In conjunction with Projeto Tamar, this project explores the impacts of climate change on the reproductive output of hawksbill and loggerheads turtles nesting in Brazil. This is the third year of the project where we are obtaining information on the thermal profile of index hawksbill and loggerhead turtle nesting beaches in Brazil to explore the spatio-temporal variability of their hatchling sex ratio. Marine turtles have temperature-dependent sex determination, where their sex ratio is determined by the nest temperature. Projected increases in temperature may skew marine turtle population′s sex ratios towards predominantly females.In the context of global warming and predicted skew in marine turtle population sex ratios it is important to have knowledge of the current and future sex ratio of hatchlings being produced by marine turtle populations. This information is critical to provide a baseline in advance of global warming, to elucidate implications from future extreme female sex biases and to help identify areas that produce a higher proportion of male hatchlings, which will be essential to inform conservation in the context of extreme female sex biases. However, usually there is a lack of wide-scale, long-term information on primary sex ratios as a baseline to infer changes from global warming and to identify nesting areas of high conservation value.
To obtain this information, we deployed 60 temperature dataloggers along the whole extent of nesting areas and environments used by hawksbill and loggerhead turtles in Brazil. Thermal profile will be monitored over three years and will be used to estimate the current sex ratio being produced at each location. This will be coupled with climate models to predict future sex ratio and to help prioritize management in light of global warming.
More information about the project can be found at: