Coral reefs are in decline, but their collapse can still be avoided with local and global action. That’s according to findings reported in the Cell Press journal Current Biology on May 9th based on an analysis that combines the latest science on reef dynamics with the latest climate models.
“People benefit by reefs having a complex structure – a little like a Manhattan skyline but underwater,” said Peter Mumby of The University of Queensland and University of Exeter. “Coral reefs provide nooks and crannies for thousands of species and provide the habitat needed to sustain productive reef fisheries. They’re also great fun to visit as a snorkeler or diver. If we carry on the way we have been, the ability of reefs to provide benefits to people will seriously decline.”
The researchers drew on hundreds of scientific studies to develop computer models of Caribbean reefs. Mumby explains, “Reefs are mostly built by living coral but the limestone structures they build are naturally eroded by other animals and plants, such as sponges. In a healthy ecosystem, reefs grow faster than they erode and the reef is able to provide habitat for thousands of fish and to support fisheries. However, human impacts including pollution, overfishing of parrotfishes, and climate change tip the balance towards erosion, meaning that the reef habitat could erode away leaving a flat, barren habitat in its place”.
The research team, including scientists from Australia, Mexico, the UK, Israel, the USA, and Germany, investigated whether it was possible for Caribbean reefs to ‘keep growing’ for the next 70 years. Professor Roberto Iglesias-Prieto, of the Universidad Nacional Autonoma de Mexico, states, “We were relieved to find that it is possible to maintain reefs but it requires countries to take the management of their reefs seriously and global action to address climate change”. Mumby elaborates, “Some people have felt that coral reef management might be futile given the problems posed by climate change, such as coral bleaching. But our research reveals that control of fishing and pollution is essential to maintain reefs and that it can have a very meaningful impact.”
Mumby and his colleagues also stress the importance of reef function in addition to reef diversity. Those functions of reefs include the provision of habitat for fisheries, the provision of a natural breakwater to reduce the size of waves reaching the shore, and so on. In very practical terms, hundreds of millions of people depend directly on reefs for their food, livelihoods, and even building materials. “If people are to continue being able to fish, snorkel, and attract tourists to reefs then they have to take great care of the ecosystem”, said Emma Kennedy, a PhD student that developed the models at the University of Exeter.
The research took place in the Caribbean under the EU-funded project Future of Reefs in a Changing Environment (FORCE, www.force-project.eu).