Science Serving Maryland's Coasts

Alan Williams, University of Arizona

Class Year: 
2019

Project Title: 

The Temperature Inside the Nests of the Diamondback Terrapin, Malaclemys terrapin, and Its Relationship with the Air Temperature of the Nesting Site

Abstract: 

The diamondback terrapin (Malaclemys terrapin), is an estuarine turtle found within brackish marshes of the eastern and gulf coasts of the United States and it is the official state reptile of Maryland. The diamondback terrapin unfortunately may become a victim of increasing global temperatures due to its temperature-dependent sex determination (TSD). Species that display TSD may produce more female than male hatchlings or vice versa depending on the temperature of the individual nest. This study used several individual nest temperatures along with the air temperatures at the nesting site, recorded in the summer of 2018, to select a predictive model with R software package rstanarm, to predict nest temperatures using known air temperatures. The regression spline mixed model was selected for having the lowest leave one out information criterion. Its accuracy was determined by using air temperatures recorded during the summer of 2019 to predict 2019 nest temperatures, and comparing the predictions to field recorded values. The RSMM had a predictive capability of 83.6-98.7% coverage of five actual nest temperatures recorded in 2019, with a predictive interval of 95%. The resulting model will inform a collaborative project evaluating climatic influence on individuals and populations of diamondback terrapins.