Germana Carillo Freshwater ecosystems are highly biodiverse and important for livelihoods and economic development. However, they are under considerable stress, with nearly 23,000 studied freshwater species facing a multitude of threats.
According to the first overall assessment of the status of 23,000 freshwater species, done by the International Union for Conservation of Nature, crabs, shrimp and dragonflies are the most threatened group of freshwater animals, while fish take a close second. The study shows a multitude of threats facing species in freshwater habitats, including pollution, agricultural chemicals, dams, and invasive species.
The research, published in Nature, found that at least 4,294 out of 23,496 freshwater species listed in the IUCN Red List are threatened with extinction. The findings underpin the urgent need for action to protect freshwater biodiversity.
Freshwater landscapes support 10% of all known species on Earth,” said Catherine Sayer, Freshwater Biodiversity Lead at IUCN and lead author of the study. “They are essential for safe drinking water for billions of people, livelihoods, flood control, and climate change mitigation. Protecting them is essential for both nature and people.”
@Nature
The study: where are the most endangered species?
The assessment identified key areas where freshwater species face the greatest threats:
- Lake Victoria
- Lake Titicaca
- Wetlands in Sri Lanka
- The Western Ghats of India
@Nature
This study showed that a greater number of endangered species than previously known exist in subterranean water systems worldwide. In North America, for example, many species of crayfish are seriously threatened. The margaritiferous crayfish, Fallicambarus jeanae, which originates from Arkansas, has been classified by the IUCN Red List as vulnerable.
The major threats to Freshwater Ecosystems
More than half of all threatened freshwater species are affected by pollution from agriculture and forestry.
In general, the main threats to freshwater ecosystems include:
- Land conversion for agriculture
- Water extraction
- Construction of dams which also disrupts the fish migration route
- Overexploitation
- Invaded alien species
Species thought to be facing the highest risk of extinction
Of those groups that were assessed, the species in order which are most under threat are:
- Crabs
- Shrimp and prawns
- Freshwater fish
- Dragonflies
