This research was designed to broaden the understanding of how timber-harvest affects aquatic macroinvertebrates in perennial and intermittent headwater streams. This study compared emergent and benthic macroinvertebrate assemblages from 20 headwater streams in the central Oregon Coast Range that varied by harvest condition and flow duration. Through comparison of the...
Recent studies of headwater streams have demonstrated their importance to overall watershed biodiversity, nutrient cycling, and energy flux. However, little attention has been paid to long-term effects of forest harvest on macroinvertebrate communities in headwater streams. This study investigated headwater stream macroinvertebrate communities in the H.J. Andrews Experimental Forest, Oregon,...
Preliminary analysis of data from this study in the mountains southwest of the Anaconda Copper Smelter, an industrial source of SO2 and heavy metal particulate, reflects a complex pattern of pollutant impact. The differential effect of smelter emissions on plant life in the study area is best explained by the...
Western spruce budworm defoliated area in the Northern Region has differed significantly across three discrete geographic zones during the past decade. Aerially visible defoliation in northern Idaho increased from 1.7 million acres in 1969 to a high of 2.2 million acres in 1974, and declined to none in 1979. Defoliated...
Many pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers
(PBDEs), and polycyclic aromatic hydrocarbons are persistent, bio-accumulative, and
toxic. These semi-volatile organic compounds (SOCs) can undergo atmospheric
transport and deposition in cold, remote ecosystems. A better understanding of their
accumulation in the fish of these ecosystems is important to better predict...
My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial and aquatic systems. I used meta-analysis to quantify the effects of UVB radiation on a diversity of aquatic organisms (Chapter 2). UVB...
Field investigations were implemented to study the interrelationships between streamflows and salmonid production during the summer-fall low flow period in two natural stream channels. Elk Creek, near Cannon Beach in Clatsop County, was the site selected for intensive investigation.
Construction of streamflow control and diversion facilities was completed in November...
Aquatic insects are essential components of healthy stream ecosystems, contributing to nutrient cycling, trophic dynamics and other ecological functions. Aquatic insect species, particularly those in the orders Ephemeroptera, Plecoptera and Trichoptera (EPT taxa) are however, extremely sensitive to insecticide contamination. Given that urban and agricultural use of synthetic pyrethroid insecticides...
The purpose of this research was to compare four different media that were used to monitor SOC atmospheric concentrations in remote ecosystems. The accumulation of semi-volatile organic compounds, including pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), was investigated in lichen, 2-year old conifer needles, resin-based passive air sampling...