swallows behavioral ecology and sociobiologySociobiology bler ProtonoProtoprotonotatiprotonotannotantaTi citrealtrea petit 1991 red winged 3834138 341 347 blackbird agelaius phoeniceusphoeni yellow LOWTHER PE 1993 brown headed cowbird molothrus ceus and ater A poole gill warbler in and FE editorsediedltoistols the budsbirds of dendroica pepetechialtechia weatherhead north america no 47 academy of natural sciences 1989 dickcissel spiza americanaamencanaamencana hatch philadelphia PA and amerleanamerican ornithologists union 1983 in parasitized nests and ejecting thethem washington DC would likely fitness MARVIL RER E AND A CRUZ 1989 impact of brown headed increase the of cowbird cowbird nestnestlingslings parasitism on the reproductive success of the solitary vireo auk 106476106log 476 480 another possible factor influencing ejection MAY RMR M AND SKS K ROBINSON 1985 population dynamics of host young could be nest shape nest shape ofalianofavianof avianavlan brood parasitism american naturalist 126 475 494 varies both within and among species twentswenttwentyy MAYFIELD HFH F 1977 brown headed cowbird of six lazuli nests from agent bunting my study site exterminationextel mi nation american birds 3110731 107 113 varied in depth from 3 to 555.55 5 cm averaging NICE MMM M 1953 the question of ten day incubation 353.53 5 cm greene et al 1996 A nest depth of periods wilson bulletin 658165 81 93 NOLAN 3 4 cm is typical of many cowbird host species V JR 1978 the ecology and behavior of the prairie waiblerwarbler dendroica discolor ornithological however there is considerable variation in monographs no 26 american oinithologistsornithologists union nest depth of cowbird bestshostsbosts harrlsonharrisonHarnson 1975 washington DC species with shallow nest cups may lose pro- NORRIS RT 1947 the cowbirds ofofpiestonpreston frith wilson portionally more young due to ejection than bulletin 598359 83 103 with deep ORTEGA CPC P AND A CRUZ 1991 A comparative study of species nest cups given the recent cowbird parasitism yellow evidence paipal asitism in headed blackbirds and in support of cowbird nestling ejec- red winged blackbirds auk ioslos10816108 16 24 tion behavior I1 would encourage researchers PAYNE RBR B 1977 the ecology ofbroodof brood parasitism in birds to consider this behavior and its potentiapotential annual review of ecology and systematics 818 1 28 PEER BDB D AND EKE K BOLLINGER 1997 common grackle impacts on cowbird fitness in future studies of crackle ouisQuisquiscalusqwscaluscaluscaius quisquisculaqwsculdcula in A poole and F gill editors nest parasitism the birds of north america no 271 academy of 288 GREAT BASIN naturalist volume 58

natural sciences philadelphia PA and american TWOMEY ACA C 1945 the bird population of an elm maple oi nithologistsornithologists union washington DC forest with special reference to aspection territorial-tectorialtemtorial PETHPLIIILJLJ 199iggi19911 adaptive tolerance of cowbird parasitism ism and coactions ecological monographs 15 by prothonotary WarbwaibleiswalwarblersWai lersbleisbiels a consequence of nest 173 205 site limitation animal behavior 4142541 425 432 weatherhead PJ 1989 sex ratios host specific repro- sconscorr TW 1979 growth and age determination of nest- ductive success and impact of brown headed cow- ling brown headed cowbirds wilson bulletin 91 birds auk 106358106log 358 366 464 466 ZAR JHJ H 1996 statisticalbiostatisticalBio analysis prentice hall upper SMITH HGH G AND R montgomerie 1991 nestling ameri- saddle river NJ can robins compete with siblings by begging behavbehag lorallorailoi101 al ecology and Sociosociobiologybiology 2930729 307 312 received 10 february 1997 TEATHERTEATIICR KLK L 1992 an experimental study of competi- accepted 27 september 1997 tion lolfoifolforfoy food between male and female testingsnestingsnestings of the redredwingwing blackbird behavioral ecology and sociobiologySocio biology 318131 81 87 great basin naturalist 583 0 1998 appp 289 291

observations OF BLACK BILLED MAGPIES PICA PICA GROOMING FERAL HORSES EQUUS CABALLUS

michael C ashleylashley1

key words black billed magpies pica pica feral horses grooming habits

on 4 march 1995 I1 was observing feral and pick for approximately 3 minmm during the horses equus caballus in the southeast sec- grooming bout this magpie climbed into the tion of the granite range in nevada latitude mane of the horse again without any adverse 4047194004719 north longitude 11918139181 west response the wind was variable 10 15 aphkph fig 1 when I1 witnessed an interaction be- and stronger gusts occasionally caused the and2nd tween a black billed magpie pica pica and 2 magpie to struggle to maintain its footing in of my study animals the magpie alighted on one instance the horse twitched dislodging the back of the ist horse and moved around the magpie the animal s back the magpie appeared to be I1 next observed 2 magpies grooming a year- scanning each new section of the horse s back ling feral horse on 12 april 1997 in the gran- as it moved occasionally making pecking move- ite basin approximately 7 km south southwest ments with its head presumably removing of the previous 2 sightings this encounter ectoparasites from the animal after about 3 lasted slightly more than 10 minmm one of the min the magpie left the ist horse and landed magpies groomed the horse s rump back and on the back of the and2nd animal it repeated its dorsal area of its neck up to the base of its searching and picking behavior this time mov- skull the and2nd magpie clung to and groomed ing onto the horse s neck and searching exten- the ventral surface of the animal s neck for sively through its mane after 5 min on the more than I1 minmm moved to the inner aspect of and2nd horse the magpie returned to the ist and the right foreleg at the hock for 4 minmm and searched its mane for more than 1 min nei- then briefly returned to grooming the under- ther horse attempted to displace the magpie side of the horse s neck although there were and both remained quiet throughout the visi- periods when one or the other of the birds was tationstations suggesting familiarity with this behav- not on the horse there were 2 magpies ior I1 was able to closely observe the magpie grooming the animal simultaneously for more behavior with a kawa 22 gox spotting scope than 5 minmm from 20 m the regularity and extent of this behavior is on 17 february 1996 I1 saw a repeat of this impossible to determine at this time in more behavior with 2 magpies and 2 different feral than 50 trips to this area I1 have witnessed horses this episode occurred approximately 2 only these 3 incidents involving magpies and km east southeast of the ist observation but feral horses the distances between observa- within the same valley A magpie landed on tions at the granite ranch site and between top of the withers of the ist horse and moved granite ranch and granite basin can lead one about its back for 3 min occasionally picking to believe that magpies in this area search for at the horse s back horses to groom rather than wait at an estab- during the same period a and2nd magpie flew lished feeding station as described by isenhartisenbart to a nearby sagebrush artemisia tridentata and desante 1985 for scrub jays apheloappelo and appeared to be watching the behavior of coma coerulescens cleaning columbian black the ist bird the and2nd magpie then flew to the tailed deer odocoileus hemionus columbianuscolumbianus back of a and2nd horse and proceeded to search that conclusion however cannot be supported

ibiologyabiology department university of nevada reno NV 89557

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77 ileoilpo100001

fig 1 locations of gloominggrooming events 1 granite ranch 4 march 1995 2 granite ranch 17 february 1996 3 granite basin 12 april 1997 enlarged hornfrombormbomm US geological survey 1 1000001100000 gerlach NYNV map by the small number of observations and lack magpies are reputed to probe sores on the of individual identification of the birds involved backs of domestic and wild animals that are in on 3 occasions I1 have seen magpies in the poor physical condition bendireBenbenderedire 1895 all of vicinity of feral horses in even more remote the horses I1 observed being groomed by mag- sites in the granite range however I1 saw no pies were in excellent condition because I1 grooming viewed the behaviors closely from 20 in with magpies exhibit a variety of opportunistic a 22 gox spotting scope I1 am confident that foraging practices including scavenging prey- grooming took place I1 suspect the magpies ing on nests groom 1993 pampush and were removing ectoparasites from the animals anthony 1993 preying on small mammals not probing sores ticks parasitiformes meta goulden 1975 and grooming large cerbiherbi stigmata are abundant mammalian ectopara vores dixon 1944 linsdale 1946 lmsdalelinsdaleamsdale sites in the granite range and are likely objects and tomich 1953 massei and benovgenov 1995 of the magpies behaviors 199819981 NOTES 291

these observations add to the number of BENDIRE CHC H 1895 life historieshistones of north amerleanamerican apparently mutualistic interactions between birds smithsonian institution washington DC DIXON JCJG 1944 california scrub jay picks ticks from corvids and large herbherbivoresivores this extensive mule deer condor 4620446 204 relationship includes 1 black billed magpies fitzpatrick GWG W AND GEG E woolfenden 1996 florida Lmlinsdalesdale 1946 yellow billed magpies pica selubscrub layjay forages on back of white tailed deeldeer con- suttahnuttahnuttalinuttalitailtaii linsdaleLmsdale and tomich 1953 and cali- dor 9842298 422 423 fornia scrub jays aphelocomaAphel calicallcailcalip GOULDEN LLL L 1975 magpie kills ground squirrel auk ocoma fornicacalifornicacalifarnicaornica 92606 dixon 1944 interacting with mule deer odo- GROOM DW 1993 magpie pica pica piepredationdation on black- coileus hemionus 2 black billed magpies bird turdus merula nests in urban areas bird study linsdale 1946 with elk cervus canadensis 405540 55 62 3 florida scrub jays aphelocomaAphelocoma coerules ISENHART FR AND DED F DESANTE 1985 observations of scrub jays cleaning ectopaiasitesectoparasites from black tailed cens with white tailed deer odocoileus virmr deer condor 8714587 145 147 ginglntimanusginianusgimanusgiianuslanusmanus fitzpatrick and woolfenden 1996 KILHAM L 1982 cleaningfeedingCleaning feeding symbiosissymbioses of common 4 scrub jays aphelocomaAphelocoma coerulescens with crows with cattle and feral hogs journal of field columbian black tailed deer odocoileus hemi- ornithology 5327553 275 276 onus columbianuscolumb isenhart and desante LINSDALE JMJ M 1946 american magpie pica pica pages ianus 133 154 in ACA C bent editorediton life histories of north abrachy 1985 5 common crows corvus brachy americanamerlean jays crows and titmice US national rhynrhynchosrhynchopschos with cattle bos taurus kilham museum bulletin 191 1982 and 6 common crows corvus brachyabrachy LINSDALE JMJ M AND PQ TOMICH 1953 A herd of mule rhynrhynchosrhynchopschos kilham 1982 florida scrub jays deeldeer university of california presspi ess berkeley MASSEI G AND P GENOV 1995 otof black aphelocomaAphel coerulescens and morris observations ocoma baber billed magpies pica pica and carriongarrioncaigaigal non crowgrowci ow corvus 1980 black billed magpies and carrion corone cornix grooming wild boar sus scroffscrofa jouljour crows corvus corone cornix with feral hogs nal of zoology london 236338236 338 343411 sus scrofdscrofascrota massei and benovgenov 1995 PAMPUSH GJG J AND RGR G ANTHONY 1993 nest success habitat utilization and nest site selection of long billed curlewscurfews in the columbia basin oregon con- my thanks to E gray and SHS H jenkins for dor 9595795 957 967 review and comments and to the bureau of land management for supporting my feral received 18 june 1997 horse research accepted 27 september 1997

literature CITED

BABER DWD W AND JGJ G MORRIS 1980 florida scrub jays foraging fromfi om feral hogs auk 9720297 202 gleatgreat basin naturalist 583 0 1998 appp 292 293

FISH PREDATION ON GIANT WATER BUG heteroptera belostomatidae EGGS IN AN ARIZONA STREAM

robert L smithl and chris iforton2ortonehorton2

key words aredusabedus heibehelbeherbertiiti brooding egg predation aquatic insect fish diet stomach contents

we caught 3 brown trout salmo trutta in water bug subfamily belostomatinaebelostomatidaeBelostoma tinae females the white mountains of east central arizona glue their eggs to the backs of their mates and just after daybreak on the morning of 20 april the males then actively brood the eggs in a 1997 the fish were taken in the south fork of variety of ways smith 1997 most belostoma the little colorado river elevation ca 2350 in tines inhabit lentic habitats but species in the ca 10 kmkin southeast of Springspringervilleerville arizona new world genus aredusabedus are stream dwellers the 3 fish ranged in size from 18 to 20 cm TL menke 1960 aredusabedus herberti occurs in ari- the brown or german trout a european zona streams at elevations of ca 1000 3000 in species has been widely distributed in the males of this species brood their eggs by united states since its introduction to north exposing them to the atmosphere while resting america in the late 19th century carlander on vegetation or rocks such that the bug is 1969 this species was introduced to the submersed with the tops of the eggs exposed white mountains of arizona sometime in the to the air when below the surface of the water 1920s miller 1972 brown trout are pro- encumbered A herberti males aerate their eggs duced in hatcheries and released in arizona by brood pumping ie rocking longitudi- streams including the little colorado river to nally about once per second to circulate water provide a sports fishery over the eggs for embryonic respiration smith pooled stomach contents of the 3 fish con- 1976 tained 27 trichoptera helicopsychidae and when aredusabedus sppapp eggs are first laid they limnephilidaelimnophilidae larvae in their cases 5 mayfly are white in color with tan caps As the eggs nymphs baetidaeBaetidae 3 plecoptera nymphs and develop they take on a grayish color and adults 2 aquatic heteroptera a naunaucoridcorid and enlarge near hatching time the dorsal portion an early instar belostomabelostomatidtid plus a variety of of the chorion becomes ash gray in all stages terrestrial insects in addition to these items of development eggs are highly conspicuous one of the trout stomachs contained 10 giant against the male s dark brown back giant water water bug aredusabedus herberti hidalgo eggs the bug ova are among the largest insect eggs eggs white in color with tan apices were in fully developed aredusabedus herherbertibertlbertibeTti eggs can reach good condition and contained mucilage on 6 mm in length and 2 minmm in width adult their distal ends from this evidence we infer aredusabedus herberti bugs range from 24524.5 to 40 that the ova had recently been laid and soon mm in length and 12512.5 to 22 minmm wide menke after their deposition consumed by the fish 1960 thus the size of adult bugs substan- brown trout are able to feed at starlight 10 4 tially exceeded the gape of the small trout we foot lamberts intensities robinson 1978 caught thus the eggs were probably eaten during the prior to this observation there have been night no reports of predation or parasitism of any giant water bugs aquatic heteroptera in kind on giant water bug eggs nor have these the family belostomatidae are found in tropical huge insect eggs ever been noted in the stom- and temperate freshwater habitats through- ach contents of fish it seems possible that out most of the world in members of the giant fisheries biologists who routinely sample sports

I1 cpiiitinentdepartment ofot entomology university of arizona tucson AZ 85721 2scljool2&jiool of0 renewablebunebeneRune wable natural resouiccsresources universityuniveisityofaiizonaof arinaailari na tucson AZ 85721

292 199811998 NOTES 293

fish stomach contents might not have recog- MENKE ASA S 1960 A taxonomic study of the genus nized giant water bug eggs for what they are aredusabedus stalstai hemiptera belostomatidae university of california publications in entomology 1639316 393 440 it is not that in however surprising these con- MILLER RRR R 1972 classification oftheodtheof the native trouts of spicuous eggs attached to actively brooding arizona with the description of a new species salmo giant water bugs would attract the interest of apache copela 19724011972 401 422 foraging fish who might regularly snatch eggs ROBINSON FW 1978 feeding by brown trout sahnosalmo trutta and arizona trout salmo apache at various light lev- from encumbered male bugs backs if this is various els unpublished master s thesis university of ari- the case fish could be significant predators of zona tucson aredusabedus sppapp eggs throughout the range of the SMITH RLR L 1976 male brooding behavior of the water genus from southern utah through arizona bug aredusabedus herberti heteroptera belostomatidae and mexico to central america it is also pos- annals of the entomological society of america 69 sible that the eggs were inadvertently ingested 740 747 1997 evolution of paternal care in the giant water when the small fish attempted to eat a very bugs heteroptera belostomatidae in JCC choe large bug the authors would be grateful for and bjB J crespi editors the evolution of social be- any additional accounts of giant water bug havior in insects and arachnids cambridge university press eggs found in fish stomachs received 28 august 1997 literature CITED accepted 27 september 1997

CARLANDER KDK D 1969 handbook of freshwater fishery biology volume 1 iowa state university press ames 752 appp

information FOR AUTHORS the great basin naturalist welcomes previously VOUCHER SPECIMENS authors are encouraged to unpublished manuscripts pertaining to the biologi- designate properly prepare label and deposit cal natural history of western north america high quality voucher specimens and cultures docu- preference will be given to concise manuscriptmanuscriptsmanuscriptsofsofof menting their research in an established permanent up to 12000 words simple species lists are dis- collection and to cite the repository in publication coucouragedraged references IN THE TEXT are cited by author and SUBMIT manuscripts to richard W baumann date eg martin 1989 or martin 1989 multiple editor great basin naturalist 290 MLBM PO box citations should be separated by commas and listed 20200 brigham young university provo UT in chronological order use et al after name of 84602020084602 0200 an accompanying cover letter must first author for citations having more than two include phone numbers of the author submitting authors the manuscript and FAX number and emailE mail acknowledgments under a centered main address when applicable the letter must also pro- headingbeading include special publication numbers when vide information describing the extent to which data appropriate text or illustrations have been used in other papers literature CITED also under a centered main or books that are published in press submitted or headingbeading lists references alphabetically in the fol- soon to be submitted elsewhere authors should lowing formats adhere to the following guidelines manuscripts not mack GD and LD flake 1980 habitat relation- so prepared may be returned for revision ships of wwaterfowlfowl broods on south dakota great ater manuscript preparation in general the stock ponds journal of wildlife management basin naturalist follows recommendations in 44695 760700 potpor scientific style and format the CBE manualforManumanualalforfor sousa WPWE 1985 disturbance and patch dynamics publishers authors editors and fth6th6tb edition on rocky intertidal shores pages 101 124 in council of biology editors inc 11 south lasalle STA pickett and PSES white editors the ecolo- street suite 1400 chicago IL 60603 USA PHONE gy of natural disturbance and patch dynamics 3122010101312 201 0101 FAX 3122010214312 201 0214 we do however academic press new york differ in our treatment of entries in literature cited coulson RN and JA witter 1984 forest ento- authors may consult the most recent issue of the mology ecology and management jobnwileyjohn wiley great basin naturalist for formatting guidelines and sons inc new york 669 appp TYPE AND DOUBLE SPACE all materials including literature cited table headings and figure legends TABLES are double spaced on separate sheets and avoid hyphenated words at the righthandright hand margins designed to fit the width of either a single column use WordwordperfectPerfect s italics feature for words to be 67gt676.7 cm or a page 14014014.0 cm use 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instructions photocopies of illustrations issn0017ISSN ool001 736147 3614 GREAT BASIN naturalist volvoiwoiwol 58as no 3 july ws1998

CONTENTS articles gap analysis of the vegetation of the intermountain semidesertsemi desert ecoregionecoregion david M stoms frank W davis kenneth L driese kelly M cassidy and michael PE murray 199 natural history of a saline mound ecosystem robert R blank james A young james D trent and debra E palmquist 217 winter macromacroinvertebrateinvertebrate communities in two montane wyoming streams christopher M pennuto frank denoyelles jr mark A conrad frank A vertucci and sharon L dewey 231 range of the brown headed cowbird in colorado past and present

I1 jameson FE chace and alexaiexalexanderadermder cruz 245 chemical and biological characteristics of desert rock pools in intermittent streams of capitol reef national park utah jill S baron toben lafrancois and boris C kondratieff 250 survivorship and cause specific mortality in five populations of mule deer

i vernon C bleich and timothy J taylor 265 persistence of subalpine forest meadow ecotonesecotones in the gunnison basin colorado andrew J schauer brian K wade and john B sowell 273 comparison of the epiproctepiproct structure of two closely related species sweltsa fidelis banks and S revelrevelstokastoka jewett plecoptera chloroperlidaeChloroperlidae jennifer K delk mary jane kilgore and bill P stark 282 notes starvation and nestling ejection as sources of mortality in parasitized lazuli bunting nests william B davison 285 observations of black billed magpies pica pica grooming feral horses equus caballus michael C ashley 289 fish predation on giant wwaterater bug heteroptera belostomatidae eggs in an arizona stream robert L smith and chris horton 292