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Why did the porcupine cross the road? ‘Critter cams’ might tell us


Tuesday, October 04, 2016

There is a term in research for the moment when theoretical brilliance touches base with real data, hoping to discover that it hasn’t led itself down the garden path. It is called “ground truth,” and it is the reason the Nature Conservancy has been photographing roadways in Coos County for the past year.

“We wanted to build the confidence that the wildlife we thought was there, are actually there,” said Pete Steckler, who is GIS and conservation project manager for the New Hampshire chapter of The Nature Conservancy.

The group put 25 motion-sensitive Bushnell cameras along a portion of Route 3 near the Connecticut River, from Lancaster north to Stratford, because it wanted to see which forest-dwelling, wide-ranging mammals were trying to cross the busy road (well, busy for Coos County), and where they were doing it.

What is a forest-dwelling, wide-ranging mammal? Steckler ticked off the list: “Bear, bobcat, lynx, porcupine, otter, mink, marten, snowshoe hare, weasel. . . . I think that’s it.” (Deer and moose are in a different category of creatures-interacting-with-roads.)

The list, he said, is based on New Hampshire Fish and Game and New Hampshire Audubon models that show “if we accommodate those, we’re meeting the needs of broader sweep of wildlife in the landscape.” Notably, these animals encompass a variety of habitats and behaviors – lynx are frightened by car noise hundreds of yards away, while porcupines don’t give a hoot about anything.

And why do they care about why animals cross the road? (Chicken jokes are almost unavoidable, but I’ll avoid them.) Because of “connectivity.” That’s a clumsy word but it’s a key concept in wildlife preservation.

Naturalists are increasingly focusing their attention not just on preserving wild lands but figuring out ways to hook those lands together so that wildlife can travel from one safe place to another – movement that is increasingly important as climate change alters ecosystems.

“Traditionally, land preservation has concentrated on hillsides, or areas that are harder to get to. It’s the connectors that we’re missing,” Steckler said.

And roads, as we all know from driving past dead skunks, are a big obstacle to that movement.

Figuring out ways to help animals cross these roads, or at least how to channel animals away from areas where they are most likely to be hit, is a big step.

But you can’t do that until you know where animals are actually trying to cross, which brings us back to the cameras.

As Steckler explained it, the Nature Conservancy used a number of ecosystem models, topography and other data, much of it based on aerial data put onto maps via GIS (geographic information systems, as you probably know), to estimate where animals were mostly likely to be crossing Route 3. But without ground truth, they weren’t sure where to focus their attention.

“We used computer models to identify areas where habitat is intact and wanted to follow that up with this camera-trapping study to give us more confidence in where we might try to implement wildlife connectivity projects,” he said.

So what did it find? Much of it was obvious, such as the fact that as you get closer to even limited development with barking dogs and noisy people, fewer animals will approach the roadside. But you can never be sure that “obvious” things are actually true unless you do a bit of ground-truthing.

A less obvious finding, Steckler said, is that steep slopes, which seem like great animal pathways because people avoid them, proved to be an obstacle.

“We expected to get a lot of movement there but we didn’t. I suspect it’s the topography was too steep, so not much moves through,” he said.

Next step is to use this information to help the Department of Transportation, local communities and private landowners decide where, and if, to do things like put up roadside animal barriers, add signs (“Caution: Meandering Porcupines Ahead”), change speed limits or do something else. The most extreme example would be animal-crossing bridges or tunnels, but those are wicked expensive and unlikely to appear any time soon.

“We’ll be deciding where can we do some projects along the road that will allow for safe conditions for the motorists, and allow for wildlife passage,” Steckler said.

The New Hampshire effort is part of a bigger project called Staying Connected (stayingconnectedinitiative.org), which covers the entire Northern Forest from New York state through the Canadian maritime provinces. It seeks to “restore and enhance landscape connections for the benefit of people and wildlife across the Northern Appalachian/Acadian region,” which makes sense because animals don’t pause at state or national borders.

The wildlife cameras are still out there gathering data. They’re involved in a pilot project with the DOT to help cut down on dangerous animal/car collisions.

And expect more cameras in the future. Similar wildlife projects are ongoing throughout the Northern Forest area, and conservation officials are trading findings to develop best practices; they even held a “camera trapping summit” to help out.

By the way, the cameras point away from the road so they won’t fill up with pictures of each passing vehicle. So don’t worry about the Nature Conservancy seeing you speed to your favorite fishing hole.

(David Brooks can be reached at 369-3313 or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)