2 . Environment and Habitat 



On the Deer lodge National Forest, B. paradoxum is found 

 in "genus communities" in the understories of mesic grasslands 

 on well developed soils in the montane and sub-alpine zones. 

 The species was not found in forests or in rockier or wetter 

 meadows which were surveyed. The populations occur on several 

 geologic formations in both upland and basin topographic 

 positions. The largest and healthiest population occurs in 

 near pristine native montane rough fescue grassland. Slides 

 of the habitats are included in Appendix F. 



Lidke and Wallace (1993) recently mapped the geology of 

 the north-central part of the Anaconda Range which includes 

 two of the population sites. This area lies near the 

 southernmost known extent of the Sapphire thrust plate and is 

 characterized by thrust faults. The underlaying geology of 

 One Hundred Acre Meadow is mapped as four units of Paleozoic 

 sedimentary rocks including limestones, dolomites, and shales 

 of the Jefferson, Maywood, Hazmark, and Red Lion formations. 

 Windy Ridge lies on the Helena formation which is composed of 

 Middle Proterozoic limy siltstones and limestones of the Belt 

 Supergroup. The Storm Lake area is not included in the 

 mapping area, but similar valleys and lake basins nearby are 

 mapped as Pleistocene Glacial till. 



The populations occur on gentle to moderate slopes of all 

 aspects at elevations ranging from 7,400 to 8,500 feet (2,250- 

 2,590 meters). The One Hundred Acre Meadow and Windy Ridge 

 sites are large meadows on exposed ridges, while the Storm 

 Lake population occurs in smaller openings in forest within a 

 steep walled basin. The soils in the area are mapped on a 

 broad scale as Inceptisols with Ustic to Udic moisture regimes 

 and Frigid to Cryic temperature regimes (U.S.D.A. Soil 

 Conservation Service 1978) , however, grassland soils are 

 usually classified as Mollisols. The soils of some Festuca 

 scabrella/F . idahoensis habitats (the habitat type at Windy 

 Ridge and perhaps at One Hundred Acre Meadow) have been 

 classified as Cryoborolls (Mueggler and Stewart 1980) . Field 

 observations characterize the soils of the population sites as 

 moderately dry to moist loams with few rocks or stones, and 

 with well developed organic horizons (0 and A). B. paradoxum 

 was not found in wetter or rockier soils. 



Lellinger (1985) indicates that species of Botrychium may 

 be favored by a "little disturbance." Lesica and Ahlenslager 

 (1993) suggest that B. paradoxum, in particular, may be 

 adapted to "ephemeral habitats." Some preference for slightly 

 disturbed microsites was also noted during this project, 

 however, by far the largest, most dense, and healthiest 

 population was found at the least disturbed site (Windy 

 Ridge) . In contrast, One Hundred Acre Meadow, a site highly 



