September 2, 2013
Saving Coral Reefs By Shocking Them Back To Life
Brett Smith for redOrbit.com - Your Universe Online
Major weather events can shock an ecosystem, but they are also part of Earth’s natural cycle, and many species are adept at recovering from an environmental shake up.
Previous studies have suggested that 70 percent of the Earth’s coral reefs are somewhat degraded – giving lead author of the report Nick Graham a sense of urgency surrounding the conservation of these ecosystems.
“We are unlikely to be able to keep many of the world’s reefs in a pristine state, but with good management we may be able to maintain them in a coral-dominated condition and in some cases we may be able to bring back reefs from a degraded state,” said Graham, a research fellow at James Cook University in Australia.
The study researchers cited desertified landscape that can develop widespread regrowth of natural vegetation following extraordinary rainfall and controls on animal grazing. The team said that coral reef custodians could take advantage of shocks to their ecosystems, such as tropical storms, to foster coral cover on depleted reefs.
“Normally we think of these shocks as damaging to coral reefs – but research suggests they are just as damaging to the organisms that can replace coral,” the researchers said in a statement. “In other words, they may act as a circuit-breaker that allows corals to regain control of a reef.”
The key to this somewhat different approach to reef conservation is the resilience of corals themselves. Healthy reefs are naturally resilient to weather-related shocks, but damaged reefs may be overrun with sea weeds that wipe out corals.
“Weed-dominated systems are pretty resilient too and, once established, it is very hard to restore the corals,” Graham said. “However a weed-dominated reef can be damaged by big storms too. Cloudy weather and seasonal changes in water temperature can also cause the weeds to die back."
“This dieback of weeds opens a window through which corals can re-establish,” he added.
The Aussie ecologist said reducing human impacts on reefs through regulation is a major first step in not only bringing corals back, but also in preventing reef loss in the first place. Reefs minimally impacted by human activity are best suited to bounce back from a traumatic event.
“Until now, the focus has mainly been on conserving small parts of a reef in marine protected areas,” said co-author David Bellwood, a marine biology professor at James Cook. “We’re talking about broader approaches to change the relationship between humans and coral reefs to reduce human impacts across the whole ecosystem.”
“Although the composition of coral reefs will likely continue to vary over time, it may be possible to maintain coral-dominated reefs and their associated ecosystem goods and services,” the paper concluded. “Scientists and managers could take advantage of opportunities for change by harnessing shocks and natural variability as potential stimuli for beneficial shifts in ecosystem states.”