Abiotic and biotic influences on the composition of nearshore marine communities of The Bahamas

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)



First Committee Member

Kathleen Sullivan Sealey - Committee Chair


This multi-year study examined the nature of relationships between various abiotic and biotic components of Bahamian nearshore marine communities. This project suggests that composition of nearshore marine communities of The Bahamas is determined by a highly complex system of interactions between various abiotic and biotic components. Accurate predictions about a site's nearshore marine community composition can likely be made if details of general spatio-temporal habitat characteristics are known.Floral assemblages were determined to be unique at each island, and showed island-specific responses to wave energy and substrate. Analyses completed at broader functional group and phyla levels of analysis resulted in decreased detection of floral responses to environmental features. Coastal benthic flora assemblages displayed negligible seasonal changes. An influence of terrestrial land-use and vegetation patterns on benthic flora composition was detected, especially on North Andros. Comparable terrestrial effects were observed using species and functional group approaches, although floral occurrences were stronger than abundances.Micro-crustacean families demonstrated quantitative responses to site, wave energy, substrate, and season factors, and qualitative responses to site and substrate types. Density and diversity showed an inverse relationship at different factor levels. Micro-crustacean assemblage composition was strongly linked to the covers of floral species and floral functional groups and the extent of anthropogenic destructive land-use patterns.Characterization of fish assemblages by beach seining is time-intensive and requires that sampling effort be distributed among different tides, times of day, and seasons to address the natural temporal variability in fish assemblages. Fish assemblages were influenced most by benthic flora characteristics, and, to a lesser extent, by micro-crustacean patterns. Covers of different floral species and functional groups helped explain observed patterns of species and trophic groups. Less abundant floral features were more important in determining multivariate fish parameters, such as species abundances. Common floral features were found to be important influences on univariate parameters.Coastal developments have been shown to directly or indirectly influence the distribution and abundances of various taxa, suggesting that careful monitoring and mitigation programs should accompany future coastal anthropogenic activities. This work provides a plan for assessing and monitoring natural and anthropogenic disturbance events in coastal ecosystems.


Biology, Ecology; Biology, Oceanography

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