Effectiveness of Drones for Freshwater Turtle Surveys Aimed Toward Detecting the Cryptic Western Chicken Turtle. (Deirochelys Reticularia Miaria).
The rise in the use of drones in wildlife research has shown promising results for conservation practices. Few studies have focused on drone surveys for aquatic freshwater turtles. This study evaluated the effectiveness of drones for detecting freshwater turtles with the primary target species being the Western Chicken Turtle (WCT; Deirochelys reticularia miaria). Two drones were employed to investigate their effectiveness for detecting freshwater turtles. 1) Videos and thermal imagery were utilized using a DJI Mavic 2 Enterprise (M2) and 2) static multispectral imagery using a DJI Phantom 4 (P4MS). Binocular aided visual surveys (BAVS) were conducted simultaneously with M2 surveys to compare and contrast methodologies. A total of 20.7 hours of video footage yielded 1916 freshwater turtle detections and 57090 photos with 1915 detections. BAVS had a cumulative time of 58.1 hours with 1096 turtle detections. Six turtle groups were detected with the M2, five with the P4MS and four with BAVS. Groups that were identified by all methods were Slider Turtles (Trachemys sp.), North American Softshell Turtles (Apalone sp.), and Common Snapping Turtles (Chelydra serpentina). A majority of all detected freshwater turtles displayed no reaction to the drones presence. The M2 had a statistically significant (p = 0.015) higher monthly catch per unit effort (CPUE) for freshwater turtles when compared to BAVS. Six WCT were detected using drone surveys (M2 = 5 and P4MS =1) while BAVS failed to detect WCT. Drone surveys were successful at detecting and identifying freshwater turtles such as the WCT when compared to BAVS, but quality data collection relies upon many internal and external factors such as camera resolution and essential habitat features. Drones are powerful tools when surveying freshwater turtles and other wildlife collecting vast amounts of data. Their implementation in future research studies concerning wildlife conservation with freshwater turtles have evident benefits in overall site accessibility, field team safety, and non-invasive rapid data collection.