AREAS OF SPECIAL CONCERN 



In the wildlife baseline study final report (DNRC 1978:191-193). wildlife 

 species or habitats of special concern were identified and briefly discussed. 

 The 4.5-year data base gathered to date, however, allows these areas of special 

 concern, which are important over the long term, to be more accurately defined. 

 This 4.5-year study period has included two moist years and two drought years, 

 as well as two severe winters and parts of three relatively mild winters. As 

 could be expected, wildlife use patterns varied greatly with the changes in 

 weather patterns. Nevertheless, some generalizations can be drawn based on the 

 long-term data. Areas of special concern in the Mine Study Area, as shown in 

 Figures 8, 11, 12. 23, and 24, are discussed below. 



Dendritic Silver Buffaloberry Coulees 



Perhaps the most unique habitat identified in the Mine Study Area is the 

 "tall coulee shrub" habitat described in the baseline study (DNRC 1978). This 

 habitat occurs in steep-walled, deeply-eroded dendritic coulees usually found 

 near ridgetops at the heads of drainages. Silver sagebrush and snowberry-rose 

 low shrub communities commonly occur on the relatively flat coulee bottoms, 

 while the upper reaches of the coulees and sheltered areas along the coulee 

 trunk support an unusually mesic and diverse assemblage of tall shrubs, most 

 often dominated by dense clones of silver buffaloberry. These sheltered areas 

 also include red-osier dogwood, serviceberry , chokecherry, and (rarely) green 

 ash and cottonw'ood. Dense stands of silver buffaloberry often occur on moderate 

 slopes adjacent to the Missouri River floodplain, and occasionally near the 

 heads or edges of box elder and green ash dominated "hardwood draws" typically 

 found further east in Montana and North Dakota (Swenson 1981). It is not known 

 whether silver buffaloberry occurs in combination with red-osier dogwood and 

 deeply-eroded coulee topography outside southern McCone, northern Prairie, and 

 east-central Dawson counties, Montana. 



Nowhere in this area were more well-developed examples of this vegetative- 

 topographic complex observed than in the northeastern portion of the Permit 

 Area. The most well-developed such coulee system is found here, and is 

 delineated in Figure 23, which shows the approximate distribution of silver 

 buffaloberry in the Mine Study Area. This coulee system provides important 

 spring-fall cover for deer, and is a key component of the major sharp-tailed 

 grouse breeding-wintering complex. Many species of birds depend on silver 

 buffaloberry for nest sites; a breeding bird census plot located in this coulee 

 system supported the greatest species diversity of all habitats sampled (DNRC 

 1978, 1979). Also, small mammal biomass was greatest in tall coulee shrub and 

 coulee trunk habitats throughout the study period (Figure 21), while the change 

 in small mammal biomass from spring to fall was greatest here in all years 

 except 1980. Most of the recommendations for future monitoring (see the 

 following chapter) are designed to further explain the structure, origin, and 

 suggested importance of this coulee system. 



Waterfowl Production Areas 



Waterfowl production in the Mine Study Area is not remarkably high, although 

 production in the original Proposed Mining Area was nearly 5/km during the very 

 wet year of 1979 (Figure 14). The eight most important stockponds in the Mine 

 Study Area for waterfowl production, with their adjacent upland nesting areas, 

 are indicated in Figure 24. These are the stockponds which had an average 



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