Home range size and movements by desert tortoises, Gopherus agassizii, in the eastern Mojave Desert

Abstract

Constructed minimum convex polygon (MCP) home ranges for free-ranging desert tortoises from a natural population. Male tortoises had significantly larger and more variable home ranges. Bootstrap analysis of the MCP polygon areas suggested substantial autocorrelation of the tortoise sightings despite a mean interval between recaptures of 3.2 days, violating an assumption of nearly all home range estimation techniques and predisposing to underestimation of the true home range area. Visual estimation suggests that MCP's for desert tortoises should include, as substantial fractions of their total area (12-56%, mean = 35%), areas with no evidence that tortoises use them. -from Authors