
Climate change and anthropogenic factors are affecting the Great Barrier Reef ecosystem, causing significant changes in the composition of fish and coral communities, which are essential for the functioning of the reefs and humanity.
A study by an international team of scientists led by Lancaster University, published in Nature Communications., has found that the Great Barrier Reef's fish communities have changed significantly since the 1990s. Analysis of data from the Australian Institute of Marine Science (AIMS) long-term monitoring, which covers more than 1200 km (from 14° to 24° S), shows that the rate of change in these ecosystems is increasing. The key factor in maintaining fish diversity is not so much the number of corals, but their species diversity, which affects the three-dimensional structure of the reef.
Changes in latitudinal patterns of diversity highlight that the greatest species declines are occurring in the northern regions of the reef, closer to the equator, where omnivorous, herbivorous and planktonic fish are declining. At the same time, in the southern regions, these groups are increasing in number, raising concerns about the possible consequences for the functioning of the reef ecosystem. Javier González-Barrios, lead author, emphasizes:
The impact of extreme conditions such as heat stress, coral bleaching and frequent tropical cyclones are major drivers of change. Seven mass coral bleaching events have been recorded between 1998 and 2024, contributing to reef degradation. According to Mike Emsley of AIMS, coral recovery does not always guarantee the return of ecosystem complexity, as changes in species composition can reduce the ability of corals to create multi-layered environments.
In addition to providing food security, reef fish perform key ecosystem functions: controlling algae growth, maintaining ecosystem balance and even contributing to the formation of beach sand. According to Professor Nick Graham, these ecological benefits are under threat due to accelerating changes in biodiversity. He emphasizes:
The study highlights the need to focus efforts on maintaining coral diversity as a foundation for conserving coral reef ecosystem services and ensuring their resilience in a changing environment.
Climate Chaos Is Changing Life on the Great Barrier Reef appeared first on Curiosity.