American Society of Naturalists

A membership society whose goal is to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance the conceptual unification of the biological sciences.

“Phenotypic plasticity for desiccation resistance, climate change and future species distributions: will plasticity have much impact?”

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Vanessa Kellermann, Shane F. McEvey, Carla M. Sgrò, and Ary A. Hoffmann (Sep 2020)

Phenotypic plasticity in desiccation resistance does not contribute much to climate change responses

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Phenotypic plasticity, the ability of an organism to rapidly adjust traits, has been proposed as an important way organisms can buffer the impacts of climate change. This is because plasticity is a way of rapidly shifting traits (within a generation) in comparison to evolution (change in allele frequencies), which is likely slower. Despite the vital role plasticity could play in how species respond to climate change, our current methods for measuring the impact of climate change – distributional models that base future suitability of environments on current distributions – rarely take plasticity into account. Researchers from Monash University in Australia set out to test the relative importance of phenotypic plasticity in buffering species from climate change in Drosophila species. The researchers firstly determined how much species could increase their desiccation resistance (ability to tolerate dry environments a trait linked to climate change resilience) via plasticity. Then, using a semi-mechanistic distributional model (modeling species distributions from traits and distributional data), they examined whether the addition of plasticity could limit the impact of climate change. If plasticity is an important buffer, they expected species to retain more of their distribution under climate change than models without plasticity. While the researchers found species could shift their desiccation resistance considerably (i.e., these traits showed plasticity), adding plasticity to their models had only a small impact on the retention of species distributions under climate change. Although some of the largest shifts in plasticity were observed in tropically restricted species, reductions in the suitability of environments under climate change for this group of species were still observed. This suggests that plasticity for desiccation resistance is unlikely to buffer this vulnerable group of species from climate change.


Abstract

While species distribution models (SDMs) are widely used to predict the vulnerability of species to climate change, they do not explicitly indicate the extent to which plastic responses ameliorate climate change impacts. Here we use data on plastic responses of 32 species of Drosophila to desiccation stress to suggest that basal resistance rather than adult hardening is relatively more important in determining species differences in desiccation resistance and sensitivity to climate change. We go on to show, using the semi-mechanistic SDM CLIMEX, that the inclusion of plasticity has some impact on current species distributions and future vulnerability for widespread species, but has little impact on the distribution of arguably more vulnerable tropically-restricted species.