Simultaneous modeling of habitat suitability, occupancy, and relative abundance: African elephants in Zimbabwe

Authors

  • Julien Martin,

    Corresponding author
    1. Florida Cooperative Fish and Wildlife Research Unit, University of Florida, Gainesville, Florida 32611-0485 USA
    2. Patuxent Wildlife Research Center, United States Geological Survey, 12100 Beech Forest Road, Laurel, Maryland 20708 USA
    •  Present address: Fish and Wildlife Research Institute, 100 8th Avenue SE, St. Petersburg, Florida 33701 USA. E-mail: julienm@ufl.edu

    Search for more papers by this author
  • Simon Chamaillé-Jammes,

    1. Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622 France
    Search for more papers by this author
  • James D. Nichols,

    1. Patuxent Wildlife Research Center, United States Geological Survey, 12100 Beech Forest Road, Laurel, Maryland 20708 USA
    Search for more papers by this author
  • Hervé Fritz,

    1. Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, 43 Boulevard du 11 Novembre 1918, Villeurbanne F-69622 France
    Search for more papers by this author
  • James E. Hines,

    1. Patuxent Wildlife Research Center, United States Geological Survey, 12100 Beech Forest Road, Laurel, Maryland 20708 USA
    Search for more papers by this author
  • Christopher J. Fonnesbeck,

    1. Department of Mathematics and Statistics, University of Otago, Dunedin, New Zealand
    Search for more papers by this author
  • Darryl I. MacKenzie,

    1. Proteus Wildlife Research Consultants, P.O. Box 5193, Dunedin, New Zealand
    Search for more papers by this author
  • Larissa L. Bailey

    1. Department of Fish, Wildlife and Conservation Biology, 1474 Campus Delivery, Fort Collins, Colorado 80523 USA
    Search for more papers by this author

  • Corresponding Editor: J. J. Millspaugh.

Abstract

The recent development of statistical models such as dynamic site occupancy models provides the opportunity to address fairly complex management and conservation problems with relatively simple models. However, surprisingly few empirical studies have simultaneously modeled habitat suitability and occupancy status of organisms over large landscapes for management purposes. Joint modeling of these components is particularly important in the context of management of wild populations, as it provides a more coherent framework to investigate the population dynamics of organisms in space and time for the application of management decision tools. We applied such an approach to the study of water hole use by African elephants in Hwange National Park, Zimbabwe. Here we show how such methodology may be implemented and derive estimates of annual transition probabilities among three dry-season states for water holes: (1) unsuitable state (dry water holes with no elephants); (2) suitable state (water hole with water) with low abundance of elephants; and (3) suitable state with high abundance of elephants. We found that annual rainfall and the number of neighboring water holes influenced the transition probabilities among these three states. Because of an increase in elephant densities in the park during the study period, we also found that transition probabilities from low abundance to high abundance states increased over time. The application of the joint habitat–occupancy models provides a coherent framework to examine how habitat suitability and factors that affect habitat suitability influence the distribution and abundance of organisms. We discuss how these simple models can further be used to apply structured decision-making tools in order to derive decisions that are optimal relative to specified management objectives. The modeling framework presented in this paper should be applicable to a wide range of existing data sets and should help to address important ecological, conservation, and management problems that deal with occupancy, relative abundance, and habitat suitability.

Ancillary