Key Traits Underlying Invasion Success: A Comparison of Gambusia Species

Biological invasions are recognized to be one of the greatest threats to natural communities and biodiversity. A central question in the study of biological invasions is: Do invasive species have certain attributes in common that contribute to their success while others fail? Despite the importance of this issue, few empirical studies have systematically tested potentially important traits or trait combinations, especially in aquatic systems. To address variation in invasiveness, studying closely related and morphologically similar taxa should allow us to identify relevant traits. A good system is the poeciliid fish Gambusia, where the differences in geographic range and invasiveness are extreme. Differences in key ecological, life history, and behavioral traits might account for the observed variation in invasiveness among Gambusia species. We propose to examine how invasive and noninvasive Gambusia species might differ in their: (1) life history responses to abiotic stress, (2) population-level responses to biotic stress, (3) community function, (4) aggression levels, and (5) dispersal patterns. We expect that the proposed work in combination with our previous experiments will provide valuable insights into which key species-specific traits enhance the probability of success of species invading novel communities.