This may be just what viral YouTube sensation Donna, the Fargo radio caller who wants to move deer crossing signs, is looking for. For approximately the past 30 years, the Highway Wilding project has been working with the Banff National Park in Alberta, Canada and other locations to find various ways of connecting large-scale landscapes, including installing wildlife “overpasses” where animals can safely cross thoroughfares.

Based on their research and ecosystem management, Highway Wilding hopes to provide solutions to reduce conflicts between wildlife and motor-transportation for the benefit of animals and humans.

In Banff National Park there are already 44 overpasses. The overpass is like a bridge over water, but the bridge is a living, breathing continuation of the habitat of the surrounding area and the water below is the Trans-Canada Highway. Liza Lester, communication officer for the Ecological Society of America said there are also some of these overpasses present in Montana, Nevada and potentially Washington state.

A different view of a wildlife overpass in Banff National Park

The project targets all animals and even plants, regardless of size, in both urban and remote areas. “If you’re a big animal, like a deer, you can move pretty easily through a landscape,” Lester said. “Other animals are smaller and need continuous habitat to know where to go. If [their habitat] is three miles away, they don’t know how to find it.”

The press release below is part of ongoing research into these various habitat connections which encompass much more than overpasses. Pulverts, or tubular underpasses, are also explored. However, the hardest part is not building these passageways, but deducing what attracts wildlife to these areas, why and what else can be done to connect natural landscapes. Find out more about the Banff Wildlife Crossings Project at Parks Canada.

Original press release issued by Ecological Society of America on October 18, 2012

We live in a human-dominated world. For many of our fellow creatures, this means a fragmented world, as human conduits to friends, family, and resources sever corridors that link the natural world. Our expanding web of highways, cities, and intensive agriculture traps many animals and plants in islands and cul-de-sacs of habitat, held back by barriers of geography or architecture from reaching mates, food, and wider resources.

A team of researchers, managers, and ecological risk assessors review the current state-of-the-art in landscape connectivity planning, offering models, case studies, and advice for coping with the uncertainty inherent in dynamic, real-world conditions in the Ecological Society of America’s 16th volume of Issues in Ecology.

Connectivity Doesn’t Always Mean Corridors

“The shortest path is not always the best path,” said author Sadie Ryan, an ecologist at the State University of New York in Syracuse. “Connectivity is not always just a straight line of greenway that you can identify from an airplane.” Connections can be conduits, or more complex extensions of habitat, looking more like a web than a greenbelt. Coastal inhabitants need the depth of the reach of tides as well as the horizontal reach of coastline habitat. Birds may be able to hop from preserve to pea-patch to backyard oasis, depending on their range and flexibility.

Connectivity models can be combined with least-cost or circuit theory economic models to help conservators make decisions about investment in land acquisition. From figure 5 of the report.

The need to move is most obvious for migratory animals and the large animals that need big tracts of territory. Most of us are aware of large and charismatic animals like deer, bear, or coyotes. But plants, and smaller, less itinerant animals, also benefit from connections to wider spaces.

“Landscape connectivity is as diverse as the animals that live in it,” said lead author Deborah Rudnick, an environmental scientist with Integral Consulting Inc, in Seattle, WA.

On the ground, managers need to address the biology of their focal species, understanding behavior, genetics, adaptation, and habitat. They have to scale up observational and experimental data to predict interactions with other wildlife and physical features of the landscape, layering on the possibility of climate changing, waterways shifting, and human life encroaching. “It’s a massive amount of info to keep in your head simultaneously. I want people to step away from this review with a sense of that complexity,” said Rudnick.

No Perfect Solutions

Opening corridors can sometimes aid the flow of invasive species and disease, as well as the species at the heart of conservation planning. All management plans involve trade-offs—whether that means obtaining the best versus the most available land, or favoring a single endangered species at the possible expense of others in its ecological community.

Some planners prefer to focus on preserving ecosystem services, rather than specific species, in an effort to preserve an ecological community more holistically. But there is no perfect solution. Unpredictable future conditions are unavoidable complications to conservation efforts, and climate change in particular could throw a ringer into the best laid plans.

“We are no longer living in a world where we can preserve perfect habitat,” said Ryan.

Mule deer approach a wildlife overpass at 10 Mile Summit on UC Highway 93 in Nevada. Fences line the highway to discourage deer from attempting to cross through traffic.

Climate Change Means Wildlife Will Move–Unpredictably

Climate change, and wildlife’s response to climate change, is not a linear process. We can’t expect all species simply to move to colder climes, nor expect ecological communities to move as complete units, said Ryan and Rudnick. Species have independent capacities to adapt and move, decoupled from the ecological relationships of predator to prey, pollinator to flower, or grazer to grass.

“We’re seeing species moving to new territory independently, remixing existing communities and shaking conservation definitions,” said Rudnick. “What do we mean by quote-un-quote conserving a community? What does it mean in the face of climate change? You cannot expect a community to stay in the place that it was in the face of major changes in their environmental conditions.”

Our models, and management, must adapt to conditions changing in real time. Flexibility is not generally a virtue of government regulations. The timescale of legal decision-making is generally much shorter than we would want in order to provide communities, both ecological and anthropological, time to adjust.

Achieving Connections for Wildlife Requires Forging Connections with People

Corridors and connections are often in the spaces between preserves, the mixed use spaces occupied by human communities. Bridging barriers for wildlife means bridging the needs of the people living in that landscape. It means working with communities to find solutions that are practical, and possible, said the authors, not just from the perspective of science, but also residents, farmers, and industry. A first step is finding a common language. Ryan said she doesn’t talk about ‘ecosystem services’ in rural Uganda. Those aren’t Rutooro words. “We ask, “Is the park beneficial to you?”” and locals might say, “It keeps the rain.” They perceive benefit from the park, but don’t describe it like a scientist. The same is true of English-speaking communities.

You build your models, said Rudnick. “Then you try to put them in the real world. Community needs—that is, human community needs—add a whole layer of complexity to real life implementation.”

Aerial overpass image courtesy of Adam Ford, Highwaywilding.org, Ground view image from Brian Sterling (bsterling) on the flickr Creative Commons, Model image from Ecological Society of America, Rudnick et al., Issues in Ecology #16, Fall 2012. Nevada deer image courtesy of Nova Simpson

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3 thoughts on “Scientists Explore New Habitat Connections, Including Wildlife Overpasses on Highways

  1. Is there any research on the effectiveness of these overpasses in reducing animal/vehicle collisions in Banff? I think that type of information might help sell the widespread use of these structures.

  2. I live in Hagerstown, Maryland and was astounded to learn that deer regularly use a large drainage pipe to pass under Route 70. I consistnetly found deer tracks inside the six-foot diamiter conduit that was approximately 75 yards long. I’m sure this would be a much less expensive alternative to building an overpass.

  3. After traveling that section of the highway for many years, and now watching what’s happened since segmenting and disconnecting the habitat I’m anxious to see the data. Just about three weeks ago i watched several Parks Canada wardens chasing a three or four year old grizzly boar up and down the side of the highway, across the median, among parked cars, up road signs, into the fences – several times. It looked like chaos, and a complete lack of organized management of the situation. Trucks and cars were lined up for miles in each direction with the bear running up and down the highway in a panic. I’d say Alberta just spent a ton of money on a problem that would have better been solved by slowing the traffic down and enforcing a slower speed limit for that relatively short section of the highway, rather than building over passes, underpasses, and long miles of fences that will need managed forever, or at least as long as there are grizzly bears. In the mean time, the rail line is killing wildlife in droves. . . Did I mention that the grizzly bear was trapped in the highway corridor? I always wondered what happens when that occurs, now I know. . . It was awful. . .

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