Behavior and the Evolution of Species Ranges

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

Explaining why species occur where they do is a fundamental problem in biology that has important implications for conservation. Species ranges are not fixed: some species are able to expand their ranges and succeed in new habitats. Why species ranges sometimes expand and what factors fuel those expansions remains poorly understood. This research will determine how the combined effects of behavior and breeding between species – hybridization – enable a species to expand its range by moving into and rapidly adapting to an entirely new habitat. Understanding such range expansions is important to both address the risks of invasive species and inform conservation planning and policy development for preserving biodiversity under global climate change. Moreover, the proposed work will support the PI’s educational activities, which will include mentoring K-12 teachers in research and developing lesson plans based on research activities, training K-12 students and undergraduates in research, and public outreach events at the North Carolina Museum of Natural Sciences, the largest natural history museum in the southeastern USA. Species range expansion is limited when populations at the range edge fail to adapt to novel habitats before they go extinct. Behavior might facilitate range expansion if behaviors that contribute to dispersal are linked to traits that promote success in novel habitats, and behavior promotes gene flow from locally adapted heterospecifics (via hybridization) that enables rapid adaptation to novel habitats. Notably, the two factors are not independent: behaviors that promote dispersal might directly promote hybridization or be linked to those that do. This proposed work will evaluate the role of behavior in the expansion of a grassland-adapted species of spadefoot toad into an entirely different biome––the desert southwestern USA. Using laboratory experiments and field surveys of natural populations, the work will achieve three aims: 1) evaluate dispersal-promoting behaviors as a potential cause of range expansion into a novel habitat; 2) determine whether dispersal-promoting behaviors are associated with behavior that mediates adaptive hybridization with a congener, and 3) examine if hybridization facilitates adaptation to a novel habitat. By achieving these aims, the proposed work will establish whether behaviors that contribute to dispersal into novel habitat are associated with behavior that enhances success in that environment. The proposed work will further determine if behaviors that mediate hybridization also promote expansion into, and adaptation to, novel habitats. Taken together, this work will provide a critical test of behavior’s hypothesized role in the evolutionary expansion of a species range. This project is jointly supported between the Division of Integrative Organismal Systems and the Division of Environmental Biology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.