AUTHORS: Deahn M. Donner, Mark Nelson - Northern Research Station, U.S. Forest Service; Christine A. Ribic, Daniel M. Wolcott - U.S. Geological Survey; Donald J. Brown, West Virginia University; Carol Bocetti, California University of Pennsylvania; Tim Greco, Michigan Department of Natural Resources
ABSTRACT: Conservation and recovery of the endangered Kirtland’s Warbler, a long-distance Neotropical-nearctic migratory songbird, requires knowledge on how changing environmental conditions can impact essential summer and wintering habitat. Shifting precipitation and temperature patterns in the Midwest may affect distribution and growth of jack pine, the species primary breeding habitat, while drying conditions and sea-level rise may threaten habitat quality and quantity within their Bahamian wintering grounds. We modeled jack pine occupancy and growth in relation to several environmental variables under current and future climate scenarios to determine if shifts in distribution and growth rate may occur. Our models projected that jack pine distribution across the Upper Midwest could decrease by up to 90% by 2099, and up to 50% of current Kirtland’s Warbler Management Areas could become unsuitable for jack pine. We also projected winter precipitation and temperature across the Bahamian archipelago and determined how much winter habitat (open lands) was susceptible to 1- and 2-m sea-level rise. Islands currently used by Kirtland’s Warbler are predicted to become warmer and wetter, except during March when the central islands are predicted to go through a drying trend that may influence food supply prior to migration. Greatest loss of open land was predicted for the northern, lower-elevation islands. From a conservation perspective, the central Bahamian islands, which currently contain the majority of the wintering population, will be critical islands on which to focus climate adaptation efforts. In the Great Lakes region, the potential loss and redistribution of jack pine habitat may require establishing additional habitat management areas or altering plantation rotations to ensure adequate breeding habitat to sustain recovery goals.
