12 



2. MINING: The French Creek (003), Mill Creek (Oil, 

 012) , and Stonewall Creek (009) populations occur 

 in historic mining districts. Recently, these 

 areas have received some renewed attention by 

 geological interests. These populations should be 

 considered in any proposed project activities that 

 might affect these areas. 



3. WEED CONTROL ACTIVITIES: Weed control activities 

 could pose a problem especially to the roadside 

 populations at Elk Lake (002), French Creek (003), 

 Stonewall Creek (009), and Mill Creek (011, 012). 

 Forest Service weed control managers should be 

 made aware of population locations. 



B. MANAGEMENT PRACTICES AND RESPONSE: A weevil 



( Rhinocyllus conicus) introduced as a biological 

 control for Carduus species (introduced Eurasian 

 species) , has a high infestation rate in populations of 

 the endemic thistle Cirsium longistvlum in the Little 

 Belt Mountains of north-central Montana. The 

 introduced weevil is lowering the fecundity of C. 

 longistylum populations at an unknown rate. This same 

 weevil is also known to infect a number of other 

 thistles in California, including C. brevistylum , also 

 a species of concern in Montana (Turner 1987b) . The 

 possibility of infestation occurring with other native 

 thistles including C. subniveum should be taken into 

 account when considering the introduction of biological 

 controls. 



C. RECOMMENDATIONS FOR MAINTAINING VIABLE POPULATIONS: It 

 is recommended that managers be made aware of the C. 

 subniveum populations with respect to any weed control 

 activities. Also, this species should be considered 

 when evaluating the impacts of proposed mining 

 activities. 



D. RECOMMENDATIONS FOR FURTHER ASSESSMENT: Only a portion 

 of the potential habitat of C. subniveum could be 

 surveyed in the time allowed. Further survey work in 

 the Tendoy and Snowcrest ranges, and particularly in 

 the Gravelly Range, may reveal that C. subniveum is 

 more common in this portion of the state. Due to small 

 population sizes and low densities, C. subniveum should 

 remain on the U.S. Forest Service Region 1 sensitive 

 species list for the Beaverhead National Forest. 



