populations in the Yellowstone area (Grayling 

 Power Pole, Grayling Arm Hebgen Lake) are subject 

 to grazing by domestic horses. J. Jacobs 

 (Gallatin National Forest) reports that horse 

 grazing does not appear to be adversely affecting 

 these latter populations of C. longispica. 



2. RECREATION AND DEVELOPMENT: Most recreational 

 activity in the Pryor and Beartooth Mountains 

 occurs during hunting season when C. longispica is 

 dormant. There is some off -road vehicle use in 

 the Pryor Mountains during the growing season; 

 however, the habitat of C. longispica usually has 

 dense sagebrush and is not prone to widespread 

 disturbance from ORVs. 



The persistence of native plants is generally not 

 compatible with housing development such as that 

 occurring in the Hebgen Lake area. 



C. RECOMMENDATIONS FOR MAINTAINING VIABLE POPULATIONS 



1. MANAGEMENT RECOMMENDATIONS: There are no 



immediate threats to populations of Castilleja 

 longispica in the Pryor or Beartooth mountains. 

 Most populations in the Yellowstone area are also 

 unthreatened. The species occurs in habitat that 

 is abundant, so other populations will undoubtedly 

 be found. Encroachment by exotics such as 

 knapweed could pose a threat in the future; 

 however, it is not known how a hemiparasite like 

 C. longispica that is reported to have a wide host 

 range will respond to a weed invasion. Two small 

 populations in the Yellowstone area are threatened 

 by residential development and exotic weed 

 encroachment. Again, other populations 

 undoubtedly occur and have yet to be located, both 

 in the Yellowstone area and throughout southwest 

 Montana. Currently there are 21 known populations 

 with an estimated 50,000-350,000 plants. Most 

 populations are secure and may be increasing under 

 livestock grazing. Current management practices 



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