This research will explore how evolution can rescue a population from extinction due to drastic changes in the environment. When those changes are rapid, the plants, animals, and other organisms living in a place can go extinct, particularly when populations are small and movement between them is difficult. Under some circumstances, rapid adaptation to altered conditions can allow those small populations to grow and avoid extinction. This project focuses on the factors that determine whether populations adapt and persist or go extinct including: the size of the place, the size of the population, the amount of genetic variation a population has, and whether movement between places is possible or not. Given rapid environmental changes that are occurring worldwide, the information gained will be crucial for successful management of both endangered species and invasive pests. Undergraduate and graduate students will be involved in the research, and outreach to the public through the Colorado State University Bug Zoo will enhance societal understanding of conservation and species management.
Theory and experiments show that adaptation can be rapid enough to prevent or delay extinctions: the process of evolutionary rescue. Most empirical studies of evolutionary rescue use haploid microorganisms. However, the species most at risk of extinction are larger diploid organisms. In these species, the standing genetic variation of deleterious alleles is high, and populations are often small, favoring drift and inbreeding relative to selection. Theoretical and empirical studies of rescue often fail to account for randomness in ecological processes or for processes that can inhibit population growth, such as density dependence, genetic drift, and inbreeding, which counter the effects of adaptive evolution. Using a model biological system (Tribolium castaneum flour beetles) the researchers will conduct experiments that manipulate population history, size, density, dispersal rate, and dispersal source, compared to non-evolving controls, and will examine consequences for fitness, extinction, and genomic diversity. The experiments will be paired with new, combined ecological and evolutionary models that will facilitate quantifying experimental results and allow the research to be generalized to other species.
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.
