Why Wildlife Corridors?

January 3, 2013

Because we’ve taken too much already. Movement is as essential to animals’ lives as are sun, water, and family; yet we North Americans have deprived our fellow denizens of most of their living and traveling spaces. Across most of the eastern United States and southeastern Canada, wildlife habitats are so diminished and fragmented by roads, dams, cities, agribusiness fields, and other human developments that only by actively protecting and restoring corridors of natural habitat — wildways — can we stanch the loss of biological diversity.

Isolated habitats, such as we see in our countries’ scatterings of small refuges and parks, can have value, and may meet the needs of relatively sedentary species; but small remnants generally will not long afford secure homes for sensitive and wide-ranging animals like bears, otters, wolves, big cats, raptors, songbirds, butterflies, trout, salmon, whales, and seals. As human-caused climate chaos worsens, many plant species, too, will be susceptible to effects of habitat fragmentation, and some will go extinct if not given grounds and waters to move northward and upward. The solutions to isolation are large interconnected wildlife reserves; and the needs they meet may be summarized in five broad categories: food, sex, cover, genes, and change.

Food — Predators need to roam widely to find ample prey. Herbivores, pollinators, and frugivores need to move with the leafing, flowering, and fruiting of plants. Many animals move seasonally to track dietary preferences. Black Bears, for example, wake from hibernation early in spring before much easy food is available. They may depend then on intact wetlands with succulent vegetation. In summer, bears may hunt smaller animals and scavenge carcasses of prey taken by other carnivores, until berries ripen in late summer. In autumn, bears feast on acorns and beech nuts. In late autumn, bears may head up to high, dense spruce/fir forests, on the way dining on mountain-ash berries, then finding dens beneath the soon-to-be snow-covered thickets.

Sex — We all want it. Some of us must travel far to find it. Attractive mates may not be available nearby; and of course, for most animals, it is crucial to choose a mate not closely related, lest inbreeding depression occur. Commonly in carnivore species, young males light out for the territory, wandering far and wide to find a home range and mate of their own. In isolated habitats, such wanderers may be shot or run over before they find safe ground; and after some generations of this, the carnivore species is likely to go locally or even regionally extinct. Some of the most poignant stories in North America today involve young male Cougars, Red Wolves, Gray Wolves, Black and Grizzly Bears, Lynx, and other wide-ranging species bravely striking out on their own. A tragic example from last year (while I was trekking 7000 miles to promote habitat connections for carnivore recovery, in a sad irony) is a young male Cougar (Mountain Lion, Panther, Catamount … same species, native to most of North America south of the Arctic), who was born in the Dakotas, roamed eastward soon after reaching maturity, made it successfully to New York’s Adirondack Park and apparently was doing fine there for awhile (partly on Nature Conservancy land, partly in Lake George Wild Forest). Not finding a mate, though, he kept moving and eventually was hit and killed by a car in Connecticut.

Cover — Wild animals need shelter just as much as domestic animals, like us, do. Intact old forests provide snags, hollow logs, rock caverns, dense vegetation, and other structure that affords animals thermal shelter and places to hide from predators and raise young. Good cover is most generously provided in unbroken natural areas. In a typical year, Moose, for instance, may seek cool and lush wetlands during summer but head up into the sub-alpine zone, where evergreen browse is ample, in autumn after the rut. Brook Trout, for another example, need cool, well oxygenated pools during the heat of summer, but may need to travel upstream or downstream in winter to livelier waters that won’t freeze.

Genes — Again, populations need to mix genetically if they are to produce healthy individuals for the long term. Just as it would be unhealthy for a small community of people to be isolated from other communities, it is unhealthy for individuals to be limited to potential mates with whom they are related. Deleterious recessive genes then express themselves; populations slowly decline through inbreeding depression. Wolves are more genetically tolerant of intra-familial pairings than are most animals, yet even among these large canids, population health depends on some young pack members striking out on their own, and joining other packs or starting new ones.

Change — Even before humans started domesticating and polluting the planet, storms, earthquakes, volcanoes, and other natural disturbances stochastically altered environmental conditions. Change is the norm in Nature, in the form of weather, succession, erosion, and other climatic, biological, and geological forces. Animals and plants may respond to changes by shifting their ranges, in part to track their climate envelopes. The double whammy of industrial civilization on the natural world is that we have pushed rates of change way beyond those to which wild species are adapted — especially in the form of global overheating, and we’ve fragmented landscapes so that species can no longer easily move to stick with their desired or required environmental conditions. Even without climate chaos, humankind would be exterminating wildlife species by the thousands per year, through habitat destruction, overkill, and introduction of invasive species (which sometimes outcompete natives). With anthropogenic climate change, extinction rates will reach catastrophic levels in the coming decades. If people do not begin reconnecting wildlife habitats and greatly reducing our emissions of carbon and other pollutants, we will exterminate millions of species in the space of a few generations; some projections have nearly one-third of wildlife species going extinct in the next century.

Wildlife corridors (also known as linkages or habitat connections or wildways) may be as narrow as a riparian buffer along a stream or wider than a mountain range. The safest rule about wildlife corridors is: the wider and wilder, the better. In many regions, we can make the greatest gains for wildlife (and for human-powered recreation) in the near term by protecting waterways and the lands alongside them, making the buffer of natural vegetation as wide as possible. At the same time, we should install safe wildlife crossings on major roads (again to the benefit of wildlife and people, as collisions with animals are reduced), and seek conservation easements or public acquisitions on private lands between existing public reserves.

We meddlesome hominids, then, can stop the extinction crisis, but doing so will require conservation and cooperation on a scale we have seldom, if ever, practiced before. We will need to protect much – probably at least half — of Earth’s areas of terrestrial and aquatic habitats in large reserves interconnected by wildlife corridors, or wildways, and buffered by compatible use zones.

In North America, we should establish continental conservation corridors (which would be mixes of public reserves and private lands where owners are offered generous financial incentives for good stewardship) through the Southeast Coastal Plain, Appalachian and Adirondack Mountains, Great Plains, Rocky Mountains, Pacific Coast Ranges, and Boreal Forest. We will also need to actively restore forests and grasslands, and sharply reduce our carbon emissions, to return CO2 levels in the atmosphere to 350 parts per million or less. (These conservation and restoration programs, by the way, could provide good jobs for millions of people.)

Conservation on this scale won’t be easy anywhere, but In New York’s Adirondack Park, thankfully, extensive wildlife habitat remains intact, so our job is more preservation than restoration. Even here, though, in what is arguably the best-protected landscape in the eastern United States, much remains to be done to keep wildlife habitats interconnected within the Park and between the Park and wildlands to the outside. Making the Adirondack Park whole will involve additions to Forest Preserve, conservation easements or voluntary stewardship agreements on private lands, and provision of safe wildlife passages across major roads.

Priorities in the Adirondacks include these:

* Restore swaths of forest through the Black River Valley to keep the western Adirondacks and Tug Hill Plateau biologically linked — especially important for Marten and possible restored populations of Cougar, Lynx, and Gray Wolf.

* Maintain forested connections through the Southern Lake Champlain Valley, so animals may move freely between New York’s Adirondacks and Vermont’s Green Mountains. Concurrently, restore connections through Vermont Valley, to keep the Taconics and Greens united.

* Complete wildlife corridors in the West Champlain Hills — botanical hotspot of Adirondacks, including Split Rock Wildway, linking Champlain Valley with High Peaks.

* Establish an A2A conservation corridor, linking Ontario’s Algonquin Park (nearest viable population of wolves) with New York’s Adirondack Park.

* Install wildlife bridges and tunnels across busy roads, especially Interstate 87, which is the major barrier to east-west movement in the Park.

* Remove unneeded, habitat-fragmenting roads and dams from the backcountry.

* Protect broad riparian buffers along and around streams, rivers, ponds, lakes, and wetlands wherever possible.

* Lead kids outside to explore our forests and lakes and learn about our natural heritage, so they know and care enough to keep it all intact, to keep the Adirondacks Forever Wild.

In sum, animals need room to roam; plants need places to propagate. Restoring natural habitats cross-country is an essential step to addressing the related crises of extinction and climate chaos. Wildways also reconnect people with the land, giving us places to hike, ski, climb, paddle, swim, and enjoy the beauty of the natural world. We will be a greater and a healthier people in a richer land if we weave back together the remnants of our natural heritage into continental conservation corridors, if we restore an Eastern Wildway: letting wild things flow freely from the Florida Everglades through the Southeast Coastal Plain, up the Appalachians, through the Tug Hill Plateau and Adirondacks, across the Maine Woods, and out to where the mountains meet the sea in Quebec’s Gaspe Peninsula.

About the author. John Davis (john@wildlandsnetwork.org), is a wildways scout and Adirondack conservationist. His views here do not necessarily represent positions taken by any particular conservation group, but are informed by many.

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