32 



plant communities, should utilize seed mixtures of non-invasive 

 and preferably native species. After weeds become established 

 within populations of sensitive plants, they may be very 

 difficult or impossible to control without harming the sensitive 

 plants. Weed prevention programs are an important part of 

 conservation management for sensitive species. Roadside spraying 

 for noxious weeds should continue, but workers should be familiar 

 with the appearance and known locations of sensitive plants, most 

 notably Penstemon lemhiensis , so that they are not inadvertently 

 sprayed. Limiting off-road vehicle use on BLM land would also 

 help to reduce the spread of weeds. 



Not all parcels of BLM land in the study area were surveyed 

 for sensitive plants. The results of this study should be 

 considered a sampling of the total area rather than an exhaustive 

 inventory. It is likely that more populations of sensitive and 

 watch plants will be found in the area and possible that 

 prospective sensitive species other than those documented by this 

 project occur in the area, especially in wetland communities. 

 Some species may be found to be more common than now thought, 

 thus reguiring reassessment of their official status; the 

 opposite may become apparent for other species. The list of 

 vascular plants (Appendix B) should also be viewed as 

 preliminary. It is intended that this report serve as a baseline 

 and reference for land managers and as a guide for future 

 sensitive plant surveys in the area. Primary range on BLM land 

 in the Horse Prairie Creek drainage is, on the whole, heavily 

 impacted and these rangelands are a center of distribution for 

 two sensitive regional endemic plants, Astragalus scaphoides and 

 Penstemon lemhiensis . Management for the conservation of these 

 species will be a challenge which will reguire new approaches and 

 cooperation between environmentalists, ranchers, and government 

 agencies. 



