RHINELLA CF. ALTIPERUVIANA NEST MICRO-ENVIROMENT SELECTION: THE IMPORTANCE OF ABIOTIC VARIABLES IN A RIGUROSUS HABITAT

ARAGON, J.; IRIBAS, F.; QUIROGA, L.; GORDILLO, L; SANABRIA, E. A.

San Juan

Congreso; Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2023

SBC

Rhinella cf. altiperuviana is a species of toad that inhabits high-altitude environments within the Andes mountain range. These habitats arecharacterized by extreme aridity and low temperatures, both of which present significant challenges for amphibian survival. Furthermore,this species can inhabit areas with high salinity levels, adding yet another obstacle to its development. R. cf. altiperuviana constructs smallnests in shallow watercourses to deposit its eggs. Although this behavior is well documented, its effect on environmental variables withinthese nests and whether their construction confers any advantages for the proper development of the species´ eggs remains unknown. TheAncho river (-31.669612 W; -68.828903 S; 1486 m.a.s.l.) was surveyed for nests containing eggs or tadpoles. Seven environmental variables(pH, salinity, water depth, water temperature, water velocity, vegetation, and soil granulometry) were measured inside these nests and inanother “nest-less” similar micro-habitat in a 50cm radius. Subsequently, logistic regressions were performed, with the presence of eggclutches as the response variable, incorporating all possible combinations of the measured variables while considering the order of theirinclusion (n=511 models). Based on Akaike Information Criterion (AIC) scores, the most parsimonious model that best explained thepresence of egg deposits of the species was selected. The best model included the variables of water temperature and water velocity. Theseresults suggest that the construction of nests helps to create a warmer and quiet environment for the eggs incubation. In conclusion, the builtof nests by R. cf. altiperuviana could be an adaptation to the low Andean temperatures, and to the high velocity of the mountain streams, inorder to prevent damage on the gelatinous egg cords.