The rivers of Australia are facing a crisis that threatens the extinction of certain species and other long-term detrimental effects as natural disasters continue to batter regions in the country.

Experts warn that the “triple whammy” of impacts — wildfires, flash floods, and drought — will take a devastating toll on ecosystems. These natural disasters are creating cascading impacts on invertebrates, platypus, and fish according to a scientist from the University of Canberra’s Institute for Applied Ecology

“There’s a real risk of losing species that we have not even gotten around to describing yet,” Prof Ross Thompson who specializes in freshwater ecology told The Guardian

In the country’s state of New South Wales, recent weeks have seen thousands of fish die in the Murray-Darling Basin and in other coastal regions. According to reports, this was likely due to the drought experienced in these areas while others are affected by ash from bushfire scorched areas flowing into rivers.

A mass fish kill in Eas Gippsland’s Brodribb River was caused by low flows according to ABC News. Local contractors have pulled out dead fish from the water weighing 1,200kg.

Heavy downpours are disturbing sediments that end up downstream. Ash and mud from scorched hectares of land are washing into rivers causing a rise in bacterial growth which leads to the starvation of fishes and the lack of oxygen for other organisms.

“The reality is that this combination of events have not been experienced by our fauna before, so the risk of things being extinct or being dramatically reduced is high,” Thompson said.