26 February 2010


This week's issue of the Missoula Independent includes an illuminating article by Michelle Nijbuis on a concept that I first heard discussed as an ecological theory a quarter century ago, when I was a student at the University of Arizona. The article describes the appearance of wolves in northwestern Colorado for the first time since their extirpation nearly a century ago. They probably migrated from the packs which were reintroduced to Montana and Wyoming in the 1990s, traveling down the Rocky Mountain corridor. By good fortune, the wolves have found refuge on a sprawling ranch owned and managed by a man who understands and fosters the total health of the ecosystem -- in short, a responsible land steward. Paul Vahldiek runs only a minimum number of cattle on his 300 square mile spread, The High Lonesome. His operation hosts hunting and fishing expeditions, but above all he encourages scientific research into all aspects of the natural world.

One important finding has been the realization that where there are no top predators, herds of grazers like elk and deer become sedentary, feeding on young shoot of aspen, willows and cottonwoods before the trees can mature. Before long those plant species start to disappear from the landscape as older trees die out. But when natural predators are present, elk and deer spend more time on the move, increasing the chances that biodiversity will flourish. This top-down effect was recognized by Aldo Leopold in the 1930s when he saw the connection between the killing of predators and "the modern curse of excess deer and elk." As the article notes, in 1980 ecologist Robert Paine coined the term "trophic cascades" to describe the ripple effects of predators on herbivores, and herbivores on plants.

Here's the tie-in to the mid-1980s debate: with regard to protecting endangered species (in this case wolves), is it better to have numerous small, scattered reserves for endangered species, or is it better to have fewer but larger reserves? For maintaining a large, diverse gene pool, clearly the latter is prefereable. Even more preferable is a newer concept -- designating large, contiguous tracts of land to accomodate not only residence but also migration. Such wildlife corridors, or wildways, allow naturally wide-ranging species (herbivore and carnivores) to do what they've always done -- roam freely.

What about ranches, farms, cities, highways? It is possible for humans and wildlife to coexist peacefully, it turns out. All it takes is for humans to rethink their assumptions (and set aside their fears, in the case of wolves), and brainstorm creative ways to allow the natural world to flourish. Wildways are an example of an accomodation that works. Here is a link to the homepage of the Wildlands Network, which was established to educate and promote large-scale wildways, including those of truly visionary scope like the Spine of the Continent Wildway (see illustration below, click to enlarge) -- a network of interlinked project which, taken together, protects the greater Rocky Mountain region with minimal impact on human activity.

No comments:

Post a Comment