Despite relatively mild weather, black bears (Ursus americanus)
in southwestern Washington entered dens and remained for an average
of 126 days. Bears entered their dens during a 5-week period which
began on 21 October. A significant difference (P < 0.05) was found
among the average dates of den entrance of...
Many of Earth’s terrestrial large carnivore species are threatened with extinction. As a result, some of the ecological effects associated with these species may be lost. With the goal of furthering large carnivore conservation research, I conduct three global scale analyses involving these species. First, I explore prey depletion as...
Mountain Quail (Oreortyx pictus) populations have declined in many areas of the western Great Basin during the past century. Yet the life history of this species is little known. From 1997 to 2000, I studied radio-marked Mountain Quail in Hell's Canyon in northeastern Oregon, in the Cascade Mountains of southwestern...
Patterns and costs of root/shoot allocations, response to reductions of above and below-ground tissue and to fertilization with nitrate and ammonium, and seasonal courses of physiological processes were measured on juvenile, small-adult, and large-adult Juniperus occidentalis growing in the field under ambient
environmental conditions in eastern Oregon.
Adult foliage had...
Montane meadows in the western Cascades of Oregon occupy approximately 5% of the landscape, but contribute greatly to the region's biodiversity. Western Cascades meadows are dynamic parts of the landscape and have contracted by over 50% in the past two hundred years in the HJ Andrews Experimental Forest (hereafter Andrews...
This is a study of the ecology of the timberline and alpine vegetation of the Three Sisters which are located in the
central Oregon Cascades. The Sisters are a close group of three 1O,000-foot volcanic peaks. Volcanic activity within the last few hundred years as well as recent glaciation have...
Previous difficulties mapping tropical forest successional stage with satellite imagery may be one of the reasons why little is known about what socioeconomic and biophysical factors control tropical secondary forest pattern over landscapes. Additional remote sensing challenges occur in regions with steep topography, because the spectral responses of land covers...
This research assesses prescribed burning as a habitat management
technique in wetlands and associated upland communities of Malheur
National Wildlife Refuge, southeastern Oregon. Experimental burns
were conducted to evaluate fire behavior and effects in wetland and
upland habitats, and, fire effects on Cirsium arvense. Wetland plant
communities were monotypic stands...
Biology of Scaptomyza apicalis Hardy (Diptera: Drosophilidae) was studied in
relation to its host, meadowfoam, Limnanthes alba, a recent oil seed crop grown in the
Willamette Valley, Oregon. Populations of flies and larvae were monitored weekly over
three consecutive crop-years beginning in 1996. Yellow sticky traps gave relative
population estimates...
A feral pig population on Santa Catalina Island, California, was
studied for 17 months beginning in July 1980. Density was estimated
to be 21 to 34 pigs/km² (95% confidence interval) using capture-recapture
techniques. Dry season home ranges determined from
radio-telemetry data were small and differed significantly between
boars and sows....
The ecology of the North Atlantic right whale (Eubalaena glacialis) was examined at three spatial scales during the summer and early fall on their northern feeding grounds. The diving and foraging behavior of right whales was investigated at spatial scales of hundreds to thousands of meters by tagging right whales...
Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within general ecology, fisheries biology, and conservation biology. The primary goal of this dissertation was to use the coral-reef fishes system...
The evolutionary relationship between Frankia and actinorhizal plants was evaluated
by reconstructing molecular phylogenetic trees from nifH, 16S rDNA, and rbcL
nucleotide sequences. Subgroupings in Frankia phylogenetic trees reconstructed from
nifH and from 16S rDNA sequences were consistent in terms of plant origins of Frankia
strains. Although the branching order...
Seasonal trends in water table level and soil moisture
for four plant community types within an irrigated eastern
Oregon riparian zone were described. Aboveground biomass,
species composition, litter, percent bareground and percent
basal cover of key plant species and life forms were measured.
The relationship between water table levels and...
The ecology of female Great Basin Canada geese (Branta
canadensis moffitti) and their broods was studied during the rearing
seasons of 1983 and 1984 on the Columbia River in southcentral
Washington. The movements and activities of 41 adult female geese,
marked with radio-transmitters, and their broods were monitored.
Adult female...