posted on 2019-03-04, 10:45authored byNatalia Fierro-Estrada, Yasmin Guadalupe González González, Donald B. Miles, Margarita Martínez Gómez, Andrés García, Isaías Hazarmabeth Salgado-Ugarte, Fausto R. Méndez de la Cruz
Ambient temperature is a primary factor affecting the physiology and
activity of reptiles. Thermoregulation involves a series of mechanisms to maintain
an organism's body temperature within a narrow range. The study of thermal ecology
of lizards is relevant for understanding their distribution, life history,
ecology and thermal requirements. Moreover, determining how species are able to
attain physiologically active body temperatures in challenging environments is necessary
for assessing the risk of extinction due to climate change, especially for
threatened endemic species. We evaluated and compared the thermal ecology of
two populations of the viviparous lizard Barisia
imbricata, at contrasting elevations (2,200 and 3,700 m). We obtained
variation in thermal data from winter through autumn for multiple years. We
determined thermal efficiency indices based on field active body temperatures, preferred
temperatures (in a thermal gradient), and operative environmental temperatures
(according to null models). We also recorded substrate and air temperatures at
the time of capture. Mean body temperature of both populations showed a
positive correlation with environmental temperatures. We found significant
seasonal differences in body temperature in both populations, and between body
temperatures of the two populations. Our results suggest that B. imbricata is an eurythermic species and
can thermoregulate actively at any given time. However, when environmental
temperatures are within the range of preferred temperatures, the species does
not engage in thermoregulatory behavior. This information expands knowledge on
the range of possible thermal responses to environmental variation within a species.