ABSTRACT 



The Pryor Mountains provide desert-like habitats unique in 

 Montana and contribute significantly to the overall biological 

 diversity of the state and the region. This study developed a 

 classification of vegetation types on USDI Bureau of Land 

 Management lands in the south Pryor Mountains, Carbon County, 

 Montana. Additionally, endemic and globally rare vegetation 

 types were identified. Using a combination of two-way indicator 

 species analysis (TWINSPAN) and detrended correspondence analysis 

 (DCA) 33 vegetation types were identified among the 197 study 

 plots. Comparisons with a "comprehensive" listing of vegetation 

 types of the western United States revealed that 9 of the types 

 from the Pryor Mountains had not been reported from elsewhere and 

 14 are rare globally. This concentration of rare vegetation 

 types, in combination with previously documented occurrences of 

 rare plant species, highlight the significant biodiversity values 

 of the Pryor Mountains. 



