Freshwater Biodiversity

IUCN Water and the Freshwater Biodiversity Unit

The IUCN Water Programme works in close collaboration with the IUCN Freshwater Biodiversity Unit (FBU), based in Cambridge

The diversity of species in freshwater habitats is high as compared to other ecosystems. Freshwater habitats cover less than 1% of the world’s surface, yet they provide a home for over 25% of all described vertebrates.

Freshwater ecosystems also provide many important goods and services including the provision of food, clean water, building materials, and flood and erosion control. The livelihoods of many of the world’s poorest communities are dependent on resources from freshwater ecosytems.

Threats such as high levels of water extraction, pollution, wetland drainage and river channelization, deforestation leading to sedimentation, introduced invasive species and over-harvesting have all had major impacts upon freshwater biodiversity.

In order to help mitigate the threats and better inform development and conservation planning processes, knowledge is needed on where freshwater species occur, how important they are for human livelihoods and ecosystem functioning, and how threatened their status is. To achieve this, information on species distributions, population trends, habitats and ecology, threats and utilization are collated and used to conduct assessments of extinction risks. This information is made available on the IUCN Red List of Threatened Species™.


Key messages

• Freshwater species are extremely threatened, possibly more so than species in the marine and terrestrial systems.

• Public awareness of the threat to freshwater species needs to be raised. Freshwater species are largely unseen by the general public, are not often considered as charismatic, and their values to people not well recognized.

• Freshwater species provide important ecosystem services, including the provision of protein and supporting livelihoods for some of the world’s poorest communities.

• Management of water resources must take account of the requirements of freshwater species. This approach is encapsulated within the Environmental Flows concept, which aims to ensure that there is enough water to maintain environmental, economic and social benefits.

• Protected areas must be designed to protect freshwater species, and employ the principles of catchment protection.


For more information

William Darwall
Manager IUCN Freshwater Biodiversity Unit

Mark Smith
Director IUCN Global Water Programme

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