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Six Species of Rattlesnakes in Joshua Tree National Park, California

Abstract

The competitive exclusion principle would seem to apply to six species of rattlesnakes in the genus Crotalus, all of which feed mostly on small mammals. In Joshua Tree National Park, California, however, six species occur in an area of just 400,000 ha. A pattern noted in ecology is that diversity at one level begets diversity at other levels. Almost 70 years of locality data combined with present field research was used as evidence for the hypothesis that these rattlesnake species mostly avoid competitive exclusion by microhabitat differences within the great diversity of ecological communities in the park. These long-term records might also indicate that the dynamics of the desert ecosystem could be changing, possibly the result of climate change and/or local urbanization.