Effects of forest degradation on abundance and microhabitat selection by ground dwelling Chaco lizards

Abstract

Abstract Human-induced degradation of Chaco forests has led to a mosaic of habitats with different forest conditions, offering different habitat suitability characteristics to the native fauna. Abundance and microhabitat use of Teius teyou, Liolaemus chacoensis, Cnemidophorus ocellifer, and Tropidurus etheridgei were analyzed in the western Chaco forest of Argentina. A mature forest that has remained undisturbed for the last 30 years (Los Colorados Biological Station, LC) and a highly disturbed forest (Campo Grande, CG) were compared through diurnal visual encounter surveys along 74 1-km transects. Lizards were assigned to the microhabitat category according to the site where they were first observed (bare ground, litter/grass/herbs, shrubs or trees). T. teyou preferred bare ground in LC, avoiding litter/grass/herbs and using shrubs according to availability, whereas in CG the species preferred shrubs, avoiding bare ground. C. ocellifer used microhabitats according to their availability in LC, whereas in CG, this species preferred shrubs and avoided the remaining microhabitats. L. chacoensis preferred bare ground in LC, using litter/grass/herbs and shrubs according to availability. In CG, the species used bare ground according to availability, preferred shrubs, and avoided litter/grass/herbs. T. etheridgei preferred bare ground in LC, avoiding litter/grass/herbs, and using shrubs according to availability, whereas in CG both bare ground and shrubs were preferred, and litter/grass/herbs was avoided. Our results suggest that microhabitat selection by lizards in the Chaco is a plastic process influenced by vegetation structure, and probably regulated by lizards' thermal requirements.