Wilderness areas are large natural environments (in excess of 5,000 acres) together with their plant and animal communities, that have been substantially unmodified by humans and in particular by human technology, or the presence of roads or permanent buildings. Ideally these environments should be primaeval in character. With increasing population and transport facilities, such areas are now subject to a level of use which endangers the local ecosystems.
In 1983, 244 million people visited national parks in the USA. In the backcountry of Wyoming's Yellowstone National Park, the increasing traffic has forced the grizzly bear into a shrinking area and is threatening its existence there. Ten national parks in the UK were visited by a total of 103 million people in 1990. The growing number of visitors is damaging footpaths and there are a host of other landuse and conservation issues which argue for more control over access and use.