Publications

In laboratory tests, young Chelydra serpentina and Trachemys scripta altered their distribution in the presence of a temperature gradient. Selection of temperatures in the gradient for hatchlings and yearlings showed that body temperatures (Tbs) of C. serpentina were lower than T. scripta, but the difference was insignificant. Relatively low Tbs could allow greater activity range and...

Radio transmitter attachment methodology is important to the design of radio telemetry studies. In 1998, we attached 5 transmitters to a captive population of Western Sandpipers (Calidris mauri) and 7 transmitters to wild Killdeer (Charadriusv ociferus) using a modified version of the Rappole and Tipton (1991) figure-8 leg-loop harness. Captive birds fitted with harnesses did not exhibit

No abstract available.

A quantitatively robust yet parsimonious air-quality monitoring network in mountainous regions requires special attention to relevant spatial and temporal scales of measurement and inference. The design of monitoring networks should focus on the objectives required by public agencies, namely: 1) determine if some threshold has been exceeded (e.g., for regulatory purposes), and 2)...

In many permanent ponds throughout western North America, the introduction of a variety of exotic fish and bullfrogs (Rana catesbeiana) correlates with declines in native amphibians. Direct effects of exotics are suspected to be responsible for the rarity of some native amphibians and are one hypothesis to explain the prevalence of amphibian declines in western North America. However...

We sought to determine whether changes in chemical composition could be a factor in increased utilization of red alder (Alnus rubra) by the two cervids, the Columbian black-tailed deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus elaphus roosevelti), during the fall in parts of the Douglas fir region of the Pacific Northwest. We found that concentrations and astringency of...

The Southwestern Willow Flycatcher (Empidonax traillii extimus) is an endangered Neotropical migrant that breeds in isolated remnants of dense riparian habitat in the southwestern United States. We estimated genetic variation at 20 breeding sites of the Southwestern Willow Flycatcher (290 individuals) using 38 amplified fragment length polymorphisms (AFLPs). Our results suggest that...

Amphibians evolved from fishes about 360 million years ago and were the first vertebrates adapted to life on land. The word amphibian means "double life." It refers to the life history of many amphibians, which spend part of their life in water and part on land. There are three major groups of amphibians: salamanders, frogs, and toads, and caecilians. Salamanders, frogs, and toads can be...

No abstract available.

Group decision making is becoming increasingly important in natural resource management and associated scientific applications, because multiple values are treated coincidentally in time and space, multiple resource specialists are needed, and multiple stakeholders must be included in the decision process. Decades of social science research on decision making in groups have provided...

Wetlands in the western Great Basin of the United States are patchily distributed and undergo extensive seasonal and annual variation in water levels. The American Avocet (Recurvirostra americana) is one of many shorebird species that use these wetlands as breeding and migratory stopover sites and must adjust to variable conditions. We used radio telemetry to determine postbreeding...

Roosts are a critical habitat component for bats and may influence their survival and fitness. We used radiotelemetry to investigate characteristics of day-roosts of female long-eared myotis (Myotis evotis) in watersheds characterized by different forest conditions and the spatial relationships between day-roosts and available water. We tracked 21 bats to 73 roosts (n = 102 occasions)...