Spatial distribution of Psammomys obesus (Rodentia, Gerbillinae) in relation to vegetation in the Negev desert of Israel

Psammomys obesus in the Negev desert constructs burrows in the beds of dry rivers (wadi) densely covered with large shrubs of Atriplex halimus and on the first fluvial terrace that is covered with scattered and low shrubs of Anabasis articulata. We suggested that the distribution of P. obesus depends on the intensity and the asynchrony pattern of vegetation of these two chenopod species. To test this suggestion, we studied the spatio-temporal distribution of P. obesus in relation to vegetation cover across these two habitats. The percentage of vegetating shrubs of A. halimus increased steadily from 1999 to 2001, while shrubs of A. articulata were much more verdant in 1999 and 2001 than in 2000. In general, intensity of vegetation of A. articulata varied more among years than that of A. halimus. In 1999 and 2001, burrows used by P. obesus were distributed almost equally between habitats, whereas in 2000 there were more inhabited burrows in the "wadi" habitat, especially those of females that were confined in this habitat. Number of inhabited burrows on the terrace varied strongly between years, while the variation in the number of inhabited burrows in the wadi bed was much less pronounced. Wadi and terrace habitats are considered as a "key" and temporary habitats, respectively.