Degree

Master of Science (MS)

Department

Biology

Document Type

Thesis

Abstract

Local adaptation is assumed to be prevalent within natural populations, but anthropogenic climate change and habitat destruction have been demonstrated to cause maladaptation. This thesis examines patterns of adaptation within two dominant grass species of our local Cajun Prairie ecosystem, Panicum virgatum and Schizachyrium scoparium. Using a provenance common garden study, our results reveal how climate change and habitat destruction have altered the patterns of adaptation within local populations. Chapter 1 examines how source climate and geographic distance predicts population fitness. Chapter 2 examines the type, magnitude, and direction of selection acting on key ecological traits of both species, as well as how close local populations are to exhibiting optimum phenotypes. Our results suggest that both species exhibit a nuanced signature of regional adaptation, where populations from the broader gulf coast region are better adapted to Cajun Prairie than more northern accessions. However, our results also provide the first documentation of a finer scale adaptation lag to temperature in dominant perennial grasses. Fitness differences resulted from selection favoring plants that were larger, had more reproductive tillers, and flowered later. Yet, plants with extreme values for these traits had lower fitness. Local populations had mean trait values lower than optimal trait values, and much of the trait variation within local populations was asymmetric around trait-fitness optima. We suggest that future conservation efforts should consider methods incorporating pre-adapted seed from warmer regions that are geographically nearby to facilitate future adaptation.

Date

2-6-2026

DOI

https://proquest.com/docview/3347938647

First Committee Chair

Nicholas Kooyers

First Committee Member

Mark Genung

Second Committee Member

Robyn Zerebecki

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