Appendix G. — (continued) 



Stipa comata - Bouteloua gracilis (STICOM-BOUGRA) 



This community is very widespread in Montana and has been 

 recorded in all portions of the state except in the northwest. 



Vegetation. — Stipa comata or S. spartea dominate this community. 

 Cover of these species is generally abundant. Other 

 characteristic graminoids include Bouteloua gracilis (well 

 represented) , Carex filifolia and/or C. eleocharis (common to 

 well represented) , and Koeleria macrantha (well represented) . If 

 Pascopyrum smithii is present its cover does not exceed 1% 

 (except in the Pascopyrum smithii phase described by Mueggler and 

 Stewart (1980)). Selaginella densa is often abundant in 

 northcentral and northeastern Montana and generally suggests 

 heavy grazing disturbance in such situations. Artemisia frigida . 

 Heterotheca villosa . Phlox hoodii . and Sphaeralcea coccinea are 

 typically present. 



Physical Setting. — This community type is characteristically 

 found on gentle to moderate slopes of any aspect on rolling 

 uplands, broad alluvial benches and fans, and valley floors. 

 Elevations range from 2000 to 6000 feet and annual precipitation 

 varies from 8 to 14 inches. The soil surface is often covered by 

 a dense mat of Selaginella densa (northeastern/northcentral 

 Montana) or in some cases may feature abundant bare soil 

 exposures. Typical soil subgroups include Typic Ustorthents, 

 Ustic Torriorthents, Borollic Calciorthids, Aridic Argiborolls, 

 and Typic Argiborolls. 



Adjacent Community Types. — This community generally occupies the 

 driest grassland sites in Montana. The Pseudoroegneria spicata - 

 Bouteloua gracilis or Pascopyrum smithii - Bouteloua gracilis (or 

 Stipa viridula ) types occur on more mesic sites. The Pascopyrum 

 types are often found in clay-rich depressions within a matrix of 

 STICOM-BOUGRA. More mesic adjacent shrublands include Artemisia 

 cana - Stipa comata on generally even or convex slopes and 

 Symphoricarpos occidentalis or Prunus virginiana communities in 

 convavities. 



Comments. — This community type has previously been described in 

 Montana by Mueggler and Stewart (1980) and in Wyoming by Ter- 

 williger et al. (1979). Additionally, Coupland (1961) describes 

 a Stipa - Bouteloua type in southern Saskatchewan and Alberta that 

 appears similar in composition to STICOM-BOUGRA. The type also 

 appears to be closely-related (perhaps ecologically equivalent) 

 to the Stipa comata - Carex filifolia type of Hansen (1985) . 



Bouteloua gracilis is considered an increaser with heavy 

 grazing in this community type while Stipa comata generally 

 decreases (Mueggler and Stewart 1980) . 



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