They include designated wilderness areas within the region's seven national forests, undeveloped portions of its two national parks, and also the surrounding lands managed by a number of federal and state agencies which have, as yet, neither roads nor legal restrictions on road-building. But t he environmental health of Greater Yellowstone's public land is also tied to the fate of the surrounding lands in private ownership. The links are many, and they are reciprocal. Agriculture needs the high quality water and the protection from flooding given by undamaged watersheds.
Wildlife needs the habitat found on private lands.
To wildlife, and from the perspective of science, public and private lands are bound together, part and parcel of the same natural system. Thus, any realistic attempt to manage ecosystems must consider both the environmental function of lands, regardless of ownership, and the lines we draw in law and practice between the public and private domains. Compared to the nation as a whole, Greater Yellowstone has a relatively small proportion of private land, but its ecological importance is great. Research has shown that many of these areas in private ownership are not only some of Greater Yellowstone's most biologically diverse or important for wildlife migration, but are also some of its most threatened by human development and use.