Isolated coral reefs not immune to local human activity

Marine scientists at The University of Queensland’s Global Change Institute and the ARC Centre for Excellence in Coral Reef Studies have shown that local human activities negatively influence coral reef ecosystems in a series of complex interactions, some of which are poorly understood by science.

A detailed underwater study was undertaken at 26 sites across the Maldives, south-west of India, as part of a XL Catlin Seaview Survey.

The scientists investigated coral reef communities adjacent to human populations ranging from zero to more than 150,000 people.

PhD candidate Kristen Brown said although marine scientists already knew human activity placed pressure on coastal reef systems, the extent to which these impacts were translated to impacts on coral reefs via changes to coral-algal competition had rarely been investigated.

“We’ve demonstrated that local human populations have a strong influence on coral reefs,” Ms Brown said.

“Many people believe that isolated reefs, near relatively small human populations, are healthier.

“Our study, however, noted a decline in certain categories of reef-building corals and an increase in dead coral and filamentous algae on reefs adjacent the densest human communities.

“Importantly, this study only provides a snapshot into the interactive dynamics of coral and algae, and seasonal and long-term investigations should be implemented.

“The results of our study have implications for the effects of human populations on coral reef communities, drawing attention to how these drivers influence reef processes such as coral-algal competition,” Ms Brown said.

Associate Professor Sophie Dove from the ARC Centre for Excellence in Coral Reef Studies at The University of Queensland said understanding these changes was becoming more and more important as global changes due to ocean warming and acidification increase.

“Understanding how these changes interact is going to be increasingly important especially as we see more frequent impacts like that of the mass coral bleaching across the Maldives in 2016,” Dr Dove said.

“This may help coral reef managers target their interventions with better outcomes.”

XL Catlin Seaview Survey Chief Scientist Professor Ove Hoegh-Guldberg said the project had enabled some of the largest ecological measurements of reef health.

“Projects such as this will allow us to put down important baselines against which we can measure progress against goals,” he said.

The XL Catlin Seaview Survey began on the Great Barrier Reef in September 2012. Following successful Great Barrier Reef and Coral Sea surveys, the project was rolled out globally thanks to the ongoing support of founding sponsor, global insurance group – XL Catlin Group Limited.

In 2014 the major campaign area was the waters of South-East Asia, while in 2015 the reefs of the Indian Ocean, including the Maldives, were surveyed. The team has recorded additional survey areas, including the Galapagos Islands, and temperate water locations including Monaco and Sydney.

Download the research paper cited above.

Media:

Kristen Brown, kristen.brown@uq.edu.au

Global Change Institute Communications, gcicomms@uq.edu.au +61 (0) 438 285 283