Population genetic techniques are now preeminent in differentiating wild populations. Natural resource managers rely on them in their efforts to restore viable populations of fish and wildlife. Overfishing adversely impacted Yelloweye Rockfish (Sebastes ruberrimus) on the U.S. West Coast in the late 20th century. Management actions included shutting down the...
Riparian forests provide a myriad of ecosystem functions for adjacent streams and rivers, and due to these linkages, changes in riparian forest conditions can have direct implications for stream ecosystems. Resource managers in the coast redwood forests (Sequoia sempervirens) of northern California (USA) are actively thinning second-growth stands to accelerate...
The natural environment provides important services and benefits to peoples’ health and lives. Conversely, environmental disservices can have negative impacts on humans such as through pollution, chemical toxins, and climate change. The combination of environmental services and disservices encompass how human health and wellbeing, and the environment are connected. As...
Non-toxic species of desiccated blue-green algae, or cyanobacteria, may offer potential for use as a fertilizer on irrigated crops. Here, the non-toxic cyanobacteria species Aphanizomenon flos-aquae (AFA), collected from Upper Klamath Lake, Oregon, was evaluated for use as a biofertilizer in a controlled experiment on Swiss chard “Bright Lights” (Beta...
Carnivores have disproportionate effects in ecological systems but understanding their exact influences on ecosystems is a matter of great complexity and debate. Predators directly impact prey by killing them, and indirectly by modifying their behavior in response to predation risk. Yet how species interact, both among members of a carnivore...
RNAseq data among copepods (Calanus pacificus) were sampled and analyzed in relation to oceanographic and climatic conditions to determine if new information derived from such an approach might assist applications that use copepods as ecosystem indicators to predict fishery yields. These samples were taken as part of long-term studies conducted...
Climate change is a global phenomenon, but natural selection occurs within landscapes. A central tenet of landscape ecology is that mobile species depend on complementary habitats, which are insufficient in isolation, but combine to support animals through the full annual cycle. For coldwater fishes, it is widely assumed that maximum...
Microplastics (<5mm diameter) are present in a considerable number of marine and aquatic species. Understanding which species, the global spatial distribution, and what quantities of microplastics are present is extremely important for understanding the potential impacts they could have on recreationally important organisms and for the assessment of risk. We...
The relationship between population characteristics and population productivity is fundamental to sustainable fisheries management, but predicting productivity remains a challenging task. Proposed mechanisms driving the variability in productivity at a given population size have included environmental and demographic factors related to the age structure of the population, but the broad-scale...
Aquatic and riparian systems in the western United States have been highly modified by anthropogenic impacts since Euro-American settlement. Ecological restoration is a practice that has been widely conducted around the world to mitigate the degradation of these systems. The majority of stream restoration efforts have focused on improving in-stream...
Many economically important Pacific salmon fisheries along the west coast of North America are mixed-stock, recreational systems, in which managers strive to account for interactions between fish, anglers, and management policy while balancing fishery access against conservation of vulnerable stocks. Specific challenges facing fisheries managers include limited control over angling...
Land-use change, particularly in the form of the conversion of primary forest to forest-matrix systems, alters species communities and species interactions. Describing these often complex and nuanced species responses is one of the great challenges in ecology. Another complementary challenge is finding and using the most efficient means for collecting...
Isotope and stomach content data from piscivorous reservoir fishes collected from Hills Creek (isotopes; 43°40′16″N 122°25′33″W) and Lookout Point (isotopes and stomach contents; 43°53′48″N 122°43′34″W) reservoirs located on the Middle Fork Willamette River, Oregon. Additional details can be found in the related publication.
Isotope sampling was conducted under OSU Institutional...
An inextricable link exists between dams and human development in the Pacific Northwest, but they can fragment rivers and reduce genetic connectivity for freshwater and anadromous fishes. Since the early-twentieth century, a series of hydropower and irrigation dams on the mainstem Klamath River, California, has fragmented migratory corridors and eliminated...
Mangrove forests store more organic carbon across ecosystem carbon pools than most other coastal and forested ecosystems, and are subject to high global rates of deforestation. For these reasons, they are recognized as prime candidates for inclusion in climate change mitigation strategies. However, the ecological drivers of regional and micro-scale...
A substantial fraction of estuarine tidal wetlands have been lost to development or other human uses in the Pacific Northwest since the 1800s. Wetland restoration, typically through tidal re-connection, can restore normal tidal hydrology to these areas and improve estuarine capacity to support ecosystem functions and services. Restoration may initiate...
The anadromous Pacific Lamprey (Entosphenus tridentatus) is a biologically and culturally important species native to the North Pacific Ocean and its adjacent freshwater tributaries. Pacific Lamprey have experienced declines in abundance and distribution throughout their native range, highlighting a need for further research on the species to better inform conservation...
The northern spotted owl (Strix occidentalis caurina; spotted owl) is of conservation concern and endemic to mature forests of the Pacific Northwest. Adult survival has a strong effect on population growth rate, but juvenile survival and recruitment are also important components of population change. Despite the importance of this life...
The life history traits of polygamous, non-territorial shorebirds like the Red Phalarope (Phalaropus fulicarius) can make it challenging to assess their population status. There are two general approaches to statistical inference used to understand shorebird (Order: Charadriiformes) population change: design-based inference, which implements an a-priori sampling scheme with known selection...
Passive acoustic monitoring is a valuable tool for observing the status of marine environments. Comparisons of underwater soundscapes over temporal and spatial scales can provide data to inform marine conservation efforts, including protection of threatened and endangered species. This dissertation utilizes passive acoustic data collected via a broadly spaced array...
Understanding prey quality and prey selection by predators is critical for management efforts aimed at identification and protection of essential habitats and prey. Marine predators must make daily foraging choices in a heterogenous and dynamic environment in order to meet the high energetic demands of migration, reproduction and foraging. With...
Livestock grazing occurs worldwide, spanning over 25% of land globally. Effective conservation of biodiversity relies upon understanding the interactions of agricultural management practices and increasingly variable weather associated with climate change. I evaluated grazing, weather and predator-prey interactions within a grazing experiment in the sagebrush ecosystem of southeastern Oregon. I...
Pacific salmon are culturally and economically important species to Southeast Alaska, where there is a history of large wild runs and supplemental production from hatchery programs. Salmon management in Alaska is divided amongst various governmental agencies. Non-governmental organizations also play a pivotal role in salmon management. To fulfill the requirements...
Animal weapons are thought to have evolved to compete for reproductive opportunities within a species. Across the diverse weapon-bearing taxa, several evolutionary trends have emerged: (1) increasing complexity and relative size across ontogeny, (2) sexual dimorphism, and (3) higher levels of random deviations from symmetry (i.e., fluctuating asymmetry) than non-weaponized...
Spatial capture-recapture (SCR) is employed for estimating abundance and density of species, particularly those that are cryptic or solitary, and evaluating how population density varies with habitat. However, it is uncertain whether estimates are biased when applied to species that aggregate, such as elk (Cervus canadensis). Wildlife managers in the...
The goal of this project was to estimate the total annual cost of salmon recovery efforts throughout the Columbia River Basin from all stakeholders, including direct and indirect costs. How much is spent on salmon recovery efforts each year in the Columbia River Basin? Depending on who you ask, you...
Pacific salmon (Oncorhynchus spp.) rearing in lakes and reservoirs have been known to become heavily infected with an ectoparasitic copepod (Salmincola californiensis). Little is known about the factors that affect the parasite infection prevalence and intensity. However, previous research suggests that the parasite may negatively affect the fitness and survival...
Pacific lamprey is an important cultural and ecological species to freshwater ecosystems of the Pacific Northwest. Lamprey often rear in low gradient portions of watersheds that have high exposure to climate warming, yet very little is known about their thermal physiology in comparison with other anadromous fishes such as Pacific...
Freshwater rearing is a critical period in the life cycle of anadromous salmonids, known to produce carry-over effects mediating long-term growth and survival. Freshwater growth is primarily determined by food availability and temperature. While many species of salmon rear in freshwater for a full year or longer, most trophic ecology...
Fisheries management that is based on quantitative assessment has commonly relied on estimating the unfished biomass of a fished stock to compare current and historical population size. Developing predictive models for this requires many years of catch and abundance data. Smaller, new, or mainly recreational fisheries may not have the...
The social sciences are increasingly used in conservation to describe interactions and relationships between humans, wildlife, and ecosystems. Scientists and policy-makers have concluded that promoting human tolerance for wildlife is critical to the success of conservation efforts. Yet, the concept of tolerance is relatively new in the context of human-wildlife...
Fundamental objectives in the field of conservation biology involve understanding the processes that influence small and declining populations and applying that knowledge to develop appropriate monitoring strategies and targeted management and conservation actions. Critical first steps in determining the relative role of factors that drive population declines involves estimation of...
Pollination is an essential ecosystem service that sustains functioning ecosystems and aids in food production. In response to recent, widespread declines of managed and native bee populations, many land managers have shown interest in developing conservation and restoration plans for enhancing native bee habitat. However, there is a lack of...
Shallow lakes exist in either a clear or turbid state, with the clear state characterized by an abundance of aquatic macrophytes, diverse aquatic biota, low water column nutrients and phytoplankton biomass, whereas the turbid state is characterized by the opposite. These two distinct states are maintained by reinforcing (positive) feedback...
The western United States has experienced large-scale degradation due to land use and land cover changes, invasion of annual grasses, and expansion of woody plants into grass and shrublands and the resultant altered fire regimes. These landscape-scale changes have coincided with declining mule deer (Odocoileus hemionus) populations, making habitat loss...
Advances in mobile autonomous vehicles for oceanographic sensing provide new opportunities for passive acoustic monitoring of marine mammals. Acoustically equipped mobile autonomous platforms, including gliders, deep-water profiling floats, and drifting surface buoys can survey for a variety of marine mammal species over intermediate spatiotemporal scales. Additionally, such mobile platforms may...
A deep neural network was developed and trained to identify the sounds of pomacentrids (damselfishes) in the National Park of American Samoa. Four years of continuous, passive acoustic data were recorded by a single stationary hydrophone. Deep neural networks enable the full utilization of such large datasets by automating laborious...
In the western United States, bighorn sheep (Ovis canadensis) have suffered major die-offs in every state since the mid-1800s, and disease from domestic sheep (Ovis aries) has been a primary factor in these events. Beginning in the early 1900s, poly-factorial, poly-microbial pneumonia was identified as a major disease affecting bighorn...
The ultimate goals of this project are to 1) provide farmers with data-based advice on maintenance and enhancement of habitat for native wildlife based on what species are using the remnant/unfarmed patches on producers farms and to 2) provide background knowledge and data to enable development of a larger project...
Grape growers seeking to protect their grapes from bird depredations have no economic guidelines for selecting one or more of several control alternatives. Many growers are not aware of the cost of applying the various control techniques, nor do they know how effective these techniques are in preventing damage to...
Anthropogenic activities have posed many threats to the oceans and marine life. Understanding how individuals are affected and physiologically respond to these threats is crucial and allows for management and conservation applications. I evaluated the overall health condition of a subpopulation of gray whales (Eschrichtius robustus) along the Oregon coast,...
As regional climates warm in the Pacific Northwest, USA, flow minima and temperature maxima may become more synchronous in headwater streams over time. The dual stresses from lower flows and warmer temperatures will be energetically costly for cold-water species such as Coastal Cutthroat Trout and Coastal Giant Salamander. Individual fates...
Animal pollination is critical to plant reproduction in agricultural and wildland ecosystems. Much of the production of seeds and fruits in natural areas, which underlie many food webs, depends on pollination services by insects. The taxon responsible for delivering the bulk of these services in most temperate systems is bees....
The greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) is a ground nesting gallinaceous bird that requires large contiguous patches of sagebrush. Sage-grouse populations have declined, especially in the Great Basin where changes in wildfire regimes and the invasion of annual grasses have contributed to habitat loss and fragmentation. During the last...
The role that anthropogenic and natural habitats in estuaries play in long-term population trends for Oregon’s nearshore marine fishes is poorly understood, in part due to limited temporal sampling. One important nearshore marine group is northeastern Pacific rockfishes (Sebastes spp.), which are highly diverse, with around 96 documented species, and...
The 1989 Exxon Valdez oil spill (EVOS) in Prince William Sound, Alaska provided impetus for a great deal of research into the ecosystems of the Northern Gulf of Alaska. Buried within the multitude of resulting impacts, which included hundreds of thousands of oiled seabirds and dramatic ecosystem shifts in the...
Human alteration of natural landscapes leads to biodiversity loss, often from a combination of area effects and fragmentation effects. Smaller habitat patches support fewer species than large ones and incur additional consequences from isolation. Efforts to preempt biodiversity loss from insular habitat fragments are complicated by individualistic species responses and...
The National Park Service has a dual mission of providing public access to exceptional natural resources, but in a manner such that these resources are left “unimpaired for the enjoyment of future generations.” Human activities in parks undoubtedly affect wildlife, but the degree to which such activities cause impairment is...
Somatic growth variation manifests from the cumulative effects of a suite of biological, ecological, and environmental processes and can have profound effects on individual fitness and species population dynamics. As ectotherms whose growth dynamics are greatly influenced by environmental factors, sea turtles display considerable variation in somatic growth within and...