A predictive model of yellow spotted river turtle (Podocnemis unifilis) encounter rates at basking sites in lowland eastern Bolivia

Abstract

This paper develops a model predicting encounter rates of the yellow-spotted river turtle (Podocnemis unifilis) based on human hunting pressure and an ecological classification of potential basking sites. We estimate Poisson regression models for turtles observed in basking surveys. Field surveys were conducted in eastern lowland Bolivia in 2000 and 2011. Our model predicts a significant correlation between turtle encounter rates and two ecological classifications – steep cliff with vegetation and muddy flats that we believe are important habitat types for these turtles. Additionally, our model supports the hypothesis that human population has a significant but less negative impact on observed turtle encounter rates. Analyses of turtle encounter rates and factors that influence it are critical for the conservation of P. unifilis turtles and the broader Amazonian ecological system.