Comparison of Home Range Size and Reproduction in Female Gopher Tortoises (Gopherus polyphemus) based on Radio-telemetry and Long-term Recapture Studies


Meeting Abstract

P1.8  Thursday, Jan. 3  Comparison of Home Range Size and Reproduction in Female Gopher Tortoises (Gopherus polyphemus) based on Radio-telemetry and Long-term Recapture Studies. MARLEY, P.M.*; MITCHELL, M.; ROSTAL, D.C.; Georgia Southern University; Georgia Southern University; Georgia Southern University pmarley1@email.georgiasouthern.edu

The Gopher tortoise (Gopherus polyphemus) is a long lived species which has experienced significant declines in population size and numbers over the past 100 years. As with many long lived species, fecundity is fairly low and information on reproductive success (hatching success, hatchling survivorship and recruitment rates) is limited to short-term studies as well. The exact longevity of this species is unknown but it is likely 80 to 100 years. In the northern portion of its range, it is known to take 18 to 20 years to reach sexual maturity. Studies on home range size are also limited in number and are based on short-term data set of one to two years. A population of female Gopher tortoises was studied to determine the statistical home range and if the short-term data based on radio-telemetry represents the long-term data. The study population of tortoises is on a longleaf pine / wiregrass ecosystem located in southeast Georgia. The long-term data set consists of recaptured tortoises over fourteen years (1994-2007). The short-term data set is based on a 3 year radio-telemetry study (2002-2004). Minimal convex polygon model and the kernel home range model will be presented. Reproductive patterns (eg. clutch size and reproductive frequency) will also be compared to home range size and yearly climatic conditions. Hatching success and hatchling size will also be reported for multiple years. This data will show how comparative the two models are with each other and if the short-term home range reflects the long-term home range. Home range size will be compared with reproductive output to determine if there is a relationship. These results will provide insight to home range requirements and possible implications for designation of refuge size.

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