The Role of Habitat and Productivity in Structuring Desert Rodent Communities

In deserts a humped relationship seems to exist between mean annual rainfall, a measure of productivity, and species diversity of desert rodents. It has also been established that the diversity of desert rodents is affected by and correlated with the structure of the habitat. However, no attempt has been made so far to integrate the influence of both structure and productivity on species diversity. It was found that the structure of the habitat, measured as % perennial cover is significantly and negatively correlated with species diversity. A significant positive correlation exists between the productivity of the habitat, measured as % annual cover, and rodent diversity. Three hypotheses were tested: a) rodent diversity is determined only by productivity, b) structure enhances coexistence, and c) rodent diversity is determined by the area. The results of stepwise multiple regression rejected the first and third hypotheses. Both the structure and the productivity of the habitat are important factors in determining the diversity of rodents. It is still unknown to what extent structure and productivity interact to enhance new mechanisms of coexistence.