The Aboriginal people of Australia and Tasmania developed and practiced sustainable management of the Great Southern Reef's abundant resources for thousands of years before Western colonisation.

Giving the Great Southern Reef its name was part of an ongoing and concerted effort to raise the public's awareness of its existence, importance, and plight.

Thanks to its location on the Indo-Australian tectonic plate, the reef has enjoyed stable environmental conditions for most of its history, but human-caused threats like anthropogenic climate change, overfishing, and marine animal invasions have caused significant damage to its unique habitats,[citation needed] including kelp die-offs and disruptions to the food web.

The cooler waters that support the biodiversity of the Great Southern Reef make it and its highly specialised inhabitants especially vulnerable to the effects of climate change.

[citation needed] The name first appeared in Australian news media in September 2015, a few months after the term was coined in an unprecedented scientific study of the reef published in the journal Marine and Freshwater Research.

A defining feature of the Great Southern Reef, kelp forests provide the primary production, habitat, and other resources needed for the high level of biodiversity in the region, which is home to thousands of species; hundreds of those are found nowhere else, and an estimated 10,000 remain to be discovered.

[7] Unfortunately, an estimated 95% of the giant kelp forests off the coast of Tasmania have died off over the past few decades due higher water temperatures and the long-spined sea urchin.

[6][8] In addition to macroalgae, sessile animals like soft corals, sea fans and other gorgonians, and colourful sponge gardens create habitats for fish and invertebrates.

The reef has multiple endemic cephalopods: the Giant Australian cuttlefish assemble in large numbers to mate, and the southern species of the blue-ringed octopus hunts with deadly tetrodotoxin.

Accelerated by the 2014-16 El Niño event, which broke multiple warming records for the Pacific Ocean, temperature fluctuations have been largely responsible for the demise of kelp forests on the Great Southern Reef.

Environmental organisations like The Wilderness Society have argued that the depth of the water and rough seas could result in a disastrous oil spill, and the continued burning of fossil fuels contributes to the warming threatening the Great Southern Reef.

[1][22] The cool, nutrient-rich waters of Australia's temperate sea provide a rich feeding ground for commercially fished animals as well; the two most lucrative fisheries in the entire country, rock lobster (~AU$375 million/year) and abalone (~AU$134 million/year), harvest their catches from the Great Southern Reef.

[24] The recent explosion in the population of long-spined sea urchins (Centrostephanus rodgersii) in the waters south of Australia has been devastating to its kelp forests.

The urchins, which are normally found north of the Great Southern Reef, have seen their range expand southward with the warm waters that themselves have caused a mass die-off of kelp.

[26] In 2022, the Tasmanian government released their strategy for "tackling the long spined sea urchin", which involves subsidising the commercial dive fishery as well as training recreational divers to protect important patches of kelp forest.

[25] Aquaculture companies have also invested in kelp farming in the region, in particular the cultivation of Asparagopsis, a red seaweed that when added in small amounts to the feed of livestock can cut their methane emissions by as much as 90%.

[29] The future of the Great Southern Reef depends on addressing human-caused climate change, as fluctuations in water temperature are primarily responsible for its decline.