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October 30, 2013

Newsletter: 

Scientists have a new tool for measuring biodiversity and identifying marine diversity ‘hotspots’, thanks to a global survey of reef fish by an international team of more than 150 trained volunteer SCUBA divers working for the non-profit organisation Reef Life Survey.

Results of the six-year survey — which collected, for the first time, detailed global information about the diversity of roles different fish species play in ecosystems — have been published in the journal Nature.

Lead author, Dr Rick Stuart-Smith, a NERP Marine Biodiversity Hub researcher with the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania, said that the survey has produced the best data set of its kind in the world, extremely cost-effectively.

‘We have data from over 1,900 sites in 40 countries, spanning 133 degrees of latitude and in all the ocean basins,’ he said.

Previously, scientists have relied on measures which use the number of species in a given area (species richness) when looking at biological diversity patterns worldwide.

As a result of the Reef Life Survey, researchers have been able to include data on the functional role of different fish species — what they eat, how they eat, their size, where they live — and the relative number of fish observed at sites for each species, to produce a more ecologically relevant measure of diversity than species counts alone.

The research has produced maps that present an alternative view of global biodiversity patterns, and has revealed some surprising new findings, according to Dr Stuart-Smith who, with Professor Graham Edgar, also of IMAS, co-founded Reef Life Survey with funding assistance from the former Commonwealth Environment Research Facilities Program and the NERP Marine Biodiversity Hub.

‘The biodiversity ‘hotspots’ (that incorporate species function and abundance) are in different areas to where species-richness hotspots are,’ Dr Stuart-Smith said.

New ‘hotspots’ of biodiversity were found in some temperate regions, including south-western Australia, as well as the Galapagos Islands, where species counts are only moderate.

This contrasts with previous measures of diversity based only on species counts that highlighted the Coral Triangle and the Caribbean as areas of highest biodiversity, with diminishing diversity at higher latitudes.

While coral reefs remain the most species-rich habitats in terms of fish, the new research strengthens arguments for more representation of some temperate and Southern Hemisphere regions in global marine protected areas to prevent the degradation of areas with unique biodiversity values.

This year, the Reef Life Survey team has been surveying Australia’s Commonwealth marine reserves, particularly the new Coral Sea Commonwealth Marine Reserve, with the help of volunteer divers operating from a private yacht.

‘We have studied 159 sites out in the Coral Sea, which covers most of the reef systems there, providing really valuable information that wouldn’t exist otherwise,’ Dr Stuart-Smith said.

Measures that incorporate functional traits are intended to complement rather than replace existing measures of ecosystem state. They provide additional opportunities for monitoring and managing the impacts of different pressures on marine communities.

Further reading:


Image:

A Reef Life Survey volunteer diver surveying a reef in the Coral Sea. Image: Graham Edgar, University of Tasmania

 Graham Edgar, University of Tasmania


Contact

Dr Rick Stuart-Smith, University of Tasmania

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