What does it take to save a species? Sometimes, high-voltage power wires
By Beth Daley, Globe Staff - November 22, 2009
FOR DECADES, NOBODY in the US had seen the bee.
The silver-haired black Epeoloides pilosula was once widespread in New England, often found where native yellow loosestrife plants grew. But as the region's pastoral landscapes gave way to forests, the bee lost its sunny open home. In 1927 it was spotted in a Needham meadow and then, despite years of searching, not again. By the start of this century, dejected bee lovers were forced to conclude that the insect was likely extinct in the US.
Then, one bright June day in 2006, eureka: The bee was found in a hillside meadow by David Wagner, a University of Connecticut conservation biologist conducting a two-year bee survey in southern New England. Once the species was confirmed, there was a celebratory Mexican dinner and a published paper that rippled through the conservation world. If a rare bee like that could be found again, biologists reasoned, maybe there were other rare bees, plants, and wildlife hidden in similar environments.
Even more remarkable, though, was the environment where this find was made: In a 250-foot-wide power line corridor off Route 163 in Southeastern Connecticut. Transmission corridors have long been considered symbols of environmental degradation, with their enormous steel skeletons and high-voltage lines slicing through forests, wetlands, and salt marshes; they divide the landscapes that thousands of species need to survive. Yet now they are gaining a new reputation: As critical homes for faltering species of birds, bees, butterflies, plants, and a host of other species.
The corridors - carefully maintained to prevent trees from growing high enough to touch tension lines - can recreate the meadow and shrubby landscape that once dominated New England. Some scientists are even looking at these corridors as grassy escape routes for animals and plants from the harsher effects of climate change as temperatures rise worldwide.
"It's hard to explain to conservation groups that [species] are being saved in the most unpopular and disturbed kinds of landscapes," said Robert Askins, a biology professor at Connecticut College who has studied birds in transmission corridors. "I was shocked originally to be working in them myself."
The idea that transmission line corridors or any human-built infrastructure may actually help species is a counterintuitive one in the conservation movement, where the emphasis is often placed on preserving a landscape - usually by leaving it alone or ensuring it remains in some "natural" state to help certain species thrive. But in crowded New England, where people have altered the landscape for so long, saving beloved species may actually take more - not less - human intervention.
As species become more integrated with the industrialized infrastructure we have constructed, people's view of nature is also changing. One reason delighted commuters on Route 128 see more turkey vultures, some naturalists suggest, is that the southern species might be enticed northward by the intricate array of highways that makes it easy for them to find road kill. And who can't be proud that Boston's skyscraper ledges have helped endangered peregrine falcons return from the brink of extinction?
"I have heard the Northeast described as a large zoo, the whole place is completely managed," said Katharine C. Parsons, senior scientist at Manomet Center for Conservation Sciences in Plymouth. She is spearheading a new effort to work with states, companies, and wildlife groups to best site, construct, and manage transmission lines. "Intervention is what we do, whether we are conservationists or not."
Parsons is looking at the possibility that new transmission corridors will serve as emergency exits for animals or plants as the climate shifts. New England is already experiencing warmer winters, lengthening springs, and more extreme weather, such as severe rainstorms. Challenged species may be thwarted from moving to better environments because of highways or other obstacles blocking their way. The corridors, Parsons and others suggest, may provide these species an easier path north.
Now, as thousands of miles of new lines are proposed across the country to move wind and other renewable energy, conservationists are beginning to think about ways the lines can also be used to help the species we want to save. That may include avoiding biological hotspots where endangered species live, ensuring the pathways serve as critical links between larger tracts of forest, and better managing the corridors to entice species that have few other places to go.
It may not be a purist's view of saving nature. But as the world gets more crowded and true natural lands disappear, it is quickly becoming what conservationists have to work with.
"You wouldn't go out and design a landscape for ecological services and put roads or transmission lines there," said Marc Lapin, a conservation biologist who teaches environmental studies at Middlebury College. "But this is looking for ecological value in something that is benefiting humans."
BEFORE EUROPEANS ARRIVED, New England's vast mature forest wasn't all shade. Beavers would regularly chew down trees, creating dams that would flood - and then drown - large sections of the forest. Lightning, or Native Americans, would spark fires that consumed thousands of trees. And winds from fierce storms would blow down enormous swaths of the woods.
A baby forest would then spring up in the disturbances' wake. Within months, grasses and wildflowers would begin to grow in the sunny break. Vines and thickets would follow. For a decade or two - before tall trees crowded out the brush and shaded the area again - the swaths would be dense growths of shrubland.
Many animals seek or require these shrubs or clumps of grass as nest sites or for feeding. Others find food and cover in the brambles and thickets. The chestnut-sided warbler and American woodcock birds, snowshoe hares, and New England cottontail all use this land. Frogs, snakes, bees, and butterflies also need or thrive in the areas - often called early successional habitat.
There was once lots of it. Most of New England was deforested by the late 19th and early 20th centuries for farmland and pastures. The majority of rocky ground was gradually abandoned. For generations, before the forest slowly took over, there was an abundance of this open landscape. Animals, plants, and insect species that thrived in that sun-loving habitat exploded. People began treasuring them.
Now, as forests mature, that landscape is disappearing. What's more, there aren't the natural disturbances that took place before Europeans arrived. Beavers are often not tolerated, and firefighters ensure forest blazes don't get out of control.
As a result, some birds cannot find the grass or shrubland they need to nest in and don't reproduce in the numbers they historically did. There are fewer swaths of meadow and shrub for many of the region's hundreds of species of native bees to pollinate, so they too have gradually disappeared. The reclusive New England cottontail rabbit, which once found safety in the impenetrable thickets of early successional habitat across the region, has not been seen in Vermont since the early 1970s and the population has plummeted throughout the region - largely because of habitat loss.
And now, love them or hate them, New England transmission line corridors are beginning to serve as substitutes for some of that shrub land - and are even being deliberately managed to do so. Decades ago, the corridors were hand or mechanically cut. Then, during the post-war suburbia boom when many more corridors were being built, companies turned to the wide use of herbicides, reducing most corridors to grassy swaths and reducing biodiversity.
In the 1950s, an independent Connecticut ecologist named Frank Egler began wondering if there was another way for the companies to ensure trees didn't grow without killing virtually everything else in the corridors.
"He wanted to know could you just take out the tall trees and leave the native plants, shrubs, and low trees," said Glenn Dreyer, director of Connecticut College's Arboretum. Egler's research showed yes - if herbicide was selectively applied to individual trees, only those trees would die. Wildflowers, grasses, and native shrubs would then take over, eventually making it more difficult for tree saplings to grow.
Northeast Utilities, which manages about 1,900 miles of transmission corridors in New England, was one of the first to buy into the idea. Today, it and other key regional transmission managers - National Grid with 2,000 miles, NStar with about 400 miles, and Central Maine Power Company with 2,100 miles, for example - say the vast majority of their corridors are managed that way. Every few years, vegetation managers rotate through the paths, placing herbicide on tall-growing trees such as ash, maple, birches, and other saplings. New England remains an exception, however, according to national transmission line experts.
"We have a well-educated population here; if you don't do things right you are going to be in trouble," said Tony Johnson, supervisor for transmission vegetation management for Northeast Utilities. The utility helped fund the study that found the almost extinct bee. "And if you do things right, you get to convert some people."
Of course, some people dismiss the idea of transmission lines as beneficial and say no herbicide should ever be used - especially in places with sensitive waterways nearby. In Eastham, Wellfleet, and Orleans this summer, residents became worried about an NStar plan to start using selective herbicide on transmission corridors that were historically mowed. The plan is on hold, according to NStar.
ONE RECENT SUNNY day, Manomet's Parsons stood knee high in brush on an arrow-straight transmission line corridor in Plymouth near Route 3. A loud, steady buzz of insects interrupted her identification of native shrub species. A dragonfly careened in the air toward her. The hilly area was covered with grasses, bushes, and small trees so dense it was impossible to walk through. A small wetland surrounded the base of a few steel structures.
As new transmission line corridors are built, Parsons and others are looking for ways to make the corridors work with the ecosystems they cross. She says some will need to avoid rare species habitat or critical wetlands. Her program, funded by the Wildlife Action Opportunities Fund - a partnership between the Doris Duke Charitable Foundation and Wildlife Conservation Society - is helping map those spots across New England and is beginning to talk to transmission line companies early on to site new ones in appropriate places. Others suggest the corridors should be built next to highways or railways to lessen the impact on forests. Scientists at The Nature Conservancy in New Hampshire are researching how and why lynx, black bear, bobcat, and other species use the corridors. Meanwhile, David King at the US Forest Service in Amherst, Jeff Collins of the Massachusetts Audubon Society, and other researchers published a paper this year suggesting that wider corridors helped threatened shrubland bird species more than narrow ones. Connecticut College's Askins came to a similar conclusion in his research.
And the tiny bee? It's not alone. Other corridors have rare plants. And a rare moth was recently found in another.
"We're finding lots of other rare plants and wildlife," said Wagner.
Beth Daley is the Globe's environment reporter. She can be reached at email@example.com.
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