Coral reef degradation has been observed worldwide over the past few decades resulting in significant decreases in coral cover and abundance. However, there has not been a clear framework established to address the crucial need for more sophisticated understanding of the fundamental ecology of corals and their response to environmental stressors. Development of a quantitative approach to coral population ecology that utilizes formal, well established principles of fishery systems science offers a new framework to address these issues. The goal of this dissertation is to establish a quantitative foundation for assessment of coral reefs by developing some essential ecological and population-dynamic components of a size-structured demographic model for coral populations of the Florida Keys coral reef ecosystem. The objective provides the potential to build a quantitative systems science framework for coral populations. A two-stage stratified random sampling design was implemented during two separate survey periods to assess coral populations. Results include precise estimates of adult (> 4 cm) population abundance for several coral species by spatially partitioning abundance and variance into species-relevant reef habitat types. Adult size structure and juvenile abundance were used to evaluate individual coral populations and infer spatial variation in recruitment, growth and survival across habitat types. Partial mortality was characterized in terms of surface area, prevalence, and size-relationships. The development of some ecological and population-dynamic components of a size-structured demographic model for coral populations demonstrates the statistical framework and metrics required for monitoring and assessment of coral reef ecosystems to meet the pressing needs of conservation of coral reef ecosystems specifically in Florida, and throughout the Caribbean and Pacific in general.

The green porcelain crab, Petrolisthes armatus, has recently invaded oyster reefs of the South Atlantic Bight at mean densities of up to several thousand individuals m-². Despite the crab’s tremendous densities and wide-spread occurrence, its population dynamics, the reasons for its success, and its ecological impacts have remained unknown. We used field monitoring in two estuaries of coastal Georgia to assess spatial and temporal patterns of distribution, demographics, reproduction, and effects on native crabs. We used field and mesocosm experiments with constructed oyster reef communities of varying native species richness and adult porcelain crab additions to assess why the invader is successful and how it impacts native species and communities. We found P. armatus distributed throughout the estuaries, primarily in the lower regions and low intertidal. Sex ratios were 1:1 throughout the year. During warmer months mean densities ranged from 1,000-11,000 crabs m-², 20-90% of mature females were gravid, and numerous recruits were present. Despite decreases in density of 64->99% in the winter, populations rebounded in the spring. Maximum mean densities were 37 times the highest densities ever recorded and population fecundity exceeded that of the native range by an order of magnitude, but correlations did not show significant negative effects of P. armatus on native crabs. Field experiments suggested that invasion was successful due to tremendous recruitment overwhelming biotic resistance by native species richness or predation. The crab only needed structure to invade, but the presence of adult conspecifics significantly enhanced recruitment (i.e., intraspecific “invasional meltdown”). We documented several impacts on native biota, including the (1) suppression of oyster growth, benthic algal biomass, native crab recruitment, and native goby densities and the (2) enhancement of bivalve recruitment, macroalgal cover, and survivorship of oyster drills. We did not, though, see an effect on native taxonomic richness. The large direct and indirect effects of P. armatus on growth, survivorship, and recruitment of virtually all of the most common native species on oyster reefs in the short-term (4-12 weeks) and at relatively low experimental densities (750-1500 crabs m-²) imply considerable long-term consequences for a major hard-substrate habitat of the South Atlantic Bight.

Thesis (M. Sc.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 69-79).

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No description available.

The thesis is an exploration into the ways in which island communities living in coral reef environments value the surrounding reef resources. This research is conducted in seven communities in the Maldives. A qualitative approach is used as this inquiry involves gaining insight of human perceptions and behaviours. Discussions and interaction with participants in community activities and participant observation were the main inquiry methods used. Specifically, the research focuses on sand from the beach, coral from the house reef and fish in the island lagoon. The exploration of reef values show that multiple reef values exist and they are constantly changing. How communities interact with the resources and how the communities itself had changed over time contribute to this change in resource value. Physical and social factors, such as resource type, availability and location, physical characteristics of islands, community size, and socio-economic conditions, contribute to the changing reef values. Based on these changing values, it is recommended to go beyond one formal governance rules that fits all. Instead local adaptations based on local ways of valuing need to be considered. A most notable change impacting reef values is the migration of families to the capital. This reduces their interactions both with the reef environment and other community members. In addition, the current globalised education is causing the development of a predominantly globalised worldview among the present generations. In this new worldview, the sacred is separated from the secular. Thus, spiritual and moral beliefs have become isolated from resource management practices. I also find it of concern that local worldviews are being negated at the expense of concern for the global environment. I highlight the importance of schooling to instil knowledge about our local environments and local worldviews. It is also through education we can re-integrate the sacred into our practices and such changes need to be starting at an individual level.

No description available.

Tropical coastal resources including coral reefs, mangroves and seagrass beds are some of the most productive ecosystems in the World. They support a variety of goods and services that may often form the backbone of the local community. In many cases they provide the main source of food, as well as providing employment and recreation opportunities. However, coastal ecosystems are increasingly under threat from high population growth rates, rapid coastal development, over exploitation of the resources, loss of critical habitats and vulnerability to natural hazards. These tropical ecosystems are sensitive and vulnerable to damage and environmental change. Their worldwide loss has led to cause for concern and widespread calls for improved management. Integrated coastal management (ICM) is seen as the way forward in dealing with this complex mix of interests, activities and demands being placed on today's coastal zones. The definition of the coastal zone will vary between locations, ideally capturing and enabling the resolution of all major coastal issues, reaching as far inland or seaward as is required to reach the goals and objectives of the management programme. ICM encompasses the management of all aspects of the coastal zone taking a multi-disciplinary approach. It includes the management of existing economic activities, planned developments, natural resource conservation and utilisation as well as being able to deal with the different user conflicts. ICM involves the integration of different institutions and stakeholder groups at and across the local to international management levels. Even though ICM efforts are increasing, there are few examples where it is really being implemented and working effectively. In this study, three ICM case studies identified similar patterns of impediments although their scope was recognised as too narrow to make generalisations. As a result, a survey was developed to build up a broader picture of the issues blocking the development of successful ICM at several locations. The survey identified the current status of ICM in the tropics and identified the main impediments to implementing effective ICM. The survey found that few locations were actually implementing, monitoring and evaluating ICM, however a number were in the process of it. It was the step between analysis and implementation that was halting many of these efforts. Tropical coastal zones can be seen to share a number of common challenges exacerbated by poverty and conflicts between coastal users. Conflict management needs to be incorporated into the management process in a way that pays particular attention to the over-extraction of resources and destructive resource use. Although the concept of integrated coastal management (ICM) has been identified as the way to deal with the multiple objectives, interests and uses of the coastal zone, in practice it is a complex process and many countries are having difficulty in implementing ICM. The most common impediments to ICM in the tropics were identified through the survey as were their impact on implementing ICM. The extent to which ICM is achieved can be linked to the impediments, described by a series of criteria, which could be used in assessing the ability of an area to implement ICM as well as identifying priority areas for concern. The results show that although public participation is commonly accepted as a major part of ICM and is one of the main impediments, it is rarely fully realised. Gaining political support and empowering agencies with sufficient authority to enforce ICM were also identified as major impediments, without which ICM efforts may well be blocked. Decision making for integrated coastal managementin volves multiple decision makers and multiple stakeholders, often with conflicting needs and interests. Decision support systems (DSS) can be developed to improve our understanding of the inter-relationships between the natural and socioeconomic variables and hence result in improved decision making. The question is whether this decision making environment is actually too complex for the development of useful and useable decision support systems. An ICM-DSS needs to be able to involve multiple decision makers and take into consideration multiple issues. This requires different disciplines to be drawn together into an integrated modelling framework. There are many techniques available to deal with different modelling needs, the constraints of inadequate data and the multi-objective decision making environment. There are also different ways of developing decision support systems and each can play a different, but nonthe- less important role within ICM. Three coastal DSSs were evaluated in terms of their design and roles in integrated coastal management and are used to evaluate the potential to develop ICM-DSSs. One of these DSSs, CORAL, is examined in detail as a case study. The model is an example of an integrated ICM model where the final result is a score-card of criteria that measure economic, environmental, social and institutional objectives. CORAL was developed for the island of Curacao in the Caribbean and the Republic of the Maldives. The development process involved stakeholder meetings and interviews to ensure that all their interests and concerns in the coastal zone were accounted for and included in the DSS. The model development was carried out in the Netherlands and on return was presented to the stakeholder groups. A second phase of the project in Curacao allowed the model to be installed on a wide number of computers. An ICM course was established as well as individual training given to the stakeholder groups involved. However, the final use of the DSS was still limited. Lessons are drawn from the CORAL experience that may assist in the development of future DSSs such as the need to involve a key organisation in the development and enable them to continue its development and maintenance after the end of the project. In addition, flexibility, adaptability and update-ability are paramount if the system is to be used beyond educational goals. The impact of ICM on a coastal system is not always readily measured and quantified, least of all in monetary terms. Economic valuation is being increasingly applied to tropical coastal ecosystems to assess their benefits in monetary terms. From the point of view of ICM, economic valuation could give monetary values to, for example, changes in production resulting from management and hence highlights the importance of management. Likewise, it can highlight the costs of inaction by quantifying the benefits of a situation with ICM and one without ICM. This not only requires the ability to link monetary values to certain environmental situations but also to model the potential changes in goods and services provided by the ecosystem as a result of management. Past analyses in ICM have often focused on the costs of management versus economic gains while change to the environment has been measured in physical terms. Economic valuation provides a potential to compare like with like and hence bring the importance of ecosystems, such as coral reefs, to the fore. Some goods provided by these coastal ecosystems are marketed and consequently have a marketdefined value associated with them. However, these ecosystems also provide a number of non-use benefits, which are not directly marketed and as a result, certain economic techniques have been developed to deal with these issues. The contingent valuation methodology (CVM) was developed as a tool to measure non-marketed goods and services of ecosystems so they can be included into costbenefit analyses. However, it is a complex technique surrounded by much controversy.

TIlis study, covering a period of eight months, was undertaken to determine if measurable changes in characteristics occur in sea water passing over a shallow coral reef. The parameters studied include salinity, temperature, current velocities, dissolved oxygen, pH, dissolved organic carbon and particulate organic and suspended inorganic carbon. Staining and microscopic observations were made to supplement the other data. The results showed noticeable increases in oxygen, pH, particulate organic and inorganic carbon abundance in the central portion of the reef, which were attributed to the influence of extensive growths of benthic algae found on the seaward edge. Dissolved organic carbon concentration increased gradually across the reef, and there is evidence that inorganic carbonate is being accumulated on the leeward side of the reef. / Typescript. Bibliography: leaves [53]-55.

Macroalgae are abundant on shallow temperate reef environments, often forming complex communities that comprise several strata. In southern Australia, these assemblages are dominated by large canopy forming taxa from the Orders Laminariales and Fucales. The presence of subtidal fucoid macroalgae differentiates these communities from that elsewhere, and emphasises the need for local studies rather than relying on generalisations made elsewhere. Like most natural systems, temperate reefs are often threatened by human activity with degradation reported from many locations in close proximity to urban settlements. The work presented in this thesis involves an examination of the temporal and spatial variability in the structure of macroalgal communities from reefs along the Adelaide (South Australia) metropolitan coast. The work looked specifically at the effects of a dispersed sediment plume, resulting from the 1997 beach sand-replenishment dredging program, on shallow sub-tidal reef systems. An examination of the structure of canopy forming phaeophycean macroalgae in Gulf St Vincent (South Australia), noted large amounts of both spatial and temporal heterogeneity. Notwithstanding, this variation was not random, but demonstrated considerable structure that could be linked to a number of important underlying processes. In particular, macroalgal assemblages appeared as a mosaic of patches, each of which comprised a high-density state clearly dominated by a single genus (Cystophora, Sargassum, or Ecklonia), or alternatively a lower density mixed assemblage (Variable Low Abundance, VLA). Macroalgal community structure appeared to be driven by biotic interactions at small scales (metres), such that patches comprised of different species of algae in high density states rarely abutted one another. Instead, VLA assemblages frequently formed a buffer being situated between these mono generic patches. In terms of successional processes, the high-density states appeared to be relatively stable whereas the VLA state, at least in some systems, was transitory. This finding was supported by the absence of intermediary high- density states (e.g. a mix of Cystophora and Ecklonia) implying that state changes must occur via the VLA state following some form of disturbance. Larger scale patterns appeared to be driven by environmental variation, with factors such as wave exposure influencing habitat suitability for individual species and thereby affecting community composition. These phenomena were examined in terms of life history strategies that tend to promote stability, and which are common in late successional taxa. The importance of properties enhancing stability and the role of disturbance was investigated experimentally using a dispersed sediment plume, which entirely engulfed two reefs, as a pulse impact. This disturbance was of particular relevance given that degradation of macroalgal communities in close proximity to the City of Adelaide has been, at least in part, attributed to the effects of elevated levels of sediment. Follow up surveys revealed that the sedimentation from the plume had primarily affected newly recruiting individuals, with few juveniles surviving to one year of age. Over the following few years, the effect of this recruitment failure cascaded into the adult stand. In broader terms, unfavourable climatic conditions prior to the start of the study, including a particularly severe El Nino event, had a widespread effect on local assemblages, causing high levels of both adult and juvenile mortality. As such, at the commencement of the study, macroalgal communities across the study area were in the process of recovery. This was observed at control sites over the duration of the study. In contrast, recruitment failure at the sediment-affected sites retarded the recovery process, exacerbating the problems associated with prior unfavourable climatic events and leaving them in a degraded state. This study demonstrated that macroalgal assemblages are equipped (under natural conditions) to handle 'normal' environmental fluctuations (such as inter-annual variability). However, the additional stress associated with certain anthropogenic impacts has the potential to push them over the limit, causing degradation. The loss of canopy macroalgae reduces the structural complexity of the system, leading to a concomitant reduction in their ability to recover. As such, these findings are of particular relevance to those charged with the responsibility for managing near-shore marine environments. The plume was created accidentally during a dredging operation for beach sand replenishment of Adelaide's eroding shoreline. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2004.