EXECUTIVE SUMMARY 



Systematic sensitive plant species surveys were conducted in three study areas on lands administered by 

 the Bureau of Land Management (BLM) in the Butte District, primarily in the Dillon Resource Area. A 

 total of thirteen sensitive species were documented in 46 new occurrences. The acquired new 

 information rounds out the sensitive species resource baseline in the Dillon Resource Area, as 

 highlighted below: 



Relative abundance was documented for two watch species that are relatively common in the Big 

 Hole and Grasshopper study areas, respectively: Astragalus platytropis and Townsendia nuttaUii 



Significant new information was collected for two species, Kochia americana and Oryzopsis 

 contracta, which were virtually unknown in Montana before this study and unknown from BLM 

 lands. 



Significant new information was collected for six sensitive species, two of wliich are 

 recommended for change to watch designation. Largest known populations of the following 

 geographically restricted or globally rare sensitive species were documented, shedding light on 

 the habitat requirements and complementary management actions in the Grasshopper Study 

 Area: Astragalus scaphoides. Astragalus terminalis, Lesquerella pulchella, and Lomatium 

 attenuatum. Largest known populations of the peripheral species Stephanomeria spinosa were 

 also found in the Upper Madison Valley Study Area. 



Information was collected for Erigeron linearis, Lesquerella pulchella, and Lomatium 

 attenuatum at new population or subpopulation sites from settings of human-caused disturbance, 

 shedding light on habitat requirements and effects of disturbance. 



Finally, additional distribution information was collected on species that were once considered as 

 State Species of Special Concern, including some which remain on the Watch List because of 

 their limited distribution. 



This work documents the sensitive species that are present in each of the study areas in order to 

 determine species status and management needs and to develop all levels of management plans on BLM 

 lands in and adjoining these areas. 



