Can variability in response to environmental change buffer organisms from anthropogenic change?

Abstract

Anthropogenic activities are greatly altering our natural environment. Environmental changes can occur rapidly, such as when non-native species are introduced. Faced with these rapid changes, organisms may not be able to evolve quickly enough to persist. Phenotypic plasticity, the ability of individuals to alter their traits within their lifetimes in response to variable environments, is a possible mechanism to buffer organisms against large and rapid environmental change. Evolutionary theory predicts that extreme, novel conditions induce more variable traits (greater variation in phenotypic plasticity) than natal habitats. This mechanism may increase the chances that populations will survive rapid environmental change because some individuals will produce traits that are appropriate to the new environment. These theoretical predictions have rarely been tested in nature, yet if true, this resiliency in the face of environmental change could mean the difference between population persistence and local extirpation. To test these predictions in nature, I contrasted the amount of among-individual variation of six populations of freshwater snails between their home (natal) environment and five novel, non-natal environments. I reared snails from all populations in both natal and non-natal environments containing novel crayfish predators and novel environmental conditions (e.g. water chemistry, temperature, flow rate, etc.). Crayfish induce phenotypic plasticity in the morphology, behavior, and life histories (e.g. rates of growth and reproduction) of multiple types of freshwater snails. Non-natal conditions also differ physiochemically from the natal environment and thus are also novel conditions that may induce changes in trait variability. Currently, I am completing the final stage of data collection: assessing variation in shell shape, shell structure, and growth rates in response to these novel environments. Ultimately, my research will enhance our understanding of how organisms respond to environmental changes and elucidate a potential mechanism of population resilience to anthropogenic alterations.

Featured image by Tony Webster on Flickr (https://flic.kr/p/2ncmHGn).