Terrestrial Biodiversity Adaptation Research Network

“There are few controlled data with which to assess the conservation role of corridors connecting refuges. If corridors were used sufficiently, they could alleviate threats from inbreeding depression and demographic stochasticity. For species that require more resources than are available in single refuges, a network of refuges connected by corridors may allow persistence. Finally, a corridor, such as a riparian forest may constitute an important habitat in its own right. A dearth of information on the degree to which different species use corridors makes it difficult to tell which of these potential advantages will be realized in any particular case. Some experimental field studies suggest that certain species will use corridors, although lack of controls usually precludes a firm statement that corridors will prevent extinction. Corridors may have costs as well as potential benefits. They may transmit contagious diseases, fires, and other catastrophes, and they may increase exposure of animals to predation, domestic animals, and poachers. Corridors also bear economic costs. For example, a bridge that would maintain a riparian corridor costs about 13 times as much per lane-mile as would a road that would sever the corridor. Also, per-unit-area management costs may be larger for corridors than for refuges. It may be cheaper to manage some species by moving individuals between refuges rather than by buying and maintaining corridors. Each case must be judged on its own merits because species-environment interactions differ. As an example, we used the case of the Florida panther (Felis concolor cotyq, of which there remain about 30. The Florida panther's potential inbreeding problems could possibly be stemmed somewhat by a corridor system, but it is far from certain that even an extensive system will save this animal, and the cost of such a system would lessen the resources that could be devoted to land acquisition and other means of aiding many other threatened species...”

http://dx.doi.org/10.1111/j.1523-1739.1987.tb00010.x

Simberloff, D. and Cox, J. (1987). Consequences and costs of conservation corridors. Conservation Biology, 1: 63–71