The part of biosphere reserve, which is strictly prohibited and protected from any external interference is called as core zone.
A buffer zone is generally a zonal area that lies between two or more other areas (often, but not necessarily, countries), but depending on the type of buffer zone, the reason for it may be to segregate regions or to conjoin them.
Common types of buffer zones are demilitarized zones, border zones and certain restrictive easement zones and green belts.
The transition zone is the zone between two different plant communities, as that between forest and prairie.