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...
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...
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...
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...
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...
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...
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,...
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...
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...
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...