Editorial Type:
Article Category: Research Article
 | 
Online Publication Date: 01 Feb 2006

Movement Patterns, Habitat Use, and Growth of Hatchling Tortoises, Gopherus polyphemus

Page Range: 68 – 76
DOI: 10.1643/0045-8511(2006)006[0068:MPHUAG]2.0.CO;2
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Abstract

Movement and activity patterns are important aspects of the ecology and conservation of any organism. Among turtles, data on the behavioral ecology of hatchling stages are lacking. To increase our knowledge of hatchling turtles, I tracked 20 hatchling gopher tortoises (Gopherus polyphemus) for up to 335 days after hatching to determine movement patterns, refugia use, microhabitat use, and home range size. Consistent with other studies, hatchling gopher tortoises moved infrequently and over very short distances through their first winter, a period during which they are presumably receiving energy from yolk stores. With the onset of warm spring weather, hatchling tortoises began to move more, most likely to obtain energy after depleting yolk stores. Refugia included both burrows and pallets (short holes in the ground), which were surrounded by a high percentage of ground cover (81.4%) and tall (>50 cm) vegetation. Home range size estimations depended heavily on the number of different locations recorded for each individual and varied from 0.0001–4.8 ha, depending on the method of calculation and longevity of the hatchling. Hatchlings moved infrequently, spent large amounts of time in burrows and under tall vegetation, and moved short distances while changing refugia. However, these data represent some of the largest home range sizes reported for G. polyphemus to date, suggesting that dispersal and the hatchling life stage are important behavioral aspects that, if neglected, may result in underestimating spatial requirements necessary to support all ecological aspects of this declining species.

Copyright: The American Society of Ichthyologists and Herpetologists
<bold>Figure 1</bold>
Figure 1

Frequency histogram of distances moved in hatchling gopher tortoises.Distance moved was defined as the distance between any two consecutive movements. Since movements were infrequent (see text), these do not necessarily represent daily or even weekly measurements


<bold>Figure 2</bold>
Figure 2

Mean number of moves and burrows or pallets dug per tortoise each month.Months without any movements indicate that tortoises were not found out of their burrow or did not move burrows during that time. Numbers above bars represent sample sizes for each month


<bold>Figure 3</bold>
Figure 3

Mean distance (+1 SD) hatchling tortoises were found from the nest site during the study period.Numbers above bars represent sample sizes for each month


<bold>Figure 4</bold>
Figure 4

Frequency of tracking events in which tortoises were away from their burrows or pallets during the course of the year


<bold>Figure 5</bold>
Figure 5

Relationship between initial carapace length and growth rate in hatchling gopher tortoises


Contributor Notes

Department of Biological Sciences, Towson University, Towson, Maryland 21252. Present address: Environmental Services Group, Glatting Jackson Inc., 33 East Pine Street, Orlando, Florida 32801. dapike22@hotmail.com

Received: 07 Feb 2005
Accepted: 22 Oct 2005
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