The largest ever study into coral in the Caribbean reveals dramatic declines in reefs but says simple steps can be made to restore them to health
With only about one-sixth of the original coral cover left, most Caribbean coral reefs may disappear in the next 20 years, primarily due to the loss of grazers in the region, according to the latest report by the Global Coral Reef Monitoring Network (GCRMN), the International Union for Conservation of Nature (IUCN) and the United Nations Environment Programme (UNEP).
The report, Status and Trends of Caribbean Coral Reefs: 1970-2012, is the most detailed and comprehensive study of its kind published to date - the result of the work of 90 experts over the course of three years. It contains the analysis of more than 35,000 surveys conducted at 90 Caribbean locations since 1970, including studies of corals, seaweeds, grazing sea urchins and fish.
The results show that the Caribbean corals have declined by more than 50 per cent since the 1970s. But according to the authors, restoring parrotfish populations and improving other management strategies, such as protection from overfishing and excessive coastal pollution, could help the reefs recover and make them more resilient to future climate change impacts.
‘The rate at which the Caribbean corals have been declining is truly alarming," says Carl Gustaf Lundin, Director of IUCN's Global Marine and Polar Programme. ‘But this study brings some very encouraging news: the fate of Caribbean corals is not beyond our control and there are some very concrete steps that we can take to help them recover.’
Climate change has long been thought to be the main culprit in coral degradation. While it does pose a serious threat by making oceans more acidic and causing coral bleaching, the report shows that the loss of parrotfish and sea urchin - the area's two main grazers - has, in fact, been the key driver of coral decline in the region. An unidentified disease led to a mass mortality of the sea urchin in 1983 and extreme fishing throughout the 20th century has brought the parrotfish population to the brink of extinction in some regions. The loss of these species breaks the delicate balance of coral ecosystems and allows algae, on which they feed, to smother the reefs.
Reefs protected from overfishing, as well as other threats such as excessive coastal pollution, tourism and coastal development, are more resilient to pressures from climate change, according to the authors.
‘Even if we could somehow make climate change disappear tomorrow, these reefs would continue their decline,’ says Jeremy Jackson, lead author of the report and IUCN's senior advisor on coral reefs. ‘We must immediately address the grazing problem for the reefs to stand any chance of surviving future climate shifts.’
Key findings of the report:
* There has been a dramatic decline in Caribbean corals of more than 50 per cent since the 1970s. The decline is not uniform and correlates only weakly with local extreme heating events, instead being mainly attributed to the severity of local stressors, in particular tourism, overfishing and pollution.
* While climate change has badly affected Caribbean corals and continues to be a major threat, well-managed reefs have bounced back suggesting that climate change is not the main determinant of current Caribbean coral health and that good management practices can save larger areas of reef if tough choices are made.
* Loss of the two main grazers, parrotfish and sea urchin, has been a key driver of coral decline in the region as it breaks the delicate balance of coral ecosystems and allows algae to smother reefs
* The massive outbreak of coral diseases and mass die-off of sea urchin close to the Panama Canal suggest that the order-of-magnitude increase in bulk shipping in the 1960s and 1970s has introduced pathogens and invasive species that have since spread in the Caribbean.
* Adopt conservation and fisheries management strategies that lead to the restoration of parrotfish populations and so restore the balance between algae and coral that characterises healthy coral reefs;
* Maximise the effect of those management strategies by incorporating necessary resources for outreach, compliance, enforcement and the examination of alternative livelihoods for those that may be affected by restrictions on the take of parrotfish;
* Consider listing the parrotfish in the Annex II and III of the SPAW Protocol (The Protocol Concerning Specially Protected Areas and Wildlife) in addition to highlighting the issue of reef herbivory in relevant Caribbean fisheries fora;
* Engage with indigenous and local communities and other stakeholders to communicate the benefits of such strategies for coral reef ecosystems, the replenishment of fisheries stocks and communities' economy.
To see an Executive Summary and full report, Status and Trends of Caribbean Coral Reefs: 1970-2012: http://bit.ly/1puLHlp
The Global Coral Reef Monitoring Network (GCRMN) was established in 1994 to support the global call for action of the International Coral Reef Initiative (ICRI) to commit to increasing research and monitoring of coral reefs in order to provide the data needed to inform policy makers to sustain coral reefs and to strengthen management. Today, the GCRMN works through a global network of stakeholders to support the management and conservation of coral reefs. The work of GCRMN focuses on increasing the scientific understanding of the status and trends of coral reef ecosystems worldwide by making reef monitoring data publicly available, linking people and existing organizations, improving the communication among GCRMN members by providing information on network activities in order to strengthen the existing capacity across regions to manage coral reefs more efficiently while adapting to the effects of climate change.