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Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. US^D^A United States Plant Community Classification ^^ Department ofAgriculture for Alpine Vegetation on the ForestService Intermountain Beaverhead National Forest, Research Station Montana General Technical Report INT-GTR-362 October 1997 CD Stephen V. Cooper Op /oIlES'SaiyiA Peter Lesica —^ I Deborah Page-Dumroese cn cn cr The Authors Laboratory in Moscow, ID. She is primarily interested in soilchangesfromtimberharvesting and sitepreparation Stephen V. Cooper is a Vegetation Ecologist with the and in maintaining long-term soil productivity in the Montana Natural Heritage Program in Helena. He has Inland Northwest. She earned a B.S. degree in natural authored several vegetation classifications pertaining resource management, an M.S. degree in forest soils, to Northern Rocky Mountain ecosystenns and is now and a Ph.D. degree in forest soils. responsible for inventorying and cataloguing the full rangeof Montana's naturalcommunitytypes. Heearned Acknowledgments a B.S. degree in biology at Union College, NY, an M.S. degree in biology at the State University of New York, and a Ph.D. degree in botany at Washington State Many employees of Beaverhead National Forest, including Dan Svoboda, Marianne Klein and Kevin University. Suzuki, provided information on study sites and ac- Peter Lesica is a Senior Scientist with Conservation cess. Bob Keane, Suzanne Reed, John Carotti, and Biology Research in Missoula, MT, and an adjunct Tim McGarvey helped with data manipulation. Jim faculty atthe Universityof Montana. He isthe authorof Sears identified many of our geological specimens. numerous articles on the flora of Montana and high- John Spence and Doug Henderson commented on an elevation plant ecology, and is currently working on a earlier draft of the manuscript. We dedicate this publi- floristic manual for Glacier National Park. cation to the memory of Doug Henderson, who helped Deborah Page-Dumroese is a Soil Scientist with the manyof us in ourbotanical explorationsofthe Northern Intermountain Research Station's Forestry Sciences Rocky Mountains. You may order additional copies of this publication by sending your mailing informationinlabelformthroughoneofthefollowingmedia. Pleasespecifythe publication title and General Technical Report number. Telephone (801) 625-5437 DG message Pubs:S22A FAX (801) 625-5129, Attn: Publications E-mail /s=pubs/[email protected] — Mailing Address Publications Ogden Service Center Rocky Mountain Research Station (formerly Intermountain Research Station) 324 25th Street Ogden, UT 84401 Rocky Mountain Research Station (formerly Intermountain Research Station) 324 25th Street Ogden, UT 84401 1 Contents Page Page Introduction 1 Moist Slopes 24 Study Area 1 Snowbed Communities 25 Vegetation 1 Carexnigricansc.t 25 Climate 2 Juncus drummondiilAntennaria lanatac.t 26 Geology and Soils 3 Phyllodoce empetriformisiAntennaria Methods and Discussion 5 lanata c.t 27 Stand Selection 5 Cassiope mertensianalCarexpaysonisc.t 27 Vegetation Sampling 5 JuncusparryilErigeron ursinusc.t 28 Taxonomic Considerations 6 Salixglaucac.t 28 Productivity 6 Wetland Communities 29 Soils 6 Deschampsia cespitosalCaltha Data Analysis 6 leptosepalac.t 29 Results 7 CarexscopulorumiCaltha leptosepalac.t 30 Key to Alpine Communities 7 Salixreticulata!Caltha leptosepalac.t 30 Caveats and Conventions 7 SalixplanifolialCarexscopulorum c.t 31 Canopy Cover Terms and Their Ordinations and Environmental Gradients 32 Complements Employed in the Key 7 Wet Sites 32 Instructions 7 Dry Sites 33 Key to Community Types 8 Soils 34 Grassland Communities Management Considerations 35 1 Festuca idahoensis/Potentilla diversifoliac.t 11 Livestock Grazing 36 Deschampsia cespitosal Vehicle Use 36 Potentilla diversifoliac.t 12 Mining 37 Hesperochloa kingiilOxytropis campestrisc.t 13 Geographic Affinities of Alpine Plant Turf Communities 13 Communities 37 Carexelynoidesc.t 13 References— 38 CarexscirpoideaJPotentilla diversifoliac.t 14 Appendix A Vascular Plant Species CarexscirpoidealGeum rossiic.t 15 Encountered in Macroplots During the Dryas octopetala/Polygonum viviparumc.t 16 Course—of the Study in 1989 and 1991 40 Salixarctica/Polygonum bistortoides c.t 16 Appendix B Mean Site Variables (±SD) Cushion Plant Communities 17 for 23 Plant Community Types in the Carexrupestris/Potentilla ovinac.t 17 Study Area 44 Geum rossii/Arenaria obtusiloba c.t 22 Appendix C—Vascular Plant Constancy Dryas octopetala/Carexrupestrisc.t 23 and Coverage (Mean and Range by ) Slope Communities 23 Community Type 46 Dry Slopes 24 Community Plant Classification for Alpine Vegetation on the Beaverhead National Forest, Montana Stephen V. Cooper Peter Lesica Deborah Page-Dumroese Introduction 3. Compare the alpine vegetation communities on the Beaverhead National Forest to those described Much ofwhatis generally consideredthe Northern from other areas ofWestern North America. Rocky Mountains floristic province is in Montana 4. Consider management implications for alpine (McLaughlin 1989). Numerous mountain ranges vegetation systems. occurinthewestern halfofthe State, manyreaching elevations above treeline. The vegetation of grass- Study Area lands, shrublands, forests, woodlands, and riparian areas of western Montana have been described and Vegetation classified (Hansen and others 1995; Mueggler and Stewart 1980; Pfisterandothers 1977). However, due Ourstudyareaencompassedeightalpinemountain to inaccessibility and relatively low economic impor- rangesthatoccur, atleastin part, onthe Beaverhead tance, few studies have described the alpine vege- NationalForest:Anaconda(colorplate1),Beaverhead, tation of the Northern Rocky Mountains. Existing Gravelly, Madison, Pioneer, Snowcrest, Tendoy, and studies include Glacier National Park (Bamberg Tobacco Root (fig. la,b). The sampled portions of and Major 1968; Choate and Habeck 1967), the Big these ranges are all east of the Continental Divide. Snowy Mountains and Flint Creek Mountains The area is semiarid, andboth upper andlower tree- (BambergandMajor1968),andtheBeartoothPlateau lines occur in all ranges. Intermountain valleys are (Johnson and Billings 1962); these studies were con- high (4,800 to 6,600 ft), and the cold, frost-prone ducted at fewer than a half-dozen sites. Recently, climate is unsuitable for the establishment of tree studies have been completed for alpine areas ofeast species that are not cold-adapted. Thus,Pseudotsuga and east-central Idaho (Brunsfeld 1981; Caicco 1983; menziesii andPinusflexilis, notPinusponderosa, are Henderson 1992; Moseley 1985; Urbanczyk and climaxdominantsoflowertreelineandextendthrough Henderson 1994). the montane to the middle of the subalpine zone. Twenty-sevenmountainrangesinMontanasupport Pinus flexilis extends onto sites drier and warmer significant alpine terrain. More than half of these thancanbe toleratedbyPseudotsuga; it also shows a ranges are in the southwestern portion ofthe State, preference for the calcareous substrates ofthis area and nine are on Beaverhead National Forest. South- (Pfister and others 1977). westernMontanais alsothemostfloristicallydiverse TheuppersubalpineiscomposedofAbieslasiocarpa, region ofthe State (Lesica and others 1984). Knowl- Picea engelmanii, Pinus contorta, P. albicaulis, and edge of alpine plant communities in this area would occasionally P. flexilis; relative proportions of these allow a more comprehensive portrayal of Northern treesdependprimarilyonsuccessionalstatus, aspect, Rocky Mountain alpine ecosystems. Our study had and to a lesser degree, substrate (Pfister and others the following objectives: 1977).Aboveapproximately8,500ft,theforestcanopy 1. Developaclassificationsystemforalpinecommu- becomes progressively more open cind dominated by nities on the Beaverhead National Forest. Pinusalbicaulis. Near treeline, thebelt ofmostlycon- 2. Relate abiotic environmental factors such as cli- tinuousforestgiveswaytoatollsofstuntedandflagged mate, soils, and landforms to the occurrence ofthese trees interspersed among nonforest vegetation. The communities. extent of true krummholz, trees not reaching much morethanwaistheightdue toice particle abrasionof 1 Figure la—Study area mountain ranges in southwestern Montana. • indicates location of sample plots. exposedsurfaces, isverylimited. Forestcommunities Climate forthis areaaredetailedbyPfisterandothers(1977). Thenonforestcommunities atorjustbelowtreeline There are no long-term weather records for high- are shrub-steppe dominated byArtemisia tridentata elevation sites inour study area. Walter-type climate ssp. uaseyana, grasslands dominated by Festuca diagrams (Walter and others 1975) for Virginia City idahoensisandDeschampsiacespitosa,andsubalpine and Lima, MT, are presented in figure 2. Although forb fields on the moister sites. Many of the plant thesestations arelocatedat5,776 and6,275ft(fig. 1), associations comprising these high-elevation steppes they illustrate the seasonal march of temperature havebeendescribedbyMuegglerandStewart 1980). and precipitation for the area. Precipitation in the Subalpinecirquebasinsoftencontainareasin(which alpine zone is undoubtedly higher, and tempera- soilmoistureisabovethatofthesurroundinguplands tures arelowerthan atthesevalley stations. Clearly, for at least part of the year. These areas support the seasonal patterns of precipitation and tempera- wetland vegetation dominated by species of Salix, ture are very similar for both stations. Compared to especiallyS.planifolia andS. wolfii,orbyherbaceous Billing's (1988) diagrams for typical alpine areas in species such as Carex scopulorum, Eleocharis New Hampshire, California, and Colorado, our study paucifLora, Juncus halticus, and Caltha leptosepala. area pattern is closest to that of Niwot Ridge, CO, Many of these subalpine wetlands are described by with the notable exception ofhaving a distinct pre- Hansen and others (1995). cipitation bulge in May and June. This spring maxi- mumalsosetsourstudyareaapartfromSierraNevada 2 BEAVERHEAD NAT O N AL V^'FOR EST BOUNDARY I STATE BOUNDARY ^ CLIMATIC STATIONS SCALE OF MILES: 2cm/ 10 MILE 9 io 20 3o — Figure lb Study area showing boundaries of tlie Beaverhead National Forest. andAppalachianalpine. Therelativelydroughtycon- snow-depth recording stations. These maps indicate ditions portrayed by our valley stations would not that precipitation increases from west to east in obtaininthealpinewhereprecipitationincreasesand the southwestern part of the State. The crests of the temperatures would be depressedby about 5.7 to Beaverhead, Snowcrest, and Tendoy ranges receive 6.8 °F (3.2 to 3.8 °C). Such adepressionwouldresult approximately 30 inches of precipitation annually. in a total of 6 months with average temperatures The Gravelly Range receives 30 to 40 inches, andthe below freezing. Some authors characterize the alpine Anaconda, Pioneer, and Tobacco Root ranges receive zone as having a climate where the monthly average 40 to 60 inches. The Madison Range atthe west edge temperature never exceeds 50 °F (10 °C) (Billings ofour study area receives 50 to 70 inches. 1988). However, the Sierra Nevadan alpine has at least3 monthsthatexceedthisfigure, andourlowest Geology and Soils elevation sites exceed it in July andAugust. Ross and Hunter (1976) present precipitation iso- Representative exposu—res from the three major pleth maps for Montana based on a large number of groupsofparentmaterials sedimentary,metamorphic, 3 bed a b c d _mm a \ \ \ \ ^ Lima, MT (1,900 m) 4.0° 273 V\irginia City, MT (1,\790 m) 5\.7° 4\13 mm 70 -I 5 - a = station name f = monthly march oftemperature b = station elevation (m) g = relatively humid season (vertical hatching, note axes c = mean annual temperature (°C) explicitly scaled so the 10° = 20 mm precipitation) d = mean annual precipitation (mm) h = period of relative drought e = monthly march of precipitation = period of mean daily minimum below 0 °C (blackened) i = months with absolute minimum below 0 °C i — Figure 2 Walter-type climaticdiagrams for two stations in the study area, Virginia City and Lima, Montana. — andigneous are foundinmountainranges ofsouth- composedprimarilyofPrecambriangneiss andschist western Montana. Sedimentary and metamorphosed with some areasonthe eastflankunderlainbyMeso- sedimentary rocks predominate in the south and zoiclimestone(Rossandothers1955).Table 1summa- west portions ofthe study area, while intrusive and rizesthenumberofplotsestablishedineachmountain metamorphic basement rocks become more common range by parent material. to the east and north (Ross and others 1955). The Soils supporting alpine vegetation have been de- crests of the southern Beaverhead, Gravelly, Snow- scribed for the Northern Rocky Mountains by crest, and Tendoy Mountains are composed ofMeso- Bamberg and Major (1968), Johnson and Billings zoic and upper Paleozoic limestones, sandstones (1962), Nimlos and McConnell (1962), and Thilenius and quartzites. The southern end of the Beaver- and Smith (1985). Soils from our study sites on sedi- head Mountains is composed of calcareous mentary parent material resembled those described Beaverhead Conglomerate. The highest point in the byBambergandMajor(1968),whilesiteswdthcrystal- Gravelly Mountains, Black Butte, is a remnant stock line parent material had soils similar to those de- ofQuaternarybasalt. The highcountry oftheTobac- scribed by Johnson and Billings (1962) and Nimlos co Root Mountains is composed ofgranite ofthe To- and McConnell (1962). In general, turfand meadow baccoRootBatholith. Mostofthealpineterraininthe soilsdevelopedfromsandstones,limestones,andshales Pioneer Mountains is underlain by granite of the were finer textured than those derived from granite, Pioneer Batholith; however, the high peaks at the quartzite, or metamorphic basement rocks. very north end ofthe range form a contact between Indicationsofcryopedogenicprocesseswereevident the intrusive igneous and Paleozoic limestones and in all ofthe mountain ranges. Solifluction lobes and dolomites. Although the main mass ofthe Anaconda terraces were common on steep, moist north slopes. Mountainsisgranitic,theeastendwherewe sampled Frostboils,rockpolygons,andstonestripeswereoften is underlain by Precambrian quartzites and lime- apparent, especiallyintheAnaconda-Pintlar,Madison, stones.ThesouthernendoftheMadisonMountainsis East Pioneer, Tendoy, and Tobacco Root Mountains. 4