Jan-Willem Jansens and Charlie O’Leary

 

Edge Effect, Core Areas and Linkages

Hunters, naturalists and biologists know that many animals migrate and hang out along edges between landscapes or ecosystems. This is not unlike how humans prefer to sit or walk at the edge of a space. Edges offer certain benefits, such as shade, better views, hiding places and more diversity, which is often essential to feel safe, sheltered and comfortable. This phenomenon is called the “edge effect.” In nature, edges are transition zones between two different ecological areas or landscape types. Due to the continuity and diverse ecological benefits of edges in the landscape, they serve as crucial habitat and pathways for many wildlife species.

Where and how wild animals want to roam and where they hang out depends largely on the animals’ needs and to what extent their needs are being met by the quality of their habitat. Scientific research has revealed that well-functioning wildlife habitat will allow for a more diverse mix of species if that area is larger and wider and if it is connected with other habitats. Ecologists call such principal habitat areas “cores” or “hubs.” The connective zones are called “linkages” or “corridors.” For certain animals their core habitats are in fact “islands” in a “sea” of less-suitable habitat. Birds follow linkages in the air (avian fly zones) to reach other “island” areas. Land animals seek specific sheltered overland pathways between core areas, for example along stream corridors and in landscape edges, to avoid open or developed areas where they are vulnerable.

 

Impacts of Isolation

Human settlement drastically impacts the size and shape of the home territory of wild animals. When core areas shrink in size or get narrower, certain animals will experience crowding and will compete with each other for space, mates, water, food and shelter.

If development, roads, fences, or lack of shelter or water prevent animals from roaming toward other core areas, animals will either stay where they are, running an increased risk of starving or dying in competitive conflicts, or they will venture out, risking their lives on highways, due to predators (including humans), or as a result of starvation and thirst. The number of animals and the number of species in an isolated core area is usually smaller than in connected areas.

As a result of such processes, numerous animal species have disappeared or gone extinct in the last few centuries, and many more continue to be threatened with extinction today. Estimates by Wildlands Network in 2011 indicate that nationwide nearly 365 million vertebrates are being killed every year on our roadways; nearly one million every day. On four million miles of roads, this means a daily mortality of one vertebrate every four miles. Annually, about 30,000 people are injured in collisions between large animals and vehicles, 300 of them fatally.

These estimates from Wildlands Network resulted from an epic trek in 2011 from Key Largo, Fla. to Quebec, Canada, by Wildlands Network founder and nationally renowned adventurer and outdoorsman John Davis. His 7,600-mile voyage, dubbed TrekEast, led Davis along the most important wilderness areas and nature preserves on the East Coast of the US. One of the most unexpected and gruesome findings on his trek was the rampant road kill he encountered everywhere he went. Roads have fragmented the land to such an extent that the wonderful preserves and conservation areas on the East Coast that still serve as core habitat for wildlife are virtually severed from each other for most non-flying vertebrates. Animals that venture to roam beyond these core habitats run a tremendous risk of falling victim to the death trap of our road system.

 

Roadblocks on the Western Wildway

While ecological core areas in the West are much larger and less fragmented by roads and developed areas than on the East Coast, there are many reasons for concern in our region. The many miles of four-lane highways with concrete safety barriers and lane dividers are formidable wildlife barriers that tend to trap animals and increase the risk of collisions.

A preliminary list of 30 critical wildlife-vehicle collision accident corridors in New Mexico, established in 2003, has only seen a few success stories of effective wildlife crossing solutions. The most notable one is the highway crossing of I-40 in Tijeras Canyon, east of Albuquerque. This corridor segment connecting the Sandias and the Manzanita Mountains was the most studied corridor in the state due to work spearheaded by the Tijeras Canyon Safe Passage Coalition. Yet, despite excellent work done by NM Priority Wildlife Linkages and staff from the NM Department of Game & Fish, the Department of Transportation, and many dedicated individuals from the private sector and conservation groups, in the decade since 2003 there has been a great lack of funds and political commitment in NM to address animal-vehicle collision problems in a more dedicated and comprehensive manner.

Additionally, oil and gas development has carved a swath of highly disturbed land, with many roads, fences, polluted water sources and degraded ecosystems across the continent from Montana to NM. The onslaught on wildlife habitat by the conventional energy sector is rapidly expanded by the development of solar- and wind farms and the plans for high-voltage transmission lines for these new renewable energy plants. The environmental community and state decision makers still have a great task ahead in balancing the needs and goals of new energy development on the one hand and ecological conservation on the other.

In the years to come, the impacts of our changing climate on water resources and vegetation communities will most likely prompt many animals to seek different habitats and adapt to large-scale changes across the landscape. The devastation of wildfires across our region, coupled with the drying of many streams and an imminent outbreak of a new cycle of pine beetles, are some of the ecological examples of large-scale transitions in our landscapes that change the character of the transition zones between habitats and that will bring many animals on the wing or on the hoof to find new habitat.

 

Strategies and Actions as Part of a Large Vision

We, as residents and landowners, can make a difference to these sobering realities for wildlife by engaging in concerted stewardship action, both at the local level of individuals and at regional levels of collaborative partnerships between conservation groups and government agencies. First of all, this will require that in order to successfully implement strategies that will benefit wildlife, we rely on public awareness of the challenges that wildlife face in our modern world. Public support for projects that enhance connectivity is crucial to receive funding and for helping to set priorities in our highly bureaucratic system of land management. So our first responsibility is to be aware of our surroundings and to understand how our actions affect natural systems and the animals that live in the wild. This will help us understand the real life-and-death challenges that animals face each and every day and drive us to take action to help preserve their basic needs for survival.

We may need to be aware, for example, that many animals are nocturnal and are afraid of humans. It is easy to forget that we share the land with an entire population of beings that sleep during the day and are active only at night. And besides, most of us work or live inside the majority of the day and have very little opportunity to be in nature and see firsthand how we are modifying habitat and creating challenges for wildlife.

Second, as stewards, we can take action to protect certain areas that constitute important wildlife pathways and habitat areas. Many public agencies and nature groups across the country, including land trusts, are working to provide the necessary open lands and corridors critical for wildlife to survive. An important tool in the protection of critical areas is the use of voluntary land-protection agreements (also known as conservation easements) to retire development rights and guarantee that the land is not converted from its natural functions. NM has seen many acres of land protected in perpetuity with this legal mechanism. While conservation easements have been used to protect core habitat areas, land trusts are now increasingly seeing the importance of protecting corridors or stepping-stone areas. Land trusts and government agencies are using computer-aided mapping of conservation values and property ownership on both local and regional levels to support the planning of open space and wildlife corridors. An important next step in easing conservation efforts is to increase the practices of sharing this information to leverage multiple missions benefiting land, people and wildlife.

Working directly with individual private landowners on wildlife enhancement and ecosystem restoration will leave a legacy of conservation on the land. Direct examples of this kind of work can be seen in the Galisteo Basin, in Albuquerque’s South Valley, in the new Río Mora Wildlife Refuge and Conservation Area, and in the recently dedicated Río Grande del Norte National Monument. Conservation work can be scaled from one acre to thousands to allow a full range of landowners to participate in a meaningful way—making contributions to the larger landscape of northern NM one property at a time.

Finally, resources that offer opportunities for getting out of doors, such as public trails, will aid in raising public awareness of the needs for connecting open space areas across the landscape. Combined with limiting development on land through conservation easements, providing nighttime friendly lighting for many species, land-use planning based on the needs of wildlife, and consulting with our neighbors who make their living from the land, we have a broad spectrum of meaningful stewardship tools to help ensure that we can hem in the impacts of our modern lifestyle to help the animal kingdom stay connected.

 

Jan-Willem Jansens is coordinator of New Mexico Wildways. 505.470.2531, jwjansens@gmail.com. Charlie O’Leary is executive director of the Santa Fe Conservation Trust. 505.989.7019, info@sfct.org, http://sfct.org

 

 

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