INTRODUCTION 



Penstemon lemhiensis is currently in Category 2 (some 

 evidence of vulnerability but not enough data to support 

 listing at this time) of the U.S. Fish and Wildlife Service 

 Notice of Review (U.S. Department of the Interior 1990). In 

 an effort to collect the data needed to support or reject 

 listing, populations of this species are being monitored in 

 southwestern Montana. Populations on the Beaverhead National 

 Forest have been monitored since 1989 (Achuff and Shelly 

 1991, Shelly 1990) . 



The species also occurs on BLM land and, in 1990, plants 

 within a BLM exclosure at the Badger Pass microwave site 

 were marked and described. In 1991, three demographic 

 monitoring transects were established in the exclosure and 

 an additional transect was established near the Horse 

 Prairie, also on BLM land. 



Observations since 1986 of Penstemon lemhiensis population 

 numbers at Badger Pass and other sites in southwestern 

 Montana documented marked changes in population size, both 

 increases and decreases (Achuff and Shelly 1991) . Such 

 changes may make a species more prone to local extirpation. 

 Thus, there is a need to better understand the demographic 

 dynamics of local populations (survivorship and 

 reproduction) so that an assessment of vulnerability can be 

 made. An increased understanding of the biology of this 

 species is also important to developing a realistic species 

 conservation strategy (Massey and Whitson 1980) . 



II. STUDY SITES 



A. BADGER PASS MICROWAVE EXCLOSURE MARKED PLANTS 



The Badger Pass microwave site is located about 20 

 miles west of Dillon on Highway 278. An access road 

 leads south from the top of the pass to the microwave 

 site and the exclosure is immediately north of the 

 tower. The marked plants within the exclosure are in 

 three groups, each referenced to a marked fencepost of 

 the perimeter fence. The plants are marked by metal 

 pins in the ground which are marked with a metal tag. 

 Some of the marked plants also occur in the three 

 monitoring transects that were established in 1991. 



Group 1 (RPl) : RPl (Reference Point 1) is the fence 

 post in the northernmost corner of the exclosure (Fig. 

 1) . The plants are located as follows: 



