Graduation Year

2006

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Marine Science

Major Professor

Joseph J. Torres, Ph.D.

Co-Major Professor

Carole C. McIvor, Ph.D.

Keywords

Mudflat, Habitat, Water depth, Connectivity, Habitat conversion and coastal transgression

Abstract

The passage of two major hurricanes across southwest Florida (Category 5, Labor Day Hurricane of 1935; Category 4, Hurricane Donna 1960) resulted in fragmentation of mangrove forest at Big Sable Creek, Everglades National Park. Over time forest fragmentation led to forest loss and patchy conversion to unvegetated mudflats. My goal was to determine the consequence of forest fragmentation on nekton (i.e., fish and decapod crustaceans) inhabiting the intertidal zone. I used block nets across intertidal rivulets to compare nekton leaving replicate forest and unvegetated mudflat sites from October, 2002 through April 2004. Overall nekton density (individuals per 100 m3) was significantly greater (rmANOVA, p < 0.001) for mangrove (212·100 m-3) than mudflat (26·100 m-3) habitats. Biomass (g per 100 m3) was also significantly greater for mangrove (715 g·100 m-3) than mudflat (20 g·100 m-3) habitats. Composition of the nekton assemblage also differed between habitat types (ANOSIM global R=0.416, p<0.001). Structure-associated species dominated forested sites, whereas schooling species dominated mudflats. When mangrove destruction and mortality results in fragmentation (Craighead and Gilbert, 1962; Smith et al., 1994; Wanless et al., 1994), nekton density and biomass will likely decline as a consequence.

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