OYSTER REEF ECOLOGY AND RESTORATION: FINDINGS FROM FIELD AND MESOCOSM STUDIES

Geraldi, Nate

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March 22, 2019

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Geraldi, Nate
- Affiliation: College of Arts and Sciences, Department of Marine Sciences

Abstract

Habitat degradation and invasive species are two of the most rampant threats to marine ecosystems worldwide. The causes of degradation include coastal development and destructive harvesting practices. My thesis focuses on how to best invest resources to restore lost habitat and the unexpected consequences of shoreline hardening. I examined the efficacy of a costly and widespread restoration practice of adding juvenile oysters to reefs to enhance reef restoration. The results from my experimental field manipulations of juvenile oysters at three oyster sanctuaries throughout the Pamlico Sound indicate that the addition of oysters does not enhance reef development because natural recruitment of oysters is not limiting and efforts should focus on deploying substrate to restore oyster reefs. In addition to restoration, understanding biotic and abiotic interactions in oyster reefs is necessary to understand population dynamics. I ran multiple mesocosm experiments on foodweb interactions in oyster reefs and found that movement and size of mud crabs influence oyster survival. In addition, natural oyster reefs and shoreline hardening structures were surveyed for native and invasive macroalgae. Codium fragile, a nonnative species, was primarily found on artificial structures while the native Codium decorticatum was found almost exclusively on intertidal oyster reefs. C. fragile also had significantly higher nitrogen removal rates and although shoreline hardening was habitat for nonnative species, this species could mitigate excess nutrient loading. Results from my research will increase the efficacy of habitat restoration and increase our understanding of interactions between habitat alteration and invasive species.

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