The influence of regional hydrology on nesting behavior and nest fate of the American alligator |
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Authors: | Cristina A Ugarte Oron L Bass William Nuttle Frank J Mazzotti Kenneth G Rice Ikuko Fujisaki Kevin RT Whelan |
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Institution: | 1. School of Natural Resources and the Environment, University of Florida, Everglades National Park, Homestead, FL 33034, USA;2. South Florida Natural Resource Center, Everglades National Park, Homestead, FL 33034, USA;3. Eco-hydrology, Ottawa, Ontario, Canada;4. University of Florida, Ft. Lauderdale Research and Education Center, 3205 College Avenue, Davie, FL 33314, USA;5. United States Geological Survey, Southeast Ecological Science Center, Gainesville, FL 32653, USA;6. South Florida Caribbean Inventory and Monitoring Network, National Park Service, Palmetto Bay, FL 33157, USA |
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Abstract: | Hydrologic conditions are critical to the nesting behavior and reproductive success of crocodilians. In South Florida, USA, growing human settlement has led to extensive surface water management and modification of historical water flows in the wetlands, which have affected regional nesting of the American alligator (Alligator mississippiensis). Although both natural and anthropogenic factors are considered to determine hydrologic conditions, the aspects of hydrological patterns that affect alligator nest effort, flooding (partial and complete), and failure (no hatchling) are unclear. We deconstructed annual hydrological patterns using harmonic models that estimated hydrological matrices including mean, amplitude, timing of peak, and periodicity of surface water depth and discharge and examined their effects on alligator nesting using survey data from Shark Slough, Everglades National Park, from 1985 to 2005. Nest effort increased in years with higher mean and lesser periodicity of water depth. A greater proportion of nests were flooded and failed when peak discharge occurred earlier in the year. Also, nest flooding rates were greater in years with greater periodicity of water depth, and nest failure rate was greater when mean discharge was higher. This study guides future water management decisions to mitigate negative impacts on reproduction of alligators and provides wildlife managers with a tool for assessing and modifying annual water management plans to conserve crocodilians and other wetland species. © 2012 The Wildlife Society. |
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Keywords: | Alligator mississippiensis discharge flooding harmonic analysis hydroperiod reproduction wetland |
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