Date of Award

Spring 2008

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

John J. Hutchens, Jr.

Second Advisor

Kevin S. Godwin

Third Advisor

Keith R. Walters

Abstract

Coastal zones across the southeastern United States are being developed rapidly because of increasing population and tourism demand. Infrastructure (e.g., homes and roadways) and other local necessities (e.g., gas stations and grocery stores) are being built to accommodate the increased population, which increases impervious surfaces (i.e., roadways and rooftops) and cleared areas (i.e., lawns). Impervious surfaces can increase the amount of nutrients and freshwater runoff entering the high salt marsh. Changes in abiotic factors potentially could affect abundance and diversity of benthic invertebrates in the high salt marsh. To determine if increased impervious surfaces and residential development were impacting the benthic invertebrate assemblage in Murrells Inlet, SC, USA, I 1) assessed both quantitative and qualitative differences in benthic invertebrate assemblages of undeveloped, developed with riparian buffer and developed without riparian buffer sites, and 2) examined soil chlorophyll a, pore-water chemistry, groundwater levels, soil particle size, root mass and amount of impervious surface and lawns at each of eleven chosen sites . Developed without buffer sites had the greatest amount of impervious surface and lawns while undeveloped sites did not have any impervious surface or lawns directly abutting the high salt marsh. Invertebrate abundances typically were greater in developed without riparian buffer sites, and lower in undeveloped sites, while developed with riparian buffer sites were always intermediate. The primary benthic invertebrate taxa found within all sites were nematodes, oligochaetes, copepods and tanaids. Nematode abundance was significantly different among treatments and greater in abundance at developed sites. Invertebrate abundance was positively correlated with root mass and chlorophyll a amounts; root mass provides habitat while chlorophyll a represents algal food for the benthos. Chlorophyll was greater at developed sites, along with invertebrate abundance. Nitrate-nitrogen in porewater was detected only at developed with riparian buffer sites. Greater abundances in several taxa (e.g., tanaids, nematodes, chironomids) at developed sites may show that changes have occurred in the high marsh, which is associated with development of the adjacent uplands. Overall development of the Murrells Inlet watershed may have affected the presence or absence of detectable differences in the benthic invertebrate assemblage among shoreline treatments. Results from this study have management implications on a localized scale, especially when zoning new areas of development along the shoreline (e.g., set-back lines, thicker riparian buffers).

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