A framework for elucidating the temperature dependence of fitness carbon dating contreversy
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.
However, no general consensus has so far emerged about the mechanisms involved and the role of phylogeny in shaping species responses has been poorly explored.
Ectotherms are especially sensitive to climate change, because their physiology is directly influenced by temperature.
Thermal preferences coincide with temperatures that maximize fitness, and individual performance rapidly drops outside the optimal range.
Present-day geographical biodiversity patterns have been strongly shaped by two distinct processes affecting range dynamics: the expansions and contractions caused by Pleistocene glacial-interglacial cycles.
As a result, population dynamics at the edges of the distribution range are critical in determining the vulnerability of species to changing climate and, ultimately, for their long-term persistence: colonization by leading populations (that is, cold limits at high elevation and latitude).
Indeed, morphological traits linked to dispersal ability (for example, mobility through body size) are commonly conserved along the phylogeny, whereas several behavioural and ecological traits related to establishment success (for example, degree of habitat specialization should decrease habitat available for the species) are thought to be more evolutionarily labile.