Demographic Comparison of Semi-urban and Wild Populations of Kinosternon chimalhuaca

Members of the mud turtle family, Kinosternidae often use man-made water sources such as cattle troughs and irrigation ditches to survive in increasingly urbanized and arid regions. However, the effects these conditions have on turtle population structure are still poorly understood. The Jalisco mud turtle (Kinosternon chimalhuaca) was first described in 1997 in a small range south of Puerto Vallarta, Mexico. Since its description, critical ecological research has remained largely nonexistent, hindering conservation and management. Our research reports the first analysis of K. chimalhuaca’s population structure in a comparative study of a pristine wild habitat in the Chamela-Cuixmala Biosphere Reserve, and a nearby semi-urban habitat in a nearby town. In 2019, our team surveyed a small ~1km irrigation ditch in the middle of this town and astonishingly captured 226 turtles, estimating a population of ~750±56 individuals. Similar trapping effort in the wild habitat surrounding the Chamela field station yielded only a dozen individuals. In town, turtles exhibited an inverted female:male ratio (~2:1, n=200) when compared to wild turtles (~1:4, n=35). Furthermore, wild turtles were found to be significantly larger in length between sites (p= 0.0004) with wild males exhibiting a more bimodal distribution. This warrants further investigation into the driving factors of abundant semi-urban populations and the significance of human-turtle interactions and in the face of global turtle declines. These findings represent a preliminary dataset prior to conducting a full comparative ecological study of population structure, diet and movement ecology at both study sites this summer