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New Animal Overpass Is Saving Wildlife

Story at-a-glance -

  • Washington is one state taking steps to reduce the danger for animals in areas where roads, including multiple-lane interstates, have been a growing type of threat to wildlife
  • The latest installment of a billion-dollar project to construct 20 animal crossings not only allows wildlife to cross a major interstate, but allows animals to continue their natural migration patterns
  • Inspiration for the Washington project was initially modeled after an underpass and overpass in Banff National Park, crossing the Trans-Canada Highway
  • Researchers put motion-detection cameras in culverts throughout the state of Maryland to learn more about how wildlife might use culverts, or storm drains, to avoid traffic
  • A camera captured the first image of wildlife using Washington State’s newest I-90 overcrossing east of Snoqualmie Pass

With the encroachment of modern civilization, with its expanding cities and increased traffic, the habitats for numerous types of wildlife are not only growing steadily smaller, but further jeopardizing the safety of animals seeking food and roaming what were once lands uninhabited by humans.

Washington is one state taking steps to reduce the danger for animals in areas where roads, including multiple-lane interstates, have been a growing type of threat to wildlife. As such, the latest installment of a billion-dollar project to construct 20 animal crossings not only allows wildlife to cross a major roadway — Washington State's Interstate 90 — but allows animals to continue their natural migration patterns.

The Washington State Department of Transportation's (WSDOT) construction on the overpass situated east of Snoqualmie Pass that connects two isolated habitats stretching from the north to the southern Cascade Mountains is projected to be complete by the fall of 2019.

Studies indicate that different types of animals have different crossing preferences as they "hoof it" from Point A to Point B on their various routes, so they've been given options to help ensure safety for as many animal species as possible. For instance, researchers discovered that while male bears seem to make their treks through underpasses, females and cubs travel on overpasses.

When video footage captured the first user of the new overpass — a coyote "prancing across the bridge and making it to the other side safe and sound" — Pet MD reported, WSDOT made an exultant Twitter announcement reflecting the elation felt by animal advocates, scientists, citizens and legislators alike:

"Nice! Our camera captured the 1st image of wildlife using the new I-90 overcrossing east of Snoqualmie Pass. This coyote safely crossed the highway, avoiding traffic, anvils, ACME rockets & roadrunners! Excited to see what other species cross!"1

Experts say the bridge still requires barrier fencing to buffer the noise of traffic, but that it's exciting to see that wildlife in Washington has already started to make good use of the safe passageways created for them. Challenges in this area of the U.S. include a limitation of only six months of the year due to inclement weather in the mountain passes.

Wildlife Crossings 'the Easiest and Most Natural Paths Forward'

Inspiration for the Washington project was initially modeled after an underpass and overpass in Banff National Park, crossing the Trans-Canada Highway. Since it opened 20 years ago, an estimated 152,000 animals have crossed that overpass safely.

According to Meagan Lott, a spokeswoman for WSDOT, the well-thought-out program for protecting wildlife in Washington came about due to collaboration between WSDOT, the Forest Service and Conservation Northwest, the latter of which got involved in 2004 after officials purchased around 40,000 acres on both sides of I-90.

The role of Conservation Northwest is varied, from marketing and explaining the project to the public, advocating for continued funding and overseeing a citizen wildlife monitoring program. Lott noted how astonishing it is to see the different types of wildlife using the undercrossing and added:

"You have a really limited bottleneck for wildlife to move from the north to south Cascades … We did a lot of animal monitoring, and this kind of showed that this was a natural migration pattern for animals coming down from the mountain."2

Two animal underpasses on the same stretch of road were already in place when construction on the latest one, costing $6.2 million, was underway. However, it's still considered a rare infrastructure, as only one other overpass exists in the state, according to Spokane, Washington's The Spokesman-Review.

To allow wildlife of all kinds to continue their long-established overland traversing patterns and do it safely, one way authorities in the state of Maryland determined what would be needed where was explained by J. Edward Gates, Ph.D., a professor at the University of Maryland's Center for Environmental Science:

"Researchers in Maryland put motion-detection cameras in culverts throughout the mid-Atlantic U.S. state to learn more about how wildlife of all kinds use culverts, or storm drains, to avoid motor traffic … Culverts are intended to channel water under a highway. But it turns out that animals of all kinds have figured out how to exploit such man-made structures to avoid becoming roadkill."3

Elk don't particularly care to use such infrastructures to get to their chosen destinations, but a wide range of other animals do. Gray wolves, grizzly bears, mule deer, black-tailed deer, red foxes, wolverines, river otters, cougars, lynx and bobcats are some of the wild animals in the Cascade Mountain range region, according to North Cascades National Park website.4

Why Balance Wildlife Habitats With Human Transportation Needs

The ecological impacts of putting in roads has been studied in relation to the mortality of animals. It severely threatens them and, in some cases, has been the leading cause of some species decline.

When a road crosses through an animal's preferred habitat, the chances increase for road mortality. For example, Highway 27 in Florida that passes over a lake inhabited by many turtles has been shown to have very high turtle mortality rates and be one of the most dangerous roads for wildlife in the U.S.5

The reasons animals end up on roadways are varied, and it sometimes impacts birds as well as four-footed species. Snakes and turtles stay longer on asphalt than they should if those surfaces have been warmed by the sun.6 Chimney swifts chasing mosquitoes frequently fly close to the ground, increasing their risk of getting hit on highways.7 Other birds are unable to initiate flight quickly enough when oncoming traffic approaches.

In Florida, authorities put a wildlife crossing in place for panthers, bears, alligators, bobcats, deer and coyotes, featured in the above video and posted by the Center for Biological Diversity. Representatives say such crossings are effective tools that can help combat needless deaths of wildlife, and represent a win-win for protecting wildlife and drivers from injury or death from collisions.

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