Consider the frustration you feel when your usual route to work is blocked off by construction.
Now imagine that your only chance to eat that day is on the other side of that road. You’re now disoriented — and starving.
This is a glimpse of what our wildlife experience when their ancestral habitat is divided and blocked by swatches of human development. Habitat fragmentation — and ultimately, habitat degradation — is a huge problem facing local wildlife. The available habitat is becoming increasingly smaller, and the quality of land is declining as well.
One way to ease the strain on animals is to ensure that those remaining patches of habitat stay intact and together. Wildlife needs to have the ability to move back and forth freely; that’s where wildlife corridors come in.
Why are wildlife corridors important?
Local wildlife require habitat connectivity to ensure they have access to ample food, breeding grounds, and safety from human dangers (like traffic collisions). To truly be connected, these patches of habitat also need proper buffers from human interference to stay robust.
When done right, wildlife corridors link human infrastructure with “ecostructure,” ensuring both live in harmony to the greatest extent possible.
What do wildlife corridors look like?
So what are some practical applications of wildlife corridors? Here are just a few examples of corridors you might see while out enjoying nature.
Fencing
This option is simple, yet useful. Corridors can be created simply by keeping wildlife restricted to areas where they are safe, and away from places where they aren’t (like roadways.) Fenced corridors can be found in crossing locations like parks and other developed areas to prevent animals from entering roadways.
Freeway overpasses
When animals need to cross busy highways, problems ensue. That’s why freeway overpasses are crucial to ensure animals (such as mountain lions, coyotes, deer, lizards, and more) have little disruption to their normal migration routes.
These overpasses are designed specifically for animals, and become mini greenbelts in themselves. And, the state already has some in the works: a 200-foot long animal overpass bridge — the largest wildlife crossing in the world — is planned to open over the 101 Freeway by 2023.
Culverts
Land animals aren’t the only ones that benefit from wildlife corridors. Fish like salmon and steelhead require free movement up and downstream, and normal culverts are often too small or angled too high.
Proper culverts can be designed to mimic the stream bed and provide uninterrupted access for these busy swimmers. This allows fish (especially anadromous fish) to access spawning grounds and repopulate for generations to come.
Underpasses
Similar to overpasses, these underpasses act like tunnels to cut through developed areas. These generally aren’t as aesthetically-pleasing as animal overpasses, but they can be integrated into otherwise cramped spaces with ease.
Greenbelts
Sometimes, the best wildlife corridors don’t require construction at all. Undeveloped or minimally developed land like ranches and parks let critters pass easily without having to navigate urban infrastructure. Keeping these areas rural leaves large patches of habitat practically untouched, vegetation and all.
Are there wildlife corridors in San Diego?
Yes! These linkages are vital to local wildlife, and they can be found right in our city.
- If you ever travel to the San Diego River valley, Mission Trails Regional Parks provides a habitat corridor that leads to the ocean.
- There are several mountain lion ranges in Southern CA between San Diego and Los Angeles which are crucial to maintain range and gene diversity throughout Liberty Canyon
- The Liberty Canyon Wildlife Crossing animal overpass is planned for 2023 to cross over ten lanes of traffic over 101 Freeway. This will let wildlife traverse in and out of the Santa Monica Mountains with ease.
A Path Forward
Wildlife corridors can be interwoven seamlessly with current infrastructure, with a little planning and creativity. With an “ecostructure” mindset, we can help native vegetation stay robust, naturalize floodplains, reduce vehicular collisions, and overall make our landscape a better place for animals and humans alike!