Projected changes in distributions of Australian tropical savanna birds under climate change using three dispersal scenarios

Authors

  • April E. Reside,

    1. CSIRO Climate Adaptation Flagship and Ecosystem Sciences, Private Mail Bag PO, Aitkenvale, Queensland, 4814, Australia.
    2. Centre for Tropical Biodiversity and Climate Change, School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, 4811, Australia.
    Search for more papers by this author
  • Jeremy VanDerWal,

    1. Centre for Tropical Biodiversity and Climate Change, School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, 4811, Australia.
    Search for more papers by this author
  • Alex S. Kutt

    1. CSIRO Climate Adaptation Flagship and Ecosystem Sciences, Private Mail Bag PO, Aitkenvale, Queensland, 4814, Australia.
    Search for more papers by this author

April E. Reside, CSIRO Climate Adaptation Flagship and Ecosystem Sciences, Private Mail Bag PO, Aitkenvale, Queensland, 4814, Australia. Tel: +617 4753864; Fax: +617 4753 8600; E-mail: april.reside@gmail.com.

Abstract

Identifying the species most vulnerable to extinction as a result of climate change is a necessary first step in mitigating biodiversity decline. Species distribution modeling (SDM) is a commonly used tool to assess potential climate change impacts on distributions of species. We use SDMs to predict geographic ranges for 243 birds of Australian tropical savannas, and to project changes in species richness and ranges under a future climate scenario between 1990 and 2080. Realistic predictions require recognition of the variability in species capacity to track climatically suitable environments. Here we assess the effect of dispersal on model results by using three approaches: full dispersal, no dispersal and a partial-dispersal scenario permitting species to track climate change at a rate of 30 km per decade. As expected, the projected distributions and richness patterns are highly sensitive to the dispersal scenario. Projected future range sizes decreased for 66% of species if full dispersal was assumed, but for 89% of species when no dispersal was assumed. However, realistic future predictions should not assume a single dispersal scenario for all species and as such, we assigned each species to the most appropriate dispersal category based on individual mobility and habitat specificity; this permitted the best estimates of where species will be in the future. Under this “realistic” dispersal scenario, projected ranges sizes decreased for 67% of species but showed that migratory and tropical-endemic birds are predicted to benefit from climate change with increasing distributional area. Richness hotspots of tropical savanna birds are expected to move, increasing in southern savannas and southward along the east coast of Australia, but decreasing in the arid zone. Understanding the complexity of effects of climate change on species’ range sizes by incorporating dispersal capacities is a crucial step toward developing adaptation policies for the conservation of vulnerable species.

Ancillary