Graduation Year


Document Type




Degree Name

Master of Science (M.S.)

Degree Granting Department

Biology (Integrative Biology)

Major Professor

David Lewis, Ph.D.

Co-Major Professor

Christina Richards, Ph.D.

Committee Member

Susan Bell, Ph.D.


carbon, feedbacks, intertidal, intraspecific, nitrogen


Biodiversity is important to ecosystem function at many scales, and variation functional traits within a species can potentially influence ecosystem functioning by altering nutrient cycling dynamics. High population extinction rates are resulting in a rapid loss of within-species biodiversity, so there is a need to better understand the importance of intraspecific variation to ecosystem-level processes. Tidal salt marshes are ideal ecosystems for investigating intraspecific variation in plant-nutrient relationships because they are dominated by a monoculture of the foundation species Spartina alterniflora, with distinct phenotypes that correspond to environmental gradients across the marsh. We conducted a field survey of existing phenotypic variation and biogeochemical characteristics in three salt marshes in South Carolina, USA, and used path analysis to model relationships among plant traits and nutrient dynamics. Leaf %N and C:N were important predictors of nitrogen and carbon cycling dynamics respectively. There were strong effects of site on soil variables, but plant traits responded most to tidal position within the marsh, indicating a potential decoupling of plant-soil feedbacks which are often tightly linked. Overall, variation in plant tissue chemistry does play a role in nutrient cycling, but other feedbacks may be broken down or obscured by hydrologic drivers in this highly dynamic ecosystem.