Evaluation of Road-Crossing Terrapene carolina major (Gulf Coast Box Turtle) in the Florida Panhandle

Road mortality often presents a serious conservation challenge for freshwater turtles. Population-level effects may be skewed toward either sex depending on habitat context and configuration, species, and season, and may be temporally variable. We opportunistically collected occurrence data for all turtle species encountered on roadways in the context of a 2-year radio-telemetry study. We primarily collected field data between March and August 2016 and 2017. We summarized the demographic and species composition of turtles encountered and conducted a logistic regression analysis to evaluate the influence of landscape variables associated with areas of high-density road crossings by Terrapene carolina major (Gulf Coast Box Turtle). In total, we observed 6 species of freshwater turtle on paved and unpaved roads, with 92% of records representing Gulf Coast Box Turtles. Of the roadway observations used to evaluate landscape variables, 91% of the records were Gulf Coast Box Turtles, 80% of which were females. Road crossings were associated with higher percentage of coniferous plantation and greater distance to floodplain swamp. Additionally, for all paved roads evaluated, the percent of individuals found alive varied from 58% to 89%. Our results were expected based on the radio-telemetry data collected on local populations; male box turtles in this area appeared to rely more heavily on floodplain swamps than confierous plantations. We recommend that researchers opportunistically collect road-occurrence data as feasible and coordinate with local partners to develop robust datasets that can be utilized to develop strategic mitigation measures.