DISSERTATION RESEARCH: The role of rapid adaptation in population establishment

Michigan State University, East Lansing MI

Investigators

Abstract

Evolution was once assumed to only occur slowly over long time scales, but many recent studies have found that rapid adaptation (adaptation that occurs over timescales observable by humans) can occur across a wide range of species and in many biological systems, and can affect ecological interactions and processes. Theory predicts that rapid adaptation can also potentially affect the establishment of species in new habitats, but there is little evidence from natural systems to support this. This project will investigate rapid adaptation in recently established plant populations, as well as how symbiotic microbes might influence plant rapid adaptation. By conducting this work at an ecological restoration site, this project will not only expand our understanding of basic ecological processes, but results of the project can be applied to make restorations more successful. This is important, as the restoration of degraded landscapes can play a critical role in biodiversity conservation, yet species sown into restorations often fail to establish. Additionally, this project includes the mentoring of undergraduate students and development of online educational materials for K-12 students. By using field experiments, reciprocal transplants, and greenhouse studies, this project aims to expand understanding of the role of rapid adaptation in population establishment in several ways. First, although empirical evidence suggests that evolution may occur rapidly enough to influence establishment, few studies consider the demographic effects of adaptation. This study will examine the demographic effects of adaptation in recently established plant populations. Second, this work aims to identify the selective agents and traits responsible for local adaptation, which few studies attempt to do. By combining selection analyses with reciprocal transplant experiments, this study will both predict evolutionary responses and test whether those predicted evolutionary shifts have actually occurred. Finally, this work will investigate the role of microbial mutualists in plant rapid adaptation by examining interactions between legumes and nitrogen-fixing bacteria and how traits mediating interactions with rhizobia have evolved in response to field environments that differ in soil nutrient availability and rhizobium community properties. The results of this work will elucidate the mechanisms underlying the relationship between rapid adaptation and population establishment.