Can They Get Here from There? Ecological Corridors

As nature enthusiasts we enjoy walking trails and catching glimpses of the wildlife species our forests have to offer. If lucky, we may stumble upon a bear, fox, or rattlesnake, and if luckier still we may even see a bobcat or otter. But, if we don’t see these things we can still take pleasure in the numerous plants and other animals we encounter on our journey through the woods.

To what extent, however, do our “trail corridors” also function as ecological corridors? In fact, this is an active area of research. Some animals, such as bobcats, tend to avoid trails with high levels of human activity, and avoidance increases if dogs are also allowed on trails. Yet, many other animals are hardly fazed by the human presence. We often see tracks of wildlife following trails as humans do. So what is the difference between an ecological corridor and a trail corridor?

An ecological corridor is a swath of land used by wildlife to get from one piece of “prime habitat” to another. In general, animals spend less time within a corridor and use it much like humans use a road. Corridor design differs depending on the species of interest. However, “the wider the better” is often the approach taken because more species can be accommodated.

Ecological corridors help mitigate the effects of habitat fragmentation, one of the major threats to biodiversity, and are especially important here in the densely populated east. Habitat fragmentation leads to isolated populations, thereby decreasing genetic diversity and increasing the chance of local extinctions. The full effects of habitat fragmentation can take decades or longer to appear and may not be readily observed. Some populations may not be isolated now, but with development could become isolated in the future. If we keep habitat connectivity in mind and maintain it through corridors and stepping stones (small patches of suitable habitat), our wildlife will have a greater chance of surviving in perpetuity.

The biggest threats to connectivity in our region are the numerous barriers which prevent animals from moving across the landscape. These barriers include roads and highways, high density developments, and man-made structures such as fences. If we identify trouble spots we can take measures to mitigate barriers with crossing structures (overpasses and underpasses) designed for animal movement or by using fences to re-route animal paths to desired locations. Increasing human awareness of high collision areas via road signs can also be a simple and effective way to aid wildlife crossings. Maintaining and enhancing wildlife connectivity is complicated and time consuming work far beyond the reach of any single organization. Effective partnerships are essential.

For the past 20 years, such partnerships have been forming across the country to work on ecological connectivity projects. One of the most famous is the Yellowstone to Yukon (Y2Y) initiative, which aims “to ensure that the world-renowned wilderness, wildlife, native plants, and natural processes of the Yellowstone to Yukon region continue to function as an interconnected web of life, capable of supporting all of its natural and human communities, for now and for future generations.” This mission reflects the overall goal of human and wildlife coexistence that we should also strive for here in the east.

In fact, there are many connectivity projects like Y2Y currently happening in the New York-New Jersey region. The Shawangunk Ridge Coalition (SRC)—an association of groups that includes the Trail Conference, Open Space Institute, The Nature Conservancy, Basha Kill Area Association, Mohonk Preserve, Friends of the Shawangunks, and others, in 2009 launched a series of meetings focused on protecting and enhancing ecological connectivity between the Catskill and Shawangunk Mountains. The group seeks to build on the decades-long effort by the Trail Conference and Open Space Institute to create protected trail corridors from the Catskills to the Delaware National Recreation Area via the Shawangunk Ridge.

“The primary goal of the Trail Conference in protecting these corridors is to preserve natural and safe connections to nature for people and wildlife,” says Trail Conference Executive Director Ed Goodell. “And we know that animals also use these corridors. Fishers (Martes pinnanti), reintroduced into the Catskills by the New York Department of Environmental Conservation, have been documented along the Shawangunk and Kittatinny ridges, reintroducing themselves to New Jersey!”

The Nature Conservancy’s Shawangunk Ridge Program Director Cara Lee, adds, "Connectivity is important because it allows animals to maintain viable populations and move or adapt to climate change while often enhancing recreation and strengthening communities."

In a somewhat more populated area, Black Rock Forest Consortium, the Open Space Institute (OSI), Orange County Land Trust, and Hudson Highlands Land Trust have been working to preserve ecological connectivity between the Highlands and Schunemunk Mountain. Over the past two years OSI acquired 183 acres, which will be conserved and protected for wildlife by the partners.

Even the New York City Parks department is taking connectivity into account. Bram Gunther, Chief of Forestry, Horticulture, and Natural Resources for NYC Parks & Recreation, says, “In our natural areas restoration work in New York City we are focused on habitat corridors as a way to increase biodiversity, increase green space, and stabilize our ecosystems. The connectivity we are trying to create in New York City also applies regionally, in our relationships with adjacent counties and states.”

These collaborative projects are important to bolster community support and understanding of the environment, to maintain healthy ecosystems, and can also ensure the hiking enjoyment of future generations.

Kate Pavlis earned a master’s degree in conservation biology from Columbia University for work researching habitat connectivity in an isolated population of Italian Brown Bears. She is Black Rock Forest Consortium Research Associate and Environmental Educator,