Effect of fire and environmental temperature on the reproductive recruitment of Neotropical freshwater turtles

Reproduction is a fundamental biological aspect of the recruitment of individuals and to maintenance of stable populations. Thus, an important question is understating the impact of human disturbances, such as fire, on reproduction success. In this study, we evaluated the effect of fire and environmental temperature on the reproductive recruitment of two Neotropical species of freshwater turtles (Podocnemis expansa, and Podocnemis unifilis). Our hypotheses are as follows: (i) nesting areas exposed to fire exhibit lower reproductive recruitment of turtles, and (ii) years with higher environmental temperatures are associated with increasing reproductive recruitment of turtles. To test these hypotheses, we used data collected from long-term monitoring of nesting sites (2006–2021) of freshwater turtles in Rio das Mortes, Central Brazil. The number of fire outbreaks and environmental temperature were our independent variables; while the number of live hatchlings per reproductive season, the number of unviable eggs, and the total number of eggs were our response variables. The findings indicated that fire harmed the reproductive recruitment of turtle species, and the total number of eggs was negatively influenced by fire and environmental temperature. Long-term monitoring and experimental studies are essential for the understanding of the relationship between human and natural effects on the Neotropical freshwater turtle population. In turn, it contributes to the implementation of effective conservation measures for freshwater turtles.