Three James Cook University researchers at the new ARC Centre of Excellence for Coral Reef Studies (CoECRS) have called for the worldwide networking of tropical marine parks and protected areas to limit the risk of large-scale extinctions under global change, in the light of new scientific findings.
Their research, published in the international science journal Nature today, finds evidence from sites across the Pacific Ocean to refute the “neutral theory of biodiversity”, which had been proposed as a framework for conservation
Scientist inspecting reef
“Worldwide, coral reefs are in decline – and it’s clear that current management approaches are not working,” says the study’s lead author, Ms Maria Dornelas. “We wanted to find out whether this new theory provided a way forward. So we decided to ask the corals.”
Ms Dornelas and Centre researcher Dr Sean Connolly, both of James Cook University, tested the theory’s predictions by teaming up with Centre Director Professor Terry Hughes (also from JCU), who had recently completed a huge survey of coral diversity at 180 sites spread over 10,000 kms from Sulawesi to French Polynesia.
“Not only did we find that the theory didn’t work,” says Dr Connolly, “it failed in a completely unexpected way, totally different from what critics of the neutral theory had been expecting. By looking closely at how and why the theory failed, we gained some new insights into how coral reefs sustain so many species.”
Their research has been hailed by Nature as “a paper that will turn our attention in a completely new direction”, in a commentary by Dr John Pandolfi of the University of Queensland. It “has clearly invigorated the debate over the importance of biological details in determining the co-existence of species within communities,” he says
Neutral theory argues that coral species colonise reefs in a random way, much like a lottery. However the team’s studies of living reefs revealed that location and environmental change play a critical role in determining what sorts of corals settle and flourish – and which ones fail to establish.
This has major implications for the long-term survival of corals – and for how marine conservation areas are managed, Dr Connolly says.
“Just because a particular location’s environment suits some corals’ specific strengths now, doesn’t mean that it will always be so. Corals need to disperse their offspring widely, so that when conditions change, some of their offspring are in places where the environment has become more suitable for them.”
The team likens this approach to biodiversity management to maintaining a balanced portfolio of investments on the stock market. Leaving all your money in one stock increases the risk of a mishap – a broad spread cushions the impact.
“Most marine protected areas (MPAs) around the world are too small and too isolated to preserve the links between populations on different reefs. This increases the risk that a rare group of animals could go extinct unless they can colonise a more favourable reef,” says Professor Hughes.
“The recent re-zoning of the Great Barrier Reef is a step in the right direction, but we need to see MPAs networked worldwide across national borders to help reefs cope with the large-scale environmental changes expected with global warming.”
Protected areas need to be close enough for marine life, including coral spawn, to flow freely between them, to give the corals the best chance of preserving their unique biodiversity as the environment changes, Ms Dornelas says. This will entail enlarging some areas and adding new ones in order to ensure long-term recovery from extreme conditions, such as cyclones, coral bleaching and human impacts on water quality.
The researchers paper “Coral reef diversity refutes the neutral theory of biodiversity” appears in the current issue of Nature (March 2, 2006)
The ARC Centre of Excellence for Coral Reef Studies is funded by the Australian Research Council, and includes James Cook University, The University of Queensland, The Australian National University, the Australian Institute of Marine Science and the Great Barrier Reef Marine Park Authority.
Dornelas, M, Connolly, SR and Hughes, TP (2006). “Coral reef diversity refutes the neutral theory of biodiversity.” Nature 440(7080): 80-82.
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Dr Maria Dornelas, ARC Centre of Excellence for Coral Reef Studies & JCU, +61 7 4781 5718 or 0415 042 352
Dr Sean Connolly, ARC Centre of Excellence for Coral Reef Studies & JCU, +61 7 4781 4242 or 04 3994 5081
Professor Terry Hughes, Director, ARC Centre of Excellence for Coral Reef Studies, +61 7 4781 4000
Jenny Lappin, ARC Centre of Excellence for Coral Reef Studies, +61 7 4781 4222