A wildlife corridor, also known as a habitat corridor, or green corridor, [1] is an designated area that connects wildlife populations that have been separated by human activities or structures, such as development, roads, or land clearings. These corridors enable movement of individuals between populations, which helps to prevent negative effects of inbreeding and reduced genetic diversity, often caused by genetic drift, that can occur in isolated populations. [2] Additionally, corridors support the re-establishment of populations that may have been reduced or wiped out due to random events like fires or disease. They can also mitigate some of the severe impacts of habitat fragmentation, [3] a result of urbanization that divides habitat areas and restricts animal movement. Habitat fragmentation from human development poses an increasing threat to biodiversity, and habitat corridors help to reduce its harmful effects. Corridors aside from their benefit to vulnerable wildlife populations can conflict with communities surrounding them when human-wildlife conflicts are involved. [4] In other communities the benefits of wildlife corridors to wildlife conservation are used and managed by indigenous communities. [5]
Habitat corridors can be considered a management tool in areas where the destruction of a natural habitats has severely impacted native species, whether due to human development or natural disasters. When land is fragmented, wildlife populations may become unstable or isolated from larger populations. [6] These management tools are used by ecologists, biologists, indigenous tribes, and other concerned parties that oversee wildlife populations. Corridors help reconnect these fragmented populations and reduce negative population fluctuations by supporting these key aspects that stabilize populations: [7]
Daniel Rosenberg et al. [8] were among the first to define the concept of wildlife corridors, developing a model that emphasized the corridors' role in facilitating movement unrestricted by the end of native vegetation or intermediate target patches of habitat. [9]
Wildlife corridors also have significant indirect effects on plant populations by increasing pollen and seed dispersal through animals movement, of various species between isolated habitat patches. [10] Corridors must be large enough to support minimum critical populations, reduce migration barriers, and maximize connectivity between populations. [11]
Wildlife corridors may also include aquatic habitats often referred to as riparian ribbons, [12] and are typically found in the form of rivers and streams. Terrestrial corridors take the form of wooded strips connecting forested areas or an urban hedgerows. [11]
Wildlife corridors can connect into federal, state, private, and tribal land which can influence the opposition or acceptance of including wildlife corridors. The development of man made structures and expansion into natural areas can have an impact on both human and wildlife. [13] Although expressions such as "freedom to roam" promote the idea of wildlife freely moving throughout natural landscapes, this same ideology does not apply to indigenous peoples. [14] The theoretical ideas of landscape connectivity present them in a purely scientific and non-political manner that fails to account for political factors that can impact success within wildlife corridors and restorative ecological practices. [14] [15] Attempts to restore habitat over time require support from the local communities that surround the habitat area, oftentimes these communities are indigenous, that a restoration project is being placed around. [16]
Indigenous knowledge of ecological landscape features across history is usually substituted with European explorers' of landscape ecology recollections when developing widescale corridor plans and within the broader ecological field. [14] [17] [13] As such there is a distinction in the use of ecological and indigenous knowledge when taking into account where wildlife populations are found, species composition within a community, and even seasonal patterns lengths and changes. [16] [18] Widespread efforts that actively involve the input of a variety of political and environmental groups are not always used in ecological restoration efforts. Currently there are some collaborations ongoing between indigenous groups surrounding wildlife corridor habitat such as the Yellowstone to Yukon Conservation Initiative which promote the conversion of previously stolen land into indigenously managed land. [14] The concern regarding land once used and lived upon by indigenous people, which now makes up habitat within wildlife corridors, and developed land that corridors cut across contribute to the Land Back movement. [14]
Managing both terrestrial and aquatic lands can have a positive economic impact on Indigenous groups that continue to rely on wildlife populations for cultural practices, fishing, hunting, etc. in a variety of natural landscapes. [13] [19] Indigenous groups face financial inequities despite the large benefits of conservation efforts; this if the result of a lack of consideration placed on how wildlife corridors can impact local communities. [13] The overlap of wildlife, specifically larger predator species, poses a physical danger to local communities. [20] Economic revenue for local groups nearby or within heavily forested areas poses a threat to human property, crops, and livestock with higher chances of wildlife encounters; fisheries can also be negatively impacted by wilderness areas. [20] Many indigenous tribes manage wildlife populations within tribal lands that are legally recognized by governments, yet these tribes lack the finances to effectively manage large swathes of habitat. [5] The Tribal Wildlife Corridors Act would allow indigenous groups across the U.S. to implement wildlife corridors with both the finances and cooperation of neighboring governmental allies to help manage tribal lands. [5]
Most species can be categorized into one of two groups: passage users and corridor dwellers.
Passage users occupy corridors for brief periods. These animals use corridors for such events as seasonal migration, juvenile dispersal or moving between different parts of a large home range. Large herbivores, medium to large carnivores, and migratory species are typical passage users. [21]
Corridor dwellers, on the other hand, can occupy a corridor for several years. Species such as plants, reptiles, amphibians, birds, insects, and small mammals may spend their entire lives in linear habitats. In such cases, the corridor must provide enough resources to support such species. [21]
Habitat corridors can be categorized based on their width, with wider corridors generally supporting greater wildlife use. [22] However, the overall effectiveness of a corridor depends more on its design that its width. [11] The following are three main categories of corridor widths:
Habitat corridors can also be classified based on their continuity. Continuous corridors are uninterrupted strips of habitat, while "stepping stone" corridors consist of small, separate patches of suitable habitat. However, stepping-stone corridors are more vulnerable to edge effects, which can reduce their effectiveness.
Corridors can also take the form of wildlife crossings, such an underpasses or overpasses that allow animals to cross man-made structures like roads, helping to reduce human-wildlife conflict, such as roadkill. Observations that underpasses tend to be more than overpasses as many animals are too timid to cross over a bridge in front of traffic and prefer the cover of an underpass. [23]
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Researchers use mark-recapture techniques and hair snares to assess genetic flow and observe how wildlife utilizes corridors. [24] Marking and recapturing animals helps track individual movement. [25]
Genetic testing is also used to evaluate migration and mating patterns. By analyzing gene flow within a population, researchers can better understand the long- term role of corridors in migration and genetic diversity. [25]
Wildlife corridors are most effective when designed with the ecology of their target species in mind. Factors such as seasonal movement, avoidance behavior, dispersal patterns, and specific habitat requirements must also be considered. [26]
Corridors are more successful when they include some degree of randomness or asymmetry and are oriented perpendicular to habitat patches. [27] [11] However, they are vulnerable to edge effects; habitat quality along the edge of a habitat fragment is often much lower than in core habitat areas.
While wildlife corridors are essential for large species that require expensive ranges; they are also crucial for smaller animals and plants, acting as ecological connectors to move between isolated habitat fragments. [28] Additionally wildlife corridors are designed to reduce human-wildlife conflicts. [29] [30]
In Alberta, Canada, overpasses have been constructed to keep animals off the Trans-Canada Highway, which passes through Banff National Park. The tops of the bridges are planted with trees and native grasses, with fences present on either side to help guide animals. [31]
In Southern California, 15 underpasses and drainage culverts were observed to see how many animals used them as corridors. They proved to be especially effective on wide-ranging species such as carnivores, mule deer, small mammals, and reptiles, even though the corridors were not intended specifically for animals. Researchers also learned that factors such as surrounding habitat, underpass dimensions, and human activity played a role in the frequency of usage. [32]
In South Carolina, five remnant areas of land were monitored; one was put in the center with the other four surrounding it. Then, a corridor was put between one of the remnants and the center. Butterflies that were placed in the center habitat were two to four times more likely to move to the connected remnant rather than the disconnected ones. Furthermore, male holly plants were placed in the center region, and female holly plants in the connected region increased by 70 percent in seed production compared to those plants in the disconnected region. Plant seed dispersal through bird droppings was noted to be the dispersal method with the largest increase within the corridor-connected patch of land. [33]
In Florida June 2021, the Florida Wildlife Corridor act was passed, securing a statewide network of nearly 18 million acres of connected ecosystems. [34] Starting from the Alabama state line, through the Florida panhandle and all the way to the Florida Keys. Containing state parks, national forests, and wildlife management areas supporting wildlife and human occupation.
The positive effects on the rates of transfer and interbreeding in vole populations. A control population in which voles were confined to their core habitat with no corridor was compared to a treatment population in their core habitat with passages that they use to move to other regions. Females typically stayed and mated within their founder population, but the rate of transfer through corridors in the males was very high. [35]
In 2001, a wolf corridor was restored through a golf course in Jasper National Park, Alberta, which successfully altered wildlife behavior and showed frequent use by the wolf population. [36] [37]
Some species are more likely to utilize habitat corridors depending on migration and mating patterns, making it essential that corridor design is targeted towards a specific species. [50] [51]
Due to space constraints, buffers are not usually implemented. [8] Without a buffer zone, corridors can become affected by disturbances from human land use change. There is a possibility that corridors could aid in the spread of invasive species, threatening native populations. [52]
Protected areas or conservation areas are locations which receive protection because of their recognized natural or cultural values. Protected areas are those areas in which human presence or the exploitation of natural resources is limited.
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.
Urban ecology is the scientific study of the relation of living organisms with each other and their surroundings in an urban environment. An urban environment refers to environments dominated by high-density residential and commercial buildings, paved surfaces, and other urban-related factors that create a unique landscape. The goal of urban ecology is to achieve a balance between human culture and the natural environment.
Habitat conservation is a management practice that seeks to conserve, protect and restore habitats and prevent species extinction, fragmentation or reduction in range. It is a priority of many groups that cannot be easily characterized in terms of any one ideology.
Wildlife crossings are structures that allow animals to cross human-made barriers safely. Wildlife crossings may include underpass tunnels or wildlife tunnels, viaducts, and overpasses or green bridges ; amphibian tunnels; fish ladders; canopy bridges ; tunnels and culverts ; and green roofs.
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes that slowly alter the layout of the physical environment, and human activity such as land conversion, which can alter the environment much faster and causes the extinction of many species. More specifically, habitat fragmentation is a process by which large and contiguous habitats get divided into smaller, isolated patches of habitats.
Ecological restoration, or ecosystem restoration, is the process of assisting the recovery of an ecosystem that has been degraded, damaged, destroyed or transformed. It is distinct from conservation in that it attempts to retroactively repair already damaged ecosystems rather than take preventative measures. Ecological restoration can reverse biodiversity loss, combat climate change, support the provision of ecosystem services and support local economies. The United Nations has named 2021-2030 the Decade on Ecosystem Restoration.
Reconciliation ecology is the branch of ecology which studies ways to encourage biodiversity in the human-dominated ecosystems of the anthropocene era. Michael Rosenzweig first articulated the concept in his book Win-Win Ecology, based on the theory that there is not enough area for all of earth's biodiversity to be saved within designated nature preserves. Therefore, humans should increase biodiversity in human-dominated landscapes. By managing for biodiversity in ways that do not decrease human utility of the system, it is a "win-win" situation for both human use and native biodiversity. The science is based in the ecological foundation of human land-use trends and species-area relationships. It has many benefits beyond protection of biodiversity, and there are numerous examples of it around the globe. Aspects of reconciliation ecology can already be found in management legislation, but there are challenges in both public acceptance and ecological success of reconciliation attempts.
Trophy hunting is a form of hunting for sport in which parts of the hunted wild animals are kept and displayed as trophies. The animal being targeted, known as the "game", is typically a mature male specimen from a popular species of collectable interests, usually of large sizes, holding impressive horns, antlers, furs, or manes. Most trophies consist of only select parts of the animal, which are prepared for display by a taxidermist. The parts most commonly kept vary by species but often include the head, hide, tusks, horns, or antlers.
The Mesoamerican Biological Corridor (MBC) is a region that consists of Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, and some southern states of Mexico. The area acts as a natural land bridge from South America to North America, which is important for species who use the bridge in migration. Due to the extensive unique habitat types, Mesoamerica contains somewhere between 7 and 10% of the world’s known species.
The Lower Guinean forests also known as the Lower Guinean-Congolian forests, are a region of coastal tropical moist broadleaf forest in West Africa, extending along the eastern coast of the Gulf of Guinea from eastern Benin through Nigeria and Cameroon.
The Backyard Wildlife Habitat is a program of the National Wildlife Federation that encourages homeowners in the United States to manage their gardens and yards as a wildlife garden, with the goal of maintaining healthy and diverse animal habitats and ecosystems. The program began in 1973. By 1998, it had impacted more than 21,000 yards and, as of 2006, has certified over 60,000 'backyards'.
In landscape ecology, landscape connectivity is, broadly, "the degree to which the landscape facilitates or impedes movement among resource patches". Alternatively, connectivity may be a continuous property of the landscape and independent of patches and paths. Connectivity includes both structural connectivity and functional connectivity. Functional connectivity includes actual connectivity and potential connectivity in which movement paths are estimated using the life-history data.
Reserve design is the process of planning and creating a nature reserve in a way that effectively accomplishes the goal of the reserve.
Translocation is the human action of moving an organism from one area and releasing it in another. In terms of wildlife conservation, its objective is to improve the conservation status of the translocated organism or to restore the function and processes of the ecosystem the organism is entering.
Umbrella species are species selected for making conservation-related decisions, typically because protecting these species indirectly protects the many other species that make up the ecological community of its habitat. Species conservation can be subjective because it is hard to determine the status of many species. The umbrella species is often either a flagship species whose conservation benefits other species or a keystone species which may be targeted for conservation due to its impact on an ecosystem. Umbrella species can be used to help select the locations of potential reserves, find the minimum size of these conservation areas or reserves, and to determine the composition, structure, and processes of ecosystems.
Defaunation is the global, local, or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient exploitation of the environment. This has resulted in the depletion of large vertebrates from ecological communities, creating what has been termed "empty forest". Defaunation differs from extinction; it includes both the disappearance of species and declines in abundance. Defaunation effects were first implied at the Symposium of Plant-Animal Interactions at the University of Campinas, Brazil in 1988 in the context of Neotropical forests. Since then, the term has gained broader usage in conservation biology as a global phenomenon.
Ecosystem management is an approach to natural resource management that aims to ensure the long-term sustainability and persistence of an ecosystem's function and services while meeting socioeconomic, political, and cultural needs. Although indigenous communities have employed sustainable ecosystem management approaches implicitly for millennia, ecosystem management emerged explicitly as a formal concept in the 1990s from a growing appreciation of the complexity of ecosystems and of humans' reliance and influence on natural systems.
Road ecology is the study of the ecological effects of roads and highways. These effects may include local effects, such as on noise, water pollution, habitat destruction/disturbance and local air quality; and the wider environmental effects of transport such as habitat fragmentation, ecosystem degradation, and climate change from vehicle emissions.
Conservation behavior is the interdisciplinary field about how animal behavior can assist in the conservation of biodiversity. It encompasses proximate and ultimate causes of behavior and incorporates disciplines including genetics, physiology, behavioral ecology, and evolution.