Pacific harbor seals (Phoca vitulina richardii) are one of Oregon’s most common coastal predators, numbering between 10,000 and 12,000 individuals (Brown et al. 2005b). They consume more than 149 species or types of marine prey within the Pacific Northwest, which include a large variety of commercially important fisheries species. Despite...
2018 Library Undergraduate Research Awards nomination materials, reflective learning essay, and research paper.
In this study, pocket gopher and gray-tailed vole holes and hills were counted within four distinct habitats using quadrats and a gridding method over a period of five field days. The study was conducted to determine which...
Migration and spawning phenology of Pacific Salmon is linked to the hydroregime, and thought to be triggered by increases in river discharge and decreases in water temperature. However, little data exists that describes direct fine-scale linkages between the hydroregime and spawning in Coho Salmon. This study evaluated the spatial and...
Year-round habitat use of marine predators provides knowledge of important marine areas throughout different life stages. Large-scale, environmental variability, both in space and time, causes changes in the behavior and distribution of marine predators that are important to quantify for conservation. In the Northern California Current System (NCCS), common murres...
Declines in populations of anadromous salmonids (Oncorhynchus spp.) in the Columbia River drainage basin have resulted in extensive programs to annually release large numbers of hatchery-raised juvenile salmonids in an effort to support salmonid restoration. The Pacific Flyway population of Caspian terns (Hydroprogne caspia) has grown from around 3,500 nesting...
Fishers (Pekania pennanti) are medium sized mustelids endemic to North America. Two fisher populations persist in Oregon: an indigenous population in southwestern Oregon, and a reintroduced population in the southern Cascade Mountains. Despite candidacy for listing under the Endangered Species Act, current information on fisher populations in Oregon is scarce....
For over 100 years, National Parks have existed to preserve America’s natural and cultural heritage for current and future generations. As environmental pressures on wildlife and habitats have increased in recent decades, National Park lands have become important protected areas for many threatened and endangered species. Conservation and management of...
Species conservation depends on robust population assessment. Data on population abundance, distribution, and connectivity are critical for effective management, especially as baseline information for newly documented populations. I describe a pygmy blue whale (Balaenoptera musculus brevicauda) population in New Zealand waters with year-round presence that overlaps with industrial activities. This...
Up to 99.9% of native North American grasslands have been degraded since European settlement, primarily due to agricultural conversion. Today, grasslands are a top priority for restoration as they provide essential habitat for many rare and endangered species; however, the majority of studies in grasslands have focused on vegetation or...
Biodiversity loss in highly diverse systems such as coral reefs has been linked to significant declines in the ecosystem functions and services provided by marine species. Ecological functioning of coral reefs and the resistance of coral reef fish communities to disturbance depend on the functional traits of species that promotes...
Characiform fishes form one of the most diverse freshwater fish clades in the world. Comprising more than 2000 species and distributed primarily in South America and Africa, characiforms vary dramatically in their ecomorphology. However, the evolutionary processes responsible for the immense ecomorphological diversity remains unknown. Recently, a study postulated that...
Humpback whales (Megaptera novaeangliae) are a widely distributed baleen whale species, well known for their diverse acoustic behavior. On high-latitude foraging grounds, humpback whales produce a suite of non-song vocalizations (“calls”) in concert with foraging and social behavior. In this dissertation I investigated the role of calls in the acoustic...
Background. Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. Growth and reproduction in this population has not been apparent...
Informed conservation of small mammals, ecosystems, and predators requires a detailed understanding of how small mammals species and communities vary in both space and time, as well as the relative cyclicity and synchrony of this variation. This variation can be especially informative to land managers interested in manipulating the abundance...
Cross-seasonal effects, where conditions in one season can have consequences in a following season, can have population-level implications for migratory species. To assess the presence of cross-seasonal effects on a migratory dabbling duck population, we examined the relative importance of habitat conditions in multiple seasons on the subsequent productivity of...
In this study, we used a combination of conventional statistical analyses and mechanistic bioenergetics models to understand the potential effects of environmental variability on growth of stream-living fishes in four headwater streams subject to upstream forest harvest. We focused on two common fish consumers in headwater streams in the Pacific...
Collaborative decision-making is often promoted as a means to achieve socially acceptable and enduring solutions to natural resource management issues, and one that holds promise for resolving “wicked” problems. However, success rates for implementation of collaborative recommendations are unknown. This paper explores challenges to collaborative salmon fishery management in Prince...
California bighorn sheep (Ovis canadensis californiana) were studied on Hart Mountain, Oregon, during the summer and fall of 1976, and the spring of 1977. The population consisted of a minimum of 196 sheep in June, 1977. The high number of lambs observed and high lamb:ewe ratios throughout both years of...
Commercial whaling during the 20th century drastically reduced many populations of great whales in the Southern Hemisphere. The Antarctic blue whale, for example, is estimated to have been reduced to less than 0.1% of its original abundance based on catch records and population dynamic models. Despite this population bottleneck, several...
From July 1985 to April 1987 the pelagic zooplankton community of Crater Lake, Oregon was studied to determine taxonomic structure, absolute and relative densities, and spatial and temporal distributional patterns. Samples were collected using vertically-towed zooplankton nets. The community structure consisted of two cladoceran and nine rotifer species, which were...