Species Diversity of Seed‐Eating Desert Rodents in Sand Dune Habitats
1973
Brown, James H.
The seed—eating rodent faunas were sampled on 18 dunes of semistabilized, wind—drifted sand in eastern California, Nevada, and western Utah. These dunes were similar in general appearance and in the form and spacing of vegetation, yet the number of common species of granivorous rodents ranged from 1 to 5. The faunas of all dunes were characterized by a regular spacing of body sizes, and the difference in size between coexisting species was inversely related to the number of species present. Differences in species diversity between dunes can be attributed to ecological, biogeographic, and evolutionary processes. A common pool of species had equal opportunity to colonize 13 of the dunes. The numbers of species inhabiting these dunes are determined primarily by ecological factors. Species diversity is most closely correlated with the predictable amount of annual rainfall, the best available estimate of the abundance of seeds. At least three dunes apparently are biogeographically depauperate; biogeographic barriers have prevented colonization of particular species that probably could exist on those dunes. Two of the dunes occur at high altitudes and these appear to be depauperate in an evolutionary sense; although these dunes seem to be capable of supporting additional rodent species, it is likely that no existing species possess the adaptations necessary to colonize them.
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