ESTIMATING POPULATION SIZE AND HATCHLING MORTALITY OF GOPHERUS POLYPHEMUS

The demography of gopher tortoises (Gopherus polyphemus) is poorly known. We excavated 1019 tortoise burrows and determined the size class distribution of a west-central Florida population of gopher tortoises. We captured 400 tortoises. Both very small juveniles and very large adults were poorly represented in this population, relative to intermediate sized individuals. The estimated annual mortality rate was 92.3% from nest-egg through the first year of life. Using the correction factor (0.614) frequently employed to estimate tortoise population size, results in an overestimate of this population by a factor of 1.4. We caution against the generic use of this correction factor to estimate tortoise population size and suggest using site- or habitat-specific correction factors.