59 



4. Status and location of presently cultivated 



material: Plants are being maintained in the 

 greenhouse at the University of Montana, 

 Missoula (Peter Lesica, pers. comm.)* 



11. Evidence of threats to survival. 



A. Present or threatened destruction, modification, or 

 curtailment of habitat or range: Silene spaldingii 

 occupies habitats in Montana that are threatened by 

 grazing. Pristine or near-pristine stands of 

 Palouse prairie are easily lost to overgrazing and 

 the resultant invasion of exotic weed species. In 

 other states (Idaho, Oregon and Washington) most of 

 the suitable habitat has been lost through 

 conversion of lands to agriculture and to 

 overgrazing. Much of the habitat where this species 

 occurs in Montana is privately owned, and thus 

 without use restrictions. Populations in these 

 areas may be in danger of extirpation. Only a small 

 portion of the habitat supporting the largest 

 population (Dancing Prairie (001)) is secure (owned 

 and managed by The Nature Conservancy, while the 

 rest of the area is owned by private individuals. 



B. Overutilization for commercial, sporting, 

 scientific, or educational purposes: No threats 

 known. 



C. Disease, predation, or grazing: In Montana, only 

 the Wild Horse Island site (002) is not threatened 

 by overgrazing. All the other sites are lightly to 

 heavily grazed. In conjunction with the extended 

 drought, grazing may be even more detrimental to 

 populations of Silene spaldingii . 



D. Inadequacy of existing regulatory mechanisms: None 

 known . 



E. Other natural or man-made factors: None known. 

 II. ASSESSMENT AND RECOMMENDATIONS 



12. General assessment of vigor, trends, and status: In 

 Montana, Silene spaldingii is presently known from ten 

 sites in Lincoln, Sanders and Flathead counties. 

 Populations have declined over the past two years, 

 probably owing to prevailing drought conditions. 

 Populations may be in danger from livestock grazing. 



