Dispersal will limit ability of mammals to track climate change in the Western Hemisphere

School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 05/2012; 109(22):8606-11. DOI: 10.1073/pnas.1116791109
Source: PubMed


As they have in response to past climatic changes, many species will shift their distributions in response to modern climate change. However, due to the unprecedented rapidity of projected climatic changes, some species may not be able to move their ranges fast enough to track shifts in suitable climates and associated habitats. Here, we investigate the ability of 493 mammals to keep pace with projected climatic changes in the Western Hemisphere. We modeled the velocities at which species will likely need to move to keep pace with projected changes in suitable climates. We compared these velocities with the velocities at which species are able to move as a function of dispersal distances and dispersal frequencies. Across the Western Hemisphere, on average, 9.2% of mammals at a given location will likely be unable to keep pace with climate change. In some places, up to 39% of mammals may be unable to track shifts in suitable climates. Eighty-seven percent of mammalian species are expected to experience reductions in range size and 20% of these range reductions will likely be due to limited dispersal abilities as opposed to reductions in the area of suitable climate. Because climate change will likely outpace the response capacity of many mammals, mammalian vulnerability to climate change may be more extensive than previously anticipated.

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    • "The second aspect concerns the adaptive capacity of organisms to move to newly suitable areas (Bradshaw and Holzapfel, 2006; Rebelo et al., 2010). Third, the localisation of the suitable niches in the future has received considerable attention (Schloss et al., 2012). "
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    • "Biogeographers and landscape ecologists are increasingly focusing attention on the role of local topoclimates and microclimates (hereafter referred to as ''microenvironments'') in mediating species' extinction risks and range shifts in response to climate change (Potter et al. 2013; Hannah et al. 2014). Mountainous topography encompasses a wide variety of microenvironments that may buffer species' exposure to climate change, allowing local retention or redistribution of species by reducing climate change velocities and providing steppingstone habitat connectivity (Loarie et al. 2009; Ackerly et al. 2010; Scherrer and Körner 2011; De Frenne et al. 2013; Lenoir et al. 2013; Hannah et al. 2014); both of these factors may be particularly important for slowly dispersing species (Schloss et al. 2012; Zhu et al. 2012; Corlett and Westcott 2013). Methods are being developed to identify and map the distribution of microenvironments across landscapes (Ashcroft et al. 2012; Dingman et al. 2013), with the goal of using this fine-scale information to improve species distribution models (SDMs) (Franklin et al. 2013) and conservation planning under climate change (Anderson et al. 2014; Keppel et al. 2015). "
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    • "Despite the increase in suitable areas for Calyptophractus by four orders of magnitude from the LIG to MH, the recovery of its populations may have been delayed by low dispersal ability (and possibly low reproductive rate) and a strong founder effect, resulting in its current numerical rarity. According to the only available estimates of the dispersal rate of fairy armadillos (0.85 and 0.72 km/y for pink and Chacoan fairy armadillos, respectively; Schloss et al., 2012), they should have been able to recolonize all suitable areas when the latter expanded at the end of LIG. These estimates, however, are based on the dispersal models provided by Sutherland et al. (2000), which used a comprehensive database (68 mammal species) that does not fully account for different lifestyles. "
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