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 use all of the resources they need to survive. Habitat fragmentation due to human development is an ever-increasing threat to biodiversity, and habitat corridors are a possible mitigation. The main goal of implementing habitat corridors is to increase biodiversity. When areas of land are broken up by human interference, population numbers become unstable and many animal and plant species become endangered. By re-connecting the fragments, the population fluctuations can decrease dramatically. Corridors can contribute to three factors that stabilize a population: Rosenberg et.al. (1995) were among the first to define what constitutes a wildlife corridor. The definitions of 'biological corridor' (i.e., wildlife corridor) had, in the early years of studying corridors, been 'vague and inconsistent, and often they confound form and function' Rosenberg et.al. developed 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. Their definition simply required that movement to a target patch via the corridor be greater that if the corridor were absent. Although corridors had originally been implemented with the assumption that they would increase biodiversity, not enough research had been done to come to a solid conclusion. The case for corridors has been built more on intuition and much less on empirical evidence (Tewksbury et al. 2002). Tewksbury et. al. claimed that the early controversies had arisen because most studies had been limited in that they had a narrow taxonomic focus and, that if corridors facilitate animal movement, they should also have strong indirect effects on plant populations due to increased pollen and seed by animals. Results of their 2002 experiment provided a large-scale experimental demonstration that habitat (or wildlife) corridors facilitate movement of disparate taxa between otherwise isolated patches even after controlling for area effects (Tewksbury et al, 2002). Another factor that needs to be taken into account is what species the corridor is intended for. Some species have reacted more positively to corridors than others. A habitat corridor could be considered as a possible solution in an area where the destruction of a natural area has greatly affected its native species. Development such as roads, buildings, and farms can interrupt plants and animals in the region being destroyed. Furthermore, natural disasters such as wildfires and floods can leave animals with no choice but to evacuate. If the habitat is not connected to a safer one, it will ultimately lead to death. A remaining portion of natural habitat is called a remnant, and such portions need to be connected because when migration decreases, extinction increases (Fleury 1997). Corridors can be made in two distinct areas—either water or land. Water corridors are called riparian ribbons and usually come in the form of rivers and streams. Land corridors come on a scale as large as wooded strips connecting larger woodland areas. However, they can also be as simple as a line of shrubs along a sidewalk (Fleury 1997). Such areas can facilitate the movement of small animals, especially birds, from tree to tree, until they find a safe habitat to rest in. Not only do minimal corridors aid in the movement of animals, they are also aesthetically pleasing, which can sometimes encourage the community to accept and support them.