NEW YORK, Jan. 8 (Xinhua) -- Nearly a quarter of animals living in rivers, lakes and other freshwater sources are threatened with extinction worldwide, according to a new research published on Wednesday.
"Huge rivers like the Amazon can appear mighty, but at the same time freshwater environments are very fragile," The Associated Press quoted study co-author Patricia Charvet, a biologist at Brazil's Federal University of Ceará, as saying.
Freshwater habitats, including rivers, lakes, ponds, streams, bogs and wetlands, cover less than 1 percent of the planet's surface, but support 10 percent of its animal species, said Catherine Sayer, a zoologist at the International Union for Conservation of Nature in England.
The researchers examined around 23,500 species of dragonflies, fish, crabs and other animals that depend exclusively on freshwater ecosystems. They found that 24 percent 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.
The tally, published in the journal Nature, is the first that time researchers have analyzed the global risk to freshwater species. Previous studies have focused on land animals including mammals, birds and reptiles.
