Pollution is the main cause Many freshwater animals are threatened with extinction
Until now, the potential loss of biodiversity in freshwater habitats had hardly been studied. Researchers have now found that almost a quarter of all freshwater animals are acutely threatened.
08.01.2025, 22:47
08.01.2025, 23:00
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- A research team has closely examined the threat to freshwater animals.
- They came to the conclusion that 24 percent of all freshwater animals are threatened with extinction.
- Crabs and shrimps are particularly at risk.
- Until now, there has been little data on the development of biodiversity in freshwater habitats.
Almost a quarter of all freshwater animals worldwide are threatened with extinction. This was reported by a research group led by the International Union for Conservation of Nature (IUCN) in the scientific journal "Nature".
The team analyzed data on more than 20,000 species - and warns of a massive loss of biodiversity in rivers, lakes and other freshwater habitats in view of the results.
The research group led by Catherine Sayer from the IUCN has assessed the extinction risk of freshwater wildlife. Freshwater includes rivers, lakes, karst and other springs as well as oases and provides a habitat for more than ten percent of all known species.
Decapods are particularly endangered
Numerous species of fish, crustaceans and dragonflies live in and around such waters - their risk of extinction has been neglected to date. To change this, the research group analyzed data on almost 23,500 species on the IUCN Red List and also identified their greatest threats.
The result: around 24 percent of all freshwater animals are critically endangered. Broken down by group, decapod crustaceans, which include crabs, crayfish and shrimps, are particularly endangered.
According to the report, 30 percent of the species examined are threatened with extinction. The figure for freshwater fish is 26 percent and 16 percent for odonates, i.e. dragonflies and damselflies.
According to the study, 89 species have been proven to be extinct since 1500 and 178 species are presumed to be extinct. Eleven species are now only found in captivity and no longer in the wild. In view of this, "urgent action is needed to prevent further species declines and losses", the researchers write.
No more excuses for inaction
Looking at the causes, the scientists found that 54% of the endangered species studied were affected by pollution, 39% by dams and water abstraction and 37% by land-use change and associated impacts, such as agriculture.
Invasive species and diseases are responsible for 28 percent of the threats. Some species are threatened by several causes at the same time. In the case of fish, the research group points to the impact of overfishing and dams that block migration routes, for example.
Overall, their analysis makes it clear that urgent action must be taken against these threats in order to prevent further decline and loss of species, the authors warn: "The lack of data on the status and distribution of freshwater biodiversity can no longer serve as an excuse for inaction."
