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What is FEOW?

FEOW (Freshwater Ecoregions of the World) is the first-ever comprehensive map and database describing the world’s freshwater biodiversity. Covering all of the Earth’s 426 freshwater ecoregions, the FEOW map and associated species data are a powerful tool for freshwater conservation. A collaborative effort between WWF and The Nature Conservancy, the project brought together 200 leading freshwater scientists to create this extensive and easily searchable resource.

In its May 2008 issue, the scientific journal BioScience published an article that formally introduces FEOW to the conservation and scientific communities.  The article, authored by 28 experts from around the world, culminates 10 years of work mapping patterns of global freshwater biodiversity. Download the article here (6 MB).

Why is freshwater important?

Freshwater ecosystems occupy only 0.8 percent of the earth’s surface, but harbor nearly six percent of all known species.

Yet, freshwater species and habitats are among the world's most endangered. In North America, the projected mean future extinction rate for freshwater animals is five times greater than that for terrestrial animals and three times the rate for coastal marine mammals -- rates within the range for tropical rainforest communities.

By 2025, two-thirds of the world's population could be facing serious water shortages.

Why is FEOW important for freshwater conservation?

So far, large-scale conservation planning efforts have rarely targeted freshwater biodiversity, partly because of insufficient data on the distributions of freshwater species worldwide.

FEOW begins to address these data gaps. Covering virtually all freshwater habitats on Earth, the ecoregion map and species data are a useful tool for:

         - underpinning global and regional conservation planning efforts (particularly to identify outstanding and imperiled freshwater systems)

         - serving as a framework for large-scale conservation strategies

         - providing a global-scale knowledge base for increasing freshwater biogeographic literacy

Fast Facts

The freshwater fish species database built for the project contains distribution data on over 13,400 species

Over 6,900 freshwater fish species are found in single ecoregions (endemic to those ecoregions)

43 ecoregions have higher than 50% endemism for freshwater fish species (i.e., half or more of the fish species are only found in that ecoregion)

The distributions of over 4,000 amphibian species that depend on fresh water during some stage of their life cycle were assessed and mapped to ecoregions.  There are 16 ecoregions with over 50% endemism for amphibians.

The distributions of over 300 freshwater turtle species were assessed, with 8 ecoregions showing 50% or higher endemism

55 ecoregions are classified as being under high stress to rivers by water use

59 ecoregions have over 50% of their area converted for human land use

147 ecoregions have one or more cities with a human population of over 1,000,000. The Central and Western Europe ecoregion scores highest with 22 of these cities.

17 ecoregions have over 20% of their area under urban landcover


Press Release: World Wildlife Fund and The Nature Conservancy Release First-Ever Comprehensive Global Map of Freshwater Systems - May 8, 2008.

Over a decade of work and contributions by more than 200 leading conservation scientists have produced a first-ever comprehensive map and database of the diversity of life in the world’s freshwater ecosystems. The map and associated fish data – a collaborative project between World Wildlife Fund and The Nature Conservancy -- are featured in the May issue of the journal BioScience.

Freshwater Ecoregions of the World divides the world’s freshwater systems into 426 distinct conservation units, many of which are rich in species but under increasing pressure from human population growth, rising water use, and habitat alteration. The comprehensive map and database ( are vital tools for conservationists trying to save the world’s freshwater ecosystems.

Among the highlights:

  • This is the first study to compile data on freshwater species -- including fish, amphibians, crocodiles and turtles -- for nearly all of the world’s inland water habitats
  • Almost 18,000 species have been mapped and placed into freshwater ecoregions.* This species list includes 13,400 fish, 4,000 amphibians, 300 turtles, and 20 crocodile species and their relatives.
  • About half of all freshwater fish are endemic, or found in only one ecoregion.
  • Portions of major rivers such as the Amazon, Congo, Ganges, Yangtze, and the rivers and streams of the American Southeast were identified as outstanding for rich fish populations and high endemism (species found nowhere else).
  • In addition, several smaller systems that had not been identified in previous global assessments, such as Congo’s Malebo Pool, the Amazon’s western piedmont, and Cuba and Hispaniola, were determined to have high numbers of endemic fish species.
  • Excessive water use for agriculture, industry, drinking and livestock are placing freshwater ecosystems in 55 ecoregions under high stress, threatening the species and habitats.
  • In another 59 ecoregions more than 50 percent of their area has already been converted from natural habitats to cropland and urban areas.

Freshwater ecosystems are the least studied parts of our natural world – they are like vast unexplored libraries, brimming with information,” said World Wildlife Fund’s Robin Abell, who headed the study. “Freshwater Ecoregions of the World allows scientists and non-scientists alike to gain a better understanding of this world and help guide efforts to save these systems and species before they are lost.”

Freshwater habitats support more than 100,000 species and provide humans with critical services such as drinking water and fisheries. Yet freshwater habitats and species are among the most imperiled in the world and have often been left out of large-scale conservation planning.

Until now there were no data on global freshwater biodiversity synthesized in a way that was useful to conservation. Collected research tended to focus only on major rivers or select hotspots, leaving out many other freshwater systems. Plus, information was not easy to access and search. As a result, it has been difficult to gain a truly comprehensive understanding of patterns of freshwater biodiversity across the globe.

The Freshwater Ecoregions of the World (FEOW) project was created to address this need. This extensive and easily searchable resource now provides access to information that can help ensure freshwater systems are well understood, promoted and protected.

The Nature Conservancy’s Carmen Revenga said Freshwater Ecoregions of the World could not have come at a more important time as competition for freshwater resources increases around the world. “Our lack of knowledge of freshwater species has hindered our efforts to conserve rivers, lakes and wetlands around the world. Simply having a map that shows areas rich in freshwater species will help us set conservation priorities and begin to put a face to these unique and essential species, which work to keep our freshwater ecosystems alive and running.”


*A freshwater ecoregion is a large area encompassing one or more freshwater systems that contains a distinct assemblage of natural freshwater communities and species. The freshwater species, dynamics, and environmental conditions within a given ecoregion are more similar to each other than to those of surrounding ecoregions and together form a conservation unit.



Brazilian Government Adopts The Nature Conservancy/World Wildlife Fund Freshwater Ecoregions in First National Freshwater Management Plan -- June 2006

The government' of Brazil has approved its first national plan for managing its freshwater resources. A critical component of this plan is the adoption of freshwater ecoregions defined through scientific studies resulting from a partnership between The Nature Conservancy and World Wildlife Fund (WWF).

The Freshwater Management Plan assures that aquatic biodiversity is an important aspect of freshwater planning for the entire country. Before, the most important considerations for the government were hydroelectric potential, navigation and water utilization regimes for drinking water, other household uses, industrial uses and irrigation. By adopting the TNC/WWF ecoregions, the Brazilian government explicitly makes biodiversity a part of the decision-making process for the use of the country's freshwater resources. This represents a great leap forward in the sustainable use of aquatic resources in Brazil.

The Conservancy began working with the Brazilian government in 2004 to incorporate the TNC/WWF ecoregions into the Freshwater Management Plan. Brazil is the first country in South America to develop such a plan, which encompasses objectives, goals and guidelines for the sustainable uses of freshwater until 2020. 

With the world's largest river basin—the Amazon—and the world's largest tropical floodplain—the Pantanal—the freshwater biodiversity of Brazil is staggering. In fact, Brazil has more freshwater fish species than any other country on Earth.

"In the Amazon River alone, there are an estimated 2,000 species of fish, more than all of North America," says David Oren, the Conservancy's Amazon Conservation Program Science Coordinator. "Only about 1,200 of those species have been described by science, however, indicating that in Brazil, as in much of the rest of the world, there is much still to be learned about freshwater biodiversity, one of the most fragile components of the Earth's natural heritage."

According to Glauco Freitas, the Conservancy's Great Rivers Partnership (GRP) manager for the Paraguay-Paraná watershed, "from the beginning of our conversations with the Brazilian government about their freshwater management plan, they have been cognizant of the importance of protecting Brazil's waters not only for the sake of their extraordinary aquatic life, but also to protect sources of water for communities. GRP actions will now be closely linked with the Freshwater Management Plan."


U.S. National Fish Habitat Action Plan incorporates freshwater ecoregions into framework

The National Fish Habitat Action Plan (NFHAP) is a broad, partnership-based approach to address declines in fish habitat across the United States.  At the core of the NFHAP is a science-based assessment of the "state" of fish habitat throughout the nation, which when completed, will be used to identify priority regions for protection, enhancement, and restoration of habitats.

The NFHAP assessment is based on a hierarchical spatial framework to organize the nation's fish habitat by type, status, and natural potential, and WWF's aquatic ecoregions are serving as the largest, organizing spatial element of that framework. WWF's aquatic ecoregion's will assist scientists and managers in understanding the diversity of habitats across the nation and in providing large-scale habitat condition scoring, critical steps for protection of the nation's aquatic resources.

NFHPA website:


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