Competition and the role of habitat selection in Gerbillus allenbyi and Meriones tristrami: a removal experiment.

In northern Israel, 2 seed-eating gerbilline rodents exhibit exclusive distributions. Gerbillus allenbyi is the only species inhabiting coastal sand dunes between Tel Aviv and Mt. Carmel. Meriones tristrami is found in the same coastal region, but is restricted to non-sandy habitats. However, in the coastal area north of Mt. Carmel where G. allenbyi does not occur, M. tristrami inhabits dunes. This type of distribution is usually interpreted to result from competition. A perturbation experiment conducted in the narrow transition strip between soil and sand in an area where the above species are sympatric revealed no ongoing competition between the species. Strong interspecific competition in the past may have resulted in genetically determined habitat selection in the present.-Authors