ABSTRACT
In physical geography and its cognate disciplines, a region is normally a spatial unit of some feature – community, ecosystem, slope, drainage basin, soil, sea, or whatever. It is characteristically smaller than an entire area of interest (such as global vegetation and global soils), but larger than its component units. Its definition rests upon several features rather than a single feature, and produces uniform (homogeneous or formal) regions or functional (nodal) regions. In ecology, a nested hierarchy of formal units covers a range of spatial scales. Small units go by various names, including sites, micro-ecosystems, land types, and land units. These small units form landscape mosaics, meso-ecosystems, land-type associations, subregions, and so on. In turn, these medium-sized spatial units form larger units, variously styled regions, ecoregions, provinces, divisions, domains, zones, ecozones, kingdoms, and so forth. These units are definable as functional regions, where flows help to sustain the integrity of the unit.
