Ecoregions are the building blocks that make up each of One Earth’s bioregions. Ecoregions are used to describe areas where ecosystems are generally similar, providing a spatial framework for the research, assessment, and monitoring of ecosystem functionality. There are several ways to define terrestrial ecoregions. The US Environmental Protection Agency uses an ecoregional framework developed in the 1980s by James Overnik with four nesting scales. Level I ecoregions are roughly comparable to what we now call “biomes.” Level II ecoregions are broad divisions of Level I, roughly equivalent in scale to One Earth’s bioregions. Level III ecoregions are an intermediate scale of ecological areas nested within Level II. Level IV ecoregions are much more detailed ecological units that most would refer to as ‘ecosystems’ nested within Level III.
An international consortium of conservation scientists recently released an updated map of the world’s terrestrial ecoregions in the paper “An Ecoregion-Based Approach to Protecting the Terrestrial Realm” (Dinerstein et al. 2017). This effort used recent advances in satellite imagery and remote sensing to identify 844 discreet ecoregions of the world (roughly equivalent to Level III ecoregions). These ecoregions provide the building blocks for the One Earth Bioregions Framework. They are widely cited in scientific literature on conservation biology and frequently used for local-scale conservation planning efforts. The ecoregions can be explored through an interactive web application developed by RESOLVE and Google Earth Engine, with detailed ecoregion profiles provided by One Earth.
The 844 terrestrial ecoregions of the Earth (Dinerstein et al. 2017) overlayed with One Earth's Bioregions polygons. A finite number of ecoregions are nested within each bioregion. Download Map (6 MB). Image credit: Karl Burkart, One Earth
