Heatwaves, herbivores and the future of the Great Southern Reef

Thomas Wernberg

UWA Oceans Institute & School of Biological Sciences, Indian Ocean Marine Research Centre M470, The University of Western Australia.

Norwegian Institute of Marine Research, Nye Flødevigveien 20, 4817, His, Norway.


The Great Southern Reef (GSR) is an interconnected ecosystem of rocky reefs dominated by kelp forests (Ecklonia radiata). Stretching across the southern coastline of Australia it is home to some of the most unique and species-rich temperate reefs in the world. Over recent decades, kelp forests have declined and been replaced by turf reefs in many regions of the GSR. A prominent cause of these habitat transformations has been warming ocean temperatures, leading to extreme marine heatwaves and intrusion of tropical herbivorous fishes. As one of the fastest warming regions in the world, the declines in Australian kelp forests are projected to intensify and the region is likely a sentinel of the Anthropocene for kelp forests worldwide.