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⁻)...
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...
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...
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...
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...
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...