I investigated Caspian terns (Sterna caspia) breeding at colonies on the Columbia Plateau (southeastern Washington and northeastern Oregon), with emphasis on the breeding and foraging ecology of Caspian terns nesting at colonies in the mid-Columbia River. I focused research at colonies where Caspian terns foraged on juvenile salmonids (Oncorhynchus spp.)...
The purpose of this study was to investigate the primary factors affecting colony size, reproductive success, and foraging patterns of Double-crested Cormorants (Phalacrocorax auritus albociliatus) nesting at East Sand Island in the Columbia River estuary, the largest colony of this species on the Pacific Coast of North America. This colony...
Small remnants of 'natural' habitats exist today throughout much of the world. Upland prairies in the Willamette Valley, Oregon have been nearly eliminated by conversion to agriculture and other uses. As a result, very few prairies remain and at least four butterfly species that require this habitat appear to be...
The distribution of Lahontan cutthroat trout Oncorhynchus clarki henshawi was assessed in a high-desert stream in southeastern Oregon where beaver Castor canadensis are abundant. Longitudinal patterns of beaver ponds, habitat, temperature, and Lahontan cutthroat trout age group distribution were identified throughout Willow Creek. Three distinct stream segments were classified based...
In the present study, the potential of low-melting point lipids, namely methyl palmitate (MP) and menhaden stearine (MS), were studied for delivery of water-soluble materials to fish larvae. Addition of the solid emulsifier, sorbitan monopalmitate (SMP) resulted in higher RE compared to the liquid emulsifier sorbitan sesquioleate (SSO). Additions of...
Gene expression profiles of tissues and cell-lines can be powerful tools for documenting the genetic response to a particular treatment, such as stressors. However, there is a paucity of information on the genetic stress response in the brain. Therefore, we attempted to profile gene expression in the brain of juvenile...
We conducted a 3-year study of helminth parasites to assess their effect on the lesser prairie-chicken Tympanuchus pallidicinctus. Helminth parasites were found in most of the examined wild prairie chicken carcasses: 95% had eye worm Oxyspirura petrowi, 92% had stomach worm Tetrameres sp., and 59% had caecal worm Subulura sp....
In this dissertation I explore the application of two novel modeling techniques for improving risk analysis of vector-borne disease and discuss their potential use in integrating environmental risk assessment that guides environmental and public health decisions. Techniques for analyzing risk have been considered inadequate due to a lack of understanding...
The migrations upstream of pre-spawned adult steelhead (Oncorhynchus mykiss) and
downstream of post-spawned steelhead (referred to as "kelts") can geographically and
temporally overlap in the Snake River, leading to management challenges for populations
listed under the Endangered Species Act (ESA). This thesis describes the development and
application of a method...
The endemic avifauna of Guam and the Mariana Islands represent a unique assemblage of bird species found nowhere else in the world and thus, are of considerable biological and conservation importance. Unfortunately, most of these species are understudied and exist in precariously low populations. The endangered Mariana Common Moorhen (Gallinula...
Little is known about Columbian black-tailed deer (Odocoileus hemionus columbianus) because of their elusive nature and the logistical difficulty of studying them in densely forested and mountainous terrain. The Oregon Department of Fish and Wildlife has identified fawn survival as an important gap in the current knowledge of demography and...
In the Pacific Northwest, regulatory agencies have recently
implemented management strategies for restoration and maintenance of wood
recruitment to streams over time. This allochthonous organic material is a
critical component in the geomorphic and biological structure of forested
streams. Mathematical models are commonly used to evaluate long-term
wood dynamics in...
Evaporation ponds that dispose of agricultural drainwater provide attractive habitat for waterbirds but may result in contaminant exposure that impairs reproduction. I estimated post-hatching survival and evaluated productivity estimates for American avocets (Recurvirostra americana) nesting at evaporation ponds in the Tulare Basin, California from 1991 to 1993. Avocets and Black-necked...
Longitudinal patterns of fish and benthic invertebrate distribution and
habitat use were similar in Thomas Creek, Oregon but clarity of these patterns
differed. I studied fish and aquatic invertebrates simultaneously, at multiple
scales, and used multivariate statistical techniques to compare responses to the
same environmental conditions. Both types of organisms...
Wild populations of fish are faced with a multitude of stressors, which may include human interaction, toxins, and disease. Benzo(a)pyrene (BaP), a known carcinogen and immunotoxin, has been reported in the stomach contents of juvenile chinook salmon, Oncorhynchus tshawytscha, in urban waterways. We investigated the impact of chronic dietary exposure...
Black rockfish (Sebastes melanops) is an important marine recreational species throughout the Pacific Northwest. Recent catch data indicate a trend of age-truncation in the black rockfish population off the Oregon coast, with older females rapidly disappearing from the population. In populations with broad age distributions, older fish may contribute disproportionately...
This thesis examined the influence of fall-spawning coho salmon on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska. During the fall of 1999 and 2000 fish rearing in ponds that received spawning salmon were...
The purpose of this study was to investigate the survival and movements of newly metamorphosed Northern Red-legged frogs (Rana aurora aurora) as they emigrated from two ephemeral breeding ponds. Quantifying survival and movement rates will be important to our understanding how changes to terrestrial and aquatic systems affect behavior and...
Relationships between the structure and composition of riparian vegetation
with channel morphology were examined in three montane meadow streams in the
headwaters of the Upper Grande Ronde River and North Fork John Day River in the
Blue Mountains, northeast Oregon. Vegetation composition, root biomass, and
channel morphology cross-sections were sampled...