PS 6-51
Developmental plasticity and the role of biotic interactions in shaping amphibian response to climate change
Rapid changes in habitable climate space have increased species extinction rates and significantly altered the evolutionary trajectories of multiple taxonomic groups. However, various mechanisms have been examined which may allow species to cope, but in general, reflect three main strategies that can be utilized to withstand climate change: behavioral evasion, adaptive evolution, or phenotypic plasticity. Phenotypic plasticity, or the expression of multiple phenotypes for a single genotype, is a means by which individuals can alter behavior, physiology, or morphology in response to environmental change. It has been hypothesized that amphibians with phenotypically plastic traits may have the potential to combat environmental heterogeneity, allowing for persistence in regions expected to undergo significant climatic change. We conducted a fully-factorial experiment to evaluate a high elevation amphibian species assemblage for their potential to plastically respond to a warming climate scenario via rapid larval growth and development. Additionally, we expect that although these species may respond individualistically to climate change, the manifestations of their responses will be large influenced by interactions with other organisms. Thus, we are expanding on the preliminary experiment to include the potential effects of biotic interactions on plastic acclimation to another climate variable, altered hydroperiod (i.e. reductions in water level).
Results/Conclusions
Under the warming climate scenario, accelerated larval growth rates were exhibited by all three amphibian species, the Cascades frog (Rana cascadae), Pacific chorus frog (Pseudacris regilla), and Western toad (Anaxyrus boreas). Plastic acclimation resulted in consistently lower weight gain over the course of larval development for both A. boreas and P. regilla. However, differences in body size over ontogeny between the two temperature treatments for these two species converged at metamorphosis, resulting in no significant differences in weight at metamorphosis regardless of temperature. An alternative trend was exhibited in R. cascadae; equality in body size between the temperature treatments throughout larval development was lost during the metamorphic climax and, instead, post-metamorphic juveniles under temperature stress were significantly smaller in both length and weight. Thus, the variability in larval plasticity suggests that physiological responses to climate change should be tested against, not only other climate stressors, but interactions within and across trophic levels.