From Upstate New York to Costa Rica, Biology Professor Tom Langen Looks at the Impact of Roads on Surrounding Environments and Finds Solutions to Mitigate Damage

What started out as a passing curiosity about road kill has transformed Associate Professor of Biology Tom Langen into an international expert on the impacts roadways have on an ecosystem.

While driving the highways in New York's North Country, the California transplant noticed something strange: large numbers of dead frogs creating a sheen of green slime across the blacktop. "I thought wow, this happens and people never think much about it. It's just an accepted part of the landscape."

But the image of the dead frogs stayed with Langen, and soon he began his own investigation. "I was interested in whether this was a benign problem or if it was evidence of a larger environmental problem," Langen says. "I discovered that there was already a community of scientists and environmentalists looking at roads and their impacts on surrounding environments, including animal populations. In terms of a discipline, road ecology is still a pretty young field. It really only dates back to the early 1990s, when a few people started pointing out the deleterious effects of roads on the environment."

Roads and the Environment
Road ecology is concerned with the impact of roads on surrounding environments and ecosystems. While the interstate system has been around for more than half a century and roads millennia before then, ecologists have traditionally looked at more pristine landscapes, those untouched by humans, and avoided areas such as roads. In recent years, however, there's been a growing realization that many of the most complex environmental problems are located in the spaces where humans and the natural world intersect.

Indeed, the expansion of the roadway network and an increase in traffic volume has resulted in significant degradation and contamination of the environments bordering roads, by altering habitats, isolating plants and animal populations, spreading pollutants and exotic species into the surrounding landscape, and increasing human access to environmentally sensitive areas. "We block roads out of our minds. We drive them all the time so we don't even think about them," Langen says. "However, if you were to look at a map you would notice roads are a dominant land use in America and all over the world. If you were to gather all the roads and right of ways in the continental U.S., it would cover the state of South Carolina."

For Langen, highways are no longer simply a means to get from one place to another, but an area of intensive research that raises fundamental questions about the nature of human impact on the earth. How can we meet human transportation needs without compromising the natural world? Should we consider migratory patterns of animals when planning and constructing highways? How do we minimize the environmental damage caused by existing roads without compromising transportation safety?

Deicing and Environmental Contamination
Four year ago, Langen and fellow researchers associated with Clarkson's Center for the Environment and Paul Smith's College of the Adirondacks formed a multidisciplinary team to assess the long-term environmental consequences of current winter road maintenance practices on soils and lakes in the Adirondack Park, and to identify alternatives that may be less environmentally harmful. The project was largely funded by the New York State Department of Transportation.

"The question we wanted to answer was how do we reduce some of the harmful effects of road deicing on the environment and still maintain safe winter travel," recalls Langen. "Road salt (sodium chloride) is readily transported through soil and into water bodies. Although non-toxic in low concentrations, at high concentrations it stresses plants and animals, ultimately eliminating native salt-intolerant species and promoting the growth of salt tolerant ones, including exotic invasive species."

In the two lakes that were the primary focus of the study, Upper Cascade Lake and Lower Cascade Lake, the scientists found concentrations of chloride that were over 100 times higher than expected in typical Adirondack lakes. The high chloride concentration was linked to the heavy road salt and sand applications along Highway 73, a well-traveled road that runs through Lake Placid.

Langen and the research team recommended that certain salt-tolerant native plants be planted along the roads to restore vegetation and soil fertility, and that a target reduction of 15 percent less road salt use should prevent the water quality of the Cascade Lakes from further deteriorating. These recommendations are currently being implemented by the Department of Transportation.

Costa Rican National Parks and the Pan-American Highway
Langen’s research stretches far beyond dead frogs and icy roads in northern New York.

The North Country professor spent the last year in Central America, supported by funding from both the National Geographic Society and the Fulbright Fellowship Program.

"Costa Rica has one of the most extensive and best-managed systems of parks and protected areas in the world," says Langen. "Many of Costa Rica's parks, which serve as natural wildlife corridors, are bisected by major national highways. This disrupts connectivity by deterring migration or by causing excessive mortality due to roadkill."

In Costa Rica, Langen and his research team studied sections of road along the Pan-American Highway, the main thoroughfare through Central America. The scientists wanted to determine what effects the increased traffic due to growing trade with the United States is having on native animal and plant populations. "The Pan-American Highway bisects one of Costa Rica’s largest national parks and cuts through a seasonal migratory route for animals moving between the upland mountain area and the lowland dry forest," says Langen.

Langen not only studied animal migration patterns and identified hot spots of road mortality in Costa Rica, he also facilitated a number of workshops to help local transportation and park officials to understand road-related problems and find ways to mitigate them. "I was training people who work in those areas but have never been trained in ecology. Many are aware of the problems; they see the evidence of dead monkeys electrocuted by the power lines that run along the roads or hotspots of roadkill."

Langen also helped mediate a discussion between the Park Service and the Ministry of Highways. Disagreements have developed over the Ministry’s plans for highway expansion and a Park Services’ initiative to promote the growth of a natural canopy of vegetation over the road to serve as a bridge for animals to safely cross the highway.

From Research to Real-World Application
Langen often works with government agencies and people in the transportation industry to find solutions to road-related environmental problems. Langen says that he'll often get a call from a New York state agency or from another state with a problem and is funded and tasked with finding a solution. "Most of the time we're not working to design new roads but retrofitting roads which have been already built," he explains.

It is the application of his research that Langen finds most rewarding. "Before I got involved in road ecology, my research was primarily academic with no immediate application. I had very little contact with people in agencies or policymakers. That is one of the attractions of road ecology. You can go from the research to the application directly."

Back in his Clarkson classroom, the hands-on application of road ecology has also attracted a number of students. Every year there are more students who are interested in his internships than slots available and, despite the harsh winter conditions, roads are studied year-round. "There is a lot of student interest in research that has a clear impact on the world."

Langen's field of expertise is also a good fit for the University. "It's a very good environment for collaborating and Clarkson has a good history of working with local agencies," he says. "As for the field of road ecology, I think it fits Clarkson's mission of using technology to solve problems to improve human life, and in this case, the environment as well."