World's Freshwater Species Mapped for the First Time

WASHINGTON, DC, May 8, 2008 (ENS) – The diversity of life in all the world’s freshwater ecosystems is for the first time displayed on a comprehensive map and held in a database. These new tools can be of use to conservationists who are trying to save freshwater ecosystems that are under increasing pressure from human population growth, rising water use, and habitat alteration.

Unveiled today, Freshwater Ecoregions of the World is a collaborative project between the World Wildlife Fund and the Nature Conservancy, two U.S. nonprofit organizations that are part of larger international networks.

Asian three-striped box turtle, Cuora
trifasciata, is one of the most
Critically Endangered freshwater
turtles in Asia. Native to southern
China and northern Vietnam, Lao
PDR and Myanmar, it is believed
to have cancer-curing properties.
(Photo © Kurt Buhlmann
courtesy IUCN)

The map and database are the result of 10 years of work and contributions by more than 200 conservation scientists.

“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,” said Abell.

This is the first study to compile data on freshwater species – fish, amphibians, crocodiles and turtles – for nearly all of the world’s inland water habitats.

Close to 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.

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.

The map and database, called “Freshwater Ecoregions of the World,” divides the world’s freshwater systems into 426 distinct conservation units.

The Fine-lined Pocketbook, Lampsilis altilis,
is an Endangered freshwater mussel
endemic to the United States. It is
found at sites in five river drainages
in Alabama. (Photo © Wendell
Haag courtesy IUCN)

Many of these units are rich in species but are under increasing pressure. Excessive water use for agriculture, industry, drinking and livestock are placing freshwater ecosystems in 55 ecoregions under high stress, threatening the species and habitats.

More than half the area in another 59 ecoregions has already been converted from natural habitats to cropland and urban areas.

Parts of major rivers such as the Amazon, Congo, Ganges, Yangtze, and the rivers and streams of the Southeastern United States were identified as outstanding for rich fish populations and high numbers of 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 fish species unique to those ecosystems.

Paretrplus menarambo is a freshwater fish
endemic to Madagascar that is
now listed as Extinct in the Wild.
The species may survive as it is
being bred in captivity in Florida.
(Photo © Paul Loiselle
courtesy IUCN)

While competition for freshwater resources increases around the world, freshwater habitats and species are among the most imperiled.

Yet these essential ecosystems have often been left out of large-scale conservation planning because data on global freshwater biodiversity has not been organized in a way that was useful to conservationists, say the project leaders.

“Our lack of knowledge of freshwater species has hindered our efforts to conserve rivers, lakes and wetlands around the world,” said the Nature Conservancy’s Carmen Revenga.

Collected research has focused on major rivers or select hotspots, leaving out many other freshwater systems, and in addition, information was not easy to access and search.

“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,” Revenga said.

The Freshwater Ecoregions of the World, FEOW, project was created to address this need. Featured in the May issue of the journal “BioScience,” the map and database are online at: For a list of contributors, click here [].

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