s 5U1»5247 Nl Icpct CLASSIFICATION OF THE PLANT COMMUNITIES OF BEAVERHEAD, SILVER BOW, AND MADISON COUNTIES, MONTANA VOLUME I (text) Robert L. DeVelice Montana Natural Heritage Program 1515 East 6th Ave., Helena, MT 59620 STATE DOCUMENTS COLLECTIOri SEP 0';i992 MONTANA STATE LIBRARY 1515 E. 6th AVE. HELENA, MONTANA 59620 1992 Montana Natural Heritage Program for Bureau of Land Management State Office Billings, Montana Assistance Agreement No. E950-A1-0006 Task Order No. 4 This document should be cited as follows: DeVelice R.L. 1992. Classification of the plant communities of Beaverhead, Silver Bow, and Madison counties, Montana. Volume I (text). Montana Natural Heritage Program, Helena, MT. 3 5 pp. HfM"" fi % % t-'.-m 3/27/92 m 2 8 1996 MISSION STATEMENT This study on Bureau of Land Management (BLM) lands is a working component of the Montana Natural Heritage Program's (MTNHP) grasslands/shrublands ecological classification project (GSCP) and The Nature Conservancy's ecology program in the western United States. The Nature Conservancy program provides key information on plant communities to be used for conservation planning, management, research, and monitoring. Although grasslands and shrublands cover about 65% of the Montana landscape, an exhaustive review of existing information (MTNHP 1990) revealed them to be the least documented vegetation types of the state. Therefore, the GSCP is designed to complete the classification over the full range of ecological conditions and to conduct regional correlations of existing classifications. The information provided by the project will be the basis for programs to model the effects of management, global changes, and other variables on the vegetation types and diversity patterns, and their implications for further management and conservation planning. The project will continue to focus on strong collaborative work with the various state and federal agencies (BLM, USFS, DSL, BIA, DOD) and other institutions (e.g. Montana universities) in order to contribute to the development of a tightly integrated state-wide classification system. ABSTRACT Interrelationships between vegetation composition and environ- ment were studied using 52 vegetation plots sampled in southwestern Montana. Using a combination of two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) 21 community types were identified. Of these types, three have not previously been described in the western United States and five have not previously been reported in Montana. All eight of these types appear to be rare in Montana. Additionally, eight TES plant species were observed within the set of sample plots. A total of 14 0 community types have now been documented from southwestern Montana, 54 of which are rare. CONTENTS INTRODUCTION ACKNOWLEDGEMENTS PREVIOUS RESEARCH STUDY AREA . . . Physiography Climate . . METHODS Data Collection , . , . Data Analysis Taxonomic Considerations 4 4 5 5 5 6 12 RESULTS AND DISCUSSION Community Type Classification Vegetation-Environmental Relationships Community Type Descriptions 1. Pinus albi caul is- Abies lasiocarpa 2 . Pinus f lexilis/Aqropyron spicatvim 3. Pinus f lexilis/Cercocarpus ledifolius . . . 4 . Pseudotsuqa menziesii/Cercocarpus ledifolius 5. Juniperus scopulorum/Artemisia tridentata 6. Juniperus scopulorum/Cercocarpus ledifolius 7 . Artemisia arbuscula/Aqropyron spicatvim . 8. Artemisia tridentata/Aqropyron spicatum 9 . Artemisia tridentata/Festuca idahoensis 10. Artemisia tripart it a/Fes tuca idahoensis 11. Atriplex nuttallii/Oryzopsis hymenoides 12. Cercocarpus ledifolius/Aqropyron spicatum 13. Cercocarpus ledifolius/Festuca idahoensis 14. Aqropyron dasystachyum/Phacelia hastata 15. Aqropyron spicatum/Oryzopsis hymenoides 16. Picea enqelmannii/Equisetum arvense . . . 17 . Populus trichocarpa/Cornus stolonifera . . 18. Salix exiqua 19. Aqropyron smithii 20. Elymus cinereus 21. Phalaris arundinacea , Special Status Plant Observations CONCLUSIONS LITERATURE CITED 12 12 12 17 17 18 18 19 20 20 21 22 22 23 24 24 25 25 26 27 27 28 29 29 30 30 32 33 INTRODUCTION This study provides a classification of plant communities in southwestern Montana. The emphasis was on locating and describing rare or previously undescribed communities and common communities in good to excellent ecological condition on selected BLM lands in the Headwaters and Dillon Resource Areas. The comprehensive class- ification was based on the integration and synthesis of both existing data and newly sampled plots. This classification will be useful in identifying sensitive communities and natural areas where management activities may need to be adjusted to maintain habitat values. Additionally, the classification provides a reference system for baseline monitoring of environmental impacts and vegeta- tion recovery and provides an ecological basis for categorizing environmental variation. This work represents a step towards developing a comprehensive classification of Montana plant communities that will provide land managers and scientists a state-wide perspective of community variation (nation-wide when correlated with other state classifica- tions) . Such a perspective is invaluable towards making sound management prescriptions and predictions, designing and inter- preting experiments, and identifying areas of critical importance for conservation. This document is divided into three volumes: Volume I provides text describing previous research, the study area, the methods used, and results of this study. Volume II provides appendices containing detailed plant community and site data recorded during this study. Volume III provides close-up and aspect photographs from each site, referenced by plot numbers. ACKNOWLEDGEMENTS The author gratefully acknowledges the financial assistance provided by the USDI Bureau of Land Management and the Montana Natural Heritage Program. Additionally, Bureau of Land Management assistance in locating and assessing some of the field sites was greatly appreciated. The author appreciated the assistance provided by Peter Achuf f and Alistair McAlpine during the initial stages of fieldwork. Peter Achuf f and Lisa Roe provided invaluable assistance in voucher specimen identification. Finally, appreciation is extended to Margaret Beer, Cedron Jones, and Diana Schwab for their conscien- tious assistance in data entry and data quality control. PREVIOUS RESEARCH Grasslands and shrublands cover about 65 percent of the Montana landscape yet are the most poorly described vegetation types of the state. In contrast, the classification of the forest types of Montana is largely complete. Filling the gap in grass- land/shrubland community type characterization constitutes a primary goal of the Montana Natural Heritage Program's grasslands/ shrublands ecological classification project of which this study is a component. This study constitutes a major and necessary step towards developing a comprehensive classification of all Montana plant communities. To date, studies characterizing grassland and shrubland communities of Montana have been of limited geographical and ecological scc.e. The most extensive existing studies include Mueggler and Stewart's (1980) in western Montana, Jorgensen's (1979) and Harvey's (1982) studies in central Montana, the DeVelice et al. (1991) study in northeastern Montana, and Hansen (1985) and Hansen and Hoffman's (1985) work in southeastern Montana. The classification of Montana's upland forest plant associa- tions provided by Pfister et al. (1977) has been refined and extended by the work of Cooper and Pfister (1981; 1985), Hansen and Hoffman (1985), Hoffman and Hansen (1981), and Roberts (1980). A comprehensive classifications of Montana riparian sites (including forested, shrub dominated, and herb dominated communities) is nearing completion (Hansen et al. 1991). Prior to initiating field sampling, literature review and data from previous research were used to develop a preliminary classifi- cation of southwestern Montana's plant communities. Forested communities in the study area have been largely described by Pfister et al. (1977) and riparian community types have been defined by Hansen et al. (1989). Mueggler and Stewart (1980) provide a relevant classification for the area but emphasized more common communities and predominantly sampled USDA Forest Service lands in their study. The present study is largely an expansion of Mueggler and Stewart's work to include descriptions of rare communities and also extends sampling onto selected BLM lands. STUDY AREA The study area basically includes the southern portion of Silver Bow County, the western portion of Madison County, and the eastern portion of Beaverhead County. Physiography The study area encompasses approximately 2.5 million acres and ranges in elevation from about 4,500 feet on the Beaverhead River at Silver Star to 11,150 feet at the summit of Torrey Mountain in the Pioneer Mountains. The diverse topography of the area is matched by a diversity of soil parent materials including hard coarse-grained metamorphic rocks, limestone, shale, sandstone, intrusive and extrusive igneous rocks, and valley fill sediments (Veseth and Montagne 1980) . The Pioneer Mountains and the Beaver- head, Gravelly, Snowcrest, and Centennial ranges all featured alpine glaciation during the Pleistocene (Montagne 1972) . Climate Most of the study area experiences a continental climate. Average annual precipitation varies from over 50 inches at the crest of the Pioneer Mountains to between 8 and 16 inches through- out the bulk of the study area (see sheets 3 and 4 in Ross and Hunter 1976) . The average length of the freeze-free season varies from less than 30 days to more than 70 days at high and low eleva- tions, respectively (see Figure 13 in Montagne et al . 1982). METHODS Data Collection Most field sampling was restricted to ten areas specifically selected by the USDI Bureau of Land Management. The ten areas examined and the survey acreages specified in the assistance agree- ment were as follows: 1. Centennial Sandhills (2400 acres) 2. Lime Gulch - Moose Creek (1000 acres) 3. Sheep Creek - Cabin Creek Slide (1000 acres) 4. Block Mountain - Hogback (500 acres) 5. Hahnkamp Island (50 acres) 6. Nemesis Mountain (100 acres) 7. Big Hole - Charcoal Gulch (350 acres) 8. Scudder Creek Exclosure (200 acres) 9. Johnson Creek Exclosure (200 acres) 10. Maiden Rock Exclosure (200 acres) General descriptions of each of these sites, including assess- ments of their biodiversity significance, current and past landuse, and suggested conservation management needs, appear in Volume II, Appendix A. In addition to the 10 sites listed above, the site basic records provided in Volume II, Appendix A include eight additional sites not specified in the assistance agreement. Within each of these areas, sampling focused on rare or previously undescribed communities and on common communities in particularly good condition. To minimize the confounding nature of heavy disturbance on vegetation occurrence, areas severely over- grazed, herbicide treated, mechanically disturbed, artificially seeded, or irrigated were not sampled. Plots were established within portions of stands that appeared to be relatively uniform in topography and vegetation structure. Within an area, one to five plots were chosen from different topographic positions and where judgement indicated a marked change in vegetation composition. Plot selection focused on contemporary stands of vegetation without reference to successional relationships among stands. No attempt was made to solely sample remnants of presettlement vegeta- tion. The data were recorded on Natural Heritage Program Community Survey (Figure 1) and Reconnaissance Soil Characterization (Figure 2) forms for each plot, and Site Survey Forms (Figure 3) for each site. Instructions for completing these three forms are provided in DeVelice (1991). The Community Survey Forms are basically the same as the general plot data and ocular plant species data forms used by the USDA Forest Service (USDA 1987) . Complete lists and canopy cover estimates of vascular plant species were recorded within each 375 m^ circular study plot. Site information such as altitude, slope, aspect, parent material, landform, and erosion characteristics were also recorded for each plot. A 20-inch deep reconnaissance soil pit was excavated at each site and information was collected to determine soil subgroup and available water holding capacity. Data Analysis Analysis focused on using a combination of classification, to determine community types, and ordination (gradient analyses), to describe general patterns of communities in relation to environ- mental factors. Classification was accomplished using two-way indicator species analysis (TWINSPAN; Hill 1979a) in the CEP MS-DOS computer package (Mohler 1987). Ordination was achieved using the detrended correspondence analysis (DCA) algorithm in the CANOCO computer package (Ter Braak 1988) . The input data were species cover variables recorded in each plot. Both TWINSPAN and DCA are based on the same mathematical strategy (i.e., reciprocal ave- raging; Hill 1979a, b) and thus offer direct comparisons between the results of ordination and classification. All default options in the TWINSPAN algorithm were used except that pseudospecies cut levels were set at 0, 5, and 20 percent cover. Also, all default options were used in running the ordina- tions except that rare species were downweighted. First, the entire data matrix of 52 stands and 268 species were analyzed. Second, to reduce the amount of variation being considered, which is substantial in the whole matrix, the species list was thinned to the 55 most characteristic species. COMMUNITY SURVEY FORM mtnhp 5/27/91 GENERAL PLOT DATA IDENTIFICATION Al PLOT NO. ^D LOCATION MO MANUAL UNITS DAY YEAR EOCODE _ft m * EXAMINER (s) PNC CT SITE STATE COUNTY PURP PREC T/ R/ PLOT TYPES PHOTOS QUADNAME S/ 4S/ PLTRL QUADCODE 4/4 COMMUNITY SIZE (acres) PLOT W SURVEY DIRECTIONS — > CONSERVATION RANKING COND Com: VIAB Com: DEFN Cora: RANK _ _ Com: MGMT: PROT: ENVIRONMENTAL FEATURES DL SOIL RPT SOIL UNIT SOIL TAXON PM LANDFORM PLOT POS SLP SHAPE ASP SLOPE % ELEVATION EROS POTENT EROS TYPE HORIZON ANGLE (%): N E S W IFSLP IFVAL SPFE GROUND COVER: S+ G+ R+ L+ W+ M+ BV+ O ' = 100° DISTURBANCE HISTORY (type, intensity, frequency, season) — > RIPARIAN FEATURES: Channel Width Channel Entrench_ Surface Water Ht.Abv.H20 Dist. from H20 GENERAL SITE DESCRIPTION (landscape features and adjacent ct's) Figure 1. Example of community survey form used, 7 OCULAR PLANT SPECIES DATA PltlDL PLOT NO. NO. SPECIES PNC COMMENTS (EODATA) — > TREES Tot Cv Tal Cv Low Cv HHt Med Cv Grd Cv CC FRBS Tot Cv Med Cv Grd Cv' MHt Low Cv CC T 1 / F 1 F 2 F 3 F 4 F 5 F 6 F 7 F 8 F 9 FIO Fll F12 F13 F14 F15 / T 2 / / T 3 / / T 4 / / T 5 / / / SHRBS Tot Cv Tal Cv Low Cv MHt Med Cv Grd Cv cc / / / / S 1 / / / S 2 / S 3 / / S 4 / / S 5 / / S 6 / / S 7 / / S 8 / / S 9 / / SIO / / 511 / / S12 / / / GRAM Tot Cv Med Cv Grd Cv MHt Low Cv CC / / / / G 1 / / G 2 / / G 3 / / G 4 / / G 5 / / G 6 / / G 7 / / G 8 / G 9 / FERN Tot Cv_ BRYO/LICH MHt Med < Low Cv Grd ( Tot Cv GIO / ~'V Gil / -V G12 / Figure 1. (continued) RECONNAISSANCE SOIL CHARACTERIZATION FORM MTNHP 5/29/91 IDENTIFICATION PLOT NO. MO DAY YEAR EST SOIL DEPTH EXAMINER (s) SOIL SUBGROUP ■ SOIL DESCRIPTION HORZ 1 DEPTH (cm) to TEXTURE_ STRUG COLOR FRAGS EFFER_ NOTES HORZ 2 DEPTH (cm) to TEXTURE_ STRUG COLOR FRAGS EFFER_ NOTES HORZ 3 STRUC DEPTH (cm) COLOR to FP-AGS TEXTURE EFFER NOTES HORZ 4 STRUC DEPTH (cm) COLOR to FRAGS TEXTURE EFFER NOTES HORZ 5 STRUC DEPTH (cm) COLOR to FRAGS TEXTURE EFFER NOTES Figure 2. Example of reconnaissance soil characterization form used. SITE SURVEY FORM MTNHP 5/27/91 IDENTIFICATION AND LOCATION SITENAME MO DAY YEAR COUNTY : QUADNAME ; .T/ R/. .T/ R/. DIRECTIONS MANUAL STATE EXAMINERS QUADCODE: SECTION(s) ^SECTION (s) ELEMENT OCCURRENCES Date: Element Name Occ. No. Plot No. Found? Found? Found? REVISIT NEEDS — > SITE DESCRIPTION/DESIGN SITE DESCRIPTION — > TOPOGRAPHIC BASE MAP: yes no 1. element locations and/or boundaries? yes no 2. both primary and secondary boundaries? Figure 3. Example of site survey form used. 10 BOUNDARY JUSTIFICATION — > PROTECTION URGENCY Ul immediate threat U2 threat w/i 5 yrs U3 threat but not w/i 5 yrs U4 no threats U5 land protected PU COMMENTS: MANAGEMENT URGENCY Ml needed this year M2 needed w/i 5 yrs (or loss) M3 needed w/i 5 yrs (or degrade) M4 may be needed in future M5 none needed MU COMMENTS: STEWARDSHIP LAND USE COMMENTS — > POTENTIAL HAZARDS — > EXOTIC FLORA/FAUNA COMMENTS — >_ OFF-SITE CONSIDERATIONS--> SITE AND ELEMENT MANAGEMENT NEEDS — > OixtlCH MAP (e.g., show: (1) EO locations, (2) study plots, (3) natural landmarks, (4) disturbance features, such as structures, trails, logging areas, etc... Include cross section if possible. Include scale and Indicate north.) Figure 3. (continued) 11 In some instances, a particular TWINSPAN class included a plot or plots that, based on field experience and ordination patterns, appeared to be better placed in a different existing TWINSPAN class. These plots were repositioned in the classification as appropriate. In addition to helping refine the classification, ordination assisted in describing and interpreting general patterns of vegeta- tion communities and environment. For example, DCA extracts the dominant compositional gradients from the species data matrix. The environmental controls of these compositional gradients are then interpreted based on comparisons with the site data. Taxonomic Considerations Nomenclature follows Hitchcock and Cronquist (1973) except for Arabis f ecunda and Lesguerella paysonii which follows Rollins (1984) and Rollins and Shaw (1973) , respectively, and Mertensia lanceolata which follows Dorn (1984). Scientific names of all species observed in this study and their code names are listed in Volume II, Appendix B. RESULTS AND DISCUSSION Community Type Classification Classification of the 52 study plots resulted in the defini- tion of 21 community types. These and 119 additional community types documented in southwestern Montana (but not sampled in this study) are listed in Volume II, Appendix C. A table of average species cover and constancy within each of the 21 sampled community types is provided in Volume II, Appendix D. Vegetation and site characteristics of each sample plot are given in Volume II, Appendix E and F, respectively. Additional general information describing each sample plot is provided as element occurrence records in Volume II, Appendix G. Finally, Volume II, Appendix H provides a comprehensive listing of condensed plant and community element occurrence records (from the MTNHP database) on BLM lands within Beaverhead, Silver Bow, and Madison counties. Vegetation-Environmental Relationships The DCA ordinations based on the 55 most characteristic species in the data set are presented in Figures 4 through 7. Ordination of all 52 plots indicates that 45 plots lie near the origin of the first and second axes and that the six riparian community types occur as outliers (Figure 4). When the first and 12 t/1 0 ©I 1© >! 0) a >i . -n (0 -^ g e o o 4-> < u Q -a c o u 0) U5 0) TJ I) (0 4J . tn c v^ o 0-1 4J -H 0) Ul r O jj Q4 IJ< c c o O -H . 4-1 T! c a w 0) T3 u o Q) (fl O a-P_g tn «3^ CM +J ^ O y) rH a o (0 (D c O c o ■M 4-) XI ■P c 0) c ^ U •H Q 4-) (0 u • -H C a) -H 3 c o -H 4J a o 0) T3 • c I c ) I < ( 1 © "Q < a, ^ s. e e o u < u Q -a u 0) ■p *^ T3 0) ^ S ■H O en r- "^ fl 0) » C t/l -P T3 O >-( U5 rH O 0) a -a jj o OJ (0 o '-• s: e x: ■^ -p -^ OJ^ O "^ O u, '-' c ^ a o "^ o V *«-" o c O -H O r; T) ^ o w o Q 0) 4J p a u u ^ •-' " c o 3 t^ •H < 4-> x: -P (0 tn 4-1 o m 0) T3 o u x: -p u-i o c o o c 0) O 1^-1 o T3 C < IT3 U Q C fl -a ■p •H u w 13 0) a 13 c (0 ■p m u (4-1 I c o c 0) jC ■P (w O •H O -^ *^::^^ 3 (0 •H tn (-1 +j ■p o U3 ^ 0) (1) OJ CO ■P o c " -p i-H C • • a-H T3 ^ g T3 0) CC U m u 3 en in 0) u -1 o cm-( e fl U1 w c 0 T3 -H CD +J ■p a (TJ -H c u ■H 0 e m o q; 1 1 O m o a >i U iJ o — >■ TJ jj -l tjl m -P c c U) 0 o •H rH •H Q n3 -p •H W c • 4-) •H r- 0 U-l rH 0) 0) aT3 ^^ 3 C n vO third axes are shown (Figure 5), the high elevation Pinus albicaulis-Abies lasiocarpa community type joins the riparian types as an outlier. The Picea enaelmannii/Equisetum arvense, the Salix exiqua, the Phalaris arundinacea, the Populus trichocarpa/Cornus stolonifera. and the Elymus cinereus community types are the most extreme outliers, highlighting their unique vegetation composition among the community types sampled. Ordination of the 4 3 non-riparian and non Pinus albicaulis- Abies lasiocarpa sample plots along the first and second axes is shown in Figure 6. The vertical axis appears to follow a soil disturbance gradient with the Aqropyron dasvstachyum/Phacelia hastata sand dune type and the Aqropyron spicatum and Atriplex nuttallii/Oryzopsis hymenoides badlands types on one end of the axis relative to sites on less erosive substrates. The horizontal axis basically follows a gradient of increasing slope steepness, soil coarse fragment content, and probability of limestone occur- rence from left to right. The five Cercocarpus ledifolius domi- nated or co-dominated types (20 plots) are clustered together in the right half of the second axis. Ordination of the 20 Cercocarpus ledifolius dominated or co- dominated sample plots along the first and second axes is shown in Figure 7. Considerable similarity in vegetation composition occurs among the five community types identified as suggested by the single C^ ledifolius cluster in Figure 6 and the overlap among four of the five types in Figure 7. Only the single C^ ledifolius/ Festuca idahoensis occurrence does not overlap with the other community types (Figure 7) . The primary distinguishing feature in composition among the C_^ ledifolius types is the presence (often with less than 5% canopy cover) or absence of a coniferous tree species. Environmentally, occurrences in the upper left hand quarter of the ordination are predominantly found on limestone derived substrates. Other locations within the ordination space have a lower probability of limestone occurrence. Community Type Descriptions 1. Pinus albicaulis-Abies lasiocarpa Type (PINALB-ABILAS; whitebark pine-subalpine fir; G5 S5) Vegetation. — Pinus albicaulis , Abies lasiocarpa , Picea engel- mannii . and occasionally Pseudotsuqa menziesii occur in varying amounts in the often open, stunted, and wind-deformed tree layer. The undergrowth is highly variable in composition and few individual species ever exceed 5% cover. Physical Setting. — The type occurs on glaciated mountain ridges and upper slopes at elevations above 8900 feet. The total cover of soil, gravel, and rock exceeds 50%. The soil surface is often unstable because of a lack of adequate vege- tation cover. 17 Soils are typically gravelly to very gravelly, feature a cryic temperature regime, and may be strongly to violently effervescent. Textures are sandy loams to loams. Soil depth is shallow to moderately deep. Available water holding capacity varies from low to medium. Adjacent Communities. — This type occurs at, or near, upper timberline. It is often bordered below by the Abies lasio- carpa-Pinus albicaulis/Vaccinium scoparium type and above by alpine scrub. Unvegetated talus slopes sometimes interfinger with this type. Other Studies. --This type has been described in Montana by Pfister et al. (1977) . 2 . Pinus flexilis/Aqropyron spicatum Type (PINFLE/AGRSPI; limber pine/bluebunch wheatgrass; G5 S4) Vegetation. — Pinus f lexilis characterizes the very open tree layer. Artemisia spp. are often present in the shrub layer. Aqropyron spicatum is well represented to abundant and Hesperochloa kingii may be common. Physical Setting. --This type occurs on steep, dry forested slopes at elevations around 7000 feet. The total cover of soil, gravel, and rock, exceeds 50%. The soil surface is often unstable because of a lack of adequate vegetation cover. Soils are generally Entisols derived from calcareous parent materials, are moderately deep, and are often violently effervescent and very gravelly. Textures range from loams to silts. Available water holding capacity varies from low to medium. Adjacent Communities. --The type occurs adjacent to, or within, the grassland/ shrubland zone and is often transitional to communities in the Aqropyron spicatum, Artemisia tridentata , and Cercocarpus ledifolius series. Unvegetated talus slopes and limestone outcrops sometimes interfinger with this type. Other Studies. — This type has been described in Montana by Pfister et al. (1977) . 3. Pinus f lexilis/Cercocarpus ledifolius Type (PINFLE/CERLED; limber pine/mountain mahogany; G3? S3?) Vegetation. --Pinus f lexilis and Juniperus scopulorum charac- terize the very open tree layer. Abundant Cercocarpus ledifo- lius characterizes the undergrowth. Other species that are generally present with cover exceeding 1% include Arcto- 18 ^taphvlos uva-ursi, Hanlopappus acaulis, Agropyron spicatum, Carex rossii, and Orvzopsis hyroenoides. Physical setting.— The type occurs on steep dip slopes and residual mountain slopes at elevations between 6000 and 6800 feet. The total cover of soil, gravel, and rock exceeds 90^ on some sites and is always higher than 30% The^°il surface is usually unstable because of the general lack of adequate vegetation cover. Soils are derived from limestone parent materials and are Lithic Ustorthents and are often very gravelly. Textures vary from sands to loams. Strong effervescence characterizes the surface of most of the soils and violent effervescence is usually present within the profile. Available water holding capacity varies from low to high. Adiacent Communities.— Adjacent communities on deeper, less rocky, and more stable soils include Pinus f lexilis/Festuca idahoensis, Pseudotsuga menziesii/Agropyron spicatum, and Pseudotsuga menziesii/Festuca idahoensis. Other Studies.— This type has not previously been reported in Montana but has been reported in Idaho, Utah, and Wyoming (Bourgeron and Engelking 1991) . 4. Pseudotsuga menziesii/cercocarpus ledifolius Type (PSEMEN/CERLED; Douglas-fir/mountain mahogany; G3? S3?) vegetation.— Pseudotsma menziesii characterizes the open tree layer, sometimes in association with Juniperus scopulorum. Abundant Cercocarpus ledifolius characterizes the undergrowth. Other species that are generally present with cover exceeding 1% include Artemisia frigida. A^ tridentata, and Agropyron spicatum. Physical setting.— The type occurs on generally steep residual mountain slopes and ridges at elevations between 5900 and 6600 feet. The total cover of soil, gravel, and rock ranges from 40 to 90%. The soil surface is usually unstable because of a general lack of adequate vegetation cover. Soils are generally derived from igneous or metamorphic parent materials and are non-effervescent (not calcareous). Textures vary from sands to clay loams and are gravelly to very cobbly. Soil depth varies from shallow to moderately deep. Available water holding capacity varies from low to medium. Adjacent Communities. —Forested communities on adjacent more mesic and less rocky sites include Pseudotsuga menziesii/ 19 Festuca idahoensis and P^ menziesii/Agropvron spicatum. Adja- cent grasslands and shrublands include Aqropyron spicatum/Poa sandberqii and Artemisia trident at a/ Aqropyron spicatum. res- pectively. Other Studies. --This type has not previously been reported in Montana but has been reported in Idaho, Utah, and Wyoming (Bourgeron and Engelking 1991) . Juniperus scopulor\im/ Artemisia tridentata Type (JUNSCO/ARTTRI; Rocky Mountain juniper/big sagebrush; G2? S2?) Vegetation. --Juniperus scopulorum is the only tree species present. Species exceeding 5% cover in the undergrov/th include Artemisia tridentata, Opuntia polyacantha, Aqropyron spicatum, Aristida lonqiseta. Bouteloua gracilis. Oryzopsis hymenoides, and Stipa comata. Physical Setting. — The type occurs on plateaus and residual mountain slopes at elevations between 5500 and 6000 feet. The total cover of soil, gravel, and rock averages 70%. The soil surface is sometimes unstable because of a lack of adequate vegetation cover. Soils are generally shallow or very shallow (i.e., lithic) and are derived from igneous or sedimentary parent materials and feature strong to violent effervescence. Tex- tures vary from sandy loams to silt loams and are gravelly to very gravelly. Available water holding capacity varies from low to medium. Adjacent Communities. — The Artemisia tridentata/ Aqropyron spicatum community type often occurs on adjacent less rocky sites with deeper soils. More mesic sites with similar soils feature the Juniperus scopulorum/Cercocarpus ledifolius community type. Other Studies. --This type has not been previously described but has been reported as a possible type in Colorado and Wyoming (Bourgeron and Engelking 1991) . Juniperus scopulorum/Cercocarpus ledifolius Type (JUNSCO/CERLED; Rocky Mountain juniper/mountain mahogany; G3 S3) Vegetation. --Juniperus scopulorum is the only tree species present. Abundant Cercocarpus ledifolius characterizes the undergrowth. Other species that are generally present with cover exceeding 1% include Artemisia f rigida, Opuntia polyacantha . Aqropyron spicatum, and Oryzopsis hymenoides . 20 Physical Setting. — The type predominantly occurs on steep dip slopes and residual mountain slopes at elevations between 5500 and 6500 feet. The total cover of soil, gravel, and rock usually exceeds 50% and the soil surface is often unstable because of a lack of adequate vegetation cover. Parent materials are predominantly quartzite or limestone and soils are generally Orthents and are shallow (lithic) and gravelly to very stony. Textures vary from loamy sands to loams. Most of the soils exhibit strong and/or violent effervescence. Available water holding capacity is mostly low due to the coarse soil textures, abundant coarse fragments, and shallow depth. Adjacent Communities. — The Juniperus scopulorum/Cercocarpus ledifolius and C^ ledifolius/Agropyron spicatum types are ecologically similar and intergrade. Of the two types, J. scopulorum/C. ledifolius occurs in slightly more mesic situa- tions. The J_^ scopulorum/ Artemisia tridentata and A^ triden- tata/Aaropvron spicatum types adjoin sl^ scopulorum/Cercocarpus ledifolius on drier sites. The Aqropvron spicatum/ Bout eloua gracilis type is often found on adjacent less rocky and less steep sites. Other Studies. — This type has been described in Montana by Chaffee (1981) . Artemisia arbuscul a/ Aqropvron spicatum Type (ARTARB/AGRSPI; low sagebrush/bluebunch wheatgrass ; G4G5 S3S4) Vegetation. — Artemisia arbuscula and Aqropvron spicatum are abundant within this community type and dominate the shrub and herb layers, respectively. Other species that are generally present with cover exceeding 1% include Artemisia friqida and Chrysothamnus nauseosus. Physical Setting. — The type predominantly occurs on steep, rocky slopes at elevations around 7000 feet. The total cover of soil, gravel, and rock usually exceeds 50% and the soil surface is often unstable because of a lack of adequate vegetation cover. Soils are generally deep Orthents and are very gravelly and sometimes violently effervescent. Textures are mostly loams. Available water holding capacity is low to medium. Adjacent Communities. — The Artemisia arbuscul a/ Aqropvron spicatum and A^ tridentata/ Aqropvron spicatum types are eco- logically similar and often adjoin one another. Of the two 21 types, the A^ tridentata type generally occurs on more mesic sites. Other Studies. --This type has been described in Montana by Mueggler and Stewart (1980). 8. Artemisia tridentata/Agropyron spicatum Type (ARTTRI/AGRSPI; big sagebrush/bluebunch wheatgrass; G5 S5) Vegetation. — Artemisia tridentata and Agropyron spicatum are abundant within this community type and dominate the shrub and herb layers, respectively. Other species that are generally present with cover exceeding 1% include Artemisia frigida . Opuntia polyacantha . Bouteloua gracilis , Poa sandbergii . and Stipa comata . Physical Setting. --The type occurs on flat to steep, rocky plateaus, dip slopes, and residual mountain slopes at eleva- tions between 5000 and 6000 feet. The total cover of soil, gravel, and rock ranges from 20 to 70% and the soil surface is stable with little or no evidence of accelerated erosion. Parent materials include igneous and metamorphic rocks. Soils are generally Calciorthids or Argiborolls and are grav- elly to very stony. The Calciorthid soils are violently effervescent in portions of the profile. Soil depth ranges from shallow to moderately deep. Textures are mostly loams to clay loams. Available water holding capacity ranges from low to high. Adjacent Communities. --The Artemisia tridentata/Agropyron spicatum and A_^ arbuscul a/ Agropyron spicatum types are eco- logically similar and often adjoin one another. Of the two types, the A_^ arbuscula type generally occurs on more xeric sites. The A_^ tridentata/Festuca idahoensis type occurs on more mesic and cooler sites. The Agropyron spicatum/ Bouteloua gracilis type is often found on adjacent less rocky and less steep sites. Other Studies. — This type has been described in Montana by Mueggler and Stewart (1980) , 9. Artemisia tridentata/Festuca idahoensis Type (ARTTRI/FESIDA; big sagebrush/Idaho fescue; G5 S4) Vegetation .--Artemisia tridentata and Festuca idahoensis are abundant within this community type and dominate the shrub and herb layers, respectively. Agropyron spicatum may also be well represented to abundant. Other species that are gener- 22 ally present with cover exceeding 1% include Koeleria cris- tata, Poa sandberqii , and Stipa comata. Physical Setting. — The type occurs on flat to steep residual mountain slopes and rolling uplands at elevations between 6000 and 7600 feet. The total cover of soil, gravel, and rock ranges from 40 to 60% and the soil surface is usually stable with little or no evidence of accelerated erosion. Parent materials include igneous and metamorphic rocks. Soils are generally Argiborolls and either lack coarse frag- ments or are gravelly to very gravelly. The soils are gener- ally not calcareous and, thus, are not effervescent. Soil depth ranges from shallow to very deep. Textures are mostly loams to clay loams. Available water holding capacity ranges from low to high. Adjacent Communities. — The Artemisia tridentata/Agropyron spicatum type occurs on more xeric and warmer sites. Other Studies. — This type has been described in Montana by Mueggler and Stewart (1980). 10. Artemisia tripart it a/Fes tuca idahoensis Type (ARTTRP/FESIDA; threetip sagebrush/Idaho fescue; G5 S3) Vegetation. — Artemisia tripartita . Festuca idahoensis . and Stipa comata are abundant within this community type. Other species that are generally well represented include Artemisia f riqida . Chrysothamnus viscidif lorus , Tetradymia canescens , Lupinus sericeus, Koeleria cristata , and Poa sandberqii . Physical Setting. --The type occurs on gently rolling uplands at elevations between 6500 and 7000 feet. Bare soil cover ranges from 10 to 30% and coarse fragment cover is generally less than 20%. The soil surface is usually stable with little or no evidence of accelerated erosion. Parent materials include eolian deposits and igneous rocks. Soils generally lack coarse fragments, are not calcareous, and are deep to very deep. Textures range from sands to sandy loams and available water holding capacity ranges from low to medium. Adjacent Communities. --The Artemisia tripart it a/ Fes tuca idahoensis and A_^ tridentata/Festuca idahoensis types are ecologically similar. Of the two types, the A_^ tripartita type generally occurs on more xeric sites. In the Centennial Valley, the Aqropyron dasystachyum/Phacelia hastata type is often found on adjacent sand dune and blow out sites. 23 other Studies. — This type has been described in Montana by Mueggler and Stewart (1980). 11. Atriplex nuttallii/Oryzopsis hymenoides Type (ATRNUT/ORYHYM; Nuttall saltbush/Indian ricegrass; G3G4 S2?) Vegetation. — Total vegetation cover in this badlands type seldom exceeds 5%. Characteristic species include Atriplex nuttallii , Chrysothamnus nauseosus . and Oryzopsis hymenoides . Physical Setting. --The type occurs on steep badland sites at elevations around 5000 feet. Bare soil cover totals at least 60% and most of the remaining ground cover is comprised of coarse fragments. The soil surface is unstable because of a lack of adequate vegetation cover and gully erosion is common. Parent materials are sedimentary rocks and soils are very shallow and poorly developed. Soils range from not gravelly to very gravelly and are non-calcareous. Textures are gener- ally very fine (e.g., silty clay loams) and available water holding capacity is low. Adjacent Communities. --Vegetation on adjacent more stable soils include the Artemisia trident at a/ Agropyron spicatum type on non-alkaline soils and the Sarcobatus verm icu la tus/ Agro- pyron smithii type on alkaline soils. Other Studies. — This type has not previously been reported in Montana but has been reported in Colorado and is listed as questionably present in Oregon and Wyoming (Bourgeron and Engelking 1991) . 12 . Cercocarpus ledifolius/ Agropyron spicatum Type (CERLED/AGRSPI ; mountain mahogany/bluebunch wheatgrass; G5 S4) Vegetation. --Cercocarpus ledifolius is abundant and the domi- nant vegetation feature of this community type. Agropyron spicatum is the only other species that is always well repre- sented with cover exceeding 5%. Physical Setting. --The type generally occurs on steep mass wasted slopes at elevations between 7000 and 8000 feet. The total cover of soil, gravel, and rock usually exceeds 50% and the soil surface is unstable because of a lack of adequate vegetation cover. Parent materials are predominantly limestone and soils are generally Ustorthents and are shallow (lithic) and very gravelly to very cobbly. Textures are mostly loams. The soils exhibit violent effervescence. Available water holding 24 capacity is low due to the coarse soil textures, abundant coarse fragments, and shallow depth. Adjacent Communities. — The Cercocarpus ledif ol ius/Aqropvron spicatum and Juniperus scopulorum/C. ledifolius types are ecologically similar and intergrade. Of the two types, J . scopulorum/C. ledifolius occurs in slightly more mesic situa- tions. The Artemisia arbuscula/Agropyron spicatum and Pinus f lexilus/A. spicatum types are sometimes found on adjacent less rocky sites with deeper soils. Other Studies. — This type has been described in Montana by Mueggler and Stewart (1980). 13. Cercocarpus ledifolius/Festuca idahoensis Type (CERLED/FESIDA; mountain mahogany/Idaho fescue; G2? S2?) Vegetation. --Cercocarpus ledifolius and Agropvron spicatum are abundant. Festuca idahoensis cover generally exceeds 5%. Other species that are generally present with cover exceeding 1% include Artemisia f rigida, A. tridentata, Opuntia poly- acantha . and Poa sandbergii . Bromus tectorum may be abundant. Physical Setting. --The type occurs on steep residual mountain slopes at elevations around 6000 feet. The total cover of soil, gravel, and rock usually exceeds 40% and the soil sur- face is stable with no evidence of accelerated erosion. Parent materials are granitic and soils are Ustorthents and are moderately deep and very cobbly. Textures vary from loamy sands to sandy loams. The soils are non-calcareous and their available water holding capacities are low due to the coarse soil textures and abundant coarse fragments. Adjacent Communities. — The Cercocarpus ledifolius/Festuca idahoensis and C_^ ledifolius/Agropyron spicatum types are ecologically similar and intergrade. Of the two types, c. ledifolius/A. spicatum occurs in slightly more xeric situa- tions. The Pseudotsuqa menziesii/F. idahoensis type may be found on adjacent more mesic sites that are less rocky and have deeper soils. Other Studies. — This type has not been previously described. 14. Aqropyron dasystachyum/Phacelia hastata Type (AGRDAS/PHAHAS; thickspike wheatgrass/silverleaf Phacelia ; G2? S2?) Vegetation. --Aqropyron dasystachyum is well represented to abundant within this community type. Other species that are 25 generally present with cover ranging from 1 to 20% include Chrvsothamnus nauseosus , Tetradvroia canescens , Eriogonum ovalifolium v. celsum, Linum perenne, Phacelia hastata , Psoralea tenuifolia , Orvzopsis hymenoides , and Stipa comata . Physical Setting. — This type has only been observed in the Centennial Valley. It occurs on sand dunes and blow outs at elevations around 6700 feet. Bare soil (sand) cover ranges from 60 to 90% and coarse fragments are absent. The soil surface is usually unstable because of a lack of adequate vegetation cover. Parent materials are eolian sand deposits. Soils are very deep Ustic Torripsamments and lack coarse fragments and are not calcareous. Textures are sands and available water holding capacity is low due to the coarse texture. Adjacent Communities. — The Artemisia tripartita/Festuca idahoensis and A^ tridentata/Festuca idahoensis types are usually found on adjacent more stable soils and sites. Other Studies. — This type has not been previously described. 15. Agropyron spicatum/Oryzopsis hymenoides Type (AGRSPI/ORYHYM; bluebunch wheatgrass/lndian ricegrass; G3? S2?) Vegetation. — Total vegetation cover in this badlands type seldom exceeds 15%. Characteristic species include Gutier- rezia sarothrae , Agropyron spicatum. Aristida lonqiseta . and Oryzopsis hymenoides. Physical Setting. --The type occurs on steep badland sites at elevations around 5500 feet. Bare soil cover totals 20 to 70% and most of the remaining ground cover is comprised of coarse fragments. The soil surface is unstable because of a lack of adequate vegetation cover and rill and sheet erosion is common. Parent materials are sedimentary rocks and soils are shallow and poorly developed. Soils range from not gravelly to very gravelly and are strongly to violently effervescent. Textures are sands to loams, and available water holding capa- city is low. Adjacent Communities. --Vegetation on adjacent more stable soils include the Artemisia tridentat a/ Agropyron spicatum and Agropyron spica turn/ Bout eloua gracilis types. 26 other Studies. — This type has not previously been reported in Montana but has been reported in Wyoming (Bourgeron and Engelking 1991) . 16. Picea enqelmannii/Equisetvun arvense Type (PICENG/EQUARV; Engelmann spruce/field horsetail; G4 S3) Vegetation. — Picea engelmannii dominates the overstory and Equisetum arvense is abundant in the undergrowth. The under- growth is typically rich in species and high in total cover. Species that are typically well represented include Linnaea borealis . Actaea rubra , Fragaria virginiana , Smilacina stellata. Thalictrum occidentale. and Calamaqrostis canaden- sis. Physical Setting. — This type occurs on wet, flat sites in alluvial basins. Elevations are around 6500 feet. The total cover of litter, wood, and moss equals or exceeds 70% of the ground surface. The soil surface is generally stable with no evidence of accelerated erosion. Soils are derived from mixed alluvial parent materials and are non-calcareous. These soils are wet throughout the year and are often richly organic, e.g., Histic Cryaquolls. Additionally, the soils are very deep, lack coarse fragments, are loamy in texture, and have a very high available water holding capacity. Adjacent Communities. — A complex of riparian forest, shrub, and graminoid communities usually occur adjacent to the Picea engelmannii /Equisetum arvense type. Other Studies. — This type has been described in Montana by Pfister et al. (1977) . 17 . Populus trichocarpa/Cornus stolonifera Type (POPTRI/CORSTO; black cottonwood/red-osier dogwood; G4 S4) Vegetation. — Populus trichocarpa dominates the overstory and Juniperus scopulorum is common in the middle layer. The undergrowth is typically rich in species and high in total cover. The pattern of occurrence of undergrowth species is often highly variable spatially reflecting the pattern of fluvial disturbances active on most Populus trichocarpa/Cornus stolonifera sites. Species that are typically well repre- sented include Cornus stolonifera. Rosa acicularis, Svmphori- carpos albus, Galium boreale, Smilacina stellata. Poa palus- tris . and Poa pratensis. 27 Physical Setting. — This type occurs on gravelly alluvial parent materials on flat flood plains and terraces in wide valley bottoms. Elevations are between 5000 and 5500 feet. Litter plus wood cover equals or exceeds 60% of the ground surface. The soil surface is generally stable with no evi- dence of accelerated erosion. Soils are often Typic Udifluvents, are very deep with textures varying from sandy to loamy, and are non-calcareous. Available water holding capacity varies from low (sandy soils high in coarse fragment content) to very high (loamy soils without coarse fragments) . Adjacent Communities. --The Phalaris arundinacea , Eleocharis spp. , and Salix exigua types occur on wetter sites. More xeric sites often feature the Artemisia tridentata/Aqropyron spicatum type. The Populus trichocarpa/ Cornus stolonifera type intergrades with the Juniperus scopulorum or the Pseudot- suqa menziesii/Cornus stolonifera types under conditions of less fluvial disturbance (Hansen et al. 1991). Other Studies. --This type has been described in Montana by Hansen et al. (1991) . 18. Salix exigua Type (SALEXI; sandbar willow; G5 S4) Vegetation. — Salix exigua dominates the overstory (often with a total canopy cover of 100%) . The undergrowth is typically very depauperate due to the intense competition with S_^ exigua and seldom exceeds 5% total cover. Species that are often present in this sparse undergrowth include Cirsium arvense , Mentha arvensis. and Phalaris arundinacea. Physical Setting. — This type occurs on gravelly alluvial parent materials on flat flood plains and terraces in wide valley bottoms. Elevations are between 5000 and 5500 feet. Litter plus wood cover equals or exceeds 60% of the ground surface and soil cover is typically around 20%. The soil surface is unstable because of a lack of adequate vegetation cover and the active fluvial disturbance regime present on S . exigua sites. Soils are often Aquic Udifluvents, are very deep with sandy textures, have a low available water holding capacity, and are non-calcareous. Coarse fragment contents vary from gravelly to very cobbly. Adjacent Communities. — Adjacent wetter sites are often open water. Adjacent drier riparian communities often feature the Populus trichocarpa/Cornus stolonifera type. 28 other studies. — This type has been described in Montana by Hansen et al. (1991). 19. Agropyron smithii Type (AGRSMI; western wheatgrass; G4 S3) Vegetation. --Agropyron smithii forms abundant cover within this type. Other species that may be well represented with greater than 5% cover include Carex stenophylla , Koeleria cristata , Poa pratensis , and Equisetum hyemale. Physical Setting. — This type occurs on alluvial parent mater- ials on flat flood plains in wide valley bottoms at elevations around 5000 feet. Litter cover equals or exceeds 50% of the ground surface. The soil surface is generally stable with no evidence of accelerated erosion. Soils are often very deep with sandy loam to clay tex- tures, have a high available water holding capacity, and are non-calcareous. Many of the soils are alkaline. Coarse fragment contents are generally low. Adjacent Communities. --Adjacent wetter communities are usually graminoid dominated, while adjacent drier sites often feature communities in the Artemisia tridentata series. Other Studies. — This type has been described in Montana by Hansen et al. (1991). 20. Elymus cinereus Type (ELYCIN; basin wildrye; G4 S2?) Vegetation. — Elymus cinereus dominates (often with a total canopy cover of 100%) . Juncus balticus and Poa pratensis may be well represented. The total cover of additional species seldom exceeds 5%. Physical Setting. — This type occurs on gravelly alluvial parent materials on flat terraces in wide valley bottoms at elevations around 5500 feet. Litter cover equals or exceeds 60% of the ground surface. The soil surface is generally stable with no evidence of accelerated erosion. Soils are often Mollisols, are very deep with loamy textures, high available water holding capacity, and are non- calcareous. Coarse fragment are generally absent. Adjacent Communities. — Adjacent wetter communities often feature the Salix exigua type while drier uplands are often 29 characterized by the Artemisia tridentata/Agropyron spicatura type. Other Studies. — This type has not previously been reported in Montana but has been reported in Colorado, Idaho, Oregon, and Washington (Bourgeron and Engelking 1991) . 2 1 . Phalaris arundinacea Type (PHAARU; reed canarygrass; G4 S4) Vegetation. — Phalaris arundinacea dominates (often with a total canopy cover of 100%) . The undergrowth is typically very depauperate due to the intense competition with P. arundinacea. Poa palustris may be well represented and Cirsium arvense and Mentha arvensis are often common. The total cover of the few additional species seldom exceeds 1%. Physical Setting. --This type occurs on gravelly alluvial parent materials on flat flood plains in wide valley bottoms at elevations around 5000 feet. Litter and soil cover equals or exceeds 30% and 20% of the ground surface, respectively. The soil surface is generally stable with no evidence of accelerated erosion. Soils are often Fluvaquents or Fluvents, are very deep with loamy sand to loam textures, medium available water holding capacity, and are non-calcareous. Coarse fragment contents vary from none to gravelly. Adjacent Communities. --Adjacent wetter sites often feature open water while adjacent drier riparian communities include the Populus trichocarpa/Cornus stolonifera type and a wide variety of other riparian types. Other Studies. — This type has been described in Montana by Hansen et al. (1991) . Special Status Plant Observations The eight TES plant species observed within the study plots, the plot numbers in which they were found, and the global and state rarity rankings for these species are presented in Table 1. Pre- liminary verification of the Lesquerella paysonii specimens by Dr. Reed Rollins of the Harvard University Herbaria suggests these specimens may be L_^ prostrata (also a SI species) . Dr. Rollins indicated in a December 11, 1991 letter that he will resolve this identification problem as soon as possible. 30 Table 1. TES plant species observations by plot number and global and state rarity rank. SPECIES/RANK PLOT NUMBERS Aaastache cusickii G3G4 Si 3C 91RD 27 Arabis fecunda G2 S2 C2 91RD 16; 91RD 17; 91RD 24 Arenaria kingii G4 SI 91RD 29; 91RD 34; 91RD 31 Astragalus cerainicus V. apus G4T3 SI 3C 91RD 37 Crvptantha fendleri G4 SI 91RD 36; 91RD 3 8 Draba densifolia G5 82 91RD 14 Erioqonum ovalifolium V. celsum (nevadense) G5T4 S2 91RD 35; 91RD 36; 91RD 37; 91RD 38; 91RD 39 Lesquerella (paysonii?) G4 SI 91RD 26; 91RD 34; 91RD 41; 91RD 4 2 31 CONCLUSIONS One function of the MTNHP is the development of a statewide database of plant community occurrences. A major limitation is the current lack of a comprehensive grassland/shrubland community classification. This study represents a step towards achieving such a comprehensive classification. Another function of the MTNHP is to provide information regarding communities and sites for conservation. A classification such as this is necessary to define and identify key elements and sites in southwestern Montana for potential long-term preservation. Similarly, government agencies could use the classification for the identification and design of natural areas. This classification can be usefully applied in stratifying vegetation/environmental variation to assess management options and results. The classification can also assist in minimizing impacts from intensive management by identifying sensitive plant communi- ties (e.g. , Aqropyron dasystachyum/Phacelia hastata) . The classi- fication also provides a tool for baseline monitoring and pre- dicting long-term vegetation responses to management activities. This capability would also assist agencies in meeting regulatory mandates (e.g., requirements of FLPMA) . Even following this study, existing classifications and data inadequately describe the grassland and shrubland communities of Montana. Major additional field sampling is necessary before a comprehensive grassland/shrubland community classification can be developed. Additional grassland/shrubland studies are planned in Montana over the next two years. This effort will provide addi- tional knowledge regarding community patterns, processes, and physical environment relations. Such knowledge will be invaluable towards developing full capability to inventory Montana communities and to increase predictive capability (e.g., build vegetation and biodiversity models) . 32 LITERATURE CITED Bourgeron, P. and L. 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