Date of Award

1-2013

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Marine Biology and Coastal Sciences

Thesis Sponsor/Dissertation Chair/Project Chair

Paul A. X. Bologna

Committee Member

Josh Galster

Committee Member

Dirk Vanderklein

Abstract

Ecosystems are broad classifications of areas where overlapping communities exist which can contain relatively high faunal and floral diversity. These communities characteristically are often influenced by external forces. Disturbances can create incongruencies in these communities and have been demonstrated to change community dynamics in varying ways. Humans are responsible for many disturbances which alter habitat and community structure and many habitat edges or ecotones are artificially created by these human disturbances. In Wakatobi National Park, Hoga Island, Indonesia, three bays exist and are in close proximity to one another with varying levels of human influence. This study investigated how anthropogenic disturbances affect seagrass communities. Boat Bay showed substantial human activity, while the other two bays (Hoga and Mushroom bays), showed limited regular human activity respectively (e.g. boat launching and snorkeling). It was hypothesized that human influences could impact seagrass communities by reducing diversity and abundance of community members and altering the overall structure of the habitat. Seagrass beds within these sites were investigated to assess how human influence may impact faunal community structure, floral characteristics, and changes in water flow. Each of these seagrass communities was divided into shallow edge, core, and deep edge sub-habitats to determine if differences existed with respect to animal density, plant density, and relative water flow, as it has been demonstrated that within habitat variability exists in Seagrass communities. In Boat Bay, the most human influenced system, animal density was lowest and no within habitat differences between edge and core regions was observed. However, in the other two bays substantial differences among the three sub-habitats were observed, suggesting strong edge effects for minimally disturbed systems. Results showed that faunal densities in Mushroom and Hoga Bays averaged 250-400 organisms m-2 on the edges, but only 100-150 organisms m-2 were identified in the core regions. Differences were also observed in the relative flow rates, where Mushroom and Hoga Bay edge dissolution rates were greater (nearly 2% greater rates of dissolution) than interior rates. Conclusions from this study indicate that human activities reduce faunal density and dampen or eliminate any edge effects existing within seagrass communities. As such, human disturbances negatively impact the within habitat structuring forces of edge effects.

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