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Resource Utilization and Coexistence of Seed-Eating Desert Rodents in Sand Dune Habitats
James H. Brown and Gerald A. Lieberman
Vol. 54, No. 4 (Jul., 1973), pp. 788-797
Published by: Wiley
Stable URL: http://www.jstor.org/stable/1935673
Page Count: 10
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As many as five species of seed-eating rodents coexist in sand dune habitats in the North American deserts. Among species occuring together the ratio of body weights of adjacent species pairs is usually greater than 1.5. The seed resources of the habitats appear to be apportioned among species chiefly in two ways: (1) rodents differentially harvest seeds of different sizes, and seed size selection is positively correlated with body size: (2) species forage in different areas relative to the cover of perennial shrubs. The species also differ in their annual activity (some are active all year, others may go torpid for short periods or hibernate for several months), but is difficult to evaluate how these differences affect the utilization of seeds. Our estimates of total overlap in resource utilization between species indicate that competition for seeds have an important influence on community structure in desert rodents. In productive habitats species that are quite similar (overlap values greater than 80%) in resource utilization are able to coexist and species diversity is high, but in less productive habitats ecologically similar species are excluded, resulting in decreased species diversity.
Ecology © 1973 Wiley