Wild Ones   Corridors for a Healthier Environment  
By Sally Elmiger

This is the first article in a series that discusses how corridors that connect natural areas can help sustain our environment, native plants, and local wildlife – and how Wild Ones can start creating them in their own communities.

The thigh bone’s connected to the backbone…the backbone’s connected to the neck bone…the neck bone’s connected to the head bone…” An African-American spiritual.

Corny maybe, but when you stop to think about it, everything that lives and moves on this Earth is connected in some way or another to everything else. As most gardeners know, we have a physical, psychological, and often emotional connection to our plants; the plants have a physical connection to the soil; the soil is home to myriad microorganisms; and the microorganisms live on the detritus from the plants that live in the soil that grow (at least in our gardens) with TLC from the gardener. The connections are often not linear, but a traditional garden would not grow and look like it does without all of these connections.

The natural world is also governed through connections. Ecosystems, such as forests or wetlands, are defined by the interactions (or connections) of the living organisms (plants and animals) with their non-living physical environment of atmosphere and soil. Ultimately, the plants and animals work on the non-living things for so long that they change the non-living things. In the same vein, as the non-living elements change, the plants and animals adapt to better take advantage of their changing environment. Other examples of ecosystems are grassland communities like prairies, surface water bodies like lakes and ponds, and river or stream systems.

Broken Connections

Over the past 50 years, developing communities have not, in general, taken into consideration the connections that exist between different ecosystems across the landscape. The building of homes and parking lots changes the way water runs over the land, often disconnecting wetlands from the uplands that provide storm water runoff – the life support of wetlands. Similarly, woodlands are cut apart by the clearing of large areas of trees for development. This can leave “patches” of plant and animal habitats across our community, a trend often referred to as “fragmentation.”

Need for Multiple Ecosystems

Like our native plants, wildlife has evolved with the environment to create a co-dependent system – an ecosystem. If the wildlife doesn’t get what it needs from its immediate surroundings, it has to look for it elsewhere. Many species of wildlife require more than one ecosystem type to survive. For example, frogs need water to reproduce, but they live much of the year in upland areas. Other animals are forced out of their birthplace to ensure that there are enough resources for the parents. However, human changes to the landscape can make this transition more difficult. It may force a species through areas that expose it to predators and other dangers such as roads, areas where there is no food or water – or the creatures may be lost and unable to find another suitable area in which to live. Fragmented landscapes also make it more difficult for plants to reproduce. The more difficult it is for pollinators to reach a certain plant species, the lower the plant’s chances of thriving. The smaller the number of plants available for interbreeding, the more limited the genetic diversity and ultimate survivability of a stand.

Effects of Fragmentation

If the spaces between the patches or fragments of remaining ecosystem are too large or dangerous to cross, some species may disappear from that patch because they can’t reproduce, or there isn’t enough food or space to sustain future generations. And then that species’ various impacts on the patch are lost and the biodiversity of the patch and its functionality are diminished.

Habitat Corridors

Habitat corridors solve many of these problems by providing links from one ecosystem to another, providing a relatively safe travel route for movement. This essentially expands the habitat to any areas that the patch is connected to. One definition of corridors is, “Avenues along which wide-ranging animals can travel, plants can propagate, genetic interchange can occur, populations can move in response to environmental changes and natural disasters, and threatened species can be replenished from other areas.”

Corridors can be composed of many things – from riverbanks to old railroad beds. They can be used just for natural area preservation, or as a conduit for people, providing connections from town to town, and possibly across regions and states.

What’s Next

This article sets the stage for the importance of corridors, and how our environment and the survival of the native plants we cherish can be enhanced and sustained by protecting and creating connections between natural areas. The next article will concentrate on the different types of corridors that can serve nature and people, while the third article will talk about communities that have discovered the benefits of planning for, and creating corridors within their boundaries, and beyond.

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Sally Elmiger has a graduate degree in Landscape Architecture from the School of Natural Resource at the University of Michigan, and works as a community and environmental planner for Carlisle/Wortman Associates, Inc. in Ann Arbor, Michigan. She is a member of the Ann Arbor (MI) Chapter of Wild Ones.

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References
Michigan Trees; Barnes, Burton V., Wagner, Warren H., Jr.; University of Michigan Press; Ann Arbor, Michigan; 1996.
American Wild Lands web site: www.wildlands.org.

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Updated: Jun 12, 2005.
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