Year
2026
Season
Summer
Paper Type
Master's Thesis
College
College of Arts and Sciences
Degree Name
Master of Science in Biology (MS)
Department
Biology
Committee Chairperson
Dr. Scott F. Jones
Second Advisor
Dr. Nikki Dix
Third Advisor
Prof. Beth Nabi
Department Chair
Dr. James Gelsleichter
College Dean
Dr. Kaveri Subrahmanyam
Abstract
Coastal freshwater wetlands provide essential ecosystem services and support high biodiversity but are increasingly threatened by saltwater intrusion through sea-level rise and storm surge. Effective management of these wetlands requires spatially explicit information to assess individual wetland vulnerability. Here, we quantify plant community diversity and composition of coastal freshwater wetlands at the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR) in Northeast Florida, USA to determine indicators of vulnerability to saltwater intrusion. Data were collected along hydrologic gradients in 8 distinct wetlands classified as depression marshes or a part of a freshwater swale complex. Ordination analysis revealed plant community composition was clustered more by site than hydrological position. Diversity indices indicated that there was not a significant difference in the number of species between swale and depression marshes but there was increased patchiness in the number of assemblages within depression marshes. Freshwater swale marshes had a greater number of assemblages between sites than depression marshes. The continuous presence of more salt-tolerant plant species and greater patchiness within sites indicate vulnerability of depression marshes to saltwater intrusion as disturbance increases the presence of more salt-tolerant, opportunistic species alongside freshwater plant species. These spatially explicit patterns of plant community diversity and composition emphasize the importance of site-specific management strategies as well as assessing biodiversity across multiple spatial scales.
Suggested Citation
Hill, Emily R., "Investigating plant community structure and diversity in coastal freshwater wetlands to identify patterns of vulnerability to saltwater intrusion" (2026). UNF Graduate Theses and Dissertations. 1465.
https://digitalcommons.unf.edu/etd/1465
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