GENERAL ASSESSMENT OF VIGOR, TRENDS AND STATUS: The 

 geographic range of Arabis fecunda consists of two 

 disjunct areas: (1) the northern area along the west 

 face of the Sapphire Range in Ravalli County and (2) 

 the southern area in the East Pioneer and Highland 

 ranges in Beaverhead and Silver Bow counties. The 

 status and trends of Arabis fecunda in these two areas 

 appears to be different. 



There are 14 known populations in the southern area, 

 and many of these are large and relatively undisturbed. 

 Weed infestations have not yet become a problem. 

 Mining activity is a potential but not a current 

 threat. Livestock grazing does occur at most sites, 

 but evidence that it is a serious threat is 

 unconvincing at this time. Monitoring studies suggest 

 that populations are stable or perhaps even growing. 

 Consequently, Arabis fecunda appears to be secure in 

 the southern portion of its range. 



There are four known populations in Ravalli County, two 

 of which are quite large. All sites have been 

 historically overgrazed, and invasion and serious 

 degradation of native habitats by Centaurea maculosa 

 occurs throughout the entire area. The area is 

 experiencing increasing pressure from human population 

 growth, so introduced weeds will likely be an 

 escalating problem. Livestock grazing will likely 

 continue into the foreseeable future. Results of 

 monitoring studies suggest that populations in Ravalli 

 County may be declining and that increased density of 

 C^ maculosa could lead to extirpation of populations. 

 It seems likely that A^ fecunda population viability in 

 this area is trending downward. 



The two areas are separated by ca . 80 miles, and the 

 habitats Arabis fecunda occupies are noticeably 

 different. Thus, there are likely to be genetically 

 distinct populations in the two areas, and the little 

 evidence available is consistent with this hypothesis. 

 Although the majority of known populations are not 

 currently threatened or endangered, Arabis fecunda may 

 be threatened in a potentially significant portion of 

 its range. 



RECOMMENDED STATUS: 



1. U.S. FISH AND WILDLIFE SERVICE: The distribution 

 and size of Arabis fecunda populations are 

 reasonably well known. However, threats and the 

 significance of potentially threatened populations 

 to the viability of the species as a whole are not 



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