Big Sagebrush (Artemisia Tridentata Vaseyana) and Longleaf Snowberry (Symphoricarpos Oreophilus) Plant Associations in Northeastern Nevada

Great Basin Naturalist

Volume 47 Number 1 Article 13

1-31-1987

Big sagebrush (Artemisia tridentata vaseyana) and longleaf snowberry (Symphoricarpos oreophilus) plant associations in northeastern Nevada

Paul T. Tueller University of Nevada, Reno

Richard E. Eckert Jr. University of Nevada, Reno

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Recommended Citation Tueller, Paul T. and Eckert, Richard E. Jr. (1987) "Big sagebrush (Artemisia tridentata vaseyana) and longleaf snowberry (Symphoricarpos oreophilus) plant associations in northeastern Nevada," Great Basin Naturalist: Vol. 47 : No. 1 , Article 13. Available at: https://scholarsarchive.byu.edu/gbn/vol47/iss1/13

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. BIG SAGEBRUSH (ARTEMISIA TRIDENTATA VASEYANA) AND LONGLEAF SNOWBERRY {SYMPHORICARPOS OREOPHILUS) PLANT ASSOCIATIONS IN NORTHEASTERN NEVADA

PaulT. Tueller' and Richard E. Eckert, Jr."

Abstract.—Artemisia tridentata/Symphoricarpos oreophilus and Symphoricarpos oreophilus!Artemisia tridentata plant associations were studied in northeastern Nevada. A 60-stand reconnaissance followed by a detailed study of 37 stands differentiated five important hal)itat types using an association table approach. Data reduction with DECO- RANA and TWINSPAN also described five plant associations that were differentiated by species occurrence and geographical distribution. All stands were found at elevations between 2,200 and 3,100 m in areas where snow accumulates and is late to melt. Stands are found on 15 families of soils that are relatively deep, often skeletal, dark colored, and productive. The dominant perennial grasses included Agropyron spicattim, Agropyron trachycaulum, and Festuca idahoensis.

Shrubby members of the genus Artemisia areas in northeastern Nevada where Arte- (sagebrush) comprise a significant portion of misia tridentata vaseyana and Symphoricar- the vegetation in the Great Basin. Sagebrush pos oreophilus are locally abundant. The

gives the dominant aspect to vegetation over a overall climate is primarily arid (Hunt 1967), wide range of altitude, chmate, geological although semiarid to subhumid conditions ex-

substrate, soils, and associated plant species. ist in many of the mountain ranges. This environmental variability has resulted in Mountain brush vegetation dominated by forms. a number of species, subspecies, and shrubs of these two species was studied by In addition, a certain amount of hybridization first selecting 60 stands in 18 mountain ranges has, no doubt, resulted in the existence of many in Elko, Eureka, Humboldt, Lander, Lin- ecotypes not yet defined (Beetle 1960, Winward coln, Nye, and White Pine counties for a de- and Tisdale 1969, and McArthur 1978). tailed reconnaissance. The plotless reconnais- Big sagebrush (Artemisia tridentata) is the sance procedure outlined by Poulton and most widely distributed and abundant species Tisdale (1961) was used to collect general veg- of the genus. Three subspecies have been etation information. A stand was selected for identified, ssp. vaseyana, ssp. tridentata, and sampling if it was homogeneous with respect ssp. wyomingensis. Extensive stands of moun- to species composition and dominance and tain big sagebrush (Artemisia tridentata ssp. had uniform relief of the soil surface. Transi- •vaseyana) occur in central and northern Ne- tional areas were avoided. For each stand, vada in high-producing plant communities at species were listed under three categories high elevations. This study was limited to (tree, shrub, or herb physiognomic layer) and stands with either Artemisia tridentata vase- given both cover class and dominance ratings. yana or snowberry (Symphoricarpos oreo- features of percent slope, philus) as the dominant or co-dominant shrub. Physiographic the stand on the The objective of this study was to character- slope aspect, position of microrelief of ize the vegetation, topography, and soils of slope, elevation, land form, and Soil profile some A. tridentata /S. oreophilus habitat the soil surface were recorded. types in northeastern Nevada. features noted were horizons, solum depth, gross differences in the texture and structure, gravel and stone. Percent Methods and quantity of cover for stone, gravel, bare soil surface, and This studv was confined to mountainous cryptogams was estimated.

'Department of Range Ecology, University of Nevada. Reno, Nevada 89512. -.Agricultural Research Service, U.S. Department of Agriculture, Department of Range. Wildlife and Forestrv. University of Nevada, Reno, 1000 Valley Road, Reno, Nevada 89512.

117 118 Great Basin Naturalist Vol. 47, No. 1

Based on results of this reconnaissance, 37 four transect lines to determine basal area of stands of vegetation in eight mountain ranges herbs. Shrub crown cover was estimated to in Elko and White Pine counties were se- the nearest 1% if less than 25% and the lected for more detailed study (Fig. 1). The nearest 5% if greater than 25%. A wire ring stands selected were considered most nearly equaling 5% of the microplot was used as an representative of the potential natural vegeta- estimation. Openings in the shrub canopy tion based on the absence of recent distur- greater than 2% were excluded from the cover bance such as excessive grazing, wildfire, and estimate. Shrub density was obtained by accelerated erosion, and on a high proportion counting individuals rooted in each mi- of grasses in the herb layer, particularly spe- croplot. The counts were summarized as num- cies of Agropyron, Festuca, and Poa. All bers per 60 m~. Shrub heights in each microplot stands were grazed by livestock during the were measured to the nearest centimeter. summer months. Studies of relict and excel- A soil profile description was made at each lent condition sagebrush vegetation in other macroplot location. Samples from the Al and portions of the Great Basin have shown that B2 horizons were analyzed for soluble salts, grasses, particularly of the genera mentioned, pH, and organic carbon. comprised a dominant portion of the herb Percent frequency and cover data were layer (Blackburn 1967, Blackburn et al. 1968b, summarized in stand tables, and the resulting c, 1969a, b, c, 1971, Passie and Hugie 1962, species groupings were used to make a subjec- Tisdale et al. 1965, Zamora and Tueller 1973). tive interpretation of the vegetation according At each study site a homogeneous stand of to the association and habitat type ecological vegetation was selected for sampling. Plant concepts. Final association interpretations and ground cover data were collected on one were based on the dominant species in each

15- X 30-m macroplot located with the long plant layer. An association is defined as a plant axis oriented up and down slope. The right- community characterized by a definite floris- hand boundary formed the baseline. Ten tic composition, physiognomy, and structure 15-m transects were located perpendicular to and growing under similar habitat conditions the baseline with five transects randomly (Hanson and Churchill 1961). The associa- placed in each half of the macroplot. Rooted tions are considered representative of poten- frequency of all species was determined in 10 tial native vegetation. A habitat type is de- 3- X 6-dm microplots placed at 1-m intervals fined as those geographic areas that support, along each transect line. Percent basal area of or are capable of supporting, one association herbaceous species was estimated in 10 3- x in the absence of disturbance (Daubenmire 6-dm microplots on 4 of the 10 frequency 1952). Habitat types are named by the charac- transects. Two wire rings, one 5% and the teristic climax plant association. other 2% of the microplot area, were used as For objective analysis of the data we used an aid in estimation. Basal areas of 1 to 10% the Cornell Ecology and Systematics com- were estimated to the nearest 1%; those puter programs DECORANA (Hill 1979) and greater than 10% were estimated to the TWINSPAN (Hill 1979). DECORANA (de- nearest 5%. Basal area for mat-forming spe- trended correspondence analysis) creates or- cies was considered as the total area encom- dinations of samples and all species. Through passed by the periphery of the mat. Dead a process of repeated averaging, sample centers of bunchgrass were excluded from the scores on the first axis of the ordination are cover estimate if they exceeded 1%. defined as the average of the scores of the Ground cover was estimated using the two species that occur in a sample. Graphs show- outside corners of the microplot frame as ing placement of species and samples in rela- points. Features recorded were basal area of tion to significant ordination axes are used plants, litter, cryptogam, bare soil surface, with eigenvalues (to show variability) to ex- gravel (2-mm to 7-cm diameter), and stone plain the axes as ecological gradients. Each of (greater than 7-cm diameter). Percent cover the first three DECORANA ordination axes was calculated from 200 points on each were analyzed by computing linear regression macroplot. coefficients with the following stand parame- Shrub characteristics were evaluated on 15 ters: elevations, radiation index (Frank and 1-m" microplots placed consecutively on the Lee 1966), shrub cover, grass cover, forb s

January 1987 TUELLER. ECKERT: NEVADA PlANT ASSOCIATIONS 119

Table 1. Artemisia tridcntata vasciiciiKi/Sijiuphoricarpos orcopltiliis associations cliaracterized in northeastern Nevada.

Number of Elevational stands range of Associations sampled stands (m)

Artemisia tridentata-Symplioricar)>os 14 2378-3010 ureophiluslAgropyron spicatum

Artemisia tridentata-Symphoricarpos 6 2592-2713 oreophilus/Agropyron trachycaiilum

Artemisia tridentata-Symphoricarpos 5 2531-2592 oreophihis/Festuca idahoensis

Symphoricarpos oreophihislArtemisia 10 2287-3003 tridentatalArgropyron spicatum

Symphoricarpos oreophihislA rtcmisia 2 2470

t ride n ta talFestu ca ida h oe n sis

cover, total cover, number of species, lati- (8) Artemisia tridentata-Purshia tridentatalFestuca tude, and longitude. TWINSPAN (two-way idahoensis Artemisia tridentata-Cercocarpos lechfoUusIAgro- indicator species analysis) successively splits (9) pyron spicatum of all the samples into halves the ordination (10) Artemisia tridentata-Clirysothamnus viscidiflorusi and identifies indicator species for each divi- Agropyron spicatum sion. The divisions are arranged in the print- (11) Symphoricarpos oreophihis-Artemisia tridentatal Agropyron s})icatiim out in order showing the closeness of similar- (12) Symphoricarpos oreophihis-Artemisia tridentatal all species. ity between groups based on The Agropyron trachycauhim result is a classification of similar stands with (13) Symphoricarpos oreophihis-Artemisia tridentatal the tightness of the groupings indexed by the Festuca idahoensis eigenvalue of the division. The resulting clas- (14) Symphoricarpos oreophihis-Artemisia tridentatal Poa sandbergii sifications for both association tables and mul- (15) Symphoricarpos oreophihis-Artemisia tridentata- tivariate approaches were compared. We Amehinchier pallidalAgropyron spicatum wanted to know if the multivariate approach, Provisional association names were given to emphasizing all species equally, would de- spe- scribe plant associations readily identifiable in groups of stands with the same dominant combination of dominant spe- the field and potentially useful to resource cies, the same managers. cies, or similar estimated cover percentages of certain species. Similarities among site factors Results such as elevation, aspect, percent slope, position on slope, and some soil characteristics Reconnaissance (texture, structure, and percent sand and clay)

Reconnaissance data allowed us to identify were used as additional classification criteria. 15 mountain brush communities based on Some of these 15 communities were judged associations. Others dominant species in the shrub and herb layer: to be serai stages of major were grouped into one of the five final desig- Artemisia tridentata-Symphoricarpos oreophihisl (1) nations and considered to be incidental vari- Agropyron spicatum ants. The remaining communities (8, 9, and (2) Artemisia tridentata-Symphoricarpos oreophihisl C h rysoth amnu s v iscidiflo ru 15) were excluded from the study because (3) Artemisia tridentata-Symphoricarpos oreophihisl they did not fit the criteria selected for the Chrysothamnus viscidifloriislAgropyron spicatum detailed analysis. (4) Artemisia tridentata-Symphoricarpos oreophihisl Festuca idahoensis Intensive Study (5) Artemisia tridentata-Symphoricarpos oreophihisl Poa sandbergii Knowledge gained during the reconnais- Artemisia tridentata-Sym))horicar))os oreophihisl (6) sance suggested that intensive work be con- Stipa comata fined to five (5) Artemisia tridentata (7) Artemisia tridentata-Purshia tridentatalAgropy- ron spicatum vaseyana-Symphoricarpos oreophilus associ- 120 Great Basin Naturalist Vol. 47, No. 1

Table 2. Average density (No. height (Ht.), and crown cover (Cv) for shrubs of the mountain brush plant associations.

Species Association

Artr-Syor/Agsp Artr-StjorlAgtr Artr-SijorlFeid Syor-Artr/Agsp Syor-Artr/Feid Ht. Cv Ht. Cv Ht. Cv Ht. Cv Ht. Cv No.'' cm'' %'' No. cm % No. cm % No. cm % No." cm % Amelanchier pallida 2 17ir' — — — — — — e67r'— — — Artemisia tridentata (Artr) 59 67 23 73 75 26 61 69 .30 49 60 17 83 72 15 Berberis repens — — — e5T — — — — — — 1 3T Chrysothammis viscidijlorus 16 19 2 18 27 2 24 30 2 28 29 5 35 34 4 Gutierrczia sarothrae e 12 T — — — — — — — — — — — — Pontentilla glandulosa — — — e34 T — — — — — — — — — Prttnus virginiana e 25 T — — — — — — — — — — — — Purshia tridentata 2 63 T e 58 T — — ————— — — Ribes velutinum — — — — — — — — — 5 33 T — — — Rosa woodsii e 31 T — — — — — — e 31 T — — — Syinphoricarpos oreophilus (Syor) 322 43 17 118 36 14 311 .39 18 394 33 21 259 43 22 Tetradymia canescens e 28 T — — — — — — — 37 T — — — a - Number per 60 m" b - Average height (cm) values calculated for stands in which individuals occurred c - Average canopy cover percentage for a square meter d - Cover values less than 1% indicated as T e - Average density value less than 1 ^ Agtr = Agropijron trachycauhim. Agsp Af:.ropyron spicatum ; Feid Festuca idahoenaia

Table 3. Constancy (Cn), frequency (Fr), and herb basal area (Cv) for species in the Artemisia tridentata vaseyanal Symphoricarpos oreophilus associations.

Artemisia tridentata vaseijana- Artemisia tridentata vaseyatia- Artemisia tridentata vaseyana- Symphoricarpos oreophilus- Symphoricarpos oreophilus- Syniphoricarpos oreophilus- Af^ropyron trachycaulum Festuca idahoensis Ap'opyron spicatum Species^ Shrubs January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 121

Table 4. Constancy (Cn), frecjuency (Fr), and herb basal area (Cv) for species in tbe Sijmphoricarpos oreophihis/ Artemisia tridentata vaseijana associations. .

122 Great Basin Naturalist Vol. 47, No. 1

Table 5. Soil surface characteristics for the associations dominated by Artejnisia tridentata vaseyana or Syinphori- carpos oreophilus

Soil surface characteristics

Plant January 1987 TUELLER, ECKERT: NEVADA PlANT ASSOCIATIONS 123

Table 6. List of soil fomilics supporting Artemisia tridcntata vasi'tiaiia and Syinphoricarpos oreophihts plant associations. .

124 Great Basin Naturalist Vol. 47, No. 1

Table 7. Summary of textural classes' and diagnostic horizons of'soils supportine; stands oH Artemisia tridentata and Symphoricarpos oreophilus

Diagnostic horizons Associations and number of stands Soil famiK' texture class sampled in control section Epipedons Subsurface horizons

Coarse- F"ine- Fine Very Loamy- Clayey- MoUic Ochric Argillic Cambic loamv loamv fine skeletal skeletal %"

Artr-Sylo/ 47 13 33 40 60 93 Agsp (14)

Artr-Svlo/ 67 16 17 67 33 83 17 Agtr (6)

Artr-Svlo/ 60 20 20 40 60 100

Feid (5)

Svlo-Artr/ 22 33 45 — — 78 22 78 22 Agsp (10)

Sylo-Artr/ 100 100 50 50

Feid (2) a - Soil family textural classitication in si)il taxouonn (Soil Survey Staff 1975) b - Percent of stands

Artr Artemisia tridentata Agtr Aoropijron trachycatiliim Sylo Symphoricarjios longiflorus Feid - Festuca idahoensis Agsp - Agropyron spicatum

of bare soil (24%) is the highest of all associa- (Table 3). Chrysothamnus viscidiflorus is one tions, and gravel cover and stone cover are 9% of four highly constant shrubs but contributes and 2%, respectively (Table 5). little to total crown cover.

Soils are both cryoboralfs and cryoborolls The total grass basal area (4.7%) is com- (Table 6). The cryoborolls are all Argic Pachic posed almost entirely of Festuca idahoensis Cryoborolls with fine-loamy to sandy-skeletal (2.7%) and Poa sandbergii (1.0%); Agropyron

textures (Table 7). The epidedons are pre- traclnjcaulum is a minor species. Only six dominantly mollic, and most soils (83%) have grass species were found. Festuca idahoensis argillic subsurface horizons. Average gravel comprises 38% of the total herbaceous basal content varies from 5 to 25%. Only one profile area and 58% of the total grass basal area. The was found on bedrock (74 cm deep). total herbaceous basal area (7.1%) and the Artemisia tridentata vaseyana—Symphori- total grass basal area (4.7%) are the highest of carpos oreophilus/Festiica idahoensis Associ- the associations studied. The total forb basal ation. —Two of the stands representing this area (2.4%) is the highest among A. triden- association are located on Spruce Mountain, tata -domiivdted stands. The forb component two on Mt. Moriah, and one in Harrison Pass. consists of 20 species. Species with 80% con- Each stand occurs in mountainous terrain on stancy or greater are Collinsia parvijlora, 19 to 29% slopes with north, east, and west Crepis acuminata, Lupinus caudatus, aspects and elevations of 2,531 to 2,592 m. Mertensia oblongifolia, Penstemon humilis, The vegetation is characterized by the dom- and Viola beckwithii. The first four species are inance of A. tridentata in the shrub layer the most abundant. (Table 2) and Festuca idahoensis in the herb Average plant basal area cover (42%) and Htter layer (Table 3). Arteitiisia tridentata cover of cover (39%) are the highest of all associations

30% constitutes 60% of the total shrub crown studied (Table 5). Gravel, stone, and cryptogam

cover and has a density of 61 plants/60 m". cover is very low. The bare soil surface (15%) is

Symphoricarpos oreophilus cover of 18% con- intermediate for all associations studied but is stitutes 36% of the total shrub crown cover the lowest with respect to other A. triden- and has a very high density (311 plants/60 m") tofa-dominated plant communities. January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 125

At least 60% of the soils are Mollie Cryobo- associations, but stone and cryptogam cover ralfs with a few Argic Pachic Cryoborolls (Ta- was the lowest of all associations. bles 6, 7). All subsurface horizons are argillic, Nearly half of the soils are fine, montmoril- and ochric epipedons are common. The most lonitic Argic Pachic Cryoborolls (Table 6). An- common soil family textural class is fine-loamv other 22% are a fine-loamy, mixed family of ' (Table 7). the same soil subgroup. Symphoricarpos oreophihis—Artemisia tri- Symphoricarpos oreophihis-Artemisia tridentata vaseijanalAgropijron spicatum Asso- dentata vaseyana/Festuca idahoensis Associ- ciation. —This association occurs in the south- ation. —Two stands represent this associa- ern Schell Creek Range with three tion, one on Mt. Moriah and the other on exceptions. Two stands are in the Jack Creek Ward Mountain in White Pine County. These area of Elko County and one stand is on stands occur on 26 and 28% slopes, respec- Spruce Mountain. Stands are found on 10 to tively, and with northeast and northwest as- 30% slopes with northerly aspects at eleva- pects at about 2,470 m. tions between 2,287 and 3,003 m. The vegetation is characterized by the dom- Robust Symphoricarpos oreophihis shrubs inance of Symphoricarpos oreophihis in the and an herb layer dominated by Agropyron shrub layer and Poa sandbergii and Festuca spicatum characterize the vegetation (Tables idahoensis in the herb layer (Tables 2, 4).

2, 4). In addition, this association has less A. The physiognomy of this association is quite tridentata (17%) than did the first three asso- distinct from other plant associations because ciations described. Symphoricarpos ore- of the lack of a noticeable sagebrush aspect. ophihis cover (21%) comprises 49% of the total These sites are snowpockets and are obviously shrub cover and has the highest shrub density dominated by S. oreophihis, a dark green (394 plants/60 m") of all associations studied. shrub generally lacking the dull gray appear- Artemisia tridentata constitutes 38% of the ance of A. tridentata. Symphoricarpos ore- shrub crown cover but has a very low density ophilus has a high density and a cover (22%) (49 plants/60 m"). Besides S. oreophihis and that comprises 53% of the total shrub crown

A. tridentata, Chrysothamnus viscidifloriis is cover (Table 2). the only other important shrub, although The average total basal area of herbaceous Ribes vehitintim has a constancy of 5% (Table vegetation (5. 1%) and the average total grass

4). basal area (3.3%) are comparatively low when Agropyron spicatum and Poa secunda have compared with the other associations in this 100% constancy in this association. Fourteen study. Poa sandbergii has 2% cover and Fes- grass species were found. Agropyron spica- tuca idahoensis has 1% cover (Table 4). Nei- tum cover (2.1%) comprises 41% of the total ther grass is clearly dominant. The association herbaceous basal area (5.9%) and 68% of the was named after Festuca idahoensis because it total grass basal area (3.1%). Lupinus cauda- is considered to be the dominant perennial tus and CoUinsia parviflora have constancies grass on these sites. Poa sandbergii composes of 100% and contribute 50% of the total forb 61% of the total grass basal area and 40% of the basal cover (28%) for 32 forb species. Merten- total basal area of herbaceous vegetation. All sia oblongifoUa and Agoseris glauca have con- other grass species have low basal area and stancies of 89% and 78%, respectively, and frequency, except Festuca idahoensis. Forbs contribute 40% of the average total forb basal are sparse; only 23 species were found, and area (Table 4). Festuca idahoensis and Senecio frequency percentages are low. The floristic canus have low constancies but comprise a structure of forbs resembles the Artetnisia tri- significant portion of the total forb basal area dentata vaseyana-Symphoricarpos oreophi- in some stands. Other forbs characteristic of hislFestuca idahoensis association, which had this association are Penstemon humiUs, Crepis both low forb constancy and frequency. acuminata, and Balsamorhiza sagittata. Highly constant forbs are CoUinsia parvi-

Plant and litter cover combined (73%) is the flora, Crepis acuminata, Mertensia oblongi- lowest of the S. oreophihis plant associations foha, Lupinus caudatus, and Viola beck- and is related to the high bare soil surface withii. percentage of 19% (Table 5). Gravel cover Bare soil surface is the lowest of the associa- (7%) was next to the highest among all the tions studied and results from a high plant and 126 Great Basin Naturalist Vol. 47, No. 1

Table 8. Number of stands sampled falling into either TWINSPAN groups or plant associations based on dominant species.

Plant January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 127

Idaho

J 6

.19 Elko

^13 tWiiincimuca • Klk( 0^15 25on 23 D 33 26 on^^

10^^11A 32

D' Lander Eureka

White PineA n 35 A 3inrn28 GROUP A-O GROUP B-D GROUP C-O GROUP D-A GROUP E-0 Nye

northeastern Nevada. The group Fig. 1. Location of detailed study sites in Elko and White Pine counties of designations indicate the location of the five TWINSPAN groupings.

ther elucidate the environmental factors asso- Axis 2 (Fig. 2) represents a gradient signifi- ciated with distribution of these stands of veg- cantly correlated with increasing elevation, a some- etation. Axis 1 (Figs. 2, 3) is significandy cor- higher solar radiation intensities, and related with decreasing latitude. A what reduced number of species. Elevation north-south distribution of the stands goes along the gradient increases from 2,600 to from approximately 41 degrees to 39 degrees 2,800 m. The radiation index increases from significant re- North latitude. This axis is also significantly 42 to 45 with a very slight but correlated with a significant reduction in the duction in the number of species. number of species/stand from 22 to 18. The distribution of the A.xis 3 standard devi- 128 Great Basin Naturalist Vol. 47, No. 1

200

9f^ Artemisia Iridentata/Symphoricarpos oreophiluslAgropyron spicatum • Artemisia tridentatalSymphoricarpos oreophiluslAgropyron trachycaulum 180 O Artemisia tridentatalSymphoricarpos oreophiluslFestuca idahoensis

Symphoricarpos oreophilusiArtemisia tridentatalAgropyron spicatum

D Symphoricarpos oreophilusiArtemisia tndentatalFestuca idahoensis 160 TWINSPAN Groups A thru E

140

120

w 5 100 - X o < »

S 80 -

- 40

20 -

20 40 60 80 100 120 140 NORTH Decreasing number of species AXIS-1

Fig. 2. DECORANA ordinations of Axis 1 and Axis 2 with separation of the five plant associations interpreted from the association table. Lines circle the TWINSPAN groups.

ations showed significant correlations with de- pos oreophiluslAgropyron trichophoriim creasing grass cover, shrub cover, and total sites are found at southern locations within vegetation cover along with an increase in the the study area and Artemisia tridentatalSy7n- number of species per stand from 17.6 to 21.5. phoricarpos oreophilusiAgropyron spicatum Grass cover decreased from 5.9 to 0.9%, stands are found further north. The other shrub cover from 57.2 to 36.1%, and total three plant associations are found at interme- vegetation cover from 65.7 to 37.6%. diate latitudes. Total vegetation cover was Ordination of the 37 stands in this study highest for Artemisia tridentatalSymphori- showed significant relationships to environ- carpos oreophiluslFestuca idahoensis stands.

mental factors. The first axis (Axis 1) is related Soils to latitude and species number in the stand and Axis 2 to elevation increases and the asso- Soils associated with these mountain brush ciated higher solar radiation intensities. Axis 3 associations are primarily mollisols or alfisols, is representative of a reduced level of shrub, although two are inceptisols. Well over half grass, and total vegetation cover. have argillic horizons that are not restrictive Further comparisons between the plant as- to rooting. pH values are generally near neu- sociations and the TWINSPAN groups show tral or slightly acidic. Epipedons are either that the Artemisia tridentatalSymphoricar- ochric or mollic with a few more of the latter. January 1987 TUELLER, ECKERT: NEVADA PLANT ASSOCIATIONS 129

200 s.d.

^ Artem/sia tridentatalSymphoricarpos oreophilusiAgmpyron spicalum tridentatalSymphoricarpos oreoptiiluslAgropyron tractiycaulum 180 Artemisia O Artemisia tridentatalSymphoricarpos oreophiluslFestuca idahoensis Symphoricarpos oreophilusiArtemisia tridentatalAgropyron spicatum D Symphoricarpos oreophilusiArtemisia tridentatai Festuca idahoensis 160 - TWINSPAN Groups A thru E

140

86^ 100 120 140 220 s.d. Decreasing number of species m NORTH SOUTH AXIS-1

Fig. 3. DECORANA ordinations showing A.xis 1 and Axis 3 with separation of the five plant associations interpreted fi-om the association table. Lines circle the TWINSPAN groups.

The soil family textural classes are mostly fine- layers, and relatively high organic matter. loamy, indicating good plant growth and rooting characteristics. Those soils that are clayey Discussion are also skeletal and indicate a good rooting

medium (Table 7). Mountain brush rangeland associations Soils supporting Festuca idahoensis have a dominated by either Artemisia tridentata deeper solum (A + B horizon) that averages 79 vaseyana or Symphoricarpos oreophihis have cm, while those soils supporting stands of ei- not been studied extensively. The works of ther Agropyron spicatum or Agropyron tra- Blackburn et al. (1968a, b, c, 1971a) list only a chaycaulum have a solum depth averaging few such associations. Most studies of the only 68 cm. The Festuca idahoensis sites also ecology of A. tridentata vegetation have gen- have a higher litter cover, lower bare soil erally ignored these low-acreage, high-pro- surface, and lower gravel and stone cover than ducing plant associations. do surface soils on the more xeric Agropyron Blackburn et al. (1969a) described an spicatum and Agropyron trachycauhim asso- Artemisia tridentatalSymphoricarpos vac- ciations. These soils are generally well cinoides association in western Nevada with drained, loamy, deep, sometimes rocky, and 30% cover of A. tridentata and only 3% cover dark colored with manv roots, no restrictive for S. vaccinoides. Blackburn et al. (1968a, 130 Great Basin Naturalist Vol. 47, No. 1

EIGENVALUE

.385

.348

.311

.274

.237

.200

.163

.126

.089 n

3 25 26 1 2 4 5 6 7 1120 21 23 24 27 28 29 30 31 33118 9 10 11||32 34 35 36 371116 17 22 19 12 14 15 18 13 I |

GROUP A GROUP B GROUP C GROUP D GROUP E

Fig. 4. TWINSPAN dendrology showing the separation of five groupings of the 37 study plots.

1971) described a low sagebrush association, nities relative to most other sagebrush-domi- Artemisia longiloba/Poa sandbergii, and an nated plant associations. Both Daubenmire Artemisia tridentatalAgropijron smithii/Poa (1970) and Franklin and Dyrness (1969) de- nevadensis association, both of which contain scribed the Festuca idahoensisi Symphoricarpos some S. oreophihis. Additionally, they de- alhus habitat type. Daubenmire found that the

scribed an Artemisia t ridentatal Symphoricar- total production of all vasculars was 30gm " while pos oreophiluslAgropijron spicatum associa- total grass production was 105m"". tion with 16.3% cover for Artemisia and The groupings differentiated with the

15.6% cover for Sipnphoricarpos . The same TWINSPAN dendrogram, apart from Groups association has 2.0% cover (or Agropijron spi- A and C, do not show a strong relationship catum and 1.0% cover for Festuca idahoensis. with the subjectively determined associations Several low serai communities were de- based on dominant species. Group A includes scribed that have some Symphoricarpos. primarily Symphoricarpos oreophiluslArte- They were Artemisia tridentata/Chrysotham- misia tridentatalAgropyron spicatum plant

nus viscidiflorus/Poa sandhergii/Wyethis mol- associations. Group C is made up of the lis, Artemisia tridentata/Chrysothamnus vis- Artemisia tridentatal Symphoricarpos ore- cidiflorus/Sitanion hystrix, and Artemisia ophiluslAgropyron spicatum plant associa- tridentatalPoa sandhergiilBalsamorhiza sag- tion. The other groupings all show greater ittata. Also they described an Artemisia tri- variability. This suggests that objective classi- dentata (10.2% cover)/Symphoricarpos ore- fication approaches based on presence and ophihis {4.5%)/Amelanchier paUida (4.5%) absence of all species may give classifications association. Mooney (1985) recently de- that differ substantially from those based on scribed seven Artemisia tridentata vaseyana the presence of designated dominant species plant associations in the Great Basin. Many of which were done here in the association table these stands contain Symphoricarpos ore- analysis. ophihis. The Artemisia-Syrnphoricarpos associa- Little biomass productivity data for these tions may represent a moisture gradient as sites are available. However, their relatively one goes from high Artemisia to low Symphor- greater number of species, deeper soils, and icarpos and the reverse. They do represent higher total ground cover lead to the conclu- relatively low-acreage, high-producing sites sion that production is high for these commu- within the Artemisia vegetation. January 1987 TUELLER, ECKERT: NEVADA PlANT ASSOCIATIONS 131

Acknowledgments Daubenmire. R F 1952. Forest vegetation of northern Idaho and adjacent Washington and its bearings on concepts of vegetation classification. Ecol. The authors are indebted to Kenneth R. Monogr. 22: 301-330. for assistance in gathering data; to Riemer 1970. Steppe vegetation of Washington. Washing- Harry Summerfield and F. F. Peterson for ton Agric. Expt. Sta. Tech. Bull. 62. 131 pp.

assistance in classification of soils; to Hugh Fr.\nk, C , and R Lee. 1966. Potential solar beam irra- on slopes. Tables for 30° to 50° latitude. Mozingo for identification oi certain taxa; and diation L'.S. Forest Service Research Paper RM-18. 116 to Ed Kleiner, Stan Smith, and Robin Tausch pp. for review of the manuscript. Hanson. H. C, and E. D Churchill 1961. The plant community. Reinhold Publishing Corp., New York. 218 pp. Literature Cited Hill, M. O 1979. DECORANA, a FORTRAN program for arranging multivariate data in an ordered two- Blackburn. W H 1967. Plant succession on selected way table by classification of the individuals and habitat types in Nevada. Unpublished thesis. Uni- attributes. Ecology and Systematics, Cornell Uni- versity of Nevada, Reno. 162 pp. versity, Ithaca, New York. Blackburn. W. H., P T. Tueller. and R E Eckert. Jr Hunt, C B 1967. Physiography of the United States. W. 1968a. Vegetation and soils of the Crowley Creek H. Freeman and Co., San Francisco. 480 pp. Watershed. Univ. Nevada E.xpt. Sta. Bull. R 42. McArthur. E 1979. Sagebrush systematics and evalua- 60 pp. tion. Pages 14-22 in Proceedings Sagebrush 1968b. \'egetation and soils of the Duckwater Water- Ecosystem Svmposium, Utah, April 1978.

shed. Univ^ Nevada E.xpt. Sta. Bull. R40. 80 pp. MOONEY, J 1985. A preliminar>- classification of high-ele- 1968c. Vegetation and soils of the Mill Creek Water- vation sagebrush-grass vegetation in northern and shed. Univ. Nevada Expt. Sta. Bull. R43. 72 pp. central Nevada. Lhipublished thesis. University of 1969a. Vegetation and soils of the Churchill Nevada. 118 pp.

Canyon Watershed. Univ. Nevada Expt. Sta. Passey, H B . AND V. T HuGiE 1962. Sagebrush on relict Bull'. R 45. 157 pp. ranges in the Snake River plains and northern 15: 273-278. 1969b. Vegetation and soils of the Pine and Great Basin. J. Range Manage. quantitative Mathew Canyon Watersheds. Univ. Nevada POULTON, C E , AND E. W. TiSDALE 1961. A Expt. Sta. Bull. R46. Hipp. method for the description and classification of 13-21. 1969c. Vegetation and soils of the Cow Creek range vegetation. J. Range Manage. 14:

Watershed. Univ. Nevada Expt. Sta. Bull. R 49. WiNWARD, A H . AND E W TiSDALE 1969. A simplified 80 pp. chemical method for sagebrush identification. 1969d. Vegetation and soils of the Coils Creek Forest, Wildlife, and Range Expt. Sta. Note No. Watershed. Univ. Nevada E.xpt. Sta. Bull. R 48. 11, March 1969. 81pp. Zamora. B., and P T. Tueller. 1973. At-tcmisia arbus- 1971. Vegetation and soils of the Rock Springs ctila, A. longiloba, and A. nova habitat types in Watershed. Univ. Nevada E.xpt. Sta. Bull. R 83. northern Nevada. Great Basin Nat. 33(4): 116 pp. 255-264.