Meeting Abstract
Anthropogenic actions are rapidly redistributing species and allowing novel colonization events. With this colonization comes exposure to new habitats and environments. Rapid changes in the environment can cause a populations mean phenotype to become mismatched with local fitness optima or limit a population’s adaptive potential. This mismatch in phenotype can drive directional selection, and while this may lead to higher mean population fitness it also leads to high mortality, affecting population dynamics. Using an experimental island system, we investigated the initial stages of colonization and some of the underlying adaptive mechanisms linked with persistence in a novel environment over three generations in the Panamanian anole (Anolis apletophallus). We transplanted hundreds of uniquely-marked adult lizards from a single source population on mainland Panama to four small islands in Lake Gatun (Panama Canal). These islands differ in habitat structure from the mainland. We conducted mark-recapture surveys to assess changes in habitat use, morphology, and population size over three years. After only a single generation, we observed several morphological changes, including a reduction in both head and toe pad size and an increase in limb length across all islands. Several of these changes correspond with changes in habitat use in ways predicted by biomechanical theory. We discuss these results in the context of contemporary evolution and eco-evolutionary dynamics, and what role these factors play in the success of populations that colonize novel environments.
