A framework for elucidating the temperature dependence of fitness
Biotic interactions or traits promoting local persistence may also enhance the variability of temperature-dependent extinction to a certain extent (Fig. In contrast, colonization at the leading edge should strongly depend on multiple dispersal and establishment traits that are subjected to various selection pressures.The influence of dispersal limitation on range expansion may ultimately lead to decreasing phylogenetic signal expected from the thermal sensitivity of species.Therefore, while climate change brings many difficulties in establishing a general understanding of species vulnerability, these findings emphasize how combining trait-based approaches in light of the species evolutionary history may offer new opportunities in facing conservation challenges..
Here, we used range shifts documented for stream fish to assess whether phylogenetic patterns in shifts at the leading and trailing edges along an altitudinal gradient resulted from conservatism of the traits involved in species response to climate change.
Idiosyncratic responses of species to climate change are underpinned by the interplay between three dimensions of climate change vulnerability, namely exposure (the extent to which the species thermal habitat changes), intrinsic sensitivity (for example, due to physiological limits or trophic specialization) and resilience capacity (species ability to avoid negative impacts of climate change through dispersal and/or microevolutionary or phenotypic changes).
Conservatism of range shifts at the leading and trailing edges of distribution can be expected to be driven by the degree of phylogenetic clustering of traits involved in responding to climate change.
The thermal safety margins, describing the warming tolerance of organisms relative to their current thermal habitat, should thus be the principal trait driving extinctions or shifts to cooler habitats.
Additional traits underlying the ability of species to respond to climate change impacts (that is, resilience ability) may, however, delay extinction at the trailing edge or impede colonization at the leading edge, although acting in opposite directions.
Stream fishes provide ideal model organisms for studying climate-induced range shifts because of their ectothermic physiology, relatively short generation times and constrained distribution within hydrographic networks, thus promoting directional shifts.