Saving our freshwater fauna by tackling biodiversity loss
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Biodiversity - Swimways
A recent article in Nature, published in early January, highlights updates from the global assessment of freshwater fauna for the IUCN Red List of Threatened Species. This assessment, which covers 23,496 freshwater species, reveals that a quarter of them are at direct risk of extinction.
This percentage includes all species categorised as threatened or extinct in the wild. Additionally, nearly 23% of freshwater species are classified as data deficient, meaning their threat status could not be fully assessed. As a result, the current estimate of threatened freshwater fauna may actually underestimate the severity of the situation.
The threats freshwater species primarily stem from pollution, dams and water extraction, overfishing, invasive species, land-use change, and agricultural impacts. These threats jeopardise the survival and reproduction of freshwater species. For example, migratory fish are particularly affected, as dams and water extraction alter hydrological flows and create physical barriers that block their migration routes. This disrupts the connectivity between habitats that is essential for spawning.
Freshwater habitats, which comprise only 1% of the Earth’s surface, support approximately half of all fish species. However, research indicates that 35% of wetlands have been lost between 1970 and 2015. Currently, 71% of the species in rivers, which face significant human-related threats, are at risk. In fact, 37% of rivers over 1,000 km no longer flow to their full length, despite their critical importance in freshwater ecosystems. These threats lead to habitat loss, degradation, and barriers that block migration routes.
Maintaining freshwater habitats and their connectivity is crucial for biodiversity and must be addressed alongside efforts in terrestrial and marine environments. The Kunming-Montreal Global Biodiversity Framework (GBF) emphasises the importance of freshwater realms, particularly through targets such as restoring at least 30% of degraded ecosystems in rivers, lakes, and wetlands (Target 2) and conserving and managing at least 30% of inland waters by 2030 (Target 3) through protected areas and other effective conservation measures (OECMs).
In conclusion, the alarming decline of freshwater biodiversity, as highlighted by the study led by Catherine Sayer, IUCN’s Freshwater Biodiversity Lead and a member of the Trans-European Swimways Programme’s Steering Committee, underscores the urgent need for action. The degradation of rivers, lakes, and wetlands threatens both ecological balance and human well-being. Ongoing pressures continue to disrupt essential ecosystem functions, including the migration pathways for fish and other aquatic species.
Our commitment to restoring river connectivity and conserving freshwater biodiversity is more crucial than ever. By implementing nature-based solutions, removing barriers, and promoting sustainable water management, we can help reverse biodiversity loss and ensure thriving freshwater ecosystems for future generations. Now is the time to act and integrate freshwater conservation into global efforts to protect nature and secure a sustainable future.