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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    • "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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    ABSTRACT: Despite having a moderately large distributional area, both the pink fairy armadillo (Chlamyphorus truncatus) and particularly the Chacoan fairy armadillo (Calyptophractus retusus), which are among the least known xenarthrans, appear to be rare or patchily distributed. Although low density in species with large range sizes has been associated with large body size, this is not the case for fairy armadillos. We propose that past climate variations may have caused their current low densities, and evaluate retractions and expansions of suitable areas of fairy armadillos by extrapolating the consensus of habitat suitability models fitted with current climatic conditions to past conditions. We found great variation in suitable area along time in both species, with a drastic reduction in the Last Interglacial (LIG) period when compared with current situation. Both the variations and the reduction during LIG were more pronounced in Calyptophractus than in Chlamyphorus. We postulate that past extreme reductions in suitable areas could cause a delay in the recovery of the populations, resulting in low densities despite climatic conditions during more benign times allowing a more widespread distribution.
    Mammalian Biology - Zeitschrift fur Saugetierkunde 07/2015; DOI:10.1016/j.mambio.2015.07.007 · 1.48 Impact Factor
    • "Dispersal limitation, for example, may prevent organisms from relocating to suitable habitat in pace with climate change, and much effort has been invested to quantify and incorporate species-specific dispersal rates into distributional change projections (e.g. Iverson et al., 2004; Barbet-Massin et al., 2012; Schloss et al., 2012). However , for mobile organisms like migratory songbirds, lags in vegetation responses to climate change are likely more limiting than dispersal rates, given that many songbirds exhibit strong associations with certain forest types and seral stages (Hobson & Schieck, 1999; Schieck & Song, 2006), somewhat independent of climatic conditions. "
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    ABSTRACT: AimSpecies and ecosystems may be unable to keep pace with rapid climate change projected for the 21st century. We evaluated an underexplored dimension of the mismatch between climate and biota: limitations to forest growth and succession affecting habitat suitability. Our objective was to inform continental-scale conservation for boreal songbirds under disequilibria between climate, vegetation and fauna.LocationBoreal and southern arctic ecoregions of North America.Methods We used forest inventory and avian survey data to classify 53 species by seral-stage affinity and applied these to generate alternative projections of changes in species' core habitat distributions based on different vegetation lag-time assumptions. We used our seral stage-modified refugia approach and the Zonation algorithm to identify multispecies boreal conservation priorities over the 21st century. We evaluated the sensitivity of land rankings to seral-stage affinity and species' weights and assessed the conservation value of the existing protected areas network compared to Zonation results.ResultsEnd-of-century projected changes in songbird distribution were reduced by up to 169% when vegetation lags were considered. Zonation land rankings based on unconstrained climate projections were concentrated at high latitudes, whereas those based on strict and modified refugia scenarios were concentrated in coastal and high-elevation areas, as well as biome transition zones, which were fairly consistent over time and species weights. The existing protected areas network covering 14% of the study area was estimated to conserve 12–14% of baseline avian biodiversity across time periods and scenarios, compared to 16–25% for top-ranked Zonation areas.Main conclusionsFor some boreal songbirds, limits to forest growth and succession may result in dramatic reductions in suitable habitat over the next century. Our seral stage-adjusted approach provides conservative and efficient boreal conservation priorities anchored around climatic macrorefugia that are robust to century-long climate change and complement the current protected areas network.
    Diversity and Distributions 07/2015; 21(9). DOI:10.1111/ddi.12356 · 3.67 Impact Factor
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    • "For example, decreasing landscape resistance is the most recommended management strategy in the published literature on climate change (Heller and Zavaleta 2009). However, species may not be able to move fast enough to keep pace with climate change velocity in many locations, regardless of the local landscape resistance (Malcolm et al. 2002, Loarie et al. 2009, Schloss et al. 2012). Hence, decreasing landscape resistance will have varying benefits across the landscape due to spatial variation in climate change velocity. "
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    ABSTRACT: Determining where biodiversity is likely to be most vulnerable to climate change and methods to reduce that vulnerability are necessary first steps to incorporate climate change into biodiversity management plans. Here, we use a spatial climate change vulnerability assessment to (1) map the potential vulnerability of terrestrial biodiversity to climate change in the northeastern United States and (2) provide guidance on how and where management actions for biodiversity could provide long-term benefits under climate change (i.e., climate-smart management considerations). Our model suggests that biodiversity will be most vulnerable in Delaware, Maryland, and the District of Columbia due to the combination of high climate change velocity, high landscape resistance, and high topoclimate homogeneity. Biodiversity is predicted to be least vulnerable in Vermont, Maine, and New Hampshire because large portions of these states have low landscape resistance, low climate change velocity, and low topoclimate homogeneity. Our spatial climate-smart management considerations suggest that: (1) high topoclimate diversity could moderate the effects of climate change across 50% of the region; (2) decreasing local landscape resistance in conjunction with other management actions could increase the benefit of those actions across 17% of the region; and (3) management actions across 24% of the region could provide long-term benefits by promoting short-term population persistence that provides a source population capable of moving in the future. The guidance and framework we provide here should allow conservation organizations to incorporate our climate-smart management considerations into management plans without drastically changing their approach to biodiversity conservation.
    Ecosphere 06/2015; 6(6). DOI:10.1890/ES15-00069.1 · 2.26 Impact Factor
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