The Importance of Wildlife Corridors

Discover how wildlife corridors are helping reconnect fragmented sections of animal habitat while increasing human safety, plus how to use your rural land to help.

Productive wildlife habitat has been described as a patchwork quilt, where each piece represents a different type of habitat needed for food, cover and nesting.

When these patches become disconnected, and wildlife can no longer move easily or safely between them, wildlife populations often suffer with significant economic damage.

This disconnection can occur in many ways.

For instance, the Virginia Department of Transportation estimates that 70,105 miles of roads crisscross the state and create isolated sections of habitat.

Urban development is another source of fragmentation. A study by McGuire, Lawler, McRae, and Theobald published in the Proceedings of the National Academy of Sciences estimates that in the United States, only 41% of natural land has sufficient connectivity for wildlife movement, and this number is significantly lower in the eastern states.

The Indiana Division of Fish and Wildlife has stated that habitat fragmentation is one of the greatest threats to wildlife populations. These animals need the ability to move between food sources and access cover to reduce the chance of predation and avoid isolating populations and limiting genetic diversity.

Habitat fragmentation also comes with an economic cost. To move between habitat types, wildlife often has to cross roads.

In the United States, the International Fund for Animal Welfare reports that “collisions between motorists and wildlife cause more than 200 human fatalities and over 26,000 injuries each year, at an annual cost to Americans of more than $8 billion.”

Wildlife corridors are one solution to reconnecting these fragmented sections of habitat.

In an article written by Susan Morse for the U.S. Fish and Wildlife Service, Morse explains, “Whether they run, swim or fly, wild animals need to complete their life cycles. We call their routes wildlife corridors.”

These corridors may take many forms. For larger roaming animals, corridors need to incorporate extensive areas.  For instance, consider that the typical range of a black bear is fifteen square miles. With seasonal changes in food sources, bears will cover a lot of ground.

In the case of small game, Michael Hook, Small Game Program Leader for the South Carolina Department of Natural Resources, notes that rabbits, quail and songbirds have been able to eke out an existence in all sorts of scraps of cover. In the past, these have occurred on fence rows, ditches and farm boundaries.

In between these two examples are hundreds of species with varying needs. Consider fish, for example.

Species such as trout, herring and shad need access to streams for spawning.

Culverts, dams and bridges often impede the ability of fish to move upstream.

Assessments of streams in Virginia by Trout Unlimited and the Fish and Wildlife Service showed that over half the streams had structures limiting fish movement.

With issues as large as this one, solutions sometimes have to be taken up at the government level. 

Already, nine states have passed legislation to protect wildlife corridors.

Among these is Florida, with the Florida Wildlife Corridor Act passed in 2021. Included in this law is $400 million in funding to acquire land or easements covering 18 million acres.

This act is expected to benefit nearly 700 species, including the Florida panther, black bear and the West Indian manatee.

In addition, the law will link natural areas to create a system of greenways that could prove to be a foundation for hiking, biking, horse riding and other uses of natural areas.

The U.S. Fish and Wildlife Service is also helping to remove fish barriers.

Over the last four years, they estimate that replacement of old culverts and removal of dams has reopened 4500 miles for fish passage.

Trout Unlimited’s (TU) Reconnect Program targets stream blockage removal to improve fish passage and reconnect streams within a river ecosystem. 

Often partnering with government agencies or local groups, TU has helped remove diversion dams, replaced small or perched (lower end suspended above the stream) culverts and addressed low-flow sections of streams, opening thousands of miles of rivers. 

As individual landowners, we also have a role to play.  

For instance, if you are building roads that cross streams, give consideration to the movement of water below these crossings to provide adequate flow.

Culverts and bridges can be constructed wide enough for the stream to flow through beneath unrestricted.

For small game, Michael Hook says it’s easy to construct wildlife corridors. “Say you have a fence or ditch line you want to create a corridor around; simply allow a 20 to 50-foot swath along the line to begin to grow. Put your bush hog away.” 

Every 2-3 years, he adds, you may want to maintain these strips with a prescribed burn or disking. Or better yet, do it in halves in alternating years to maintain some of this favorable habitat continuously.

It’s easy to forget the roles we can play in keeping this patchwork of wildlife habitat connected. 

With the efforts of individuals, organizations, and government perhaps this is one issue we will start to see on the mend.