Marine researchers from Macquarie University, the Wildlife Conservation Society and other groups have compiled a worldwide map including high temperatures, ultra-violet radiation, weather systems, sedimentation, as well as stress-reducing factors such as temperature variability and tidal dynamics.
Lead author, Joseph Maina, is a doctoral student at Macquarie University. "Coral reefs around the globe are under pressure from a variety of factors such as higher temperatures, sedimentation, and human-related activities such as fishing and coastal development," he says. "The key to effectively identifying where conservation efforts are most likely to succeed is finding reefs where high biodiversity and low stress intersect."
The researchers, including Maina and supervisor Joshua Madin, grouped the world's tropical coral reef systems into two clusters, based on the sum of their stress exposure grades and factors that reinforce and reduce these stresses.
The first cluster looked at coral regions in South East Asia, Micronesia, the Eastern Pacific, and the central Indian Ocean, characterised by high radiation stress, with few stress-reducing factors.
The second cluster looked at the Caribbean, Great Barrier Reef, Central Pacific, Polynesia, and the Western Indian Ocean, regions characterised by moderate to high rates of radiation exposure but also with high rates of reducing factors.
Overall, stress factors such as surface temperature, ultra-violet radiation, and doldrums were the most significant factor for reinforcing and reducing ecosystem stress, and one that ecosystem management has no control over. What is controllable, however, is the mitigation of human impacts that reinforce radiation stress and where managers decide to locate their protected areas.
The authors recommend that the study results can be used to formulate management strategies that would include activities such as fishing restrictions, and the management of watersheds through improved agricultural practices and reforestation of coastal watersheds that play a role in health coral systems.
The authors include: Joseph M. Maina of Macquarie University, Timothy R. McClanahan of the Wildlife Conservation Society; Valentijn Venus of Netherlands Institute for Geo-Information Science and Earth Observation; Mebrahtu Ateweberhan of the University of Warwick; and Joshua Madin of Macquarie University, Sydney, Australia.