Publications

The current ecological condition of the Rocky Mountains can be viewed from two somewhat opposing perspectives. The first is that human occupation has had relatively little effect on the Rockies: large natural, if not pristine, areas remain, and the region's open spaces provide wildlife habitat, majestic scenery, and a sense of wildness. Unlike the situation in, say, the Swiss Alps, where...

To people worldwide, the Rocky Mountains of the United States and Canada represent a last bastion of nature in its purest and rawest form-unspoiled forests teeming with elk and deer stalked by mountain lions and grizzly bears; bald eagles nesting near lakes and rivers; fat, feisty native trout in rushing mountain streams; and dazzling arrays of wildflowers in lush meadows. In fact, the...

We analyzed a time series of estimates of elk (Cervus elaphus) numbers on the northern Yellowstone winter range from 1964 to 1979 and 1986 to 1995 using a variety of discrete time stochastic population dynamic models. These models included adjustments for density, an increase in the area of winter range used by elk, lagged effects of the weather covariates of spring precipitation, snow...

A decision support system for the management of the Rocky Mountain Population of Trumpeter Swans (Cygnus buccinators) is being developed. As part of this, three expert systems are also in development: one for assessing the quality of Trumpeter Swan breeding habitat; one for making water level recommendations in montane, palustrine wetlands; and one for assessing the contribution a...

The contents of this Annual Report summarize results of monitoring and research from the 2001 field season. The report also contains a summary of nuisance grizzly bear (Ursus arctos horribilis) management actions. In addition to our normal monitoring, we completed an array of studies addressing the potential impacts of winter recreation on denning grizzly bears. This research was in...

No abstract available.

Abstract not available

Pronghorn antelope in Yellowstone National Park (YNP) persist in a small population that historically has experienced recurrent, sometimes dramatic declines. They apparently are isolated from other pronghorns, depend partly on private lands for winter range, experience heavy predation of fawns, and concentrate during winter in a relatively small area, thereby increasing their...

Increasing winter use of steep, high-elevation terrain by backcountry recreationists has elevated concern about disturbance of denning grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE). To help identify areas where such conflicts might occur, we developed a spatially explicit model to predict potential denning areas in the GYE. Using a scan area of 630 m around each...

Reduced water depth in dry years has been proposed to interact with ultraviolet- B (UV-B) radiation and a pathogenic fungus to cause episodes of high mortality of amphibian embryos. Observations of breeding phenology of boreal chorus frogs (Pseudacris maculata) in Colorado from 1986 to 2001 show that dry years result in earlier breeding. The earliest and latest dates of maximum calling...

No abstract available.

Chronic Wasting Disease (CWD) has appeared widely in the media lately, but has actually been around for a while. It was first recognized in Colorado in 1967, in a captive research herd of mule deer. Its rapid expansion, to include eight states and two provinces by the year 2002, has created a crisis.