Rare corals breed their way out ...( Rare corals may be smarter than we t...)

Rare corals may be smarter than we thought. Faced with a dire shortage of mates of their own kind, new research suggests they may be able to cross-breed with certain other coral species to breed themselves out of a one-way trip to extinction.

This finding, released by scientists at the ARC Centre of Excellence for Coral Reef Studies, has raised hopes for the ability of the world's corals to withstand the rigors of changing climates and human impacts, says lead author Zoe Richards.

"Coral reefs worldwide face a variety of marine and land-based threats and hundreds of corals are now on the red list of threatened species. It is often assumed that rare coral species face higher risks of extinction than common species because they have very small effective population sizes, which implies that they may have limited genetic diversity and high levels of inbreeding and therefore be unable to adapt to changing conditions," Zoe says.

"When we studied some particularly rare species of Acropora (staghorn corals), which you might expect to be highly vulnerable to extinction, we found some of them were actually hybrids in other words they had cross-bred with other Acropora species. This breaks all the traditional rules about what a species is." By hybridising with other species, these rare corals draw on genetic variation in other species, increasing their own potential to adapt to changing conditions.

"At this stage how it came about and who the breeding partners are isn't entirely clear, but what is evident is that rare corals previously thought vulnerable to extinction may have more ability to adapt than initally expected" she explains.

Acropora are the main reef-builders throughout the Indian and Pacific Oceans, and so of critical importance to the ability of reefs to cope with changing conditions. However, till now, very few clear cut examples of hybridisiation were known, and some people did not even accept that corals can
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