INTRODUCTION 



This study was conducted by the Montana Natural Heritage 

 Program for the Parks Division of Region Five in the Montana 

 Department of Fish, Wildlife, and Parks. The purpose was to 

 locate or assess the potential for occurrences of Montana Plant 

 Species of Special Concern (MPSSC) on selected lands in Region 

 Five. MPSSC are those plant taxa listed by the Montana Natural 

 Heritage Program which are "rare, endemic, disjunct, 

 threatened, or endangered throughout their range or in Montana, 

 vulnerable to extirpation from Montana, or in need of further 

 research" (Heidel and Poole 1993). The information yielded by 

 this project will be used by the Department of Fish, Wildlife, 

 and Parks to prepare a weed control management plan 

 Environmental Impact Statement in keeping with the Montana 

 Environmental Protection Act. 



Lands administered by Region Five of Montana Fish, 

 Wildlife and Parks Department consist of Fishing Access Sites, 

 Fish Hatcheries, State Parks, and Wildlife Management Areas, 

 spanning six southcentral Montana counties: Big Horn, Carbon, 

 Stillwater, Sweetgrass, Wheatland, and Yellowstone. Most sites 

 are located at relatively low elevations in bottomlands along 

 the Big Horn, Boulder, Musselshell, Stillwater, and Yellowstone 

 rivers and along Rock Creek. 



The surface geology at most sites is generally of alluvial 

 origin. Plants occupying alluvial substrates tend to be 

 generalist, as Welsh et al. (1987) have noted for the Utah 

 flora. Thus, the plant species of concern expected at these 

 sites are those which are peripheral in Montana with broader 

 ranges outside the state (e.g. Eupatorium maculatum and 

 Viburnum lentago) . These low elevation settings are 

 historically areas of settlement, extensive habitat conversion 

 and heavy use. The successional nature of the habitat and 

 historic patterns of use make these sites prone to weed 

 invasion. 



A few sites are located in foothills adjacent to the 

 major drainages or otherwise include upland habitat. The Pryor 

 Mountains and Big Horn Canyon areas are near some of these 

 Region Five lands and harbor some of the highest known 

 concentrations of endemic MPSSC in the state. Endemic species 

 have distribution ranges restricted within state boundaries or 

 within a small area that crosses state boundaries. Thus, 

 endemic plant species of special concern may also be expected 

 at some state sites that have intact upland habitat and 

 proximity to the Big Horn / Pryor Mountain areas. 



