Corals right out on the exposed edges of the world鈥檚 great coral reef zones may hold an important clue to the survival of coral ecosystems facing intensifying pressure from human activities and climate change.
In a paper in the international journal Science, researchers Professor John Pandolfi of the ARC Centre of Excellence for Coral Reef Studies and 宅男导航, and Professor Ann Budd of the University of Iowa have released new evidence showing that the evolutionary action on coral reefs is not in their 鈥榟ot spots鈥� 鈥� but out on the fringes, where corals struggle to survive.
Their trailblazing research is calling for a re-think about how to protect corals and other at-risk species under climate change.
鈥淲e think we may have to pay just as much attention to protecting the edges of the ranges of coral species, where corals are fewer and less diverse, as we are currently paying to the places of rich coral biodiversity,鈥� Professor Pandolfi says.
鈥淭here are two main reasons.
"First, this appears to be where corals are evolving most quickly, giving rise to new species, in response to all the challenges they encounter, and where they appear to hybridize with one another most readily, potentially as a survival tactic.
鈥淎nd second, it is on the edges of their ranges that the corals are likely to encounter significant impacts from climate change 鈥� and hence, where we need to act to protect them.鈥�
In their research Professor Pandolfi and Professor Budd have pioneered a new approach to assessing the conservation significance of a population of species 鈥� not simply looking at how many species are present, but also the rate of evolution going on among them.
鈥淓volution is the key to survival for life on Earth, and we feel it makes good sense to assess an area or ecosystem by its evolutionary potential rather than just the number of species it holds,鈥� he said.
鈥淚n terms of species richness, these fringe areas can鈥檛 compete with the spectacular hotspots of biodiversity which we normally protect with Marine Parks and other important measures.
"But in terms of evolutionary innovation, our work suggests they can be way out in front.鈥�
The researchers argue that there is a need to anticipate the evolutionary potential of populations at the edge of their inhabited ranges when considering likely effects of climate change on the species.
鈥淵ou鈥檇 really hate to lose the populations that are really showing high levels of adaptation and change,鈥� Professor Pandolfi said.
In order to compare the rates of evolution in corals, the team studied existing and fossil corals, going back for several hundreds of thousands of years, collected across the Caribbean.
鈥淥ne thing we noticed was that not only speciation but also hybridization 鈥� inter-breeding among coral species 鈥� was going on at the edges much more than in the heart of their range.
"Both mechanisms are ways that the rate of coral evolution speeds up and generates evolutionary novelty over time, in order to cope with the more hostile conditions the corals encounter on the fringes of their distributions,鈥� Professor Budd said.
鈥淥ur data suggest that species edge zones play an important role in evolutionary innovation,鈥� the researchers said.
鈥淎s such, we believe that species edge zones and peripheral areas, together with population connectivity, should play a prominent role in the future design (number, placement, size) of marine reserves.鈥�
Their paper 鈥淓volutionary novelty is concentrated at the edge of coral species distributions鈥� by Ann F. Budd and John M. Pandolfi, is published in the current issue of Science, June 18, 2010.
More information:
Professor John Pandolfi, COECRS and 宅男导航, +61 (0)7 3365 3050 or +61 (0)400 982 301.
Professor Ann Budd, The University of Iowa, +1 518 963 8832 or +1 319 538 7183.
Jenny Lappin, CoECRS, 07 4781 4222
Jan King, 宅男导航 Communications Manager, +61 (0)7 3365 1120
