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lemhiensis in Montana have been impacted by 

 livestock grazing. As discussed in I.7.B.2., 

 significant declines have been noted in three 

 populations in the southern Pioneer Mountains. 

 Of these, one occurs in an area of moderate to 

 heavy livestock use (Ermont Gulch (014)). 

 Seventy-six plants were counted there in 1986, 

 but only one plant was found in 1989. Similar 

 declines were noted at Badger Pass (005) and 

 Red Butte (012) ; however, these sites did not 

 appear to have been grazed recently, and there 

 is an exclosure at the Badger Pass site that 

 was constructed to prevent impacts from 

 grazing. Thus, although grazing may have 

 caused the decline at Ermont Gulch, the 

 decreases there and in the two other 

 populations may have been related to other 

 factors (i.e., the severe drought conditions 

 that prevailed in 1988) . Browsing of flowering 

 stems, by native ungulates and/or livestock, 

 has also been observed in several populations 

 (see I.8.C. 1. ) . 



2. Existing threats: Grazing use is ongoing 

 throughout much of the species' range in 

 southwestern Montana, and it is likely that 

 impacts to some individuals are occurring as a 

 result. 



3. Potential threats: Browsing by native animals 

 and livestock is likely to continue in the 

 future. The monitoring transects established 

 in 1989 (Shelly 1990b) will provide data that 

 can be used to assess the resultant impacts on 

 population demography. 



D. Inadequacy of existing regulatory mechanisms: There 

 are currently no state statutes that provide 

 protection for rare or endangered plant species in 

 Montana. 



E. Other natural or man-made factors: Of the 35 known 

 populations in Montana, 17 (49%) of them consist of 

 fewer than 50 individuals, and 11 (31%) contain 

 fewer than 20 individuals. These low population 

 numbers may render the species vulnerable to 

 extirpation in many parts of its range in the state. 

 Also, these small populations, many of which are 

 very isolated, may be less exposed to effective 

 pollinators, especially the vespid wasp that appears 

 to be specific to P. lemhiensis . Lastly, the 

 observed declines in two populations, where no 

 direct disturbance was observed, suggests that the 



