A large area of land or water that contains a geographically distinct assemblage of natural communities that:
(a) Share a large majority of their species and ecological dynamics;
(b) Share similar environmental conditions, and;
(c) Interact ecologically in ways that are critical for their long-term persistence (source: WWF). In contrast to biomes, an ecoregion is generally geographically specific, at a much finer scale. For example, the “East African Montane Forest” eco-region of Kenya (WWF eco-region classification) is a geographically specific and coherent example of the globally occurring “tropical and subtropical forest” biome.