The Influence of Riparian and Adjacent Habitats on Small Mammal Distributions in Grand Teton National Park, Wyoming

Abstract

Riparian ecosystems are among the most productive biological systems providing food, water, shade, and cover for wildlife (Thomas et al. 1979). Furthermore, they may display a greater diversity of plant and animal species and vegetative structure than adjacent ecosystems (USDI 1986). Previous investigators have sought to document rodent associations within riparian vegetation (Moor and Bradley 1975, Anderson et al. 1977, Boeer and Schmidly 1977, Gier and Best 1980, Paul 1981, Cross 1985, Doyle 1986, 1990, MacCraken et al. 1985, Anthony et al. 1987). Generally, these studies demonstrate that riparian habitats contain higher abundance and lower diversity of small mammal species when compared to adjacent upland sites or nearby sites which contained variable non-riparian habitats. Odum (1978) states that for wildlife populations, the riparian zone provides a classic example of the ecological pririciple of "edge effect". This effect is exerted by adjoining communities on the population structure within the ecotone which often contains greater numbers of species and higher densities of some species then either adjoining communities. He further states that density and diversity of species tend to be higher at the land-water ecotone than in adjacent communities. This relationship between edge effect and wildlife has not been well documented (Forman and Godron 1986) in part, because research has focused more on induced edges created by corridors than by patches (Yahner 1988).