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Landscape aspects of oyster reefs : fragmentation and habitat utilization

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Heather D. Harwell (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Lynn Leonard

Abstract: The functional value of oyster reefs is recognized in many estuarine systems, with increasing interest in oyster reef restoration for ecological function rather than for fishery production. Reefs provide structure and refuge for juvenile fish and crustaceans, and may be a locus for predator foraging. However, reef morphology influences the relative value of refuge and forage functions, and reef utilization by benthic, epibenthic, and nektonic organisms. Reef fragmentation will increase the edge to interior ratio, and may enhance use by organisms that favor edge regions, or decrease use by species requiring more interior habitat. The influence of fragmentation was examined using created intertidal oyster reefs and natural reef patches in southeastern North Carolina. Created reef treatments included a uniform circular reef, a small fragmented reef, a large fragmented reef, and reference natural reef and mudflat areas. In addition, uniform and fragmented patch reefs in two nearby tidal creeks were also sampled. All treatments were sampled immediately after construction in June 2002, and then quarterly over two years, targeting infauna, epifauna, and nekton. Effects of fragmentation on infuana were variable, with a combination of positive and negative species-specific responses. However, preferential use of large fragmented reefs over small fragmented reefs was observed for Lagodon rhomboides, Panopeus herbstii, and Geukensia demissa, suggesting that the small fragmented reefs were most likely below the patch size threshold at which edge effects become beneficial. Implications are that oyster reef fragmentation may be an important factor for restoration managers to consider when designing reefs in which increased habitat utilization is a primary goal. Although a degree of fragmentation may be beneficial for some species, once fragmentation leads to a loss of reef area below critical thresholds, degradation effects on habitat utilization could be great.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Keywords
Estuarine animals--Habitat--North Carolina, Oysters--Ecology--North Carolina , Oysters--Habitat--North Carolina, Reef ecology--North Carolina, Reefs--Morphology--North Carolina
Subjects
Reefs -- Morphology -- North Carolina
Estuarine animals -- Habitat -- North Carolina
Oysters -- Habitat -- North Carolina
Oysters -- Ecology -- North Carolina
Reef ecology -- North Carolina