Wildlife corridors are necessary because they maintain biodiversity, allow populations to interbreed, and provide access to larger habitats.
Wildlife corridors connecting core reserves are crucial since they increase the effective amount of habitat that is available for species and effectively reverse habitat fragmentation. This is especially important for migratory animals and those with large home ranges. Larger habitats support greater biodiversity, larger populations, and a wider range of food sources and shelter. They also allow populations to interbreed, improving long-term genetic viability. However, Wildlife Corridors cannot substitute for large areas of protected habitat like those in core reserve systems.
At the largest scale, Wildlife Corridors must be wide enough to allow easy movement for even the largest mammals, including grizzlies, cougars, and wolves. Widths of several miles are typical. However, Wildlife Corridors can serve at smaller scales to provide habitat connectivity for other species, including amphibians, fish, and birds. They are particularly beneficial along riparian corridors, where they provide both aquatic and terrestrial connectivity. In urban areas, they can provide significant recreational opportunities and important linkages in a highly fragmented landscape. Whenever possible, urban and rural parks and open spaces should be linked to form functional Wildlife Corridors, which can then be joined to outlying core reserves.
Since wildlife corridors are typically narrow and vulnerable, they must be managed with extreme caution. For instance, pesticide use next to a corridor might have destructive impacts on pollinators, in turn reducing plant diversity. In many cases, ecological forestry, agriculture, and other non-extractive land-uses can be made compatible with wildlife corridors with special management practices acknowledging the needs of species using the corridor.
When roads or other infrastructure cross a Wildlife Corridor, it is essential to maintain transportation connections that do not diminish the effectiveness of the corridor. Multiple intersecting wildlife corridors offering multiple pathways between core reserves provide important resiliency to a wildlands network.
Identify critical existing or potential wildlife corridors between core reserves, protect them, and mange them for ecosystem connectivity.
Examples of this pattern in action:
Mattole Valley wildlife "mosaic"
For watershed organizing and restoration, the Mattole Restoration Council of Northern California stands out as a pioneering model. In this classic article of bioregional literature, Freeman House, one of the initiators of the Mattole effort, details the Council's history and broader lessons drawn from that experience. This article appeared in Whole Earth Review, Spring 1990.
I-90 Ocean to Mountain Corridor
The Greenway Education Program focuses on the challenge of sustaining a healthy, natural environment in balance with the needs of a growing population. A key element of the Greenway plan is preserving forests along the Interstate 90 corridor in Washington State.
Victoria's Sea-to-Sea Green/Blue Belt Alliance
A greenbelt of wilderness and parkland from Goldstream Park to the Sooke Basin. One of the links is a small property between Ayum Creek and the Galloping Goose trail. Sea-to-Sea Green/Blue Belt Alliance (a new coalition of seven local conservation organizations).
Organizations whose work incorporate this pattern:
Hudson, W.E. Landscape Linkages and Biodiversity. Island Press. Washington, DC. 1991.
Little, C.E. Greenways for America. John Hopkins University Press. Baltimore, MD. 1990.
Smith, Daniel S and Paul Cawood Hellmund, eds.. Ecology of Greenways: Design and Function of Linear Conservation Areas. University of Minnesota Press. Minneapolis, MN. 1993.