Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 55-60). / vi, 60 leaves, bound ill., map 29 cm

Thesis (Ph.D.)--University of Western Australia, 2006.

Thesis (M.A.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vi, 36 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 31-36).

Thesis (M.S.)--Baylor University, 2008. / Includes bibliographical references (p. 85-89).

Thesis (Ph. D.)--University of Hawaii at Manoa, 2003. / Includes bibliographical references.

Thesis (doctoral)--Universität, Bochum, 2003. / Includes bibliographical references (p. 215-227).

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Coral reefs are arguably the most threatened marine habitat because of multiple anthropogenic stressors degrading the health and resilience of these systems. In the past 20 years there have been increasing observations of mass coral bleaching and mortality associated with increasing water temperatures in the tropics. Reefs provide ecosystem services worth billions of dollars to people living in tropical coastal areas and are the architects of one of the most beautiful structures found on earth. Conserving these habitats is paramount, and conservation planning must contend with climate change along with local and regional stressors. In this thesis Watamu Marine National Park in Kenya is used as a case study of the current challenges facing the conservation of reefs in a warming world. The Western Indian Ocean suffered dramatic bleaching during 1998, which caused the mortality of 70% of Watamu's corals. Using datasets from the 1980s to present the historical trajectory of Watamu's reef community is presented. The current ecosystem resilience is assessed to suggest how this reef will respond to future climate stress. It appears that Watamu's coral community has remained in an altered state post-1998, which, based on its past thermal stress and current coral community, should be resistant to future bleaching. Watamu's resilience and reef health is compared with other locations in the Indian Ocean, including reefs in Kenya and the Maldives that bleached in 1998 and examples from Mozambique and Sumatra of reefs with little evidence of historical thermal stress. Resilience is a multi-faceted process with different major components and numerous interacting factors, which act synergistically on the reef community. Conservation options and opportunities are discussed for the 6 locations examined, using current resilience models and theory as a framework for identifying priority actions. Local and regional-scale human impacts on shallow marine habitats during the last 50 years has been dramatic, and with global-scale climate change as an additional major threat, the next 50 years will be critical for the future of reefs. The locations visited during this study showed encouraging signs of resilience to past thermal stress, with evidence to suggest that corals are acclimatising and/or adapting to increasing water temperatures. The future of reefs in locations like Watamu is uncertain. Better understanding of reef ecology, appropriate conservation techniques and ultimately greater public concern for reefs is required to ensure that there is a future for these ecosystems in the Indian Ocean.

Invasive species can severely disrupt biological communities through their interactions with native organisms, yet little is known about the response of marine predators to the establishment of a competitive invasive fish. In the western Atlantic, invasive Indo-Pacific lionfishes (Pterois spp.) may represent a novel competitor to several commercially and ecologically important native species. However, there is a scarcity of empirical research documenting comparative resource use of cohabitant lionfish and native fishes, as well the physiological consequences that may result from interspecific interactions with the invasive species. For this thesis, I conducted two studies designed to elucidate the strength of resource use overlap and potential competition among invasive lionfish and an ecologically similar serranid, the Graysby (Cephalopholis cruentata), along a contiguous coral-reef ledge in Biscayne National Park, South Florida. My first study aimed to determine whether lionfish and Graysby could be classified as competitors through comparisons of Graysby population size, diet, and condition across a range of ambient lionfish biomass. Using stable isotope and gut content analyses, I measured a difference in Graysby diet on sites with larger populations of lionfish, specifically a smaller breadth of resource use and lower consumption of teleost fish prey. Despite a shift in diet, Graysby condition did not vary with lionfish biomass, and thus this study did not provide unequivocal evidence of competition between the two species. However, based on a high amount of apparent overlap in interspecific resource use, competitive interactions between lionfish and species such as Graysby remain likely in systems with more limiting prey or shelter. For my second study, I measured stable isotope values of muscle, liver, and eye lens layers in lionfish and Graysby to further compare individual and population-level patterns of diet and habitat use. The use of eye lenses as metabolically stable chronological recorders of stable isotopes has vast potential to provide insight about animal life history, but has not yet been applied to describe trends in resource use among invasive and native species. To aid these analyses I created a rudimentary map of spatial isotopic variation along the reef ledge of Biscayne National Park, which could serve as a frame of reference to study local-scale animal movements. Isotopic differences between liver and muscle samples suggested a broader range of movement in lionfish than Graysby, important for understanding the relative scale of habitat use in these species. In eye lenses, stable isotope values increased logarithmically with lens radius (i.e. fish size), likely reflecting patterns of trophic growth. There was a high amount of variability among the shapes of eye lens isotopic chronologies, particularly those of lionfish, yielding further information about movement and individual resource use specificity in these species. The results of this thesis are the first to compare native predator diet and condition across a range of invasive lionfish biomass, as well as the first to measure size-structured trends in the resource use of individual lionfish. Together, these results enhance our understanding of the potential for competition among lionfish and native mesopredators, an important objective for researchers studying how this highly invasive species interacts with surrounding ecological communities.

Oyster reefs support diverse estuarine communities and food webs. Factors controlling oyster reef community development were studied on restored reefs in the St. Lucie Estuary. Freshwater discharges create stresses that cause oyster mortality, habitat loss and reduction in reef community diversity. Using structural equation modeling, it was demonstrated that salinity, turbidity, and chlorophyll-a gradients influence oysters and some reef invertebrate species, but did not support the predictions of the Intermediate Disturbance Hypothesis. In contrast, diversity and species richness were greatest at low stress sites. A field experiment showed that topographic relief and architectural complexity enhanced colonization and growth of reef-building species (e.g.oysters and mussels). The relief by complexity interaction had a higher order, synergistic effect on oyster abundance. When considered separately, increasing relief further enhanced dominant sessile taxa (cirripeds and ascideans) ; while, increasing complexity supported greater species richness and the abundance of cirripeds. / by Elizabeth A. Salewski. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.