The New York Times recently published "Thinking Anew About a Migratory Barrier: Roads" in which reporter Jim Robbins explores the impacts of road development on wildlife habitat at Glacier National Park in Montana.
Noting that scientists now understand the impacts of roads crisscrossing the landscape, Robbins writes "Some experts believe that habitat fragmentation, the slicing and dicing of large landscapes into small pieces with roads, homes and other development, is the biggest of all environmental problems."
Dr. Michael Soulé, retired biologist and founder of the Society for Conservation Biology is quoted: "It's bigger than climate change. While the serious effects from climate change are 30 years away, there's nothing left to save then if we don't deal with fragmentation. And the spearhead of fragmentation are roads."
For perspective as to the enormous roads which have been built along forested Appalachian ridgetops for industrial wind energy projects, Windaction.org examined these images prepared by Dan Boone, which provide before and after aerial photos of the very southern end of the NedPower windplant in West Virginia. The NedPower facility is the most recently constructed wind energy project in the mid-Atlantic region, comprised of 132 2-MW Gamesa wind turbines, each nearly 400 foot tall and a 3-blade rotor assembly with diameter of more than 260 feet.
The average width of the area bulldozed for the road corridor and other project infrastructure varies from about 75 to 100 feet. We estimate that over a square mile of forest was lost due to this one wind facility, about 650 acres, or roughly 5 acres of forest cleared on average for each wind turbine. The forest acreage loss is greatly exceeded by the amount of ecologically-significant "forest-interior" habitat that was eliminated by the extensive fragmentation of the area's forest coverage.
From an ecological perspective, roads create "edges" which severely affect "forest interior" wildlife. For example, woodland birds which nest near forest "edges" are more likely 1) to have their eggs or young taken by scavengers/predators who disproportionately frequent "edges", and 2) to be "parasitized" by brown-headed cowbirds who lay their eggs in other birds' nests. In addition, there are a host of ecological concerns associated with created "edges" within the "forest interior" such as:
1) increased sunlight and evapotranspiration (drying) which changes vegetation structure and composition along the zone of forest that adjoins edges, with penetrating effects up to several hundreds of feet, and
2) greatly increased dispersal and colonization of forest edges by invasive, non-native species of plants and animals.
Wind developers typically downplay the size of the roads and press for mitigation to compensate for the impacts. But it's nonsensical to assume 'X' acres of disturbed forest-interior can be mitigated with 'Y' acres of some arbitrary parcel some distance away.
Trisha White, director of the Habitat and Highways Campaign for Defenders of Wildlife notes, "the downside of mitigating road impact is thinking that it heals all wounds. The biggest danger is thinking that we can put in new roads with crossings and things will be just fine. There are so many more impacts. Nothing could be more incorrect.”