Date of Award:

12-2023

Document Type:

Dissertation

Degree Name:

Master of Science (MS)

Department:

Biology

Committee Chair(s)

Becky Williams

Committee

Becky Williams

Committee

Zach Gompert

Committee

Karen Mock

Abstract

Understanding a species dispersal ecology and population dynamics is essential to effectively manage and conserve a species. As advancing technology improves our knowledge of species movements, it is becoming clear that many species form metapopulations to some extent. A metapopulation is a network of interconnected subpopulations that exchange reproductive individuals with subpopulations occupying nearby patches. Metapopulations have been observed in a variety of species, ranging from plants to vertebrates, and can vary greatly in their dynamics (level of connectivity and gene flow) based on the species behavior and life history strategy.

Forming a metapopulation can add much resilience to the subpopulation. A steady inflow of new individuals can protect the subpopulation from inbreeding depression and adds more standing variation for natural selection to work on. However, as the metapopulation breaks down and patches become isolated, that resilience is quickly lost. Habitat fragmentation due to anthropogenic changes poses a significant danger to metapopulations. Understanding these metapopulation dynamics is of key importance to formulating effective and efficient conservation and management plans. Information such as where, when, and how these species are dispersing can tell us how to best preserve these paths and maintain the metapopulation structure.

One species that forms a highly extensive metapopulation, is the American goshawk (Accipiter atricapillus). In this study we evaluated the metapopulation genomics of American goshawks in the Intermountain West by investigating the genetic diversity and differentiation, as well as gene flow and connectivity, of four subpopulations. The goshawk metapopulation is connected mainly through the natal dispersal of juveniles. Natal dispersal has been and continues to be very hard to track due the technological limitations.

Here we show that genomics can offer an alternative when species cannot be easily tracked. While specific dispersal routes cannot be elucidated, we were able to discover the level and direction of gene flow between subpopulations, giving a rough idea of where and how far individuals were dispersing. We found little to no differentiation and very high gene flow between these subpopulations despite the hundreds of kilometers between them. There was no geographic structuring shown both by an isolation by distance test and a correlation test between geographic distances and the estimated number of migrants exchanged. This information is vital to understanding the species movements and ecology in order to create an effective management plan.

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