The term "ecotone" can be defined as a transition area between two adjacent ecological communities. It usually has some common characteristics of each bordering community and often contains species not found in either of the two. Ecotones exist at different scales. It may be the edge of your back yard where it butts up against a bayou or patch of woods. It can be a 20-mile wide strip that separates the eastern front of the Rocky Mountains from the Great Plains or the northern evergreen forests from the tundra.