The open road is a dangerous place, especially if you're not in a car. But thanks to a new "road ecology" project, people who defy these dangers on bicycles and on foot are uniting to help their carless counterparts in the animal kingdom, who often bear an added burden of not quite grasping the risks.
Led by Adventurers and Scientists for Conservation, the project seizes on the recent trend of citizen science, crowd-sourcing roadkill data from volunteers worldwide. While anyone can report a sighting — including people in cars — ASC executive director Gregg Treinish says cyclists and pedestrians have a unique appreciation for animals' vulnerability on roads, which many motorists treat as single-purpose car corridors.
"It's a scary prospect while you're road biking that you could get hit by a car," Treinish says. "And it happens. Maybe not as often as with wildlife, but it does happen."
By amassing so much data, researchers hope to learn which species are most affected by road traffic, as well as when, where and how often they're hit. This would not only reveal threats to individual species and populations, but may also identify potential "roadkill hotspots." If there are places where traffic is unusually deadly to animals, more data might build support for tackling the problem, whether by adding animal-crossing signs, building wildlife overpasses or simply lowering speed limits.
The ASC's Roadkill Survey expands on two smaller, state-level projects set up in California and Maine over the past three years, both developed by the University of California-Davis' Road Ecology Center. The REC opened in 2003 to study "the impact of roads on natural landscapes and human communities," and it's now working with the ASC to let citizen scientists "collect data anywhere there are roads," Treinish says.
It's also easy to report the data, thanks to an online form and a smartphone app designed by iNaturalist. Photos help, but they aren't necessary — organizers mainly want basic details about the animal, location and time. The ability to collect this kind of data so quickly and on such a large scale is a big deal, says UC-Davis ecologist and REC director Fraser Shilling, because it's paving the way for an unprecedented cache of information about wildlife, both living and dead.
"There are two stories here," Shilling says. "One is understanding what causes roadkill, where there might be more roadkill than other places, and where we can start doing something about it. The other story is that there are no large-scale wildlife observation systems in the world, no standardized protocols. This is that system, taking people's observations and mapping them out over space and time. If we do this over years and years, we can learn really important stuff."
The global survey is still in its early stages, but local research has already shed some light on roadkill in recent years, Shilling adds. The busiest highways have low roadkill rates because animals rarely try to cross, while urban roads are generally clear due to sparser wildlife in cities. Most roadkill occurs on "less busy, but still high-speed, rural highways and roads," Shilling says, adding that curvy roads are worse.
Raccoons were the most common roadkill in California last year with 1,693 reported, followed by striped skunks (1,372), ground squirrels (845), opossums (763) and mule deer (761). The top casualties in Maine were eastern gray squirrels (503), porcupines (447), raccoons (266), striped skunks (214) and wild turkeys (212). Nationwide, the REC estimates there are up to 2 million animal-vehicle collisions every year. And these aren't just bad for wildlife — striking big animals like deer can also hurt motorists, and Shilling points out many crashes occur when drivers swerve to dodge a collision.
Manmade wildlife overpasses can help some animals avoid roads, from common varieties like raccoons and white-tailed deer to endangered species like a recently spotted Canadian lynx. Walls and fences may also work, but in general, Shilling is skeptical that building new infrastructure will make a dent in roadkill rates.
"There's roadkill everywhere," he says. "There are very few hotspots. Hotspots are a convenient fantasy for conservation planners. They make it seem like you can solve the problem by building overpasses, but it's really a much broader problem about human behavior." No certain type of vehicle stands out as a top roadkill culprit, although most cars, trucks and SUVs that hit animals do have one thing in common, he adds: "The type of car that's most likely to cause roadkill is a fast-moving one."
Speed is often the deciding factor in all kinds of traffic accidents, and wildlife collisions are no different. Shilling doesn't entirely dismiss building overpasses, but he says focusing on driving habits instead would be more effective and produce broader benefits: "There are places in the world with speed limits for wildlife. When we have people driving 75 or 80 mph through the Sierra Nevada, we're going to be losing wildlife. If we want to protect wildlife, we need to address the problem."
And the first step in addressing a problem is understanding it — something that's much easier now with citizen scientists pitching in. "I still have an old box of roadkill observations that a fish and game biologist was recording, and it's all hard copy," Shilling says. "It's great data, but it's sitting in a box. It's really hard to share it, and a system like this makes it easy to standardize the reporting and share the data."