douqlasii is a species complex with various 

 entities such as austinae in the process of 

 becoming distinct species. 



G. POPULATION ECOLOGY 



1. BIOLOGICAL INTERACTIONS 



a. COMPETITION: In Montana, Polycfonum doucflasii 



ssp. austinae (#006) occurs primarily on 

 shale barrens which are almost devoid of 

 other vegetation. Its persistence on an 

 isolated shale mound of less than 15 square 

 meters under extremely heavy invasion by 

 Bromus tectorum reflects a competetive 

 resiliency. Should this pattern repeat, or 

 its known population numbers significantly 

 increase, this will warrant its deletion from 

 the Region 1 - U.S. Forest Service list and 

 the Montana Natural Heritage Program list. 



b. HERBIVORY: The habitat of Polygonum douqlasii 



ssp. austinae does not lend itself to 

 livestock grazing. Livestock trails cross 

 some of the populations. Invasion of annual 

 species like Bromus tectorum from surrounding 

 grassland may be fostered by heavy grazing 

 (see preceding discussion under Competition) . 



II. ASSESSMENT AND MANAGEMENT RECOMMENDATIONS 



A. THREATS TO CURRENTLY KNOWN POPULATIONS: In the Helena 



National Forest, a population along readouts is 

 threatened by slope destabilization and future 

 maintenance and construction activities. Exotic plants 

 are invading at two other Helena National Forest sites, 

 and may pose potential dangers from competition. The 

 degree of mining threats has not been ascertained. 



B. MANAGEMENT PRACTICES AND RESPONSE: One population on the 



Helena National Forest is persisting in spite of heavy 

 grazing and the severe invasion of exotic plants 

 throughout the small pocket of suitable habitat. 



C. RECOMMENDATIONS FOR MAINTAINING VIABLE POPULATIONS: Road 



maintenance crews and their supervisors should be 

 notified of the location of the population occurring 

 near the road. A detailed map with the location of the 

 population should be provided to the road maintenance 

 staff. This could reduce or eliminate unnecessary 

 impacts or the loss of this site. 



71 



