Freshwater Ecoregions of the World

Freshwater Ecoregions of the World provides a new global biogeographic regionalization of the Earth's freshwater biodiversity.
Covering virtually all freshwater habitats on Earth, this first-ever ecoregion map, together with associated species data, is a critical tool for underpinning global and regional conservation planning efforts, particularly to
  • identify outstanding and imperiled freshwater systems;
  • for serving as a logical framework for large-scale conservation strategies; and
  • for providing a global-scale knowledge base for increasing freshwater biogeographic literacy.

Background

Freshwater species and habitats are, on average, more imperiled than their terrestrial counterparts. Yet, large-scale conservation planning efforts have rarely targeted freshwater biodiversity.
This is due in part to the fact that there has been a severe lack of data on the distributions of freshwater species.

Existing worldwide species-level data have covered only the largest river basins or selected hotspots, rather than all inland waters. Additionally, such data have made little attempt to describe biogeographic patterns.

Freshwater Ecoregions of the World (FEOW) is a collaborative project providing the first global biogeographic regionalization of the Earth's freshwater biodiversity, and bringing together biodiversity and threat data for the resulting ecoregions.
The freshwater ecoregion map encompasses 426 units, whose boundaries generally - though not always - correspond with those of watersheds (also known as drainage basins or catchments).

Within individual ecoregions there will be turnover of species, such as when moving up or down a river system, but taken as a whole an ecoregion will typically have a distinct evolutionary history and/or ecological processes.

Biodiversity data
...has been brought together for each ecoregion to include richness and endemism numbers for freshwater fish, amphibians, turtles, and crocodiles.

Threat analyses
...include examination of land cover conversion, the presence of large cities, urban land cover, area equipped for irrigation, human footprint, and water stress.

Conservation Applications
Information describing freshwater species has been dispersed and difficult to access, if it exists at all. This project begins to fill the gap, providing a basic level of information on freshwater biogeography and biodiversity that complements parallel terrestrial and marine efforts.

Therefore at global and regional scales the ecoregion map can be used to distinguish distinct units of freshwater biodiversity to be represented in conservation efforts.
A freshwater ecoregion is defined as a large area encompassing one or more freshwater systems that contains a distinct assemblage of natural freshwater communities and species.
/ ©: WWF / Nature Conservancy
Freshwater Ecoregions Map Tool
© WWF / Nature Conservancy

Fast Facts on the Map

  • 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

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