MELBOURNE, Oct. 13 (Xinhua) -- A team of marine ecologists has completed a 12-day scientific expedition at the southernmost point of the Australian continent to document reef biodiversity.

The expedition, conducted in March, was along the remote south coast of the Australian island state of Tasmania to Port Davey in the state's remote southwest at "the last climate refuge for species of the Great Southern Reef," according to a statement released Monday by the University of Tasmania (UTAS).

The researchers surveyed biodiversity at remote, previously unsurveyed reefs off southern Tasmania, including Pedra Branca, Mewstone Rock, and Maatsuyker Island's remnant giant kelp forests, to record reference conditions for ongoing kelp forest restoration in eastern Tasmania, it said.

They also revisited historical sites within the Port Davey marine protected area to monitor long-term trends in reef health, said Scott Bennett, a marine ecologist at the UTAS Institute for Marine and Antarctic Studies, who led the study.

"The surveys at Pedra Branca and Mewstone reefs were highlights of the trip," Bennett said, adding, "Those reefs are immensely productive, with enormous forests of bull kelp down to 25-meter depths, and huge biomasses of bait fish, endemic reef fish and seals."

However, the team was concerned to report the first sighting of the range-expanding Long-spined sea urchin (Centrostephanus rodgersii) at Pedra Branca, literally "the southernmost point that this species can reach in Australia," Bennett said.

This urchin is known for its destructive overgrazing of kelp forests, turning vibrant habitats into barren rocky areas, which threatens biodiversity and the health of reef ecosystems in Tasmania, according to the Great Southern Reef Foundation.

"Surveys from southern Tasmania provide critical information about what reef species are doing at the coolest edge of their distribution, and it's a vital reference point that will equip us to better understand how climate change is affecting reef species in Australia," Bennett said. ■