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Evaluating Effects of Everglades Restoration on American Crocodile Populations in South Florida Using a Spatially-Explicit, Stage-Based Population Model

  • Hydrologic Restoration
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Abstract

The distribution and abundance of the American crocodile (Crocodylus acutus) in the Florida Everglades is dependent on the timing, amount, and location of freshwater flow. One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore historic freshwater flows to American crocodile habitat throughout the Everglades. To predict the impacts on the crocodile population from planned restoration activities, we created a stage-based spatially explicit crocodile population model that incorporated regional hydrology models and American crocodile research and monitoring data. Growth and survival were influenced by salinity, water depth, and density-dependent interactions. A stage-structured spatial model was used with discrete spatial convolution to direct crocodiles toward attractive sources where conditions were favorable. The model predicted that CERP would have both positive and negative impacts on American crocodile growth, survival, and distribution. Overall, crocodile populations across south Florida were predicted to decrease approximately 3 % with the implementation of CERP compared to future conditions without restoration, but local increases up to 30 % occurred in the Joe Bay area near Taylor Slough, and local decreases up to 30 % occurred in the vicinity of Buttonwood Canal due to changes in salinity and freshwater flows.

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Acknowledgments

This work was supported by USGS Greater Everglades Priority Ecosystems Science. Use of trade, product, or firm names does not imply endorsement by the U.S. Government.

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Authors and Affiliations

  1. US Geological Survey, Southeast Ecological Science Center, 2201 NW 40th Terrace, Gainesville, FL, 32605, USA

    Timothy W. Green, Daniel H. Slone & Kenneth G. Rice

  2. US Geological Survey, Florida Water Science Center, 3110 SW 9th Avenue, Fort Lauderdale, FL, 33315, USA

    Eric D. Swain & Melinda Lohmann

  3. US Geological Survey, Southeast Ecological Science Center, 3205 College Avenue, Davie, FL, 33314, USA

    Michael S. Cherkiss

  4. Department of Wildlife Ecology and Conservation, University of Florida, 3205 College Avenue, Davie, FL, 33314, USA

    Frank J. Mazzotti

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  1. Timothy W. Green
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  2. Daniel H. Slone
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  3. Eric D. Swain
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  4. Michael S. Cherkiss
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  5. Melinda Lohmann
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  6. Frank J. Mazzotti
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  7. Kenneth G. Rice
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Correspondence to Daniel H. Slone.

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Green, T.W., Slone, D.H., Swain, E.D. et al. Evaluating Effects of Everglades Restoration on American Crocodile Populations in South Florida Using a Spatially-Explicit, Stage-Based Population Model. Wetlands 34 (Suppl 1), 213–224 (2014). https://doi.org/10.1007/s13157-012-0370-0

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  • DOI: https://doi.org/10.1007/s13157-012-0370-0

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