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 community types have now been documented from southwestern 

 Montana, 54 of which are rare. 



