23 



D. Habitat 



1. Associated vegetation: Penstemon lemhiensis typically grows 

 in sagebrush steppe (mostly Artemisia tridentata/Festuca 

 idahoensis and Artemisia tridentata/Elymus spicatus habitat 

 types) but also occurs in coniferous forests and forest/step 

 ecotones (Shelly 1990). All of the BLM populations in the 

 study area are in steppe habitats usually dominated by 

 Artemisia tridentata, but in one case by Artemisia 

 tripartita. Common associates in addition to the dominant 

 sagebrush and grass species include Balsamorhiza sagittata, 

 Castilleja pallescens, Chrysothamnus viscidiflorus , Fragaria 

 vesca, and Orthocarpus luteus . Vegetation at the individual 

 sites is described in the general site description fields of 

 the EORs in Appendix C. 



2. Topography: In Montana, Penstemon lemhiensis grows on steep 

 to gentle slopes (usually with east to southwest aspects) 

 and flats in the basins, foothills, and lower mountains from 

 4,150 to 8,100 feet (Shelly 1990). 



3. Soil relations: Lemhi beardtongue grows in a variety of 

 soils, ranging in texture from fine clays to sand (Ramsetter 

 1983), and derived from granite and sedimentary rocks, 

 including limestone and basin sediments (Shelly 1990). The 

 soils are usually dry and are often gravelly. The species 

 seems to be adapted to some level of soil disturbance, as 

 evidenced by its occurrence on steep, rocky slopes, in 

 eroded areas, and along roadsides. 



E. Population demography and biology 



1. Demographic details: The average number of plants per 



population in Montana calculated from 35 recently surveyed 

 occurrences was 128, and a total of 4,420-4,525 plants were 

 estimated to have been observed in the state (Shelly 1990). 

 The populations on BLM land in the study area are all guite 

 small, the largest (Roberts Gulch, 015) consisting of 54 

 plants in 1986. In recent years, when attempts were made to 

 relocate populations in the study area, some could not be 

 found (Frog Creek, 024 and Dutch Creek, 035), and numbers of 

 plants had declined in others (Roberts Gulch, 015 and Bloody 

 Dick Creek 2, 029). Similar declines, in numbers of 

 flowering and vegetative plants, have been documented by 

 demographic monitoring plots in recent years (J. S. Shelly, 

 unpublished data); although the numbers of seedlings 

 increased dramatically in 1993, a cool, wet year, most of 

 these were dead by 1994. A demographic monitoring transect 

 has been established in the study area on a road cut near 

 Horse Prairie Guard Station (027). Additional demographic 

 details for the individual populations in the study area are 



