Ecoregion (ecological region): definition, characteristics and conservation

Key characteristics

Although ecoregions vary widely in size and content, they are generally defined by a combination of physical and biological attributes. Typical characteristics include:

• dominant vegetation types and species assemblages;
• climate patterns such as temperature and rainfall regimes;
• geology and soils that influence habitat structure and productivity;
• hydrology for freshwater ecoregions, or oceanographic conditions for marine variants;
• ecological processes and interactions (for example fire regimes, nutrient cycles, or predator–prey relationships) that shape communities.

When mapped for conservation or research, ecoregion boundaries usually approximate the original extent of natural communities before recent large-scale human modification. Many classification efforts distinguish terrestrial, freshwater and marine ecoregions to reflect these different sets of drivers and taxa; see examples of natural communities and species considerations in species and community assessments.

History and development of the concept

The idea of grouping landscapes by shared ecological attributes emerged from biogeography and landscape ecology in the 20th century as scientists sought units that were meaningful for studying biodiversity patterns and ecological processes. Over time, conservation organizations and government agencies adopted ecoregions as practical spatial units for planning, monitoring and reporting. One widely used modern definition is that provided by the World Wide Fund for Nature (WWF), which frames an ecoregion as "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." The WWF has mapped 825 terrestrial ecoregions and roughly 450 freshwater ecoregions worldwide; learn more about WWF mapping efforts at WWF.

Uses, examples and importance

Ecoregions are used in conservation planning, setting priorities for protection, and designing restoration strategies. For instance, the WWF identified the "Global 200"—a set of ecoregions selected for their exceptional biodiversity and conservation value—to guide international conservation investments; information on that initiative is summarized at Global 200. Practical applications include identifying representative protected areas, targeting species recovery actions, and organizing monitoring programs to detect ecological change. Conservation actions often rely on the ecoregion concept to maintain ecological integrity across landscapes and waterscapes and to link local projects to regional goals, such as efforts described under conservation planning frameworks.

Types and distinctions

It is important to distinguish ecoregions from related terms: a biome describes a global-scale category of similar climate and dominant life forms (for example tropical rainforest or tundra), while a habitat refers to the specific environment used by a species. Ecoregions sit between these scales: they are finer than realms and biomes but broader than individual habitats. They can be classified into terrestrial, freshwater and marine categories, each requiring different datasets and criteria when mapping. Because ecoregion boundaries reflect ecological gradients rather than strict lines, maps are best interpreted as managerial tools that help to organize conservation, research and education rather than as immutable borders.

Overall, the ecoregion concept provides a pragmatic way to link biological diversity with geography and to prioritize actions that sustain ecological processes at scales meaningful to species and ecosystems.