Recently, attempts to improve decision making in species management have focussed on uncertainties associated with modelling temporal fluctuations in populations. Reducing model uncertainty is challenging; while larger samples improve estimation of species trajectories and reduce statistical errors, they typically amplify variability in observed trajectories. In particular, traditional modelling approaches aimed at estimating population trajectories usually do not account well for nonlinearities and uncertainties associated with multi-scale observations characteristic of large spatio-temporal surveys. We present a Bayesian semi-parametric hierarchical model for simultaneously quantifying uncertainties associated with model structure and parameters, and scale-specific variability over time. We estimate uncertainty across a four-tiered spatial hierarchy of coral cover from the Great Barrier Reef. Coral variability is well described; however, our results show that, in the absence of additional model specifications, conclusions regarding coral trajectories become highly uncertain when considering multiple reefs, suggesting that management should focus more at the scale of individual reefs. The approach presented facilitates the description and estimation of population trajectories and associated uncertainties when variability cannot be attributed to specific causes and origins. We argue that our model can unlock value contained in large-scale datasets, provide guidance for understanding sources of uncertainty, and support better informed decision making.
Outbreaks of coral diseases are one of the greatest threats to reef corals in the Caribbean, yet the mechanisms that lead to coral diseases are still largely unknown. Here we examined the spatial-temporal dynamics of white-pox disease on Acropora palmata coral colonies of known genotypes. We took a Bayesian approach, using Integrated Nested Laplace Approximation algorithms, to examine which covariates influenced the presence of white-pox disease over seven years. We showed that colony size, genetic susceptibility of the coral host, and high-water temperatures were the primary tested variables that were positively associated with the presence of white-pox disease on A. palmata colonies. Our study also showed that neither distance from previously diseased individuals, nor colony location, influenced the dynamics of white-pox disease. These results suggest that white-pox disease was most likely a consequence of anomalously high water temperatures that selectively compromised the oldest colonies and the most susceptible coral genotypes.
Coral reefs and their societal benefits are in decline, chiefly due to overfishing, pollution and inappropriate coastal development. Strengthened management is possible, but collective failure to build the needed political will to act diminishes lives of millions of people along tropical coasts. Political will can be built, but it requires committed leadership and sustained investment of time and resources. Accepting failure as inevitable is inappropriate.
Coral reefs have largely declined across multiple spatial scales due to a combination of local-scale anthropogenic impacts, and due to regional-global climate change. This has resulted in a significant loss of entire coral functional groups, including western Atlantic Staghorn coral (Acropora cervicornis) biotopes, and in a net decline of coral reef ecosystem resilience, ecological functions, services and benefits. Low-tech coral farming has become one of the most important tools to help restore depleted coral reefs across the Wider Caribbean Region. We tested a community-based, low-tech coral farming approach in Culebra Island, Puerto Rico, aimed at adapting to climate change-related impacts through a two-year project to propagate A. cervicornis under two contrasting fishing management conditions, in coastal areas experimenting significant land use changes. Extreme rainfall events and recurrent tropical storms and hurricanes had major site-and method-specific impacts on project outcome, particularly in areas adjacent to deforested lands and subjected to recurrent impacts from land-based source pollution (LBSP) and runoff. Overall, coral survival rate in “A frame” units improved from 73% during 2011-2012 to 81% during 2012-2013. Coral survival rate improved to 97% in horizontal line nurseries (HLN) incorporated during 2012-2013. Percent tissue cover ranged from 86% to 91% in “A frames”, but reached 98% in HLN. Mean coral skeletal extension was 27 cm/y in “A frames” and 40 cm/y in HLN. These growth rates were up to 545% to 857% faster than previous reports from coral farms from other parts of the Caribbean, and up to 438% faster than wild colonies. Branch production and branchiness index (no. harvestable branches > 6 cm) increased by several orders of magnitude in comparison to the original colonies at the beginning of the project. Coral mortality was associated to hurricane physical impacts and sediment-laden runoff impacts associated to extreme rainfall and deforestation of adjacent lands. This raises a challenging question regarding the impact of chronic high sea surface temperature (SST), in combination with recurrent high nutrient pulses, in fostering increased coral growth at the expense of coral physiological conditions which may compromise corals resistance to disturbance. Achieving successful local management of reefs and adjacent lands is vital to maintain the sustained net production in coral farms and of reef structure, and the provision of the important ecosystem services that they provide. These measures are vital for buying time for reefs while global action on climate change is implemented. Adaptive community-based strategies are critical to strengthen institutional management efforts. But government agencies need to transparently build local trust, empower local stakeholders, and foster co-management to be fully successful. Failing to achieve that could make community-based coral reef rehabilitation more challenging, and could potentially drive rapidly declining, transient coral reefs into the slippery slope to slime.
Reef managers cannot fight global warming through mitigation at local scale, but they can use information on thermal patterns to plan for reserve networks that maximize the probability of persistence of their reef system. Here we assess previous methods for the design of reserves for climate change and present a new approach to prioritize areas for conservation that leverages the most desirable properties of previous approaches. The new method moves the science of reserve design for climate change a step forwards by: (1) recognizing the role of seasonal acclimation in increasing the limits of environmental tolerance of corals and ameliorating the bleaching response; (2) using the best proxy for acclimatization currently available; (3) including information from several bleaching events, which frequency is likely to increase in the future; (4) assessing relevant variability at country scales, where most management plans are carried out. We demonstrate the method in Honduras, where a reassessment of the marine spatial plan is in progress.
Coral cover has declined rapidly on Caribbean reefs since the early 1980s, reducing carbonate production and reef growth. Using a cross-regional dataset, we show that widespread reductions in bioerosion rates—a key carbonate cycling process—have accompanied carbonate production declines. Bioerosion by parrotfish, urchins, endolithic sponges and microendoliths collectively averages 2 G (where G = kg CaCO3 m−2 yr−1) (range 0.96–3.67 G). This rate is at least 75% lower than that reported from Caribbean reefs prior to their shift towards their present degraded state. Despite chronic overfishing, parrotfish are the dominant bioeroders, but erosion rates are reduced from averages of approximately 4 to 1.6 G. Urchin erosion rates have declined further and are functionally irrelevant to bioerosion on most reefs. These changes demonstrate a fundamental shift in Caribbean reef carbonate budget dynamics. To-date, reduced bioerosion rates have partially offset carbonate production declines, limiting the extent to which more widespread transitions to negative budget states have occurred. However, given the poor prognosis for coral recovery in the Caribbean and reported shifts to coral community states dominated by slower calcifying taxa, a continued transition from production to bioerosion-controlled budget states, which will increasingly threaten reef growth, is predicted.
Outbreaks of Acropora and Diadema diseases in the 1970s and early 1980s, overpopulation in the form of too many tourists, and overfishing are the three best predictors of the decline in Caribbean coral cover over the past 30 or more years based on the data available. Coastal pollution is undoubtedly increasingly significant but there are still too little data to tell. Increasingly warming seas pose an ominous threat but so far extreme heating events have had only localized effects and could not have been responsible for the greatest losses of Caribbean corals that had occurred throughout most of the wider Caribbean region by the early to mid 1990s.
In summary, the degradation of Caribbean reefs has unfolded in three distinct phases:
- Massive losses of Acropora since the mid 1970s to early 1980s due to WBD. These losses are unrelated to any obvious global environmental change and may have been due to introduced pathogens associated with enormous increases in ballast water discharge from bulk carrier shipping since the 1960s.
- Very large increase in macroalgal cover and decrease in coral cover at most overfished locations following the 1983 mass mortality of Diadema due to an unidentified and probably exotic pathogen. The phase shift in coral to macroalgal dominance reached a peak at most locations by the mid 1990s and has persisted throughout most of the Caribbean for 25 years. Numerous experiments provide a link between macroalgal increase and coral decline. Macroalgae reduce coral recruitment and growth, are commonly toxic, and may induce coral disease.
- Continuation of the patterns established in Phase 2 exacerbated by even greater overfishing, coastal pollution, explosions in tourism, and extreme warming events that in combination have been particularly severe in the northeastern Caribbean and Florida Keys where extreme bleaching followed by outbreaks of coral disease have caused the greatest declines.
Interrelationships Between Corals and Fisheries is derived from a workshop held by the Gulf of Mexico Fishery Management Council in Tampa, Florida in May 2013, where world authorities came together to discuss the current problems in managing tropical fisheries and offered suggestions for future directions for both researchers and environmental resource managers. This book addresses current and emerging threats as well as challenges and opportunities for managing corals and associated fisheries. It provides an information baseline toward a better understanding of how corals and the consequences of coral condition influence fish populations, especially as they relate to management of those populations.
The book contains content from presentations modified as a result of interactions and discussions with colleagues and peer reviews by global experts in corals and fisheries. Many chapters include additional materials not presented in the workshop. There are also papers that were not presented at the workshop but contribute to the central theme of the book. Topics covered include:
- Global decline in coral reefs and impacts on fishery yields
- Distribution and diversity in the Gulf of Mexico
- Implementation of Coral Habitat Areas of Particular Concern (CHAPCs)
- Deepwater coral/sponge habitats
- Coral populations on offshore platforms
- Mangrove connectivity for sustaining coral reef fisheries
- Restoring deepwater coral ecosystems and fisheries after the Deepwater Horizon oil spill
- Predictive mapping of coral reef fish
Covering a range of subject matter, most of the chapters offer suggestions for future research on the interrelationships between corals and fisheries. In addition, the final chapter presents a summary on these interrelationships and discusses managing them for the future.
A key element of the Caribbean region’s vulnerability to climate change is the threat to coral reef ecosystems. Regional Heads of Government throughout the Caribbean have recognized the important role that coral reefs play in national economies and their crucial contribution to sustainable development. Accordingly, governments, regional leaders and coastal communities have begun to take measures to address the region’s vulnerability and build resilience to climate change.
The Coral Reef Plan of Action provides a roadmap for navigating the challenges of sustainably managing coral reefs to protect biological diversity while sustaining provision of goods and services that these ecosystems provide to the people of the Caribbean.
The plan presents a set of objectives for improving the outlook for Caribbean reefs by 2018. These are the result of regional consultations that identified the priority needs expressed by regional leaders, stakeholders, officials and experts who together have accumulated the experience required for tackling the issues faced in the sustainable management of Caribbean coral reefs. The objectives are grouped under four goals:
- Improve the health and resilience of Caribbean coral reefs
- Strengthen adaptive capacity of communities
- Build foundations for national and regional action
- Advocate globally for stronger action on climate change
Investment in achieving the goals and objectives in this plan will be further guided through development of an associated implementation plan, and a program of monitoring, evaluation and reporting. With the support of the Caribbean Community Climate Change Centre, the Caribbean Regional Fisheries Mechanism will lead implementation of this plan to ensure it has the best chance of building the resilience of coral reefs to the impacts of climate variability and change in the Caribbean region.
This Coral Reef Plan of Action is aligned with relevant initiatives, sub-regional strategies and plans targeted at Caribbean coral reefs. These include the Caribbean Regional Fisheries Mechanism’s Climate Change Adaptation and Disaster Risk Management Strategy and Action Plan, the 2012 Report Card for the Mesoamerican Reef, and the Strategic Action Programme for the Sustainable Management of the Shared Living Marine Resources of the Caribbean Large Marine Ecosystems and Adjacent Regions (CLME+SAP).
The Plan supports the vision articulated in the Liliendaal Declaration and contributes to strategic elements and goals elaborated in the Regional Framework for Achieving Development Resilient to Climate Change (Regional Framework) and its associated Implementation Plan (see Appendix 1). Through an integrated approach across these strategic initiatives, the Coral Reef Plan of Action will help build regional coordination and national commitment, motivate actions and stimulate much-needed support and investment from the international community in a coordinated effort to improve the outlook for Caribbean coral reefs.
The project has produced a handbook that aims to provide reef managers with tools, information and recommendations on management of coral reef ecosystems. The handbook sections range from ecological history and biogeography, resilience as well as climate change issues to fisheries, governance and the monitoring of coral reef ecosystems.
Within each section are practical stand-alone ‘briefs’. These briefs offer concise information on particular reef-related issues, utilising some of the most recent scientific research to inform management actions. Each of the briefings is a unique grab-and-go resource. The accessible format also provides a useful resource for students, researchers, policy-makers and anyone interested in the future of Caribbean coral reefs.