Daniel Pascucci

Ph.D. Candidate, Louisiana State University

2022 Conference Travel Grant Type 2

Differences in the Resilience of Wetlands Towards Lateral Marsh Retreat Due in Salt Marsh-Mangrove Ecotones in Coastal Louisiana

As climate change continues to progress the status of ecosystems globally will be changed by climate driven regime shifts. One such regime shift occurring in the Gulf of Mexico is the transition from marsh systems dominated by Spartina alterniflora to ecotones containing both Spartina and Avicennia germinans. This state change presents a potential positive change as the more robust root system of A. germinans may facilitate the creation of a wetland with more resilience towards wave driven lateral edge retreat. In order to test this hypothesis a remote sensing analysis was performed along coastal Louisiana, comparing erosion between marsh and mangrove dominated edges over 7 years. These erosion rates were also related to estimated values of wave power in order to determine site specific influences on retreat rates. The relationships studied indicate a potentially strong link between the allometry of A. germinans, the magnitude of wave power exposure and the resilience of mangrove dominated edges towards lateral edge retreat such that edges exposed to high wave power may be too unstable for mangroves to establish long enough to have a positive effect on edge retreat. Understanding these relationships is key to assessing the value of these novel systems going forward.