Biodiversity ignores national and other political boundaries, so a more relevant conservation planning unit is required - WWF addresses this need with ecoregions.
What is an Ecoregion?
An ecoregion is defined as a large area of land or water that contains a geographically distinct assemblage of natural communities that
share a large majority of their species and ecological dynamics;
share similar environmental conditions, and;
interact ecologically in ways that are critical for their long-term persistence.
The Conservation Science Program has identified 825 terrestrial ecoregions across the globe, and a set of approximately 500 freshwater ecoregions is under development (WWF has not yet developed an analogous global framework of marine ecoregions).