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; GERMAN OSCAR GARCIA; VEGA LAURA; ISACCH JUAN PABLO

JOURNAL OF THERMAL BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

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

0306-4565

The present study describes and compares the thermal behavior of individuals of Liolaemus wiegmannii inhabiting patches of natural grassland and modified patches with exotic trees of Acacia longifolia, analyzing the factors affecting its behavior. Thermal behavior of L. wiegmannii was assessed by radiotracking 22 adult individuals in a coastal dune area from Argentina. In order to account individual responses we analyzed the factors affecting thermal behavior using Generalized Linear Mixed Models. Thermal 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. In natural and modified patches, L. wiegmannii regulated its body temperature by shuttling between different microhabitats that varied in their exposure to sunlight at different times of the day; however, in patches with A. longifolia individuals varied in the choice of plants that used as shaded places to mitigate high microenvironmental temperatures and were more exposed to full shade sites and less to warm sand where to bask, with negative consequences for its thermal biology.