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Coral Reefs (1995) 14:17%181 Coral Reels 9 Springer-Verlag 1995 Perspective Science and management of coral reefs: problems and prospects S. M. Wells UNDP/GEF Coastal Zone Management Project, P.O. Box 1884,BelizeCity, Belize,Central America Accepted: 27 June 1995 Introduction The role of science in the management of natural resources has been discussed in a number of recent publications (Bernal and Holligan 1992; Ehrlich and Dailey 1993; Healey and Hennessey 1994; Levin 1993; Ludwig et al. 1993; Williams 1994) and research priorities have been hotly debated among reef scientists. Opinions span a continuum of views between two extremes. On the one hand, some scientists, such as Ludwig et al. (1993), have suggested that research is of little relevance to people dependent on scarce resources, particularly in crowded developing countries, and that the main constraints to successful management are political and socio-economic. Conversely, as Wilkinson (1993) has pointed out, others feel that more research is necessary before appropriate strategies and policies can be fully developed and refined. At the base of many of these opinions is the growing concern among both scientists and managers that, despite an increase in scientific knowledge, there appear to be many more management failures than successes. Part of the problem is the long-standing dichotomy between pure (or academic) research and applied research, a dichotomy that is not restricted to reef science (Harmon 1994). Increasingly, however, the boundaries between these are blurred with pure research leading to the development and testing of methods and hypotheses that are subsequently used by applied scientists to provide information for management. Nevertheless, there may be a conflict with the manager. The fundamental scientific principle that no hypothesis is ever absolutely proven frequently conflicts with the manager's need for clear and conclusive results with which to justify his or her actions. Scientists and managers tend to work at different confidence levels; scientists require a confidence level of 95-99%, whereas 70-80% may be perfectly adequate for managers, given financial and time constraints (Wilkinson 1993). Despite these obstacles, few people would contest the notion that many aspects of sound reef management are based on research, whether applied or pure, and that numerous existing research programmes have important management applications for the future. Scientific studies over the last few decades have identified the major factors that can induce change in coral reefs (e.g. reviews by Hatcher et al. 1989; Grigg and Dollar 1991; Richmond 1993; Sebens 1994). There is fairly widespread consensus that the impacts causing greatest degradation are human-induced activities that result in nutrification, over-exploitation and sedimentation, as well as ENSO warming events and storm-induced waves (Ginsburg 1994). Studies on natural hazards, sea level change and climate change on coral reefs, and the development of techniques such as sclerochronology, have been central in providing managers and policy makers with an understanding of the geological history of reefs and their responses over time (Buddemeier 1993), which is essential to the development of appropriate management strategies. The current focus on integrated coastal zone management in the tropics has been in part stimulated by research on the impacts of sediments (Rogers 1990), nutrients (Tomascik and Sander 1985; Maragos et al. 1985), and land-based sources of pollution on corals. Research on the relationships between corals and their zooxanthellae, on the role of nitrogen and phosphorus in calcification, and on other aspects of coral growth and physiology (Kinsey and Davies 1979; Belda et al. 1993) is fine-tuning this knowledge. The technology necessary to halt many of these impacts is now largely available as a result of such findings, even if its use is often hampered by lack of trained and experienced personnel and funding: examples include engineering techniques that minimize run-offand siltation, and sewage disposal methods that reduce nutrient enrichment, such as dry composting toilets and open ocean deep outfalls. Although the division between pure and applied research is particularly evident in the field of fisheries science, research on the nature and diversity of reef resources has been instrumental in helping managers to recognise that the traditional single species approach is not 178 appropriate. Recent research has provided evidence that marine sanctuaries in which fishing is prohibited can play a major role in reef fisheries management (e.g. Polunin and Roberts 1993; Russ et al. 1993; Watson and Ormond 1994). Demonstrations of the robust and dynamic nature of some reef communities have helped to show that under certain circumstances reef restoration may be feasible (e.g. Guzman 1991; Clark and Edwards 1993), a concept that a few years ago might not even have been considered. Scientists have also been responsible for the development of surveying and monitoring methods that are being applied in management programmes, and have led the search for common methodologies that can be used on a worldwide scale. The involvement of social scientists in reef research has also led to greater attention being paid to economic issues (e.g. Hodgson and Dixon 1988), and to new approaches to reef management, such as community participation (e.g. White et al. 1994). Perhaps of greatest importance is the role that reef scientists have played and continue to play in education and training, providing future generations with the knowledge and skills to carry out good management or appropriate research. Current research priorities for management Reef research priorities have been discussed at many meetings, both scientific and management, in recent years including those convened by the European Union (Davies et al. 1992), the International Center for Living Aquatic Resources Management (ICLARM) (Munro and Munro 1994), the 4th World Congress on National Parks and Protected Areas (Wells 1994), the International Council of Scientific Unions (ICSU) / Scientific Committee on Problems of the Environment (SCOPE) (Done et al. in press) and the International Coral Reef Initiative (ICRI 1995). Jeremy Woodley's 1988 conclusion that "explanations lag behind the events, and we are a long way from prediction or control" is apposite. Both prediction and control are essential for good management, and research directed at providing the necessary knowledge is still a high priority. Science can help to reduce uncertainty in the outcome of management actions and improve the range and selection of management approaches. Increasing basic knowledge Good management decisions require sound scientific data, providing information on what to manage, for what purpose, and in what order or priority. The various regional and international databases, such as ICLARM's ReefBase, are already revealing the extent to which baseline information is lacking. A ranking of priority sites for reef (and other habitat) conservation has long been in demand by aid agencies and conservation bodies, at national, regional and international levels, but efforts towards this have been hampered by the poor information base. Internationally recognised criteria have been drawn up for the selection of protected areas, but using them objectively is often impossible because of the lack of data on parameters such as diversity, endemism, representativeness, or uniqueness. Reliable estimates of species diversity in the marine environment are not yet available, and the concept of prioritising 'hotspots' of high diversity, an approach used in the terrestrial environment (e.g. Pressey et al. 1993), may not be suitable. The reefs of South-east Asia have the highest species diversity, but it would clearly not be appropriate to focus all reef management efforts in this part of the world. Part of the solution is further descriptive research to determine the biota of reefs and their adjacent habitats. Such information is basic to both pure and applied science and it is unfortunate that taxonomic work and the preparation of inventories are currently often ranked low in the hierarchy of research topics for funding and support. Programmes such as Systematics Agenda 2000, which has the ambitious objectives of discovering, describing and classifying the world's species, have been proposed to counteract this attitude. Further work is needed on the interactions between reefs, mangroves and seagrasses, how sediments are buffered, and the movements of organisms between these interlinked habitats. Integrated coastal zone management is now a guiding principle, but a full understanding of the dynamics and interlinkages within the coastal zone is still lacking. The current interest in biodiversity and its role in ecosystem function may also stimulate relevant studies. Great geographical variety has been found in the structure of reef communities, with steep gradients in species diversity both latitudinally and longitudinally, but it is not clear how this affects the functioning of reefs. Although species diversity is much lower in, for example, French Polynesia and Hawaii than in Southeast Asia and the West Pacific (even to the extent of a total absence of certain taxa such as crinoids), thriving reefs still exist. Similarly there is little evidence that net calcification rates differ significantly on reefs having widely different numbers of coral species; and the relationship between productivity and biodiversity is similarly poorly understood (Done et al. in press). At the same time, loss of certain reef species, such as those primarily responsible for calcification or controlling algal cover, can have a major impact on reef health and functioning. A greater understanding of these keystone species, which include urchins, herbivores and certain predators, is essential, so that management can be directed towards safeguarding the critical ecological processes that are necessary for the growth and health of reefs (Agardy 1994). One process which is clearly crucial is dispersal and recruitment of reef organisms. Very little is known about source areas for larvae and whether some reefs act as 'stepping stones' for species dispersal. If reefs do not reseed themselves, larval dispersal needs to be tracked so that reefs 'up-stream' can be identified and protected as appropriate, and reefs down-stream can be considered in the light of the fact that they may need replenishment from elsewhere. Linked to this is the need for further research on the population genetics of reef organisms to determine their origins and the spatial boundaries of populations. For example, recent work on giant clams suggests that there may be three distinct genetic populations for each 179 species within the Pacific and that conservation measures will need to address each population (Benzie 1992). The genetics of corals and their zooxanthellae has scarcely been touched upon, but an understanding of this may be essential to interpreting the susceptibility of corals to bleaching and a whole range of stressors. New molecular and genetic techniques that are becoming increasingly available may mean that rapid progress can be made on this front (Buddemeier and Fautin 1993). Management priorities for individual species are often dictated by their economic importance, which has tended to mean that most attention has been directed towards those that are commercially valuable and that are, or at least in past have been, abundant. However, further work is also needed on the role of rare species which may not appear to have ecological importance on the reef. Veron (1992) and McAllister et al. (1994) have shown that many coral and fish species may be 'rarer' and have more localised distributions than previously thought, and Carlton (1993) suggests that extinctions of rare species in the marine environment can easily be over-looked. Better evidence for environmental change and its causes and consequences Many uncertainties are involved in the interpretation of the history of a reef and in the prediction o fits future. Data showing how both natural events and human activities affect the health of a reef is vital for the reef manager for several reasons. 1. If the cause of change on a reef is not known, finding the correct management solution is difficult. If changes are due to 'natural events' the management approach will be different from that used if the cause is human-induced and can therefore be reversed by changing people's behaviour. In practice, many changes are due to a combination of factors which further complicates the management approach. 2. Environmental lmpact Assessments (EIAs), damage mitigation and insurance cases increasingly require 'proof that a reef has been or will be damaged through a certain impact. EIAs, now a legal requirement before any development in many countries, need good science and accessible data. 3. Good scientific data are important to convince policy makers, funding agencies, and society in general that management is necessary. If the observed changes are of no particular consequence, either ecologically or economically, it may not be worth putting time and money into management. Finding the cause of change on a reef is often only possible through longterm monitoring or ecological research studies, such as the work carried out since the 1970s on the Jamaican reefs by Hughes (1994). Hughes showed that reef decline was the result of the combined impact of overfishing (particularly of herbivorous fish), hurricane damage and urchin disease. The management solution in this case would be to increase populations of herbivorous fish and/or urchins which would allow coral recruitment to increase. This could be achieved by controlling overfishing, or through a more interventionist approach such as restocking. Certain types of impact are still poorly understood, often because their effects are unpredictable. For example, oil spills sometimes have serious longterm effects on coral communities and reef growth (Guzman et al. 1994), but in other cases there may not appear to be any significant damage (Downing and Roberts 1993; Vogt, this issue). If oil spill contingency planning is to be successful and costeffective, better knowledge of these issues is required. Similarly the impacts of chemical pollution, heavy metals and other such pollutants need further study. A better understanding of how much use or disturbance a reef can sustain before major changes occur would also contribute to better management. The 'carrying capacity' of a reef (and any other ecosystem) would seem to be a useful concept but has proved difficult to measure; it is generally easier to see where carrying capacity has been exceeded, and a reef has declined beyond the limits of acceptable change, than to identify the point where optimum use is being made. Studies on the physiological tolerance to pollutants and sediments are urgently required for common species at different life stages. Also needed is the development of methodologies for the assessment of reef 'health', such as the identification of appropriate bioindicators and bioassay procedures that will assess sublethal effects. In particular, there is a need to know how settlement and recruitment are affected by pollutants. Such information will help show changes in reef condition at a sufficiently early stage for managers to take corrective action. It will provide information on the long term dynamics of a reef and whether its regeneration will occur in a time scale relevant to society (Brown and Howard 1985). Advocacy for better reef management still lacks good information that will convince policy and decision makers. It is now clear that although the main causes of damage to reefs are relatively well known, information on the global extent of reef degradation is still very poor (Ginsburg 1994). Broad scale rapid ecological assessments, combined with monitoring programmes, are essential before such information can be gathered. Ideally, assessments should be more than snapshots in time but also take into account the recent past history of a given reef (Grigg, this issue). If the methods are appropriately designed, this type of programme will go a long way towards answering questions such as which reefs are still relatively unimpacted and whether some reefs are more vulnerable than others. Well-presented scientific documentation of impacts, which predict the course events could take and indicate methods of control, are also essential, DawsonShepherd et al. (1992; 1994) illustrate how this can be achieved in the context of an evaluation of the impact of coral mining in the Maldives. Development of more science-based management procedures and of methods to evaluate their effectiveness Several aspects of reef management could benefit from advice and input from scientists. For example, although 180 the scientific rationale for marine reserves is now being studied (e.g. Polunin and Roberts 1993; Roberts and Polunin 1993), many questions remain unanswered. Information is still needed on optimum and minimum sizes, shape, and location (particularly in relation to ocean currents and the dispersal patterns of species) of protected areas, on the effectiveness of core, buffer and other zoning strategies, on seasonal or rotational harvesting closures, and on the effectiveness of protected areas in promoting the recovery of depleted reef resources and restoration of habitat. This will require detailed studies on the population dynamics of species within the protected area, including rates and direction of movement of different life stages across the boundaries, as well as on human activities within the area. The high species diversity and spatial heterogeneity of reef fisheries suggest that they require different management approaches from those used in other fisheries. Research on reef fish is still largely concerned with understanding qualitative patterns (such as the role of recruitment in determining the distribution of a species), rather than on obtaining quantitative information about ecological processes that could be incorporated into stock assessments and models. Furthermore, many fish ecologists have focused on the small, easily observed, less mobile species such as damselfish, whose behaviour and ecology often differ greatly from that of commercial species (Medley et al. 1993). With the exceptions of a few species such as spiny lobsters and giant clams, research directed at understanding the impact of exploitation of reef invertebrates is particularly sparse (Jamieson 1993). For example, few data are available on which to base strategies for coral harvesting and it is a controversial issue as to what extent corals can be exploited and still fulfil their ecological functions on a reef (Wells et al. 1994). In addition to further work on reproductive biology, population dynamics and genetics of commercially important species, a more manipulative and experimental approach to fisheries research has also been advocated (Medley et al. 1993). The concept of adaptive management, which has recently been promoted particularly in the context of fisheries management (Ludwig et al. 1993; Medley et al. 1993), provides a good framework in which scientists and managers can work together. This requires the setting up of management measures in such a way that their efficacy can be objectively tested through experiment, and the creation and maintenance of a feedback loop between the scientist and the manager, so that measures and goals can be revised according to new information about environmental and social changes. There are many instances of management actions providing natural 'experiments', or scientific research leading to recommendations that could be tested in a management setting. Greater advantage should be taken of these opportunities. For example, work by Grigg et al. (1984) in French Frigate Shoals suggested that, to achieve greater yield, reefs could be harvested at lower levels in the food chain, or that the top predators could be cropped to release predator-pressure on selected prey. These recommendations have not been tested, although some studies show that loss of certain predators on a reef may lead to deleterious shifts in reef community resulting in loss of productivity (Roberts in press). Similarly, there are few scientific studies evaluating the success of management measures. There is an important role for researchers in testing different approaches and techniques, particularly where there may be a choice between various options. Measurements of the 'success' of particular management strategies would involve a number of parameters such as changes in reef condition, reef resource abundance and yields, and the income and quality of life of people dependent on reefs. Such critical appraisals would provide guidelines and feedback for future management, and a better understanding of how management affects the direction and processes of natural change. Conclusion It should be recognised that many principles of reef management do not need further research, as they involve changing human behaviour and activities in order to remove or reduce impacts on reefs. Much of the time of a reef manager is taken up with social, economic and political issues: the integration of reef management into broad coastal zone management objectives; the development of community participation and co-management; and the organisation of training and education pro-grammes so that people in countries where reefs are located are able to take responsibility for their sustainable management. Perhaps the main obstacle to be overcome is poor communication (Harmon 1994). Many reef scientists are already strongly convinced of the need to communicate their results and the implications of these for management and conservation policy (Hatcher et al. 1989), but they may however need to understand that reef managers are not always able or willing to act on their advice because of political, economic or social factors. Pure research is increasingly being conducted within a framework of goals identified as important to society. Funding is invariably easier to obtain if it can be demonstrated that the research will have some ultimate benefit in management terms, and much research is being commissioned because of the need for practical solutions. As the complexity of management becomes more apparent and managers themselves call for more scientific support and advice, the role that science has to play in perceiving and defining problems, understanding the mechanisms involved and strategically assessing potential solutions, becomes more central. Often, only a slight adjustment to a project is required in order for data to be collected that is of direct value to a reef manager. Partnerships built between scientists and managers engaged in adaptive management efforts may lead to more rapid progress in managing reefs and may banish the 'science and management' dichotomy once and for all. Acknowledgements. 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