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Comparison of nekton utilization of smooth cordgrass (Spartina alterniflora) marsh based on marsh size and degree of isolation from like habitat : do size and site location matter?

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
David L. Meyer (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Courtney Hackney

Abstract: Influence of salt marsh size and proximity to like habitat on nekton use was examined. Comparisons were made among six naturally occurring isolated island marshes, three each of small (~400-1,000 m ) and large 2 (~3,000-10,000 m2) island size classes and six paired mainland marshes (at least 76,000 m2 in size). Two species representing opposites for dispersal ability and life history strategies, mummichog (Fundulus heteroclitus) and pinfish (Lagodon rhomboides), were used as representative species to examine population patterns. Fundulus heteroclitus exclusively utilized marsh habitats and not adjacent shallow flats during high tide while L. rhomboides utilized both. At high tide island marshes acted as a refuge for F. heteroclitus among shallow water flat habitats. Densities of marsh dependent species, including F. heteroclitus, were an order of magnitude lower within the large island compared to the mainland marshes, and nonexistent within small island marshes. Similarities among mainland and large island marshes for larvae and disparity in juvenile F. heteroclitus abundances suggested a bottleneck constrained adult and juvenile F. heteroclitus populations at large island marshes. Differential predation rates among marsh types significantly contributed to disparities in young of year abundance. Patterns of abundance suggest two crucial time periods for F. heteroclitus population maintenance, one during late spring/early summer spawn-recruitment and the second during the dispersal/emigration during the late fall/winter time period when water temperatures are colder and predator levels are significantly reduced. In contrast, L. rhomboides recruitment and dispersal occurs simultaneously during the late fall/winter when low predator levels create an optimal time for recruitment to estuaries.

Additional Information

Publication
Dissertation
A Dissertation Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy
Language: English
Date: 2009
Keywords
Fishes--Habitat, Lagodon rhomboides--Ecology, Mummichog--Ecology, Nekton--Environmental aspects--North Carolina, Predatory marine animals--Ecology, Salt marsh animals--North Carolina, Salt marsh ecology--North Carolina
Subjects
Salt marsh ecology -- North Carolina
Salt marsh animals -- North Carolina
Lagodon rhomboides -- Ecology
Mummichog -- Ecology
Nekton -- Environmental aspects -- North Carolina
Fishes -- Habitat
Predatory marine animals -- Ecology