Gopher Tortoise Nest Detection at Camp Shelby, Mississippi

摘要

ABSTRACT: Declining populations of the gopher tortoise (Gopherus polyphemus) have prompted management efforts including methods to increase egg clutch survival. Estimates are that as many as 88 percent of all clutches are being destroyed by predation. The most popular protection method has been to locate the clutch and protect it from predation with a metal cage or hardware screen. Locating the clutch without damaging or extensively disturbing the eggs requires highly skilled personnel, and traditional techniques for nest location appear to be unusable for populations in western areas where soils contain a higher clay fraction. The analysis reported here focused on the use of ground penetrating radar (GPR), multi-frequency frequency domain electromagnetism, shallow seismic reflection, electrical resistivity, magnetic field gradient, and thermal imaging for nest detection. Though all instrumentation methods have proven worth within their dedicated disciplines, none were truly successful at locating G. polyphemus clutches in the field in Southern Mississippi. GPR appeared the most viable, though the particular methods used could not be called successful in this trial. Thus, reliance on any of these techniques is not recommended for critical surveys intended to accurately locate tortoise nests and egg clutches.