Chapter 7 



SPATIAL AND SOCIAL DISTRIBUTION 



Spatial Distribution 



General Patterns 



Generally, mule deer occurred throughout the study area. 

 Thus, our analysis primarily relates to patterns of dispersion 

 or the spatial distribution of individuals within the 

 population (Pennak 1964). Spatial and temporal patterns and 

 factors influencing dispersion were determined by plotting the 

 locations of deer observed during 32 aerial surveys from 

 autumn 1976 through spring 1984 within 953 28.8-ha blocks 

 generated for the area. Prior to 1976, deer observed during 

 aerial surveys were assigned to 1 of 10 multi-sized 

 subdivisions of the area. Those locations and locations of 

 deer observed along vehicle routes during 1960-1964 within 3.9 

 km 2 blocks (Mackie 1970) provided insight to general, long- 

 term changes in distribution. 



The general pattern of dispersion or intensity of use of 

 the area, based on relative numbers of mule deer observed in 

 28.8-ha blocks during all aerial surveys from 1976 through 

 spring 1984 (Fig. 7.1) indicated that spatial distribution was 

 neither uniform nor random. Rather, it followed a clumped or 

 aggregated pattern. Both general and local aggregation, 

 characterized by areas of relatively high deer density 

 bordered by areas of declining density, was apparent. 



Across the area as a whole, moderate to dense 

 concentrations generally extended across broken terrain along 

 slopes and coulees between major ridgetops and major coulee or 

 river bottoms. Highest contiguous densities occurred in the 

 northwestern portion of the area between Sand Creek and the 

 Missouri River. Blocks in which deer were never or only 

 rarely recorded were primarily in open prairie habitat along 

 the southern and southwestern fringes, larger expanses of 

 sagebrush-grassland along major ridges, large open coulee 

 bottoms within a few kilometers of the Missouri River, and 

 bottomlands along the river. These areas did not comprise 

 yearlong habitat for mule deer and received only occasional 

 seasonal or transitory use. 



Within this general pattern, aggregated areas of high 

 density were surrounded roughly concentrically by areas of 

 lower, declining use. A quantitative representation of 

 concentric distribution around high density blocks (Table 7.1) 

 indicated that adjacent blocks were not randomly distributed 

 among the 4 density categories (X 2 = 164.6, 3 df, P < 0.0001). 

 Other blocks of high density were significantly over 



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