The common Acropora corals occur mainly on reef crests, flats and slopes, whereas several of the rare species occupy more marginal habitats, such as the deeper or extremely shallow water zones where the common species do not grow.
"When we looked at the genetic history of rare corals, we found that they exhibited unexpected patterns of genetic diversity. This suggests that, rather than being the dying remnants of once-common species, they may actually be coral pioneers pushing into new environments and developing new traits by virtue of the interbreeding that has enabled them to survive there.
"This is good news, to the extent that it suggests that corals may have evolved genetic strategies for survival in unusual niches and may prove tougher to exterminate than many people feared. With such tricks up their sleeve, it is even possible that the rare corals of today could become the common corals of the future."
Corresponding author Professor David Miller of CoECRS and James Cook University says the discovery is a refreshing piece of good news amid the frequently gloomy reportage about corals nowadays. "One would expect that rare corals would be especially at risk, but we've found that some appear to have developed mechanisms for coping with rarity," he says.
"Hybridising with another species actually makes a lot of genetic sense if you are rare and the next colony of your species may be hundreds of kilometres away. It suggests these creatures are far more resilient that we thought, based on what we know from the behavior of land animals."
|Contact: Zoe Richards|
ARC Centre of Excellence in Coral Reef Studies