24% of Freshwater Species at Risk of Extinction

Nearly a quarter of animals living in rivers, lakes, and other freshwater sources are threatened with extinction, according to new research published Wednesday. "Huge rivers like the Amazon can appear mighty, but at the same time freshwater environments are very fragile," said study co-author Patricia Charvet, a biologist at Brazil's Federal University of Ceara, per the AP.

• Freshwater habitats—including rivers, lakes, ponds, streams, bogs, and wetlands—cover less than 1% of the planet's surface, but support 10% of its animal species, said Catherine Sayer, a zoologist at the International Union for Conservation of Nature in England. and a study co-author.

• The researchers examined around 23,500 species of dragonflies, fish, crabs, and other animals that depend exclusively on freshwater ecosystems. They found that 24% were at risk of extinction—classified as vulnerable, endangered, or critically endangered—due to compounding threats from pollution, dams, water extraction, agriculture, invasive species, climate change, and other disruptions.
• "Most species don't have just one threat putting them at risk of extinction, but many threats acting together," said Sayer.
• The tally, published in the journal Nature, is the first that time researchers have analyzed the global risk to freshwater species. Duke University ecologist Stuart Pimm, who was not involved in the study, called it "a long-awaited and hugely important paper." Nearly "every big river in North America and Europe is massively modified" through damming, putting freshwater species at risk," he said.

(More threatened species stories.)