Publications

Depleted uranium (DU) has been used as a substitute for the fissionable enriched uranium component of atomic weapons tested at Los Alamos National Laboratory (LANL) (Los Alamos, NM, USA) since the early 1950s, resulting in considerable concentrations of DU in the soils within the test sites. Although the movement of DU into major aquatic systems has been shown to be minimal, there are...

We investigated the efficacy of management to reduce the impact of Caspian tern (Sterna caspia) predation on survival of juvenile salmonids (Oncorhynchus spp.) in the Columbia River estuary. Resource managers sought to relocate approximately 9,000 pairs of terns nesting on Rice Island (river km 34) to East Sand Island (river km 8), where terns were expected to prey on fewer juvenile...

We determined production and survival of elk (Cervus elaphus nelsoni) calves in Michigan using a variety of methods to index herd productivity. Calf production in Michigan was comparable with the highest rates ever recorded for North American elk. Calf survival averaged 0.90 (SD = 0.05), 0.97 (SD = 0.04) and 0.87 (SD = 0.05) for summer, winter and annually, 1987-1991. Calf survival rates...

We examined the potential role of food limitation in constraining the recovery of sea otters Enhydra lutris in Prince William Sound, Alaska, following the 'Exxon Valdez' oil spill. The spill resulted in the removal of a large number of sea otters in 1989, and as of 1998, the portion of the population in the heavily oiled northern Knight Island region had not fully recovered. Between 1996...

We compared cavity-nesting bird communities in aspen (Populus tremuloides) woodland fragments classified on the basis of vegetation structure (tree density) and landscape context (surrounding vegetation). We found very few cavity nesters in fragments predominantly surrounded by forests. Fragments adjacent to meadows contained more species and a greater abundance of cavity nesters...

We used a supplemental-feeding experiment, the doubly labeled water technique, and a model-selection approach based upon the Akaike Information Criterion to examine effects of food availability on energy expenditure rates of Black-legged Kittiwakes (Rissa tridactyla) raising young. Energy expenditure rates of supplementally fed females (n = 14) and males (n = 16) were 34 and 20% lower...

In this paper, we briefly discuss some of the fundamental problems arising from the inherent complexity of larger-scale ecological systems. We examine the tenuous assumption of a direct correspondence between ecological data and theory, we comment on a recent report that evaluated the efficacy of fragmentation experiments, and we briefly assess its implications for ecological research...

The objective of this study was to determine dietary overlap between blueback herring and threadfin shad in J. Strom Thrumond Reservoir, South Carolina/Georgia. We also evaluated prey selectivity for each speices and diet differences between two size categories of blueback herring. Diet and zooplankton samples were collected every other month from April 1992 to February 1994. We examined...

The concurrent effects of increasing atmospheric CO2 concentration, climate variability, and cropland establishment and abandonment on terrestrial carbon storage between 1920 and 1992 were assessed using a standard simulation protocol with four process-based terrestrial biosphere models. Over the long-term(1920–1992), the simulations yielded a time history of terrestrial uptake that is...

Park managers are concerned that moose (Alces alces), caribou (Rangifer tarandus), and grizzly bears (Ursus arctos) may be avoiding areas along the 130 km road through Denali National Park as a result of high traffic volume, thus decreasing opportunities for visitors to view wildlife. A wildlife monitoring system was developed in 1996 that used 19 landscape level view sheds, stratified...

We assessed short-term variability and long-term change in the composition of the littoral fish community in Spirit Lake, Iowa. Fish were sampled in several locations at night with large beach seines during spring, summer and fall of 1995–1998. Long-term changes were inferred from comparison with a similar study conducted over 70 y earlier in Spirit Lake. We found 26 species in the...

We studied nutrient reserve dynamics of female Lesser Scaup (Aythya affinis) to identify sources of intraspecific variation in strategies of nutrient acquisition for meeting the high nutritional and energetic costs of egg formation. We collected data from interior Alaska and combined these with data for Lesser Scaup from midcontinent breeding areas (Afton and Ankney 1991), allowing a...