Ecotone
An ecotone is a transitional area between two plant communities, where these meet and integrate. Examples include areas between grassland and forest, estuary and lagoon, and freshwater and sea water. An ecotone may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and grassland ecosystems). 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.