Scientists raise biodiversity concerns in worldwide reef study

An international group of marine scientists, including two UTS researchers, has warned reef systems are at greater risk from human pressures than previously thought.

New information on the biodiversity and health of reefs has been released in an international paper that calls for greater marine protection of reef systems and challenges existing beliefs about biodiversity and biomass on reefs.

The collaboration of scientists from 49 nations has demonstrated that the efficiency of reef fish systems to produce goods and services to humanity increases with the number of species.

UTS marine biologists Professor David Booth and Dr David Feary were part of the team that recently published its findings in the journal PLoS Biology.

Professor Booth said the two year study involved 55 researchers visiting and examining reefs around the world to analyse human impact and the biodiversity of each reef ecosystem.

"We found the closer a reef is to human population the more severe the impact," Professor Booth said. "Reefs provide vital goods and services for humanity, including food, shelter and coastal protection, along with income from tourism, and we need to provide much better protection for them."

Dr Feary said that the conclusions from the research challenged traditional thinking about the biomass and biodiversity of reefs.

"Traditional thinking was that reef fish biodiversity reaches a certain point where increasing the number of species on the reef would not increase the available biomass," Dr Feary said. "From this study we have concluded that this is incorrect, the greater biodiversity of an ecosystem the more biomass."

The study also demonstrated that reef fish biomass reduced with increasing human population density.  The scientists argue that this is due to the selective loss of large fishes, which are often more efficient in turning food into biomass and whose lack of competitors precludes their replacement by other species.

Professor Booth said dense human populations were associated with heavy overfishing, land use, and coastal development.

"This highlights the challenge behind the management required to adequately protect coral reefs and the need to focus on alternative economic and policy tools that address reef degradation," he said.

Dr Feary said the results were critical to understanding how reef ecosystems are being increasingly affected by human development.

"It underlines that current management approaches are insufficient to protect marine biodiversity on a large scale, and that holistic approaches combining natural and social systems are needed."

by Alexandra Berriman

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