Literaturdatenbank
Literaturdatenbank |
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Swarth, C. W., & Quinlan, M. M. , Using plot surveys to assess eastern box turtle (terrapene carolina carolina) density and site fidelity. Paper presented at Third Box Turtle Conservation Workshop.
Added by: Admin (14 Aug 2008 20:33:48 UTC) |
| Resource type: Proceedings Article BibTeX citation key: Swarth2007a View all bibliographic details  |
Categories: General Keywords: Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Quinlan, Swarth Collection: Third Box Turtle Conservation Workshop |
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| Abstract |
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Determining the density or merely just the presence of box turtles in an area can be a challenge for resource agencies that might need to make population assessments. Box turtles are generally spatially dispersed; they are cryptically colored; and they can remain hidden and immobile for days or even weeks beneath leaf litter and branches, or within dense vegetation. As a result, multiple site surveys may be necessary to accurately document their occurrence and abundance. In order to measure the density and site fidelity in a population of individually-marked eastern box turtles, we conducted 175 plot surveys from 2000 to 2007. Plots measured 100m X 100m (N=11) and were placed in a mixed-deciduous forest adjacent to a freshwater tidal wetland at the Jug Bay Wetlands Sanctuary, Patuxent River, Maryland. Surveys in a single plot were made every 7 to 14 days, extending from early May to mid-October. Each survey was conducted by 4 to 9 searchers and took about 45 to 60 minutes to complete. Mean single-survey density varied from 1.1 to 4.5 turtles/ha; these are minimal estimates because not all turtles in a plot are observed. High single counts yielded 8 to 9 turtles/ha. About 15% of surveys yielded no turtles. As many as 26 to 29 different turtles were recorded using a single one hectare plot over the course of several years. A high degree of site fidelity was confirmed for males and females: 41% of turtles were observed 3 or more times, and 3 turtles were observed 25 or more times on surveys. Based on this study, 8 to 10 surveys within the same plot over a season may be required to obtain a reasonable estimate of density. Plots adjacent to wetlands supported significantly more turtles and had higher densities than plots that were several hundred meters from wetlands. The proximity of water and wetlands appear to be important on a local scale for determining turtle habitat selection and home range size. Repeat surveys within one hectare plots are an effective method for measuring box turtle density and could be a useful tool for assessing population status in selected areas throughout the species’ range.
Added by: Admin |