The short-term duration of most ecological studies can make it difficult to capture the long-term dynamics of ecosystems and populations. Infrequent or high-impact events can be missed, or erroneously documented as baselines. Long-term ecological research enables a deeper understanding of complex processes, provides a foundation for future insights, and can...
Our understanding of nitrogen (N) and phosphorus (P) variability in forested stream systems with minimal disturbance is confounded by the complex interactions of hydrologic and biogeochemical controls. In this thesis, our studies evaluate the variability of stream water N and P in a forested, headwater system in the Oregon Coast...
The structure of food webs and how they relate to community stability has been an important debate in ecology. Specifically, predictability of web shape and how it influenced by surrounding landscapes is one of the main goals of such discussions. Headwater streams provide a study template that is of interest...
The Middle Fork John Day Basin in Northeastern Oregon is prime habitat for spring Chinook salmon and Steelhead trout. In 2008, a major tributary supporting rearing habitat, Big Boulder Creek, was restored to its historic mid-valley channel along a 1 km stretch of stream 800 m upstream of the mouth....
Stream temperature is a water quality parameter that directly influences
the quality of aquatic habitat, particularly for cold-water species such as Pacific
salmonids. Forest harvesting adjacent to a stream can increase the amount of
solar radiation the stream receives, which can elevate stream temperatures
and impair aquatic habitat. Oregon Forest...
Humans have drastically altered the physical habitat and food web structure of stream ecosystems. Two major impacts humans have had on Pacific Northwest streams are modification of streamside forests (as a result of agriculture, land development, and timber harvest), and declines in the return of wild anadromous salmon to headwater...
Wildfire management has grown increasingly complex in recent years,
particularly in the West and in the Wildland-Urban Interface (WUI) where a steady
population growth has resulted in greater risk to people and property. Recent trends
suggest the process of recovering from large fires (>100,000 acres) will become
increasingly important to...
Land use alters the physical and biological structure of stream ecosystems and potentially alters their capacity to process nitrogen (N), an essential nutrient that has nearly doubled in abundance on the biosphere
during the past century from human activities. In this dissertation, I quantified uptake and transformation of nitrate (NO₃⁻)...
Barriers to the movement of aquatic organisms can increase the genetic and spatial isolation of populations and may decrease the viability of these regional populations. Focus on culvert passage issues has increased as federal agencies attempt to inventory and replace road-crossing stream culverts that are barriers to the movement of...
Evaluations were performed on three stream temperature prediction models: Heat
Source 5.6, SSTEMP 3.9, and Brown's equation. Each model was evaluated using data
collected from three Coastal Oregon and two western Cascade streams. Stream temperature
simulations were performed on two forested reaches, one clearcut reach, and one buffered
reach, for...
Abstract
Understanding the effects of climate change on forest ecosystems requires exploration of the relationships of different components of the system, such as the response of biota to local hydrology, temperature, precipitation, and elevation. The Long-term Ecological Research Program at the H. J. Andrews Experimental Forest, located in the Western...
In the Pacific Northwest ecoregion of North America, sculpins represent a major constituent of freshwater assemblages in coastal rivers. Based on their prevalence and abundance, sculpins are likely important ecologically, yet little is known of their interactions with co-occurring species, such as widely studied salmon and trout (salmonines). In this...
Watershed management is widely recognized as an important component of healthy ecosystems and its success depends on cultivating the good will, stewardship values, and participation of citizens. Because much of the streamside land in Oregon is in private ownership activities on public lands will not be enough to protect salmon...
The role of riparian forests in maintaining temperatures of headwater streams is well established and is a foundation of forest practice rules designed to protect streamwater quality. However, detailed investigation is still needed quantifying specific characteristics of stream systems that affect streamwater temperature including riparian features, stream morphology, and subsurface...
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...
Small mountainous watersheds are disproportionate sources of land-derived particulate organic matter (POM) to long-term sinks like lake bottoms and the ocean. As such, these ecosystems are an essential component of the global carbon cycle. The burial of POM in lacustrine and marine sediments contributes to the drawdown of atmospheric CO2...
Wetland restoration mitigates effects of agricultural development on water quality, flooding, and habitat loss. Multi-objective optimization for wetland locations and sizes has not included objective functions for water quality, hydrology, and habitat in unison, limiting analysis of trade-offs among these ecosystem services. This study establishes two methods to improve the...
The Middle Fork John Day River is composed of low gradient, alluvial valley
segments separated by constrained, canyon-like reaches, and has a history of multiple
land-uses. These factors can alter the physical and biological structure of streams, and
disrupt the longitudinal river continuum. I examined habitat, fish, macroinvertebrates,
and primary...
Headwater streams are an integral part of the ecological health of the greater stream network as they provide valuable biological habitat, provide upwards to 95% of total in channel flow, while providing downstream reaches with important constituents such as sediment and woody debris. Small headwater streams are particularly susceptible to...
Stream temperature, as an important component of stream ecosystems, can be affected by forest harvesting through removal of riparian shade and changes in hydrology. Riparian Management Areas
(RMAs), as implemented through the current Oregon Forest Practice Rules, are designed, in part, to maintain stream temperature following forest harvesting. However, effectiveness...
Ecological resources available to freshwater fish shift spatially, temporally and across life stages. To better understand how spatial-temporal availability of resources influence fish, I examined the phenologies of hatching and emergence of Coho Salmon (Oncorhynchus kisutch) in streams with contrasting and strongly defined seasonal thermal variability. The study streams included...
This study documented the influence of the completion agenda on decision-making by community college career and technical education (CTE) deans. Ten career and technical programs deans were identified as the sample for the study. Washington State was selected because of the Student Achievement Initiative that was developed as a completion...
Studies of the effects of forest harvest on streams and fish have a long history in the Pacific Northwest. Results of this work have prompted development of new forest harvest practices that are more protective of these resources, but the effectiveness of these new practices has not been fully evaluated....
This study evaluates the functional organization of stream fish assemblages in response to streamflow factors and biotic interactions across a range of spatial scale. The study area for this project includes 109 stream reaches located on tributaries to the upper Missouri River in the northern Great Plains. Fish distribution data...
The spatial and dynamic pattern of landscape changes has a profound effect on the supply of environmental services, including the provision of habitat for fish and wildlife. Spatial heterogeneity is a common feature of landscapes in the Pacific Northwest, most notably in areas important to the production of salmonid fish...
Global Positioning System (GPS) and Geographic Information System (GIS) technologies were employed to evaluate cattle occupancy of three landscape attributes on three different grazing allotments administered by the Wallowa Whitman National Forest in Northeast Oregon. Topographic characteristics of slope; 0-4%, 4-12%, 12-35% and >35% were evaluated as well as north...
In this report, three studies are presented that utilize computations to predict transformations, identities, and properties of environmental organic molecules. Each study shows how computations can lead to models of chemical behavior. The importance of this research is rooted in the need for understanding how human behavior and health intersect...
In the past 3-5 years, two federal agencies, the Forest Service (FS) and the National Park Service (NPS), have initiated pilot programs in concessioner-operation of developed-site government recreation facilities, specifically family campgrounds and related facilities. These programs have been generally successful by agency measure, and consequently, both agencies have modified...
Viability and dispersal of ascospores of Anisogramma anomala, the cause of eastern filbert blight (EFB) on European hazelnut, from diseased branches pruned from trees were measured. In each of two years, branches bearing stromata of A. anomala were cut in mid-December and compared to branches cut near budbreak in March,...
Decline of western sage grouse (Centrocercus urophasianus phaios)
in Oregon may be related to the reduced availability of foods in upland
sagebrush (Artemisia)-grasslands used for brood-rearing. The goal of
this study was to determine primary foods of chicks and the short-term
response of brood-rearing habitat to prescribed burning at Hart...
Managing Microdochium patch on intensively manicured annual bluegrass putting greens is a challenge for turfgrass professionals in cool-humid climates similar to the Pacific Northwest. Fungicides are the predominant means to mitigate damage caused by this fungal pathogen, however pesticide restrictions are making it even more challenging to suppress Microdochium patch....
Host-parasite interactions between the pathogen, Sphaerulina musiva, and its host, Populus spp., were examined in a series of studies. In the first study, variation in resistance of Populus nigra from 7 locations in Europe was differentiated based on the parameters cankers per cm and disease severity score. The analysis evaluated...
Reintroduction programs are increasingly being used to save animals from extinction and aid in their recovery. The California Condor (Gymnogyps californianus), one of the most endangered birds in the world, is a remarkable example of how reintroduction programs can help rapidly increase a species' population numbers and range following a...
The feasibility of utilizing LANDSAT MSS data in assessing surface cover types and areal extent of clearcut and shelterwood cut harvest sites in southern Oregon was investigated. The research utilized extensive 'ground truth' information to evaluate the LANDSAT data. A three faceted ground truth collection scheme analyzed 1) U.S. Forest...