Not any piece of real estate will provide an effective biological corridor. Key factors that must be considered in producing a robust corridor include: (a) appropriate geometry of the corridor; (b) suitability of the plant association within the corridor to support the floral and faunal uses (Hilty et al. 2006) of the corridor; (c) suitability of abiotic factors within the corridor; and (d) absence of any alien species that could disrupt the metabolisms or functions of native species intended to use the corridor.
Habitat corridors can also minimize interaction between humans and wildlife by allowing predators, such as wolves and bears, to hunt for food in other locations, minimizing their threat to people. The corridors can also serve to minimize wildlife encroachment into human populated areas during natural disasters such as wildfires or floods.
Habitat fragmentation can lead to an overall reduction in species population and potentially local extinction of a plant or animal species. As Evans notes, species affected by habitat fragmentation become increasingly vulnerable to natural disasters and predation and are also more susceptible to inbreeding, increasing the prevalence of genetic defects.
Creating and maintaining biological corridors are important steps towards restoring natural habitats that have been fragmented by natural and human induced processes. By re-establishing and supporting biodiversity, many species are given an opportunity to continue existence in the wild. Conservation organizations continue to research and identify areas that are suitable for these connections, and educate the public about methods of creating habitat corridors.
Corridors are identified based on their role in:
facilitating seasonal movement (migration, altitudinal migration);
facilitating movement through highly modified landscapes and access to unexploited habitat;
improving dispersal success;
increasing the effective size of meta-populations by allowing for the exchange of genes between subpopulations ;
allowing colonisation of empty patches and prevent and reverse local extinction;
providing habitat for resident populations; and
maintaining landscape scale ecological and evolutionary processes along geological, hydrological, altitudinal and climatic gradients and provide for ecological responses to climate change.
A strategic corridor network should function effectively for a large range of species, particularly threatened species. Corridor selection should address issues of dimensionality (length/width), habitat type, quality and diversity, habitat patchiness within the corridor and consider potential edge effects when prescribing corridor widths.
Primary environmental corridors are concentrations of significant natural resources at least 400 acres in area, at least two miles in length, and at least 200 feet in width. Secondary environmental corridors are concentrations of significant natural resources at least 100 acres in area and at least one mile in length. Isolated natural resource areas are those remaining significant natural resources at least five acres in area and at least 200 feet in width.
When linkages are broken and blocks of habitat are fragmented, one effect is that the remaining areas often leave wildlife more vulnerable to outside predators.
Fish and wildlife populations, native plant distribution, and even clean water all depend on movement through environmental corridors. For example, wildlife populations isolated in one wooded location can overpopulate, die out, or cause problems for neighbors if there are not adequate corridors to allow the population to move about freely.
Environmental corridors are complex ecosystems that provide an avenue for wildlife movement, protection of natural resources, and green space buffers for humans. These “lifelines for living” help support human, wildlife, and natural resource communities.