J. MANAGEMENT PRACTICES 



1. MINING: Contact zones between granitic intrusions 

 and Madison limestone are often areas of 

 commercial mineral deposits (Alt and Hyndman 

 1986) . This is the same geologic situation that 

 provides the habitat for Arabis fecunda . Nine of 

 fourteen sites in the southern portion of the 

 range are in close proximity to old mines. 

 However, Fish Creek is the only site with an 

 active mine nearby. It is not known how past or 

 present activity has affected A^ fecunda 

 populations 



2. LIVESTOCK GRAZING: All known populations of 

 Arabis fecunda except Spring Gulch II are subject 

 to cattle grazing. Grazing is light in some areas 

 such as Lime Gulch, Cattle Gulch and Canyon Creek, 

 but heavy in others such as Birch Creek and Jerry 

 Creek. Livestock are important vectors for exotic 

 weed infestations. Effects of livestock grazing 

 are discussed under Facilitation (G.2) and Other 

 Negative Interactions (G.5) above. 



3. RECREATION: All sites on public land managed by 

 federal agencies are open to hunting. Portions of 

 the Tucker Creek and South Fork Tucker Creek sites 

 are in or near the boundaries of the Humbug Spires 

 wilderness study area. None of the sites show 

 evidence of off-road vehicle use. The effects of 

 recreation on A^ fecunda populations are not known 

 but are probably negligible. 



K. EVIDENCE OF THREATS TO SURVIVAL 



1. EXOTIC WEED ENCROACHMENT: Centaurea maculosa is 

 present at all known Arabis fecunda sites in 

 Ravalli County. At most sites the infestations 

 are severe. This aggressive exotic has been shown 

 to have adverse effects on many native species 

 including A^ fecunda (Lesica and Shelly, 

 submitted) . Currently C^ maculosa does not occur 

 at any of the Beaverhead or Silver Bow county A^ 

 fecunda sites, but it does occur in these counties 

 and could become a problem in the near future. 



2. LIVESTOCK GRAZING: Livestock grazing occurs at 

 most Arabis fecunda sites, although heavy grazing 

 is reported for fewer than half the sites. 

 Evidence for negative effects of livestock on A. 

 fecunda are equivocal. Direct herbivory has never 

 been observed and is probably rare. However, 



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