Impacts of Thermal Variation on the Life-history Traits of Patagonian Herpetofauna

PIANTONI, CARLA; KUBISCH, ERIKA; GUTIÉRREZ, JOEL; ITURRA-CID, MYRIAM; IBARGÜENGOYTÍA, NORA

Westin Westminster Hotel Westminster, Colorado, EEUU

Simposio; American Physiological Society Intersociety Meeting, Global Change and Global Science: Comparative Physiology in a Changing World; 2010

American Physiological Society

Thermal constraints on activity may be the main source of geographical variation in reproduction and growth in lizards and amphibians inhabiting the Andes and Patagonian steppe. We used skeletochronology to estimate the thermal environment impacts on growth rates, age at sexual maturity and longevity. Shorter activity periods associated with high altitudes and latitudes result in lower growth rates, extended life-span, delayed maturity, and prolonged reproductive cycles, a combination that results in low fecundity. Accordingly, populations of Liolaemus multicolor and L. irregularis from the Andean region of Salta and the Patagonian Phymaturus tenebrosus reach maturity between the ages of 7 and 11 and life spans from 10 to 19 years. Intra-specific studies have shown that H. darwini achieves maturity between the ages of 3-4 but longevity increases with latitude, resulting in a maximum of 7 hatchlings against 5 at lower latitudes. A different pattern is seen in L. pictus argentinus: high altitude populations attain maturity one year earlier and have a shorter life-span, resulting in the same number of hatchlings than those at low altitudes. Strategies of Andean amphibians differ: life span of Pleurodema thaul is 5 years in all populations but severe environmental conditions are associated with maturity delay, higher annual growth rates and larger body size. Our preliminary results provide a framework for analyzing the eco-physiological responses of Patagonian herpetofauna to environmental changes.