A wildlife corridor, also called a habitat corridor or green corridor, is an area that links groups of animals that have been separated by human activities such as industrialization, farming, city growth, roads, land clearing, and other developments. These corridors help reduce the effects of habitat fragmentation, which occurs when natural areas are divided into smaller parts, limiting animal movement. This fragmentation is often caused by fast-growing cities and transportation networks. Habitat fragmentation from human activities harms biodiversity, and wildlife corridors help lessen these negative effects. By allowing animals to move between areas, corridors prevent problems like inbreeding and low genetic diversity in small, isolated groups. They also help plants by spreading pollen and seeds through animals that move between separated habitats. In addition, corridors support wildlife resilience during climate change by connecting warmer and cooler areas. However, corridors near human settlements can sometimes increase conflicts between people and animals, which need to be managed carefully.

Purpose

Habitat corridors are a way to help manage areas where natural habitats have been damaged, which can harm biodiversity. When land is broken into pieces, wildlife populations may become unstable or separated from larger groups. Habitat corridors can be created by local communities, citizen groups, scientists, Indigenous people, land managers, urban planners, and others involved. Because of climate change, corridors can also connect cooler areas with warmer areas, helping animals and plants move as their homes change. Corridors should be large enough to support small but important populations, remove barriers that stop animals from moving, and help populations stay connected.

Corridors help reconnect and stabilize broken-up populations by supporting important processes for biodiversity:

• Colonization: Animals can move to new areas when food or other resources are limited in their main home.
• Migration: Animals that move seasonally can travel more safely and easily without being blocked by human-made barriers.
• Interbreeding: Animals can find mates in nearby areas, which increases genetic diversity.

Wildlife corridors have many definitions. They can be any space that allows animals to move, share genes, and let plants grow and reproduce. Other definitions include a long stretch of connected land, a path that animals with large ranges can use to travel between habitats, areas where plants can grow and spread, and places where animals can move because of changes in their environment, such as wildfires, floods, or climate change. These corridors also help vulnerable species grow their populations by connecting them to other habitat areas.

Wildlife corridors improve habitat connectivity, which means how well plants and animals can move between different habitat areas.

Types of corridors

Habitat corridors can be grouped based on their width, with wider corridors usually supporting more wildlife use. However, how well a corridor works depends on both its design and its width.

Habitat corridors can also be grouped based on their continuity. Continuous corridors are unbroken strips of habitat, while "stepping stone" corridors consist of small, separate patches of suitable habitat.

Wildlife corridors include aquatic habitats, such as riparian zones. Areas along rivers can act as wildlife corridors, helping animals move between land and water. Removing barriers in rivers helps restore connections in aquatic habitats, increasing the size of habitats available for species.

Corridors can include structures like underpasses or overpasses. These allow animals to cross human-made structures, such as highways or canals, which can reduce the number of animals killed by vehicles. Some animals prefer underpasses, while others prefer overpasses.

Wildlife overpasses and underpasses help different species move because animals often have different preferences for crossing structures. For example, in Banff National Park, black bears and mountain lions often choose underpasses, which offer a darker, more protected path across the Trans-Canada Highway. Grizzly bears and large animals, like elk, often use overpasses. Large animals and carnivores regularly use underpasses, while smaller animals had fewer sightings in underpasses between 2008 and 2018. Studies in Banff show that animals may take several years to get used to using overpasses and underpasses, but they often do.

Wildlife corridors can take many forms, such as long, unbroken areas of habitat or a series of smaller habitat patches. In conservation ecology, the SLOSS dilemma (whether to protect one large area of habitat or several small areas) has been debated for many years. Large, connected areas, like national parks, have often been the focus of conservation plans. However, studies show that protecting many small areas and connecting them—especially to a large area—can sometimes help more species survive.

In a wildlife corridor, connecting several small habitat areas, called "stepping stones," can help reduce biodiversity loss and habitat fragmentation. Connecting small habitat patches also helps species adapt to climate changes and maintain genetic diversity. In forests, connecting high-quality "stepping stone" habitats can reduce fragmentation. To find good areas for a wildlife corridor, it is important to consider how far they are from protected areas, existing corridors in the area, which areas have many species, and which habitats are key for biodiversity.

Wildlife corridors can also be created in urban areas, such as cities and towns. Urban areas often have high biodiversity, but urbanization can affect biodiversity in many ways, including changing animal behavior, the number of species, and genetic diversity. Urban areas usually have less biodiversity, but many have many types of vascular plants. Corridors, whether long, unbroken stretches of habitat or "stepping stones," can help improve biodiversity in urban areas.

Wildlife corridor usage

Most species can be grouped into one of two groups: passage users and corridor dwellers.

Passage users use corridors for short periods of time, meaning they can cross a corridor in a few hours. They use corridors for activities such as seasonal migration, moving to new areas as young animals, or traveling between parts of a large home range. Large herbivores, medium to large carnivores, and migratory species are common examples of passage users.

Corridor dwellers, however, can live in a corridor for many years. Species like plants, reptiles, amphibians, birds, insects, and small mammals may spend their entire lives in narrow habitats. In these cases, the corridor must provide enough food, water, and shelter to support these species.

In wildlife corridors, researchers can use mark-recapture methods and hair snares to study how animals move and how genes are shared between populations. Marking and recapturing animals helps scientists track where individuals go.

Researchers can also use genetic testing to study migration and how animals mate. By examining how genes move within a group, scientists can learn more about the long-term importance of wildlife corridors for migration and genetic diversity.

Monitoring how animals use wildlife corridors can also be done with tools that are easy for people to use. For example, to study bird populations, tools like eBird and i-Tree can be helpful.

Additionally, monitoring animal use can be done by looking at data from camera traps.

Corridor planning

Wildlife corridors work best when they are planned with care, taking into account how animals and plants live together. This includes considering how animals move during different seasons, how they avoid dangers, how they spread out to find new areas, and what kind of homes they need.

Designing corridors can help increase the variety of plants and animals. This can be done by making the corridors a little irregular or not perfectly balanced and by placing them so they cross habitat areas at an angle. However, this design might create edge effects, which are areas near the edges of habitats where the environment is not as good as in the middle parts.

Fencing is an important part of planning wildlife corridors. It can be used with structures like overpasses and underpasses along roads to help reduce the number of animals that are hurt by vehicles. Sometimes, it is not possible to put fencing along the entire road, so it is important to add fencing in places where many animals are killed by cars. When planning fences, people are discussing whether it is better to use many short fences or a few long ones. Many short fences might not work as well because animals can move around them more easily, which increases the chance of them being hurt.

Wildlife corridors can be created with the help of many different groups, including the public, local communities, water management groups, recreation departments, non-governmental organizations, government agencies, and landowners. To successfully create wildlife corridors, these groups must share the same goals and vision. It is also important to have clear rules and laws that govern the corridor, programs that encourage businesses to support the corridor, and research that identifies the best places to build corridors. These places include areas with high-quality habitats and areas that are near other corridors, which help connect different habitats.

Indigenous knowledge

The growth of human activities into natural areas affects both people and animals. When trying to restore habitats, it is important to get help from the local communities, including Indigenous groups, who live near the areas being restored.

Sometimes, ecological restoration projects do not include the ideas of many different groups. Instead, knowledge from Indigenous people about nature is often replaced with ideas from settlers when planning wildlife corridors and large-scale conservation efforts. This can lead to differences in understanding where animals live, what kinds of animals are present, and how their habits change with the seasons. Indigenous views about movement believe that the ability to make choices about where to go helps create strong relationships with the land. These relationships, called "expansive Indigenous modes of relationship," can help guide future conservation efforts. For example, the Yellowstone to Yukon Conservation Initiative is described as a new way of thinking about conservation, even though Indigenous groups, like the Flathead Nation, have long practiced similar methods, such as managing bison across large areas. Some people worry that the language used about connecting habitats focuses more on settler ideas, which is a concern raised by the Land Back movement.

Managing land and water areas can help Indigenous groups who depend on wildlife for traditions like fishing and hunting. Many Indigenous communities manage wildlife, but they often have limited money to care for large areas of habitat. In Canada, in 2025, Parks Canada and the province of British Columbia announced $8 million in funding for wildlife corridors and Indigenous stewardship. Also in Canada, a Mi'kmaw organization in Nova Scotia received $491,000 from Parks Canada's National Program for Ecological Corridors to help manage wildlife corridors on the land.

Human-wildlife conflict

Corridors can overlap with places where people live, leading to conflicts between wildlife and humans. These conflicts happen because wildlife habitats are damaged, and animals and people compete for resources. Conflicts can result in animals being killed on roads, animals eating crops, animals attacking livestock, or people being hurt or killed. In India, for example, many corridors that connect large areas of habitat also overlap with human settlements, such as rural villages. People in these areas respond to conflicts by using methods like poisoning animals, trapping them, or harming them. These actions can harm conservation efforts.

To reduce conflicts, different strategies have been used. In India, methods such as building fences, moving animals to new areas, and sterilizing wildlife have been tried. These methods are often costly and require a lot of effort.

Encouraging better attitudes toward wildlife corridors is another way to reduce conflicts. This can include offering financial rewards, such as direct payments for ecosystem services (PES), which give money to landowners and farmers for using practices that lower conflicts with wildlife.

Other methods to reduce conflicts include community-based approaches. In parts of Africa and Asia, groups of farmers work together to protect their crops. When they see animals, like elephants, they alert each other and make noise to scare the animals away. This system helps reduce damage to crops.

Examples

In Banff National Park, Alberta, Canada, a network of wildlife overpasses and underpasses was created in the 1980s to help animals avoid accidents on the Trans-Canada Highway. This system includes six overpasses and 38 underpasses. Parks Canada built the project, which covers more than 180 kilometers along the highway. It has reduced animal collisions by 80%. Animals such as red foxes, hoary marmots, snakes, and boreal toads have used these crossings more than 200,000 times. Large carnivores, like bears and wolves, have 50–100% fewer deaths from highway accidents than before the project. Ungulates, such as elk, now have nearly zero deaths from highway accidents. The overpasses have trees and native grasses, and fences on both sides help guide animals away from the highway.

In 2001, a wildlife corridor was built across a golf course in Jasper National Park, Alberta. This corridor was frequently used by wolves.

Along the Delhi-Mumbai Expressway, near the Ranthambore Tiger Reserve, a 3.5-kilometer wildlife overpass network was built. Each section is about 500 meters long. The project also includes a 1.2-kilometer underpass. By 2026, the project was partially completed.

In Southern California, researchers studied 15 underpasses and drainage culverts to see how many animals used them as corridors. These structures helped carnivores, mule deer, small mammals, and reptiles, even though they were not built specifically for animals. Scientists found that factors like nearby habitat, underpass size, and human activity influenced how often animals used these structures.

In South Carolina, an experiment studied butterfly movement and plant reproduction in five areas of land. The areas included a central habitat, four surrounding patches, and a wildlife corridor connecting the central area to one patch. Butterflies placed in the central area were two to four times more likely to move to the connected patch than to disconnected patches. Male holly plants were placed in the central area, and female holly plants in the connected patch produced 70% more seeds than those in disconnected patches. Seed dispersal through bird droppings increased the most in the connected area.

In the United States, the Florida Wildlife Corridor Act was passed in June 2021. This law created a network of nearly 18 million acres of connected ecosystems. The corridor starts at the Alabama border, goes through the Florida panhandle, and ends at the Florida Keys. It includes state parks, national forests, wildlife management areas, farmland, and ranches.

The Darlington Ecological Corridor in Montreal, Canada, is an example of an urban wildlife corridor. It connects Mount Royal, a city park, to a railway corridor through the Côte-des-Neiges-Notre-Dame-de-Grâce borough. The project began in 2014 as a collaboration between Université de Montréal researchers, the borough, and local groups like Éco-Pivot. Originally designed to help foxes on Mount Royal, the project expanded to include community food gardens, pollinator gardens, and natural stormwater management using rain gardens. The goal is to restore biodiversity and improve food security in Montreal.

The Mont Boullé Ecological Corridor in Jean Drapeau Park on Île-Ste-Hélène, Montreal, Canada, is another urban wildlife corridor. In 2023, the park started a project to create a dense forest on the island, planting over 27,000 plants, including small plants, shrubs, and trees. The project includes removing invasive species, building paths to protect new plants, creating a 334-square-meter valley to improve water infiltration, restoring historic stoneworks and trails, adding water fountains, and protecting nearby archaeological sites.

Examples of other wildlife corridors include:
– Paséo Pantera (also known as the Mesoamerican Biological Corridor or Paséo del Jaguar), which ended in 2018 due to funding issues.
– European Green Belt.
– Yukon to Yellowstone Conservation Initiative in the Americas.
– National Ecological Network in the Netherlands.
– Kanha-Pench corridor along NH 44 in India.
– Terai Arc Landscapes in the Lower Himalayan Region.
– Banff National Park’s network of wildlife corridors in Canada.