The Herbivore-Based Trophic System 385 



FIGURE 10-16. Relative habitat utilization by herbivores near Prudhoe 

 Bay. The numerals above the habitats refer to vegetation types identified 

 by Webber and Walker (1975) for the Prudhoe Bay region. 



with large low-centered polygons, a habitat little used by lemmings at 

 Barrow. Furthermore, the areas most favored by brown lemmings are 

 also heavily utilized by caribou, whose trampling disturbs the habitat. 

 Both factors may account for the modest lemming populations in the 

 Prudhoe Bay region. 



Caribou represent the largest biomass of herbivores in the Prudhoe 

 Bay region (Table 10-3). Because of their mobility caribou utilize a wide 

 variety of landforms and vegetation types, and a large study area must be 

 considered. During 1972-73 a resident population of 200 to 500 animals 

 inhabited the Prudhoe Bay region, a 2340-km^ area of Coastal Plain 

 bounded by the Kuparuk and Sagavanirktok Rivers in the west and east 

 and by Prudhoe Bay on the north and the White Hills toward the south. 

 These caribou constitute a portion of the Central Arctic caribou herd 

 which has been identified in recent years by Cameron and Whitten 

 (1979). During summer migratory herds of up to 3000 caribou may also 

 pass through the region, and when they are under severe insect attack 

 thousands may be concentrated in the coastal sand dunes associated with 

 the river systems. 



