Along the mountainous roadways that connect Western North Carolina to East Tennessee, wildlife mortality caused by vehicle collisions is rapidly rising. With a boom in tourism growth and an increasing human population in the area, this already dire situation will only get worse without proper, careful mitigation.
In the last two decades, there has been a substantial increase in traffic volume along Interstate 40 in the Pigeon River Gorge, which runs through this wild and scenic area bridging the two states. As of 2022, more than 28,500 vehicles pass through the 28-mile stretch of highway each day.
This corridor, which connects the Great Smoky Mountains National Park to other wild and public lands in the area, is home to large populations of black bear, elk, deer, bobcats, coyotes and other species both large and small. Furthermore, projected movements of climate-driven species suggest there will soon be a high concentration of animals migrating through southeastern North America into the Appalachians.
Driven by a desire to see beautiful, pristine landscapes and the wildlife harbored within, more than 12.5 million people visit the Great Smoky Mountains National Park each year, with many more visiting the region as a whole. But the animals of the national park don’t recognize invisible boundaries, roaming freely in and out of its borders.
Just like us, they travel in search of shelter, food and mates — and, to do this, they have to first cross our roads.
The I-40 corridor, like many other roadways around the nation, is fragmenting these species’ habitat, creating a “barrier effect” that separates wildlife from their needs. Habitat destruction and fragmentation are particularly threatening to far-dispersing species like black bear and elk that seek seasonal breeding and foraging opportunities outside park boundaries.
The questions we must answer are: Where do they go, when, and why?
Home, food and family often lie on the other side of the highway, and choosing not to cross can lead to the decreased health of entire populations — or even extirpation. But for each individual animal, crossing can also mean death.
A tally of records from collision reports, DOT maintenance staff in Tennessee and North Carolina, weekly driving surveys from researchers, and the N.C. Wildlife Resources Commission showed 162 large mammals were killed on I-40 between 2018 and 2022. Bear account for the largest share of the roadkill — in the last four years, at least 92 bear, 69 deer and one elk have died on that single stretch of highway. The figures likely represent an undercount.
From September 2018 to December 2020, researchers Steve Goodman and Liz Hillard tallied 140 bear, deer, and elk dead along the highway in the study area, with some of the data provided by N.C. Department of Transportation and N.C. Wildlife Federation.
It’s no surprise that bear fatalities from vehicle collisions have been on the rise in recent years as Western North Carolina’s population of up to 9,000 bears continues to grow by 5%-7% every year, according to the N.C. Wildlife Resources Commission.
Reducing mortality and lessening the barrier effect within the I-40 corridor is paramount to increasing the safe flow of animals in and out of the national park and to adjacent public lands. The first step to mitigation is gaining an understanding of how these animals navigate the landscape.
• Wildlife mortality rates are rapidly rising.
• 26,000 vehicles pass through the 28-mile stretch of highway in the Pigeon River Gorge daily — fragmenting species habitat and creating a barrier effect.
• Wildlife–vehicle collision-related costs add up to roughly $12 billion in the U.S. annually.
• The cost of a deer-vehicle collision averages around $6,000. Running into an elk can cost upwards of $17,000.
• Every 26 seconds (or less) a driver hits an animal in the United States, making highways one of the greatest barriers to wildlife movement.
• In addition to killing 1-2 million large animals every year, these collisions cause 200 human fatalities and more than 26,000 injuries nationwide.
• Road mortality is a serious threat to 21 endangered and threatened species in the U.S.
• Wildlife crossing structures have been shown to reduce motorist collisions involving wildlife by up to 97%.
The Importance of Species Diversity
Why is the loss of a single animal species important? Even the smallest species is part of the natural balance that keeps all of us alive. This balance is known as species diversity.
John Muir, who was one of the first to work hard to protect animals’ homelands from being destroyed, said, “When we try to pick out anything by itself, we find it hitched to everything else in the universe.” In other words, if something we do affects one type of animal, it can also affect many others, including humans.
The famous scientist and author E. O. Wilson pointed out that, “if insects were to vanish, the environment would collapse into chaos.” So, for all of us to thrive and be whole as a planet, we need to think about the needs of every type of creature, large and small alike.