Genetic Responses to Fragmentation: Conservation Genetics of the Threatened Dakota Skipper (Hesperia dacotae)

Noah Brady

Date of Award

2017

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Saarinen, Emily

Area of Concentration

Biology

Abstract

Habitats across the globe are increasingly fragmented by development. When habitat becomes fragmented, populations are isolated and harmful inbreeding depression can lead to reductions of fitness. Conservation genetics is a discipline that utilizes the information found in the genetics of populations to help protect species, and it can be used to measure the effect of fragmentation on population viability. In this study, I used conservation genetics techniques to quantify the genetic diversity and structure of the Dakota skipper (Hesperia dacotae). The Dakota skipper is an inhabitant of Midwestern tall grass prairie. Intensive agricultural development beginning in the late 19th century has eliminated 99% of this habitat and populations of H. dacotae are assumed to have declined in association. I used seven neutral microsatellite loci to measure the genetic diversity and structure of H. dacotae in 176 individuals from ten populations across the species’ range. My results show relatively high levels of genetic diversity (����= 0.649) and relatively low genetic differentiation (������ = 0.008-0.033). As these findings do not match what I expected given the species low dispersal capabilities and the extent of habitat fragmentation, I propose three possible explanations: 1) extant populations are large enough to prevent genetic drift; 2) extant populations maintain gene flow through stepping stone populations; and 3) there is a time lag between the response of the genetic markers I used and the potential population fragmentation. These three explanations represent different population structures, and I end this thesis by broadly explaining the different management schemes that each explanation would require.

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