Thousands of freshwater species are threatened with extinction

Freshwater ecosystems cover less than 1% of Earth’s surface, yet they support 10% of all known species.

A recent study published in the journal Nature warns that nearly a quarter of freshwater species face extinction. Thousands of fish, crab, and dragonfly species could disappear in the coming decades unless urgent conservation efforts take place.

The extinction threat

A comprehensive assessment of almost 24,000 freshwater species found that 24% are at risk. Among them, nearly 1,000 species are critically endangered, and 200 may already be extinct.

However, these numbers might only scratch the surface. Scientists lack data on many species, making it difficult to assess their full extinction risk.

“Lack of data on freshwater biodiversity can no longer be used as an excuse for inaction,” said Catherine Sayer, the study’s lead author. She highlights how freshwater habitats support human life by providing drinking water, livelihoods, flood control, and climate change mitigation.

Habitat loss of freshwater species

Freshwater environments are among the most threatened on Earth. As global demand for food, water, and resources rises, these ecosystems face increasing pressure.

Wetlands, including bogs, mangroves, and salt marshes, have suffered immense losses. Since 1700, an area the size of India – 3.4 million square kilometers – has been destroyed.

The loss of wetlands does not only affect wildlife. These ecosystems play a crucial role in climate regulation, water filtration, and flood control.

Other freshwater sources, such as rivers, suffer from excessive water extraction and dam construction. Some, like the Colorado River, no longer reach the sea.

Additional threats to freshwater species

Pollution further endangers freshwater species. Industrial waste, plastic debris, and agricultural runoff contaminate rivers and lakes. Many pesticides used to kill pests also harm aquatic creatures, especially during vulnerable life stages.

Despite these growing threats, freshwater species remain understudied. Dr. Topiltzin Contreras MacBeath, a co-author of the study, calls for increased investment in monitoring freshwater biodiversity to guide conservation efforts.

“It is essential that freshwater species data are actively included in conservation strategies and water use management to support healthy freshwater ecosystems,” noted Dr. MacBeath.

Which freshwater species are most at risk?

The study was focused on four groups that are deeply connected to freshwater ecosystems: decapods, odonates, mollusks, and fish.

Decapods: Crabs, lobsters, and shrimp

Decapods include crustaceans like crabs, crayfish, and shrimp. About 30% of freshwater decapods face extinction, primarily due to pollution.

Pesticides used in farming contaminate waterways, harming crustaceans, especially when they molt.

Odonates: Dragonflies and damselflies

Dragonflies and damselflies spend much of their lives as aquatic nymphs before becoming airborne predators. Habitat destruction threatens over half of these species.

Wetlands converted to farmland and deforestation have significantly reduced their numbers.

Mollusks: Snails, mussels, and oysters

Mollusks, including freshwater snails and mussels, were not included in the study due to limited data.

However, previous research suggests that about one-third of mollusk species are endangered. This omission likely means the true percentage of at-risk freshwater species is even higher.

Freshwater fish

Fish populations suffer from habitat destruction, overfishing, and pollution. Dams fragment river systems, reducing breeding grounds and food availability.

Saving freshwater species from extinction

Freshwater ecosystems – such as rivers, lakes, wetlands, and streams – exist across multiple countries and continents. Since water flows freely across borders, conservation efforts in one place may not be effective unless neighboring regions also take action.

For example, if one country pollutes a river, the impact is felt downstream in other countries. This makes protecting freshwater species a global challenge, requiring cooperation between governments, conservation groups, and local communities.

To stop freshwater species extinctions, we need a united effort. Countries must work together to manage water use responsibly, ensuring that rivers and lakes do not dry up due to overuse.

Governments should enforce stricter laws to prevent industries from polluting water sources. Investing in conservation programs and restoring damaged ecosystems can also help protect species from disappearing.

Preserving freshwater ecosystems goes beyond safeguarding wildlife. These habitats are essential for providing clean drinking water, sustaining agriculture, and mitigating natural disasters like floods.

They also support the livelihoods of millions, offering food and employment through activities like fishing and farming.

The study is published in the journal Nature.

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