Soils, landforms, geology, topography, and aerial photography 

 were used to select areas to sample, based on what was known 

 about sensitive species' habitat requirements. We tried to 

 relocate historical collections to determine their current status 

 and extent and expand the survey to potential habitat. This 

 report summarizes the findings of the field inventory, including 

 information on areas surveyed, rare plant status, locations, and 

 habitat profiles particularly as they apply to the Helena 

 National Forest study areas, other significant sites, and further 

 details relevant to management decisions and future research. 



THE STUDY AREA 



The Big Belt and Elkhorn Mountains dominate the skyline east and 

 south of Helena, respectively, in south central Montana (Figure 

 1) . They lie as isolated mountain ranges on opposite sides of 

 the Missouri River Valley, eastern outliers of the Rocky 

 Mountains. 



These mountain ranges are made up mainly of continuous blocks of 

 land administered by Helena National Forest. The Big Belt 

 Mountains lie entirely within Helena National Forest 

 administrative boundaries, part of the Townsend and Helena Ranger 

 Districts. The Elkhorn Mountains are mainly in the Helena 

 National Forest, except for the southwestern corner lying in the 

 Deerlodge National Forest. It is part of the Townsend Ranger 

 District. For management purposes, the Big Belt and Elkhorn 

 Mountains are considered separate ecosystem units. 



These mountains are a geologic mix of sedimentary, 

 metasedimentary, and igneous rocks, with elevations ranging from 

 less than 4000 feet to almost 9500 feet. Climate is also quite 

 variable with an average annual precipitation low of just over 11 

 inches in Townsend to a high of over 27 inches in the Tizer Basin 

 in the Elkhorn Mountains (U.S. Forest Service 1992b) and a high 

 of over 43 inches on Boulder Baldy in the Big Belt range (U.S. 

 Forest Service 1992c) . Temperature varies from winter and summer 

 means of 18.1°F and 67.9°F in Helena, 24.8°F and 69.9°F at Holter 

 Dam, 19.7°F and 66.8°F in Townsend, and 19.6°F and 65.4°F at 

 Boulder State School (U.S. Department of Commerce 1982) . 

 Temperature data are not compiled for the mountain areas, but in 

 general the mountainous areas are cooler although winter 

 inversions may trap cold air in the valleys while the mountain 

 temperatures remain more moderate. Due to the mix of parent 

 materials and climatic variability, soils and plant communities 

 are also diverse. Grasslands and shrublands at lower elevations 

 blend into forests at middle and upper sites which give way to 

 subalpine and alpine zones or bare ridges at the highest points. 

 Wetlands are also important features, including numerous riparian 

 areas, wet meadows, marshes, and bogs. 



