[3] An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line.
The word ecotone was coined (and its etymology given) in 1904 in "The Development and Structure of Vegetation" (Lincoln, Nebraska: Botanical Seminar) by Frederic E. Clements.
Lastly, the abundance of introduced species in an ecotone can reveal the type of biome or efficiency of the two communities sharing space.
Changes in the physical environment may produce a sharp boundary, as in the example of the interface between areas of forest and cleared land.
Mountain ranges often create such ecotones, due to the wide variety of climatic conditions experienced on their slopes.
Different intensity of disturbances can cause landslides, land shifts, or movement of sediment that can create these vegetation patches and ecotones.
[3] The phenomenon of increased variety of plants as well as animals at the community junction is called the edge effect and is essentially due to a locally broader range of suitable environmental conditions or ecological niches.