Wildlife corridor
A wildlife corridor, habitat corridor, or green corridor is an area of habitat connecting wildlife populations separated by human activities or structures (such as roads, development, or logging). This allows an exchange of individuals between populations, which may help prevent the negative effects of inbreeding, and reduced genetic diversity (via genetic drift) that often occur within isolated populations. Corridors may also help facilitate the re-establishment of populations that have been reduced or eliminated due to random events (such as fires or disease). This may potentially moderate some of the worst effects of habitat fragmentation, wherein urbanization can split up habitat areas, causing animals to lose both their natural habitat and the ability to move between regions to access resources. Habitat fragmentation due to human development is an ever-increasing threat to biodiversity, and habitat corridors serve to manage its effects. Purpose Habitat corridors can be considered a management tool in places where the destruction of a natural area has greatly affected its native species, whether as a result of human development or natural disasters. When areas of land are broken up, populations can become unstable or fragmented. Corridors can reconnect fragmented populations and reduce population fluctuations by contributing to three factors that can help to stabilize a population: Colonization—animals are able to move and occupy new areas when food sources or other natural resources are lacking in their core habitat. Migration—species that relocate seasonally can do so more safely and effectively when it does not interfere with human development barriers. Interbreeding—animals can find new mates in neighboring regions, increasing genetic diversity. Rosenberg et al. were among the first to define what constitutes a wildlife corridor, developing a conceptual model that emphasized the role of a wildlife corridor as a facilitator of movement that is not restricted by requirements of native vegetation or intermediate target patches of habitat. Wildlife corridors additionally, have strong indirect effects on plant populations by increasing pollen and seed dispersal from animals, facilitating movement of disparate taxa between isolated patches. Corridors must be large enough to support minimum critical populations, reduce migration barriers, and maximize connectivity between populations. Wildlife corridors may also encompass aquatic habitats (often called riparian ribbons) and usually come in the form of rivers and streams. Terrestrial corridors can come in the form of wooded strips connecting woodland areas or an urban hedge. Users Species can generally be categorized in one of two groups; passage users and corridor dwellers. Passage users occupy corridors for brief periods of time. These animals use corridors for such events as seasonal migration, dispersal of a juvenile, or moving between parts of a large home range. Animals such as large herbivores, medium to large carnivores, and migratory species are passage users. Corridor dwellers can occupy the passage anywhere from several days to several years. Species such as plants, reptiles, amphibians, birds, insects, and small mammals can spend their entire lives in linear habitats. In this case, the corridor must provide sufficient resources to support such species. Types Habitat corridors can