In the past, researchers would study tropical-reef response to single events – such as a hurricane, tropical cyclone, or coral bleaching – to evaluate its ability to bounce back.
“People wrote about these as one-off events,” explains Dr. Hughes, a professor at James Cook University in Townsville. “But on longer time frames – from decades to centuries – those are recurrent events. We’re now asking: How can this system, on a scale of thousands of kilometers, absorb recurring disturbances without going belly-up? Resilience is about the system absorbing changes” and conservation managers “being proactive in anticipating them.”
Scott Wooldridge is developing a “state of the reef” computer model at AIMS that will allow conservation managers to rank the resilience potential for different reefs or reef segments. The model has the potential for use worldwide. So far, he’s included three elements: adequate levels of grazing fish on the reef to keep algae at bay, water quality, and increased heat- tolerance among coral – which he acknowledges is the weakest link in the chain in terms of biological research.
The model points to some disturbing results. Australia – and specifically, the Great Barrier Reef Marine Park Authority – may have chosen the wrong approach when it set up its no-take areas, he says.
His preliminary results suggest that the northern third of the reef probably should get the most conservation attention. The park agency, by contrast, set aside ecologically representative areas scattered throughout the reef. That made sense at the time, Dr. Wooldridge says, given what scientists then knew. But the northern segment is more pristine and faces fewer stresses because fewer people live and visit there. While it will likely feel the bleaching effects of climate change more strongly at first than reef sections farther south, it still stands a good chance of surviving. Thus it will be able to provide the larvae that will ride prevailing currents south to reseed portions of the reef that are under greater multiple stresses.
It’s a controversial notion, Wooldridge acknowledges, and calls into question the strategy over which the government spent so much time and political capital.
“With proper management, you can still have a viable reef by 2050,” he says. “But the implications are that we need to conserve more in the north.”