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Burgess, Brock Ty

University of British Columbia

Invasive species are a primary driver of global biodiversity decline, especially on islands, which face elevated extinction rates. Across the Haida Gwaii archipelago (Canada), islands with invasive Sitka black-tailed deer (Odocoileus hemionus sitkensis) exhibit significantly lower species richness and population decline of ecologically and culturally important species. My doctoral research uses population genomics to understand patterns of deer movement across Haida Gwaii and to develop and apply genetic tools for informing management. Using genotypic data at ~13,000 single nucleotide polymorphisms (SNPs) from 181 deer sampled throughout the archipelago, I detected little population structure across 14 islands and evidence of contemporary inter-island deer movement; however, the culturally significant island of SGang Gwaay exhibited genetic isolation, constituting a possible eradication target. Overall, the high connectivity indicated sustainable eradications are likely not possible in most cases, and alternative management interventions are required. I then developed a Genotyping-in-Thousands by sequencing (GT-seq) panel to evaluate and support deer management throughout the archipelago. Using paired high-quality tissue and non-invasive feces and hair, I optimized the panel for poor-quality samples, demonstrating high levels of genotyping success (90.3%) and sample retention (97.6%) at 244 SNPs, then performed a proof-of-concept application to simultaneously provide individual and sex identification, and relatedness estimations. Finally, I investigated the genetic and demographic consequences of deer management using genotypic data collected via GT-seq from pre- and post-cull samples from two offshore islands, including SG̲ang Gwaay. Pre-cull samples showed signals of historical isolation. Moreover, post-cull deer exhibited significantly lower levels of genetic diversity that further strengthened the observed isolation, highlighting the importance of interpreting population genetics studies within the context of previous management operations. Collectively, these studies will directly inform deer management to help restore ecological integrity within Haida Gwaii. More broadly, my research demonstrates the utility of population genomics for improving invasive species management on islands and provides researchers with a cost-effective workflow for efficient high-density genotyping of poor-quality samples typical of elusive or at-risk species.

Text

2022-07-22

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/82193

Biology

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/