Publications

Many national parks, national forests, and other public land units exist in highly changeable regional environments. Often the parks and forests themselves serve as important catalysts of change in the levels of tourism, outdoor recreation participation, and contribution of traveling publics to local and regional economies. Resource managers are called upon to protect lands in their

We model the spatial distribution of snow across a mountain basin using an approach that combines binary decision tree and geostatistical techniques. In April 1997 and 1998, intensive snow surveys were conducted in the 6.9‐km2 Loch Vale watershed (LVWS), Rocky Mountain National Park, Colorado. Binary decision trees were used to model the large‐scale variations in snow depth, while the...

No abstract available.

No abstract available.

Is it appropriate to intervene in designated wilderness areas that have been "untrammeled by man" and, as a result, no longer retain their "primeval character and influence" as called for in the 1964 Wilderness Act? We explore this wilderness management dilemma - whether we can or should actively manage wilderness conditions to restore and protect wilderness and other values - by asking...

This report summarizes results of a visit by the report authors to Marinduque Island, Philippines, in May 2000. The purpose of the visit was to conduct a preliminary examination of environmental problems created by a 1996 tailings spill from the Marcopper open-pit copper mine. The mine was operated from 1969-1996 by Macropper Mining Corperation, under 39.9% ownership, and design and...

Denitrification measurements were made under simulated field conditions using sediment cores and water collected from the Hemet/San Jacinto Multipurpose Demonstration Wetland (Riverside County, California, USA). The 9.9 ha constructed wetland is used to both polish ammonia-dominated secondary municipal effluent and provide migratory bird habitat. The wetland was originally constructed as...

We analyzed factors that contributed to the success of 100 translocations of bighorn sheep within six western states between 1923 and 1997. We categorized the populations as unsuccessful (i.e., extirpated or remnant,

In 1995, mapping and classification of riparian vegetation along the Mojave River in southern California revealed an 8-km reach in which riparian cottonwoods (Populus fremontii Wats.) were stressed or dying. We tested a set of predictions based on the inference that cottonwood decline was an indirect result of lowered water-table levels following flood-related channel incision...

The virile crayfish (Orconectes virilis), an aggressive polytrophic species, has been introduced into many Arizona streams. I investigated competition and predation between this crayfish and several native Arizona fishes. I conducted field experiments to assess competition for food between crayfish and fish, and laboratory experiments to examine competition for shelter and food, and...

Floodplain plant–herbivore–hydroperiod interactions have received little attention despite their potential as determinants of floodplain structure and functioning. We used five types of exclosures to differentially exclude small-, medium-, and large-sized mammals from accessing Fremont cottonwood (Populus deltoides Marshall subsp. wizlizenii (Watson) Eckenwalder) seedlings and saplings...

1. Knowledge of synchrony in trends is important to determining regional responses of lakes to disturbances such as atmospheric deposition and climate change. We explored the temporal coherence of physical and chemical characteristics of two series of mostly alpine lakes in nearby basins of the Colorado Rocky Mountains. Using year-to-year variation over a 10-year period, we asked whether...