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Spatial distribution and risk analysis data for diamond-backed terrapins relative to crab trapping, Savannah Coastal Refuge Complex, USA

Data for journal manuscript: Spatial distribution of estuarine diamond-backed terrapins (Malaclemys terrapin) and risk analysis from commercial blue crab (Callinectes sapidus) trapping at the Savannah Coastal Refuges Complex, USA


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Thomas, M., Puffer, S.R., Lovich, J.E., Ironside, K.E., and Yackulic, C.B., 2018, Spatial distribution and risk analysis data for diamond-backed terrapins relative to crab trapping, Savannah Coastal Refuge Complex, USA: U.S. Geological Survey data release,


There were five objects for compiling these data: 1) to conduct a systematic inventory of diamond-backed terrapins (Malaclemys terrapin) using headcount surveys on four National Wildlife Refuges (Harris Neck, Blackbeard Island, Wassaw, and Wolf Island) that are a part of the greater Savannah Coastal Refuges Complex in southeast Georgia, USA; 2) to use occupancy modeling to determine detection probability and distribution of diamondback terrapins; 3) to perform risk assessments of these terrapin populations in relation to crabbing pressure; 4) to generate maps with associated GIS files of terrapin relative densities related to crabbing pressure; and 5) to provide scientific information that will allow for effective management of diamond-backed [...]


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The purpose of this project was to examine crabbing pressure in relation to terrapin occupancy on Georgia National Wildlife Refuges. In 2015 we conducted headcount surveys of tidal creeks along four different National Wildlife Refuges (Blackbear, Wassaw, Wolf, and Harris Neck) during which we documented the numbers of crab traps seen during these surveys, as well as whether or not we detected any terrapins within the tidal creeks. The data related to crabbing pressure is compiled under the Crab_Pot_Data sheet, and the data related to terrapin detections on refuges is found under the Terrapin_Data sheet. Additionally, we measured a variety of different enviornmental and observer related variables to examine the effects of both enviornmental conditions and observer bias on terrapin detection. These data can all be found under the Head_Count_Data sheet. Data was collected simultaneously for each sheet but that is it. For example while doing headcounts we were also noting crab trap locations.


The authors of these data request that data users contact them regarding intended use and to assist with understanding limitations and interpretation. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.

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DOI doi:10.5066/F7PN94W3

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