| Servheen, Sandstrom | Christopher, Per | Ecosystem management and linkage zones for grizzly bears and other large carnivores in the northern Rocky Mountains in Montana and Idaho. | 1993 | Endangered Species Technical Bulletin, Vol. XVIII, No. 3 |
This paper discusses landscape ecology and linkage zones in the context of grizzly bear management . The authors use the term linkage zones in sustitution for corridors, and define it as "combinations of landscape structural factors that allow wildlife to move through, and live within, areas influenced by human actions." Linkage zones are seen as a vital need for grizzly bears and other large carnivores due to increased fragmentation of habitat.
The premise for this paper is the fact that many formerly intact ecosystems supporting large mammals have been divided to the point that they have lost considerable value as wildlife habitat. Most of this fragmentation has been directly caused by human activity, and usually occurs in linear patterns, such as valley bottoms. This linear pattern inhibits movement and increases mortality rates. The authors attempt to use landscape ecology as an approach to evalutate habitat, GIS was also used to evaluate habitat, assess degree of fragmentation, and evaluate disturbance and mortality risk.
The traditional approach to evaluating habitat for grizzly bears has been based on the availability of food types. The authors try a new approach based on human activity. Scores were assigned for various human activities based on general knowledge of known bear responses. Scores for human residences and developments, open roads, hiding cover and riparian zones were used as layers for a map. Using this map, 5 wildlife linkage zones across the Swan/Clearwater Valleys were located. In these places, the effects of human activity are currently at lower levels.
The authors finish by suggesting several management options on maintaining grizzly bear and other large carnivore populations, including a "team approach" to management because of the intermingled ownership of lands within many linkage zones, an intergrated ecosystem management approach, and limiting fragmentation.