DOI
https://doi.org/10.25772/F06B-GN41
Author ORCID Identifier
https://orcid.org/0000-0003-1539-1369
Defense Date
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Integrative Life Sciences
First Advisor
Chris Gough
Second Advisor
Ben Bond-Lamberty
Third Advisor
David Chan
Fourth Advisor
Catherine Hulshof
Fifth Advisor
Beth Lawrence
Abstract
Ecological disturbances impact core ecosystem functions, including production and biogeochemical cycling, by precipitating changes in biodiversity, physical environmental variables, vegetation structure, and functional trait distributions. As disturbance patterns intensify and abruptly transition to novel regimes under global change, future trajectories of ecosystem functions, including carbon (C) uptake and storage, are uncertain. A more complete understanding of the mechanisms underpinning ecosystem stability (or ability to return to baseline functioning) following disturbance is needed to forecast future C cycling.
Replicated ecosystem-scale disturbance experiments, particularly when coupled with modeling, are required to rigorously test hypothesized trajectories of ecosystem structural and functional change following disturbance and to yield greater insight into the mechanistic basis for stability. The NSF-funded Forest Resilience Threshold Experiment (FoRTE) is one such experiment aimed at disentangling and mechanistically understanding the drivers of temperate forest stability in response to simultaneous successional change and moderate-severity disturbance. FoRTE presents a valuable opportunity to research how ecosystem structural and functional attributes both respond to disturbance and mediate disturbance impacts on C cycling across a replicated gradient of disturbance severity. The specific focus of my research is understanding the role that leaf functional traits (i.e. morphological, biochemical, and physiological characteristics controlling function and conferring fitness) play in supporting ecosystem C cycling resistance and resilience.
Leaf functional traits, including both intra- and interspecific variability and plasticity, regulate whole-canopy photosynthetic response to disturbance, as surviving trees are poised to acquire and use the resources that senescing trees no longer take up. Moreover, leaf functional trait distributions are important to constrain for ecosystem modeling of the C cycle, and constitute highly influential model parameters that also often contribute substantial uncertainty to model predictions. Although leaf functional trait distributions have been extensively characterized in global databases such as TRY, few studies have examined how these distributions change along gradients of disturbance severity and whether these changes affect model forecasts of C cycling response to disturbance.
The overarching goal of my dissertation is to leverage the multi-faceted FoRTE project, as well as a relatively new eddy covariance C flux tower located within a Virginia-based wetland restoration site, to address four interrelated thematic questions.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
7-25-2024
Included in
Forest Biology Commons, Other Ecology and Evolutionary Biology Commons, Terrestrial and Aquatic Ecology Commons