If highways can imperil grizzlies in remote areas, they're even more of a menace to wildlife in settled regions.
To watch a grizzly bear in the wild is to see nature at its most indomitable. A grizzly can drive a wolf pack away from elk it killed in the spring, and then can rove hundreds of miles throughout the summer to find pine nuts, moths and trout to subsist on.
But even grizzlies run into trouble where they encounter highways. Two grizzly sows were killed by trucks in the past couple of years trying to cross a two-lane route leading to Glacier National Park. And, the four-lane Interstate 90 corridor through Montana will probably deter Yellowstone National Park's isolated grizzly population from wandering north to breed with other remaining bears to assure a threatened species' survival.
If highways imperil North America's most redoubtable animal, even in the Rocky Mountain backcountry, they're even more of a menace to wildlife that's still hanging on in more settled regions of the country. Cars and trucks on American roads kill 1 million birds and animals a day. Traffic collisions with wildlife cost 177 people their lives in 2001 and injured nearly 30,000.
The roadkill issue also provides a glimpse into insidious environmental damage. Asphalt pavement, metal guardrails and concrete Jersey barriers fracture forests, wetlands and grasslands, especially along the rural-urban fringe surrounding big metropolitan areas. Some wildlife, such as deer, can thrive, but many others may be doomed when they're segregated into small and isolated populations. With 4 million miles of roads now crisscrossing the country, "we're doing a number on biodiversity across America, and we need to repair that," says Richard T. T. Forman, a Harvard University professor and co-author of "Road Ecology."
Governments can mend the landscape. As highway engineers begin to replace old and crumbling bridges and rebuild country lanes that suburban growth has turned into traffic-choked thoroughfares, governments can redesign this infrastructure to reconnect wildlife populations.
As David J. Scott, the Vermont Agency of Transportation project director, points out, "if you're going to lengthen a bridge anyway, by adding 10 or 20 feet on either side you can provide a natural corridor for the animals." Florida's transportation program has taken even more proactive measures, building 24 underpasses along I-74 to give endangered Florida panthers safe passage beneath the roadway. Florida has also installed passes for black bears, deer and turtles that have suffered heavy losses along the roads built as subdivisions spread across their habitat. Massachusetts has constructed a culvert for salamanders, and Vermont is putting up 3-foot-high fabric fences to keep frogs from Lake Champlain marshes from crossing the road.
Protecting wildlife doesn't come without some controversy. Near Orlando, a task force appointed by Florida Governor Jeb Bush has recommended redesigning a controversial bypass project to build a 7- mile-long elevated parkway to protect natural springs and let black bears move freely beneath the roadway. Apopka and Lake County officials are campaigning against the redesign. They think it cuts short the region's economic prospects. Of course, highway engineers and local officials have been moaning for years that dealing with environmental concerns delays important road-building projects.
But others now rising through state agency ranks recognize that it makes more sense to take wildlife impacts seriously and incorporate solutions into well-designed plans that don't invite protracted legal challenges. Vermont's agency has brought state Natural Resources Agency biologists into preparations for the rebuilding of a state highway near Lake Champlain, and Florida is setting up interagency teams to review all road-building plans to make sure they mesh with the state's comprehensive plan for preserving wildlife habitat. The U.S. Congress has directed every state to develop similar biodiversity plans. Geographic information system technology gives governments a powerful tool for determining where wild animals are likely to move. Then engineers can redesign roads so the animals can go there.
The White House is streamlining federal environmental reviews, which means states need to do their biology homework. Federal officials are, for instance, expediting Montana's project to widen a 50-mile stretch of U.S. 93 where the two grizzlies died in traffic. To their credit, state officials and two Native American tribes are ready with plans to incorporate 40 culverts and underpasses beneath the refurbished road to accommodate a rich multiplicity of fish and wildlife along the highway. They'll also build a 150-foot-wide "land bridge," covered with native vegetation, where wolves, mountain lions, bobcats, elk and grouse commonly cross the right of way.
The bridge also will let grizzlies move south from the Bob Marshall Wilderness toward the Bitterroot Mountains. Biologists are thinking ahead about similar I-90 crossings that could re-establish links all the way to the Yellowstone ecosystem. The U.S. 93 bridge will cost $2 million or more, but that's not too much to pay to give grizzlies a better chance to survive.