Tropical instability waves (TIWs) are prominent seasonal features in both the equatorial Pacific and Atlantic Oceans. This work quantifies their role in modulating the distributions of nutrients and phytoplankton biomass. Using an eight year record of biannual ship observations along the Tropical Atmosphere Ocean (TAO) buoy array, cruise sections crossing...
Understanding how N availability influences base cation stores is critical for long-term ecosystem sustainability. Indices of nitrogen (N) availability and the distribution of nutrients in plant biomass, soil, and soil water were examined across ten young, unpolluted Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range spanning a three-fold soil...
As a key factor contributing to slope stability, in-stream habitat for aquatic species (e.g., salmonids), nutrient cycling, and corridors for upland species, riparian vegetation and its maintenance is of critical conservation importance. Subsequently, the chronic degradation of aquatic and riparian ecosystems in the semi-arid and arid landscapes of the western...
Understanding the impact of humans on the environment has long been a topic of scholarly interest and debate. As environmental problems mount, accounts of historic ecological conditions and the factors of change become increasingly useful. This study considers competing schools of interpretation about human impacts on ecological landscapes and develops...
The Western Lake Survey (WLS) of 1985 documented the status of lake water chemistry across the western US and inferred population representations of various subregions and geomorphic units via statistically analyses. Results from this 1985 study indicated that lakes of the Oregon Cascades had the second most pristine and dilute...
Ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta var. murrayana) forests of south-central Oregon have been extensively researched over the last century. However, little information has been reported on overstory composition and stand structure shifts associated with fire exclusion within inter-mixed ponderosa pine and lodgepole pine stands of the...
Recognizing the importance of native black cottonwood-dominated riparian
forests is especially important to preserve, protect, and manage for biodiversity in
the Willamette River Valley. Species composition, structure, and biomass along a
successional gradient from stand initiation to late succession of black cottonwood
(Populus balsamfera L. subsp. trichocarpa (T. & G.)...
Metals are a persistent form of freshwater pollution and have been shown to bioaccumulate in aquatic macroinvertebrates through direct contact with contaminated water, sediments, and through consumption of contaminated organisms. This research explored the longitudinal bioaccumulation patterns of 5 common trace metals (Cr, Cu, Zn, Cd, and Pb) in the...
The "unusual" behavior of agricultural land prices is the subject of considerable debate and controversy and is the object of this research. There is little doubt that land prices have been increasing steadily since 1959 and dramatically throughout the decade of the 1970's. However, there is widespread disagreement among economists,...
From 1979 through 1984 the economic bases of rural
Oregon counties have undergone structural change. Nonwage
income, especially transfer payments, has played an
important role in these changes. Demographic changes in
rural counties have contributed to the growth in unearned
income.
The economic structure of rural Oregon counties was
estimated...