The concept of bioregionalism is earth-based, as opposed to politically-based as states and countries are. A bioregion is an identifiable geographical area of interacting life-systems that is relatively self-sustaining. Planning and development without regard to bioregions results in water pollution from upstream activities, industrial soot falling in residential areas, and highways dividing communities. It means that states will increasingly find themselves in dispute, or with the need to cooperate, over management of bioregions which are distributed between them, as activities in one state can have effect across the border.
A bioregion is part of the earth's surface whose rough boundaries are determined by natural rather than human dictates, distinguishable from other areas by attributes of flora, fauna, water, climate, soils and land forms, and the human settlements and cultures those attributes have given rise to. A bioregion has an internal integrity. It can be discretely described in terms of its rivers and catchments, its land systems, its vegetation types and ecosystems, even though the geographic boundaries may differ for each characteristic and be indeterminate on the ground. Bioregions can be as large as the Baltic Sea and the land of the surrounding countries which drains into it, or as small as a coastal dune system with its underground aquifer enclosed by cliffs, although here it would be nested into a bioregion of larger scale which would include the near-shore coastal waters and the hinterland.
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.