Site fidelity of wood turtles (Glyptemys insculpta) in the northern Lower Peninsula of Michigan

Background/Question/Methods Freshwater pond turtles (family Emydidae) require habitats ranging from aquatic to terrestrial. The combination of these variables means that small disturbances in their environment go unnoticed, and conservation opportunities are often overlooked. Information on turtle movement and habitat utilization, including site fidelity is important in maintaining current populations. Wood turtles (Glyptemys insculpta) in northern Michigan are an example of a freshwater species with little habitat utilization data available. A population of wood turtles near the Au Sable River in northern Michigan was studied over 7 years. 142 turtles were located in or around a 42 km stretch of the river. Turtle positions were recorded using GPS +/- 3 meters. Some turtles were affixed with transmitters and were relocated using radio telemetry, but all were uniquely notched for identification. The data were then analyzed using ESRI’s Arc 9 software.

Results/Conclusions Of 11 multi year data sets, 9 showed site fidelity between years. The high incidence of site fidelity in this population, compared to data from other populations of freshwater turtles, makes the preservation of these specific sites important as the turtles are not likely to move to other areas of the river, regardless of the potential the habitat has for supporting turtles.