Effects of management on functional diversity in restored tallgrass prairie plant communities

Committee members: Barber, Nicholas A.; Duvall, Melvin R.Advisor: Jones, Holly P.Includes illustrations.Includes bibliographical references.While recent studies have embraced evaluating ecosystems through functional diversity, the focus on interspecific trait changes may limit their usefulness and application. Functional traits (traits that explain species' responses to environmental conditions and their ecosystem roles) can provide a more nuanced understanding of how disturbances shape plant communities and the functions they perform. Further, the inclusion of intraspecific trait responses can explain a significant portion of these relationships. In ecosystem restorations, management strategies can act as environmental drivers and disturbances that affect community structure. This study examined how three environmental drivers (grazer presence, prescribed fire, and age) in restored grasslands influence plant functional trait diversity and values and if these influences differ when intraspecific trait variation is incorporated. Further, relationships between functional characteristics of communities and an ecosystem function, aboveground productivity, were measured. Functional diversity consistently decreased with age across multiple functional diversity metrics, both when using fixed trait values and intraspecific trait variation. Increased functional diversity, measured as functional evenness, promoted productivity, but both evenness and productivity declined with site age. This functional diversity and ecosystem function relationship was only observed when using intraspecific trait data, emphasizing the importance of accounting for plasticity in functional ecology studies. These results of this study support the environment-trait-function framework and demonstrate the importance of intraspecific trait variation. In ecosystems with weaker environmental gradients, the inclusion of intraspecific changes may be more influential than species turnover in identifying functional diversity and ecosystem function responses. Accounting for this source of variation may improve predictive models and general community ecology rules. Additionally, testing ecology principles in the context of restoration and identifying community responses to disturbances is critical for improving the predictability and success of restoration outcomes.M.S. (Master of Science