PULLMAN– The Wildlife Society has honored coauthors Donald Katnik and Robert Wielgus with its 2006 Outstanding Publication Award for a paper that overturns widely held notions of resource use and avoidance by animals in the wild.
The results described in the paper will likely change the way assessments of habitat and wildlife -especially endangered species – are conducted.
Wielgus is director of the Large Carnivore Conservation Laboratory at Washington State University. Katnik, now at the Maine Department of Inland Fisheries and Wildlife, is a former WSU graduate student in Natural Resource Sciences who was under the direction of Wielgus. The paper is a result of Katnik’s doctoral research.
Wildlife biologists have assumed that it is reasonable to compare entire landscapes with the much more limited home ranges of particular species. Mathematical modeling of what a particular species uses, or not, within a landscape are based on that assumption. But that assumption is wrong, according to Wielgus.
“There’s been a baseline assumption of what animals are or are not using in a particular landscape,” Wielgus said. “The assumption is that very large areas, termed landscapes, are comparable to much smaller ones that wildlife biologists call home ranges. It is a classic example of scale error.”
He said it’s like comparing apples and oranges. “If habitat elements, such as preferred foods and sheltering areas, were distributed equally across landscapes, then comparing landscapes to home ranges would work. But that’s never the case. Old-growth forest, for example, is not randomly or equally spread across a landscape; rather, it is available to animals in clumps.”
“A specific animal’s territory is limited by a number of factors,” Wielgus said, “in particular the presence of competing animals, and so a home range does not contain everything in a landscape the animal might otherwise use. Certain elements of a landscape are simply not available.”
The conceptual problem arose because ecological mathematicians do not usually have field experience and so do not take into account the fact that landscape resources are unequally divided up by the animals that use them.
“The math is elegant,” Wielgus conceded “but, we show in our paper, the results have a ninety percent error rate.”
Such results, however, typically form the basis of wildlife management plans.
Wielgus said the solution that he and Katnik hit upon was to compare equal-sized areas. By randomly distributing home-range-sized areas across a landscape, the scale error is avoided and a true pattern of animals’ resource use is revealed.
“It’s a paradigm shift,” Wielgus said. “The new analytical technique revises a practice employed by wildlife biologists and managers for more than twenty years.”
Although use of the analytical technique described in the award-winning paper will take time to trickle down, Wielgus said that the result will likely be the reassessment of existing wildlife management plans.
The Wildlife Society is an international professional organization of wildlife researchers and management professionals. The paper, published in 2006 in the Journal of Wildlife Management, is entitled “Landscape Proportions versus Monte Carlo Simulated Home Ranges for Estimating Habitat Availability.”
