Two ecologically important lamprey species found in the endorheic Goose Lake Basin face conservation threats; however, relatively little is known about their habitat needs or spatial distribution. Lamprey and their habitat are often found to be patchy; to evaluate these relationships for the lamprey in this basin, I utilized a...
There could be a geospatial and socio-ecological intersection between climate change, energy production, and sustainable fisheries management in the United States. Marine renewable energy generation efforts are currently being planned, studied, and initially implemented in the country as a response to climate change. The Bureau of Ocean Energy Management is...
Natural resources are essential to humanity. With the increase in global development in recent decades, people must monitor the state of the environment, whose disturbance has a more significant impact on society than before. However, conventional environmental monitoring is challenged in highly dynamic ecosystems and large areas. As a solution,...
Small-scale fisheries account for at least 40 percent of global fisheries catch, 90 percent of the people employed along capture fisheries value chains operate in small-scale fisheries, and 45 million women participate in small-scale fisheries globally. The past few years have brought warnings from policymakers and resource managers about risks...
The cultivated potato (Solanum tuberosum) is one of the most important food crops in the United States, as well as globally. As demand rises, growers in the Pacific Northwest are revisiting their crop management strategies to determine whether there are additional ways to enhance crop productivity while managing plant and...
The assessment of habitat quality for wild populations requires evaluation of vital rates associated with the use of that habitat. Factors associated with bottom-up (forage) or top-down (predation) regulation and the relative contribution of these processes on ungulate populations are difficult to quantify, especially for a cryptic, but widely distributed...
How the direct and indirect effects of species interactions cascade to affect community structure, functioning, and stability is a fundamental question in ecology. In temperate kelp forests, species interactions, in conjunction with environmental processes, produce rich spatiotemporal dynamics.
Arguably the most dramatic of these are abrupt shifts in community state,...
Relative to other systems in the PNW, the rain-dominated, coastal watersheds of western Oregon have shallow aquifers. Given the seasonality of streamflow and storage limitations in coastal, rain-dominated watersheds, changes in the temporal patterns of precipitation have the potential to magnify the risk of extreme streamflow conditions during both high-...
The local presence or absence of individual botanical species can be predicted with high accuracy by a simple feed-forward neural network, using only local climate data to make inference. This study proposes a framework for learning these predictive models, demonstrates highly accurate predictions for species with a sufficiently large area...
G.K. Chesterton once stated, “I am concerned with a certain way of looking at life, which was created in me by the fairytales, but has since been meekly ratified by the mere facts….The only words that ever satisfied me as describing Nature are the terms used in the fairy book,...
Forest harvesting and climate change induced shifts in precipitation characteristics (i.e., intensity, type) may affect how water is partitioned on the landscape, with more water potentially being lost to evaporation or groundwater, and less water being partitioned into the stream. Long-term, paired watershed data allows us to assess these possible...
Ecology is focused on understanding how organisms interact with each other and their environments, across ecological, spatial, and temporal scales. Thus, understanding how processes and patterns of ecological systems change across space and time is a principle goal for conservation biologist globally. While many approaches exist for investigating the changing...
Standard geostatistical models used in abundance prediction assume that observed counts on each site are made without error. However, in some wildlife populations, assuming perfect detection of animal or plant counts is unrealistic.
We first construct an adjustment to a finite population block kriging (FPBK) estimator that allows the possibility...
After a 40-year absence from Oregon’s landscape, expanding gray wolf (Canis lupus) populations are reestablishing elements of interspecific competition with sympatric large carnivores, like cougars (Puma concolor). This presents new challenges for management of large carnivores and their ungulate prey populations (e.g., elk, Cervus canadensis nelsoni; mule deer, Odocoileus hemionus)...
Models of a species’ distribution and models of a species’ spatially explicit density are valuable tools for conservation. They allow researchers to estimate changes in distributions, densities, and populations, based on changing environmental conditions. To trust such estimates, however, the quality of models is exceedingly important. Model performance can be...
Forested, mountain landscapes in the Pacific Northwest (PNW) are changing at an unprecedented rate, largely due to shifts in the regional climate regime. Documented climatic trends across the PNW include increasing wildfire frequency and intensity and an increasingly ephemeral snowpack, especially at moderate elevations. One relationship that has yet to...
Forests should be monitored and measured frequently to ensure its sustainability and continuity of carbon sequestration. However, conventional monitoring methods are costly and labor intensive. New technologies, such as unmanned aircraft systems (UAS) can be used as an alternative method to monitor and measure forests. The objective of this study...
In many traditional computer graphics applications, rendered scenes typically utilize 3D meshes to represent objects within an environment. As the demand to further improve the realism of graphics applications increases, such as for movies and games, it is becoming more important to represent the inner volumes of object meshes. In...
Environmental magnetic techniques have been used to discriminate sources of sediments from a variety of natural and anthropogenic sources. In many studies, magnetic properties such as susceptibility, have served as a proxy for heavy metal concentrations. In these cases, there tends to be enhancement of magnetic minerals. The study presented...
In this thesis, the spatial patterns of vegetation and soils of reference and restored tidal marshes were compared to determine the extent to which restored sites differ from the reference site after 40 years of restoration. Vegetation surveys of 1m x 1m plots were conducted along previously-established transects of salt...
Climate change is predicted to affect ecosystems, including systems already stressed by human impacts. One ecosystem that is already highly impacted by human land use is the cold headwater stream system of the Pacific Northwest. One method of assessing the function of an ecosystem is by using an indicator species....
Despite more than two centuries of exploration, including more than six million deep wellbores with depths exceeding 40,000 feet in some parts of the world, our ability to constrain subsurface processes and properties remains limited. Characteristics of the subsurface vary and can be analyzed on a variety of spatial scales....
The marine environment is under increasing pressure from human activities worldwide, particularly in coastal waters, creating a need to better understand fine-scale distributions of highly mobile species that occur in the area, as they are frequently most threatened. Harbor porpoise (Phocoena phocoena) occur frequently in Oregon’s nearshore habitat, but due...
Climate-induced range overlap can result in novel interactions between similar species and potentially lead to competitive exclusion. The Western Antarctic Peninsula is one of the most rapidly warming regions on Earth and is experiencing a poleward climate migration. This transition from a polar to sub-polar environment has resulted in a...
This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data were gathered at four to seven locations along South Sister Creek in 2006, 2012, and 2013 and were used to explore...
In 1994, with the approval of the Northwest Forest Plan, the livelihood of individuals in the surrounding communities of the Siuslaw National Forest and Siuslaw Watershed were further impacted by already diminished traditional timber practices. In 2003, the United States Forest Service developed an innovative program, stewardship contracting, aimed at...
In the Oregon Cascade Range, conifer encroachment has reduced the extent of mountain meadows by as much as 50% since the mid-1940s. Although encroachment results in a general decline of meadow species abundance and diversity, species differ in their sensitivities to encroachment: some show rapid declines whereas others persist in...
As a result of a warming climate, subsequent declining snowpack, and a century of fire suppression, forest fires are increasing across the western United States. However, we still do not fully understand how forest fire effects snowpack energy balance, nor the volume and availability of snow melt and associated water...
Illuminated contour lines, where line width and color are varied based on an angle of illumination, date back to the mid-nineteenth century, but their effectiveness compared to conventional contour lines has not been fully examined. Currently, illuminated contour lines are not widely used in computer-based cartography because they are not...
Volcanic hazard maps inform the public on the nature and extent of the hazards that threaten them, but these maps are often challenging for those who are not trained in map use or geology. The maps in this study focus on lahars, a dangerous, fast, and far-reaching volcanic hazard that...
Population trends and patterns in species distributions are the major currencies used to examine responses by biodiversity to changing environments. Effective conservation recommendations require that models of both distribution dynamics and population trends accurately reflect reality. However, identification of the appropriate temporal and spatial scales of animal response, and then...
Relief shading is the most common type of cartographic relief representation for print and digital maps. Manual relief shading results in informative and visually pleasing representations of terrain, but it is time consuming and expensive to produce. Current analytical relief shading can be created quickly, but the resulting maps are...
Invasion by non-native plants into natural areas is an important component of global change that threatens biodiversity and ecosystem structure and function. Mountains are currently among the least invaded ecosystems, however, these biodiversity hotspots are increasingly under threat of exotic plant invasion. Evaluation of plant species distribution patterns in mountain...
Despite holding substantial ecological value, wetlands in the United States have experienced a significant decline in both area and function over the past century with the majority of freshwater wetland loss attributed to agricultural conversion. Agriculture is the second largest industry in the State of Oregon and the State places...
Flexible electronics processing techniques were applied to integrate a glucose sensor with a hormone-delivery catheter in order to create a cheap and minimally invasive method for patients with type 1 diabetes to continually monitor and control their blood sugar levels. Ultimately, this work intends to move toward the development of...
To assist with risk-assessment with deepwater and ultra-deepwater prospects for offshore energy extraction as well as provide a useful tool for oil spill response, a spatially-explicit model was developed for comprehensive simulations of a blowout event from the wellhead to final fate and degradation. The Blowout and Spill Occurrence Model...
The study of the diversity of multivariate objects shares common characteristics across disciplines, including ecology and organizational management. Nevertheless, experts in these two disciplines have adopted somewhat separate diversity concepts and analysis techniques, limiting the ability of potentially sharing and cross comparing these concerns. Moreover, while complex diversity data may...
Forest canopy cover presents a major challenge for remote sensing of fractional snow-covered area (ƒSCA). Snow cover is systematically underestimated where satellites sensors cannot penetrate the forest canopy. Current canopy adjustments scale observable ƒSCA with the vegetation fraction, assuming that snow cover distributions are similar between sub-canopy and open locations....
California's water resources vary throughout the state owing to the regions varying topography, diverse climate, and the distribution of precipitation. Most of the state's precipitation falls over the northern coastal range and the western slopes of the Sierra Nevada Mountains. Winter snowpack that accumulates within these mountain basins serves as...
The western United States is experiencing significant changes in wildfire and snow regimes as a result of warming temperatures. An amplification of wildfire activity and reduction in snow water equivalent, snow covered area, and earlier spring snowmelt are documented trends that are projected to continue into the future. With an...
Range, areas of concentrated activity, and dispersal characteristics for juvenile Steller sea lions Eumetopias jubatus in the endangered western population (west of 144° W in the Gulf of Alaska) are poorly understood. This study quantified space use by analyzing post-release telemetric tracking data from satellite transmitters externally attached to n...
The link between aboveground net primary productivity (ANPP) and resource gradients generated by complex terrain (solar radiation, nutrients, and moisture) has been established in the literature. Belowground ecosystem stocks and functions, such as soil organic carbon (SOC), dissolved organic carbon (DOC), and belowground productivity have also been related to the...
This study examined the distribution and behavior of adult spring chinook salmon
(Oncorhynchus tshawytscha) related to patterns of stream temperature and physical
habitat at channel unit, reach, and basin-wide spatial scales in both a wilderness stream
and a disturbed stream in the John Day River basin in northeastern Oregon. Thermal...
In this thesis I present the results of a comprehensive assessment of the Pacific-North American (PNA) teleconnection pattern in general circulation models (GCMs) and a regional climate model (RCM). The PNA teleconnection pattern is a quasi-stationary wave field over the North Pacific and North America that has long been recognized...
Networks of distributed, remote sensors are providing ecological scientists with a view of our environment that is unprecedented in detail. However, these networks are subject to harsh conditions, which lead to malfunctions in individual sensors and failures in network communications. This behavior manifests as corrupt or missing measurements in the...
A new high-throughput culturing (HTC) method using a low nutrient
heterotrophic medium (LNHM) has led to the isolation of many novel strains of
oligotrophic bacteria from marine ecosystems. Four strains belonging to a single
dade, HTCC2151, HTCC218OT, HTCC2178T and HTCC2188T, were isolated
from the coast of Oregon by the HTC...
Recent work in machine learning concerns the detection and identification of bird species from audio recordings of their vocalizations. Such analysis can yield valuable ecological information concerning the activity and distribution of species in the wild. Current species-identification methods require individual syllables of bird audio as input, but field-collected audio...
Ever expanding pressures on the health and productivity of our oceans and coasts from threats such as coastal development and climate change are stressing the need to consider the full spectrum of factors, scales, datasets, opinions, and trade-offs for current and future coastal management actions (Guerry 2009; McLeod and Leslie...
Recruitment of larvae from the plankton is an important determinant of
community structure in marine systems. In populations of many marine species,
recruitment determines the basic demographic parameters of immigration, emigration,
and reproduction. Moreover, the effect of recruitment as an "ecological subsidy" can
determine the strength of interactions among species...
Biological invasions provide a unique opportunity to study the mechanisms that regulate community composition and ecosystem function. Invasive species that are also ecosystem engineers can substantially alter physical features in an environment, and this can lead to cascading effects on the biological community. Aquatic-terrestrial interface ecosystems are excellent systems to...
This thesis consists of three subsequent parts addressing the applications of stochastic
processes to the analysis and solutions of parabolic equations with discontinuous coefficients
that are of mathematical interest.
The first two parts consist of three manuscripts, in which we analyze solutions
of Fickian convection dispersion equations with discontinuous coefficients...
Invasion by nonnative brook trout (Salvelinus fontinalis) often results in replacement of bull trout (Salvelinus confluentus) in western North America, but the causal mechanisms are not well understood. Removal of brook trout from 1992 to 2000 from Sun Creek in southern Oregon, provided an opportunity to investigate the changes in...
In an effort to restore summer flows in the Walla Walla River to provide passage
and habitat for ESA (endangered species act) listed bull and steelhead trout irrigation
districts left 13 cubic-feet-per-second (c.f.s) (0.37 m ³/s) in the main channel during
irrigation season (May-November) for the first time in over...
This dissertation focuses on the evolutionary forces of genetic drift and gene flow in frog populations. The balance of these two forces and the force of mutation largely determine the amount of neutral genetic variation within populations as well as the degree of genetic similarity among populations. The stochastic evolutionary...
Satellite imagery has been a useful tool in monitoring land cover changes, including changes within protected areas. In the 1980’s and 1990’s Honduras created over 100 protected areas, yet few resources have been dedicated to their management. This study used Landsat satellite imagery to evaluate deforestation in the Río Plátano...
Comparative investigations based on volcanic morphology suffer from the lack of a large terrestrial baseline for comparison. To fill this gap, the Lava Flow Morphology Database (LAMDA) was proposed as a GIS based central clearinghouse for remote and field investigations of volcanic morphology. This study presents an analysis of LAMDA’S...
Knowledge about vegetation patterns and ecological processes in unmanaged, late-successional
watersheds is needed to provide a foundation for forest management strategies
aimed at conserving native biodiversity. I examined influences of environmental variability
and disturbance history on forest structure and composition in the Cummins Creek
Wilderness, located on the central Oregon...
Fire history and fire regimes were reconstructed for a 450 km² area in the central
western Oregon Cascades, using tree-ring analysis of fire scars and tree origin years at
137 sampled clearcuts. I described temporal patterns of fire frequency, severity, and size,
and interpreted topographic influences on fire frequency and...
The El Niño/Southern Oscillation (ENSO) affects millions of people via global teleconnections in the form of drought and torrential rainfall that impact agriculture and food production in many countries. Yet how ENSO will respond to a warming world is uncertain and a greatly debated topic. The Intergovernmental Panel on Climate...
Dead wood patterns and dynamics vary with biophysical factors, disturbance history, ownership, and management practices. Through field and modeling studies, I examined the current and potential future amounts of dead wood in two landscapes and region-wide in the Coastal Province of Oregon. The objectives of the first study were to...
Shifting climate patterns in the Columbia River basin are affecting snow pack, and, as a result, stream flow throughout the region. In the Oregon Cascades, ever growing populations, and their associated activities, place increasing stress on an already over allocated hydrologic system. Political pressures, including the possibility of renegotiation or...
In undisturbed N-limited forested catchments, DON may represent over 90% of the total N lost in streams. Some ecologists have suggested that plant-derived reactive polyphenols may be responsible for DON binding and transport because polyphenol-protein complexes are known to precipitate out of solution, bind to mineral surfaces or organic matter...
Disturbances are a prevalent and important part of ecosystems. Many landscape patterns that we find today were created, maintained, and changed by natural disturbance regimes. This is especially true for fire, which has historically been a common, natural disturbance in the western U.S forests and grasslands and many other parts...
Patterns of western hemlock regeneration were studied in relation to forest structural development and environment in the Oregon Coast Range. Density of western
hemlock seedlings was examined across the climatic gradient from cool, moist coastal
areas to the seasonally hot and dry Willamette Valley Margin. Seedling densities were most strongly...
The dominant controls on flow generation in steep, forested hillslopes are poorly understood. This dissertation examined the dominant flow processes operating at the hillslope scale, using a combined macroscale measurement and model development and analysis framework. Irrigation experiments at two steep forested hillslopes were conducted to isolate individual hillslope flow...
Sediment production and delivery in Pacific Northwest
coastal streams can have damaging effects on channel
morphology and anadromous fish habitat. The research in
Pistol River was designed to determine if a link exists
between sediment delivery processes and degradation of fish
habitat. Objectives of this basin-wide analysis were to:
1)...
The age, or residence time of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways and source of water in a single integrated measure. While there has been tremendous recent interest in residence time to characterize catchments, there are few studies that quantify residence...
In this dissertation, new theory and its applications are developed to predict three properties of complex ecological communities: stability, equilibrium response, and non-equilibrium dynamics. First, a graph-theoretic analysis identifies the interconnections in a complex ecosystem that promote or diminish stability (Chapter 2). The hierarchy of interactions that influences stability and...
This dissertation had three main objectives: 1) investigate the role of macro and micro geomorphology in determining lizard distributions in the Southern California Mojave Desert; 2) develop a spatially explicit lizard habitat model based upon geomorphology; and, 3) determine the interactive effects of geomorphology, roads, and land use in defining...
The study examines the effect of forest clearance on fire occurrences in major islands of Indonesia, namely: Borneo, Sumatra, Sulawesi and Irian Jaya. The working hypothesis of the study is that forest clearing is a necessary predecessor for extensive fires to occur. The study is designed to test the idea...
An integrative method for monitoring glacier geometry change and mass balance is presented and applied to the Pacific Northwest, USA. Acting as a baseline for interpretation of future changes in glacier size and shape, we first derive a new inventory of regional glacier cover using remotely sensed data. To investigate...
Most recent research on stream amphibians in the Pacific Northwest has focused on associations with reach-level or stand-level environmental features. Little is known about landscape-level distributions of these species or landscape-level aspects of their life-histories. I used a watershed-wide sample and logistic regression to develop models and maps of probability...
Geospatial technology is a rapidly growing and changing field. The term geospatial technology (GST) refers to geographical information systems (GIS), global positioning systems (GPS), and remote sensing (RS), all emerging technologies that assist the user in the collection, analysis, and interpretation of spatial data. The speed at which new fields...
The EPA’s Western Ecology Division (WED) had been accumulating geographic information system (GIS) data files for up to 20 years. There was no index or catalog for these files; locating data became more difficult over time. More that 4 Tb of data existed on numerous disk volumes in hundreds of...
Hunter-gatherers depend on naturally occurring resources and, in order to survive, must overcome resource procurement challenges inherent in their environment. One challenge relates to the temporal and spatial availability of resources, which hunter-gatherers address, in part, through the strategic use of space to position themselves for optimal access to necessary...
This research examines the downstream fining phenomenon as it operates in coastal gravel-bed rivers of Oregon. Downstream fining is a change in bed composition toward smaller sediment sizes in the downstream direction. Changes in stream flow discharge and channel slope affect the rate of bed-load transport, thereby altering the downstream...
The purpose of this dissertation was to define macrolichen community gradients in relation to succession, grazing and the environment. First, species scores indicating when macrolichen species appeared following disturbance were derived from the literature. Weighted averaging of these data with a community matrix created a successional score for each sample...
Warming of the terrestrial biosphere due to the anthropogenic addition of carbon dioxide to the earth’s atmosphere is becoming a major focus of scientific inquiry. Predictions of the extent of this warming are hampered by uncertainty in the ability of the earth’s ecosystems to counteract this effect by sequestering carbon...