Freshwater ecosystems, covering just 1% of Earth’s surface, are home to more than 10% of the world’s known species. Despite their critical importance, these ecosystems are facing increasing threats, according to a comprehensive new study on global freshwater biodiversity.
Researchers examined 23,496 freshwater species, including fish, crustaceans like crabs and shrimp, and insects such as dragonflies and damselflies. The findings were alarming—24% of these species are at high risk of extinction. The primary threats identified were pollution, dam construction, water extraction, agricultural activities, invasive species, and overharvesting.
“Pollution and habitat loss from human activities are accelerating extinction rates in freshwater environments,” explained Catherine Sayer, lead author of the study published in Nature. Sayer, who leads the freshwater biodiversity unit at the International Union for Conservation of Nature (IUCN), emphasized the urgent need for conservation efforts.
Among the endangered species are those with exotic names, such as the mini blue bee shrimp from Sulawesi, Indonesia; the Seychelles duskhawker dragonfly; and the Atlantic helicopter damselfly in Brazil. Threatened fish species include the shortnose sucker in Oregon and California and the humpbacked mahseer from India.
This study is significant because it provides a broad, holistic view of freshwater ecosystem health by examining species from different roles within food webs. These findings complement existing research on mammals, birds, and amphibians, further underscoring the shared pressures faced by life in freshwater habitats.
Since 1970, more than one-third of inland wetlands, including rivers, lakes, and peatlands, have disappeared. The study found that crustaceans are the most vulnerable, with 30% of species threatened, followed by fish (26%) and dragonflies and damselflies (16%).
Ian Harrison, a freshwater conservationist at Northern Arizona University and a co-author of the study, stressed the ecological and economic importance of these systems. “Freshwater ecosystems provide essential services like carbon sequestration, fisheries, medicinal resources, and cultural value. Their contributions to human well-being are estimated at $50 trillion annually,” Harrison said.
The study identified four critical areas where conservation needs are most urgent: Lake Victoria in East Africa, Lake Titicaca in South America, and freshwater regions in western India and Sri Lanka.
Lake Victoria, bordered by Kenya, Tanzania, and Uganda, suffers from pollution, agricultural runoff, invasive species like the Nile perch, and water hyacinth. Similarly, Lake Titicaca, situated between Peru and Bolivia, faces comparable threats. Both lakes are vital habitats for diverse fish species.
“There is a pressing need to integrate freshwater conservation into global water resource management,” said Harrison. “Sustainable solutions must balance ecological preservation with human needs for water.”
This study offers valuable insights by highlighting the most threatened regions and species, providing a foundation for tracking conservation progress. By identifying gaps in protection, it can guide policymakers and environmentalists in creating effective strategies to safeguard these vital ecosystems.
