Resource partitioning patterns between two sympatric lizard species from Algeria

Food habits and daily activity patterns were studied in sympatric populations of the lizards Psammodromus algirus and Acanthodactylus erythrurus (Lacertidae) from the Parc National d’El Kala, north-eastern Algeria. In this area, these two species inhabited nearly the same microhabitats and were similar in terms of body length and weight. Both species were insectivorous, and fed primarily upon Coleoptera, Formicidae, and Diptera. The interspecific diet overlap was very high in terms of both the total number of prey items and the per cent of lizards containing a given food type. Null model analysis by Monte Carlo simulations (using the RA2 and RA3 algorithms) revealed that the high diet overlap values were not produced by chance. Daily activity patterns differed intraspecifically depending on the season, and interspecifically during both spring and summer. It is possible that the interspecific differences in daily activity patterns may help facilitating coexistence of the two study species. The high diet overlap may depend on the convergent eco-physiological needs of these two species in the arid environment, which forces them to apply a similar foraging strategy, i.e. preying on a few abundant and easily found prey sources.