Habitat modeling and conservation of the Western Chicken Turtle (Deirochelys reticularia miaria)

Authors: W. A. Ryberg, B. D. Wolaver, H. L. Prestridge, B. J. Labay, J. P. Pierre, R. A. Costley, C. S. Adams, B. C. Bowers, T. J. Hibbitts

The Western Chicken Turtle (Deirochelys reticularia miaria) is considered rare and declining throughout its range, although no population surveys have been conducted range-wide. Uncertainty regarding population status and perceived threats to habitat convinced the U.S. Fish and Wildlife Service to consider Endangered Species Act protection for the subspecies. The goal of this study was to inform the listing process by describing the biological and conservation requirements for Western Chicken Turtles. We modeled potentially suitable habitat throughout the range of the subspecies and quantified current and future threats to that habitat in Texas, USA. Potentially suitable habitats with the highest probability of occurrence were concentrated in southeast Texas and southwest Louisiana, especially where low elevation wetlands were in high density. Wetland loss and fragmentation in urban and urbanizing rural areas, particularly around Houston, represent the greatest current and future threats to habitat in Texas. Population surveys targeting potentially suitable habitat indicate that this subspecies is rare. From 4 February to 6 July 2015, we conducted 1,491 visual observation and road-cruising surveys across 107 counties, and recorded 2,458 aquatic trap nights at five sites near historical localities. Between 15 April and 5 May 2015, each survey method produced a single Western Chicken Turtle observation (n = 3). Current population threats from commercial harvest and export appear insignificant for this subspecies, although continued monitoring of wild populations is recommended. We also recommend expanded wetland protection policies for areas identified as high quality habitat that are under the greatest threat.