Communicating clearly about conservation corridors

Conflicting definitions lead to confusion when people communicate about ‘corridors’, particularly when they come from different disciplinary backgrounds. Usage of ‘corridor’ in game management, island biogeography, and metapopulation literature focused on function, namely, the movement of flora and fauna from one area to another. A structural usage of the term arose in the field of landscape ecology as it developed in North America with the matrix–patch–corridor paradigm of landscape structure. ‘Corridor’ is now used to describe both the structural and functional aspects of linear landscape features, often implicitly, in a wide range of disciplinary literature. Lack of a clear and consistent terminology leads to confusion about the goals or implied functions of corridors. Consequently, the manner in which corridors should be designed, managed, and evaluated is also unclear. Proper design and management of a corridor depends critically on a clear and explicit statement of its intended functions. If corridors are not designed to perform well-defined functions, the outcome may be disappointing, or even deleterious. The roles corridors play derive from six ecological functions: habitat, conduit, filter, barrier, source, and sink. These ecological functions have been recognized widely and adopted by a number of disciplines, including conservation biology, wildlife management, landscape ecology, and landscape planning. We review briefly the history of the term ‘corridor’ in the context of conservation, catalog some of its definitions and uses, review the functions of corridors, and differentiate between the structural and functional aspects of corridors. We reject the notion of defining ‘corridor’ succinctly, because of the complex and multiple functions a corridor may serve. Instead, we suggest that conservationists and planners consider and document explicitly all of the possible functions of corridors when designing them. Addressing explicitly these functions when designing a corridor should eliminate much of the confusion surrounding their roles, and focus attention on establishing design criteria for corridors that function as intended.