O efeito de gradientes ambientais de ordem estrutural e climática na distribuição de lagartos (Squamata: sphaerodactylidae) ao longo de um interflúvio na Amazônia Ocidental

Abstract

Both environmental physical factors and climate variables can affect the distribution of organisms in such a way that each species should show an optimal position within a given gradient in which it reaches maximum abundance. In this context, lizards are excellent models for research on the effect of environment on the occurrence and abundance of species, because their thermal ecology and versatility in the use of the environment incite strong responses to environmental heterogeneity. We investigated the distribution of three species of Sphaerodactylidae lizards (Chatogekko amazonicus, Gonatodes humeralis and G. hasemani) using active counting methods in 156 sampling units arranged in 14 sampling modules in a transect of about 900 km along the interfluve between the rivers Purus and Madeira, in Brazilian Amazonia. The effect of seven independent environmental variables on the occurrence and abundance of each species was tested using logistic regression models and multiple linear models, respectively. We observed that environmental factors of structural nature, especially related to the physical composition of the soil, were important in the local distribution of species. At the regional level, climatic factors, especially related to changes in temperature, exerted a critical role. The distribution patterns of species reflected the environmental heterogeneity present in the interfluve and showed particularities, suggesting that the interactions between the life history of each species and the environment shape their distributions idiosyncratically.