An ecoregion is a large area of water or land 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. Biological distinctiveness is a scale-dependent assessment of the biological importance of an ecoregion based on species richness, endemism, relative scarcity of ecoregion type and rarity of ecological phenomena. Biological distinctiveness classes are "globally outstanding", "regionally outstanding", "regionally important" and "locally important".
Plantlife, UK and the French Ministry of Environment organized the conference Planta Europa, the first European conference on the conservation of wild plants, in Hyères, France, on 2-8 September 1995. Planta Europa has since developed into a network with the mission of conserving the wild plants of Europe and their habitats. The flagship project of the network is the identification of Important Plant Areas (IPAs) in Europe. IPAs are "natural or semi-natural sites exhibiting exceptional botanical richness and/or supporting an outstanding assemblage of rare, threatened and/or endemic plant species and/or vegetation of high botanical value". Planta Europa aims to produce a country-by-country list of IPAs in Europe on the basis of common criteria. IUCN will cooperate with Planta Europa in this work.