Two field corn experiments were conducted on a Woodburn silt loam soil near Corvallis, Oregon, in 1972-1973 to investigate the effects of certain soil management practices on the yield and performance of corn (Zea mays L.). Experiment I involved variables that included three corn row spacings (76, 114, and 152...
The complexity of human/riverine systems has led to an increasing focus on land
use patterns and policy. My goal is to understand the dynamics of a coupled human and
natural system. The central question is how people in the community of Scio, Oregon
perceive flooding, water quality, and riparian habitat....
Once abundant in their native range, Pacific salmon species (Oncorhynchus spp.) were widely distributed across the northern Pacific Rim from South Korea and Japan to the Sacramento River in California. Remaining populations are subject to population-level threats, including pathogens. The freshwater parasitic copepod Salmincola californiensis is associated with the reduced...
A severe wildfire burned 454 hectares of a second-growth Douglas-fir forest
in 1977 on a north-facing slope in Pattee Canyon, near Missoula, Montana. The
slope was aerially seeded with a grass mixture, from which Dactylis glomerata
established best. Community structure, conifer regeneration, and the impact of the
seeded grass on...
In 1968, Congress passed the Wild and Scenic River Act
creating a system of rivers protected from dams and other
development. By 1987, segments of four Oregon rivers were
protected by the Wild and Scenic River System: the Rogue,
Illinois, Owyhee, and a portion of the Snake along the
Idaho...
Populations of organisms are influenced by both top-down (predator driven) and bottom-up (environment or resource driven) effects. Seabird research has largely focused on bottom-up factors influencing reproduction, with little emphasis on top-down. Our goal was to better understand top-down impacts on colonial nesting seabirds over a range of spatio-temporal scales....
Northern anchovy (Engraulis mordax) are a dominant forage fish in the California Current large marine ecosystem (CCLME). However, little is known about northern anchovy abundance, distribution, age structure, or population fluctuations relative to ocean conditions in the eastern boundary upwelling system off the U.S. West Coast. This thesis includes three...
In recent decades the habitat of North American beaver (Castor canadensis) has expanded from boreal forests into pan-Arctic tundra ecosystems. It is unknown how the advance of beavers into Arctic watersheds will impact microbial communities responsible for the mineralization of organic matter (OM), which has implications for carbon cycling. To...