Meeting Abstract

90.1  Sunday, Jan. 6  Anthropogenic stressors and the evolutionary potential of amphibian populations WELCH, A.M.; College of Charleston, SC welcha@cofc.edu

Virtually all habitats on Earth have been affected by human activities. Understanding and mitigating the ecological consequences of anthropogenic habitat modification require addressing how multiple stressors interact to affect the long-term viability of populations. In addition to diminishing population numbers, exposure to anthropogenic stressors can lead to the evolution of increased tolerance via natural selection. However, the evolution of tolerance to one stressor may compromise a population’s ability to tolerate or adapt to different stressors in the future. To address how natural selection imposed by different stressors may impact a population’s evolutionary potential, I investigated genetic variation in tolerance to two different stressors as well as the genetic correlations between tolerances to these different stress regimes. Southern toad, Anaxyrus terrestris, tadpoles from a series of half-sibships were subjected to increased salinity, the common insecticide carbaryl, both, or neither, and genetic variances and covariances were estimated. If tolerance to different stressors is genetically correlated, adaptation to one stressor should lead to improved tolerance to the other stressor. On the other hand, if tolerance to one stress regime is not genetically correlated with tolerance to another, then the reduction in genetic variation that occurs as a population adapts to one stressor would make it more difficult to evolve tolerance to future stressors, putting the population at further risk. Because anthropogenic stressors are and will continue to be an important part of many habitats, the long-term persistence of populations will depend on how these stressors influence not only population sizes but also a population’s ability to respond adaptively to future stressors.