Degree

Master of Science (MS)

Department

Environmental Resource Science

Document Type

Thesis

Abstract

As sea level rise and coastal subsidence increase coastal Louisiana's vulnerability to saltwater intrusion (SWI) events, accurate and rapid monitoring of vegetation responses to these events is becoming increasingly important. In this study, we utilized unmanned aerial vehicle (UAV) multispectral imagery to assess short-term vegetation responses to simulated SWI events in the Visser’s Experimental Wetland Complex in Saint Martinville, Louisiana. Vegetation patches of two common freshwater wetland species, Panicum hemitomon (Maidencane) and Typha domingensis (Southern Cattail), were exposed to 5 ppt salinity for 6-, 10-, and 17-day durations. Multispectral imagery of both species was collected before and after each SWI event, alongside in situ carbon dioxide and methane flux measurements using closed chambers at the patch scale. We calculated six vegetation indices (VIs) to quantify canopy-scale responses and evaluate whether changes in VIs were associated with shifts in gas fluxes. Our results indicate significant relationships between the changes in CH4 vegetation fluxes and changes in all 6 VIs (p < 0.05), whereas relationships with CO₂ fluxes were not significant and more variable (p > 0.05). These results demonstrate both the possible use and limitations of UAV-based multispectral imagery for monitoring vegetation responses to acute SWI and underscore the need to integrate spectral, hydrologic, and biogeochemical measurements when evaluating climate feedback from coastal freshwater wetlands.

Date

2-6-2026

DOI

https://proquest.com/docview/3347957066

First Committee Chair

Jorge Villa

First Committee Member

Heather Kirkpatrick

Second Committee Member

Mark McDonald

Third Committee Member

Robyn Zerebecki

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