(Can marine reserves / sanctuaries help fight the impacts of climate change on coral reefs)
The summer of 2016 will be remembered by ocean lovers and marine scientists as the year that the world’s colourful coral reefs turned skeletal white on an unprecedented scale. It could also be a turning point in how we view the role of protected areas in the future of our oceans.
Over the past month evidence has slowly emerged showing mass devastation of coral reefs that has been caused by a monster El Nino weather event combined with unprecedented ocean temperatures linked to global climate change. In Australia bleaching occurred on over ninety percent of reefs on the mighty Great Barrier Reef and similar figures were recorded off Western Australia’s diverse Pilbara Coast. Even the robust corals of the Kimberley were hit, with bleaching recorded throughout the southern Kimberley, although the remote North may have escaped for now thanks to favourable ocean currents.
This mass bleaching should act as yet another dead canary in the coal mine, warning us to accelerate the change to less polluting energy sources. The shift to renewable energies must happen fast for there to be any hope of saving many reefs. But given some climate change is already locked in, what else can we do to help save our coral reefs and the wildlife, livelihoods and industries they support?
Fortunately, this summer there was also some good news. Just as the scale of the unprecedented coral bleaching was beginning to sink in, some researchers from the Great Barrier Reef published a new study that highlighted how marine reserves were helping coral reefs to resist a range of disturbances including bleaching, and to recover more quickly from damage.
It is well documented that within marine reserves (also known as sanctuary zones or green zones) there is on average a significant increase in the size, population and diversity of marine life. However, this study also found new evidence that these sanctuary areas also provide resilience against other threats. The authors found that across a range of disturbance factors, including bleaching, the impact was reduced by 38% for fish and by 25% for corals compared with unprotected reefs. In addition the reefs recovered faster, for example taking six years rather than nine to recover from a crown of thorns starfish outbreak.
It seems that the corals and fish in the ecosystem help to protect each other from harm and recover from damage.
For a long time climate change has been an outlier in debates on marine reserves. This emerging research on the benefits of habitat resilience means that our changing climate is yet another driver for the establishment of new marine reserves alongside biodiversity conservation and science. As the scientists who published this study said, “No-take marine reserves host not only more and bigger fishes, but more resilient communities that might decline at slower rates.”
Coral bleaching is the most dramatic of a number of symptoms of climate change in our oceans. In Australia, many species are already moving south changing the nature of reefs and other habitats that have been relatively stable for thousands of years. Overall, our oceans and fisheries are becoming increasingly volatile and vulnerable. This bodes badly for ocean wildlife and people who depend on it, particularly the large number of fully and overexploited fisheries that are still pushing stocks to the limits based on historical assumptions about ocean productivity. It may even be an issue for those fisheries considered well managed that may not be able to keep up with rapid change in the environment that supports them.
Increasing the resilience of our ocean ecosystems, and particularly our coral reefs, is an essential part of responding to the threats of climate change. A range of strategies are useful, but at the heart of this response there needs to be an accelerated expansion of marine reserves. This will help to ensure that our marine biodiversity is on the best possible footing to deal with the changes that are already occurring in our oceans.
Fortunately the link between marine reserves and coral reef resilience has already been recognized by Western Australia’s Environment Minister Albert Jacob. In his comments on the discovery that corals were bleaching in the Kimberley, he pointed to the Government’s plans for marine parks in the region as one response that can be employed in the fight to protect reefs as our climate changes. Hopefully other Environment Ministers around Australia will follow suit and lead the way in the creation of new marine reserves whilst also addressing the causes of climate change.
We now need to accelerate efforts to protect key habitats and to create a broader reserve network in our oceans, starting with world class protection for the Kimberley Coast and by restoring the marine sanctuary network in Australia’s Commonwealth waters. Other key areas such as Western Australia’s South Coast biodiversity hotspot also need urgent attention.