Factors affecting the thermal behavior of the sand lizard Liolaemus wiegmannii in natural and modified grasslands of temperate coastal dunes from Argentina.

BLOCK, CAROLINA; STELLATELLI, OSCAR; VEGA, LAURA E.; ISACCH JUAN P.

JOURNAL OF THERMAL BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 38 p. 560 - 569

0306-4565

In lizards, as ectotherms, the behavior is a major contributor for achieving different body temperatures. Thermal behavior and microhabitat use of Liolaemus wiegmannii was assessed by radiotracking 22 adult individuals inhabiting patches of natural grassland and patches modified by the exotic tree Acacia longifolia in a coastal area from Argentina. We analyzed the factors affecting its behavior and microhabitat use in both types of patches using Generalized Linear Mixed Models. Thermoregulatory behavior of L. wiegmannii was mainly affected by the time of day and the substrate temperature. The individuals basking on bare sand in the morning, shifted to filtered sunlight during midday and to the shade of clump and erect stems herbs during the afternoon. The individuals were buried into sand when the substrate temperature was low and the wind speed was high. The use of sub shrubs and shrub could not be explained solely by thermal factors; hence, other aspects of the ecology of lizards (e.g. predation risk or food availability) could play an important role. In modified patches there were a greater proportion of individuals using full shade and clump herbs but a less proportion using bare sand than in natural patches. Disturbed zones may cause lower body temperatures and a reduced thermoregulatory efficiency of this species.