Semester of Graduation

August 2026

Degree

Master of Renewable Natural Resources (SRNR)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

Salt marsh estuaries are ecologically significant coastal ecosystems that provide essential habitat for fish and invertebrate communities but are experiencing significant global declines due to natural processes and human activities. Restoration strategies are increasingly used to mitigate habitat loss and promote ecosystem recovery. However, their long-term effectiveness in supporting ecological function remains uncertain. This thesis examined how restoration strategies and habitat characteristics shape the ecological function of saltmarsh edge habitats, with a particular focus on fish and invertebrate assemblages and the nursery value of modified coastal ecosystems. I compared fish and invertebrate presence and abundance around two salt marsh restoration projects, living shoreline breakwaters and marsh creation sites, with adjacent unmodified, reference marsh using six fisheries-independent survey methods. Around living shorelines, assemblages of small-bodied fish and invertebrates differed between the living shoreline and reference sites, and the abundance of juvenile and small-bodied individuals was lower at the marsh edge of living shoreline sites compared to reference sites. In contrast, assemblages of larger and more mobile species did not differ between the living shoreline and reference sites but did differ between the two structure types present, driven primarily by large-bodied predatory species. At marsh creation sites and areas dominated by Phragmites australis, observed species richness was greater at reference marshes than restored marshes across all gear types, while patterns in nekton abundance and biomass varied among species and life-history groups. Species exhibiting ontogenetic habitat shifts showed stronger responses to restoration status and P. australis abundance than non-shifting species. Collectively, these findings indicate that habitat quality and ecological function may be better reflected by body-size distributions and life-history characteristics than by assemblage or abundance metrics alone. Habitat heterogeneity and structural complexity influenced species presence and abundance, particularly for juvenile fishes and invertebrates. Furthermore, these studies highlight the importance of multi-gear approaches for evaluating restoration outcomes across a broad range of species, body sizes, and ecological functions. As salt marsh restoration efforts expand globally in response to coastal erosion and land loss, incorporating ecological function into restoration design and evaluation will be increasingly important for supporting resilient coastal ecosystems and fisheries.

Date

7-16-2026

Committee Chair

Jeffrey Plumlee

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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Available for download on Friday, July 16, 2027

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