Research ArticleECOLOGY

Plasticity reveals hidden resistance to extinction under climate change in the global hotspot of salamander diversity

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Science Advances  11 Jul 2018:
Vol. 4, no. 7, eaar5471
DOI: 10.1126/sciadv.aar5471
  • Fig. 1 Acclimatization of physiological traits in the global hotspot of salamander diversity.

    The species richness of the salamander diversity hotspot (60) inset on top of the eastern United States with the geographic range of the P. jordani species complex outlined in black (A). Mean values with SDs of environmental and physiological measurements (adjusted for mass) showing that high VPDs (B) coincide with ri (C), and high temperatures (D) were associated with low volume of oxygen consumption (E) across the seasonal time points.

  • Fig. 2 Acclimatization and avoidance behavior reduces extinction risk in the core of salamander diversity hotspot.

    Estimates of energy balance (ranging from green to red) and extinction (grayscale) as warming progresses through time (top to bottom) demonstrate that acclimatization and avoidance behavior reverse extinction in the core of the global hotspot of salamander diversity. Green regions are predicted to have sufficient energy for reproduction, orange regions are in negative energy balance, and grayscale regions are extinct. The grayscale also indicates the elevation ranging from black (80 m) to white (2300 m). The left panels do not include acclimatization, the middle panels include acclimatization, and the right panels include acclimatization and avoidance behavior. The black outline represents the range limits for the P. jordani species complex. The maps have a spatial resolution of 1 km2 over an area of 430 km × 530 km.

  • Fig. 3 Extinction risk is highest for juvenile salamanders.

    (A) The effects of acclimatization and avoidance behavior are illustrated using empty circles (no acclimatization or avoidance behavior), half-filled circles (acclimatization only), and full circles (acclimatization and avoidance behavior). Each panel illustrates how warming influences extinction risk within the geographic range for each body size (2 to 5 g) over the next century. Average proportions of extinct regions with SDs of four body size classes are shown. (B to E) The spatial distribution of energy balance and extinction for each corresponding body size (2 to 5 g) reveals that juvenile salamanders are disproportionately affected by warming.

  • Fig. 4 Adaptations or plastic responses required to reverse extinction in the most sensitive life stage.

    The required phenotypic changes required to maintain habitat suitability under climate warming by (A) changing ri relative to the observed distribution of ri in our experiments, (C) maximizing energy intake, and (E) minimizing energetic costs. Below the phenotypic responses, we demonstrate the reductions of extinction risk and increased energy balance throughout the geographic range of the species complex (B, D, and F). Green regions are predicted to have sufficient energy for growth and survival, orange regions are in negative energy balance, and grayscale regions are extinct. The maps have a spatial resolution of 1 km2 over an area of 430 km × 530 km.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/7/eaar5471/DC1

    Supplementary Materials and Methods

    Table S1. Analysis of covariance and effect sizes for seasonal acclimatization demonstrates that surface area and month have the greatest influence on skin resistance to water loss (ri).

    Table S2. Analysis of covariance and effect size for the seasonal acclimatization experiment demonstrates that surface area and month had the greatest effect on metabolic rate (V . O2) during the summer.

    Table S3. Analysis of covariance and effect size on the simulated data from the mechanistic SDM illustrates that mass had the largest influence on the number of extinct regions in the species range model.

    Fig. S1. Experimental evidence for physiological plasticity of skin resistance to water loss.

    Fig. S2. Predicted and observed values of nighttime temperatures and VPDs at our field site near Cullowhee, NC.

    Fig. S3. Estimated rise in VPDs through time under climate change and the spatial distribution of VPDs in 2100.

    Fig. S4. Flow chart of foraging-energetic model used to estimate extinction.

    References (6167)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • Table S1. Analysis of covariance and effect sizes for seasonal acclimatization demonstrates that surface area and month have the greatest influence on skin resistance to water loss (ri).
    • Table S2. Analysis of covariance and effect size for the seasonal acclimatization experiment demonstrates that surface area and month had the greatest effect on metabolic rate ( V . O2) during the summer.
    • Table S3. Analysis of covariance and effect size on the simulated data from the mechanistic SDM illustrates that mass had the largest influence on the number of extinct regions in the species range model.
    • Fig. S1. Experimental evidence for physiological plasticity of skin resistance to water loss.
    • Fig. S2. Predicted and observed values of nighttime temperatures and VPDs at our field site near Cullowhee, NC.
    • Fig. S3. Estimated rise in VPDs through time under climate change and the spatial distribution of VPDs in 2100.
    • Fig. S4. Flow chart of foraging-energetic model used to estimate extinction.
    • References (6167)

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