Developing accurate predictive distribution models requires adequately representing relevant spatial and temporal scales, as these scales are ultimately reflective of the relationships between distributions and influential environmental conditions. In this research, we considered both spatial and temporal scale and the influence each has on predicting broad-scale distributions of two disparate...
The Consortium of Universities for the Advancement of Hydrologic Sciences, Inc. (CUAHSI) began the Hydrologic Measurement Facility (HMF) program in June 2005 to advance hydrologic measurement capability within the research community. To provide guidance for this effort, a recent survey assessed the level of need among the hydrological sciences community...
We examined how the experiences of World War II and Korean War veterans,
including prewar, warzone, and postwar factors, affected PTSD symptoms in later life.
This dissertation consists of two studies. In Study 1, four different hypotheses from a
lifespan approach were examined (King et al., 1996): stress evaporation (only...
Fires affect animals mainly through effects on their habitat. Fires often cause short-term increases in wildlife foods that contribute to increases in populations of some animals. These increases are moderated by the animals’ ability to thrive in the altered, often simplified, structure of the postfire environment. The extent of fire...
Waterborne fecal contamination poses serious risks to human health and can disrupt aquatic ecosystems. Molecular marker methods are widely used to identify and, in some cases, quantify the sources of contamination and guide management decisions regarding water resource protection. However, methods to detect some likely sources of fecal contamination such...
Throughout many of the world’s mountain ranges snowpack accumulates during the winter and into the spring, providing a natural reservoir for water. As this reservoir melts, it fills streams and recharges groundwater for over 1 billion people globally. Despite its importance to water resources, our understanding of the storage capacity...
The biodiversity of most marine communities is more or less dependent on continuous invasions from sources with greater richness. These ongoing, natural invasions have become greatly augmented by ship traffic in numerous estuaries and harbors where the native biota has been diminished or lost due to habitat destruction and pollution....
Full Text:
ef-
fects of invasive species at the community level (Rick-
lefs 1987, Karlson et al. 2004, Witman et
Strongly bimodal, basalt-rhyolite volcanism of the High Lava Plains Province of Oregon followed the Middle Miocene flood basalts of the Pacific Northwest and extends to recent time. During the 8 m.y. of volcanism recorded in the central High Lava Plains, in western Harney Basin, three distinct mafic magmatic trends originate...
Multiple episodes of Oligocene and younger silicic volcanism are represented in the high lava plateau of central and southeastern Oregon. From 12 Ma to Recent, volcanism is strongly bimodal with nearly equal volumes of basalt and rhyolite. It is characterized by moderate to high silica (SiO₂ > 72 wt. %)...
Continental flood basalts represent short-lived but immense blasts of mafic magma to the continental crust. The youngest and smallest continental flood basalt worldwide, the Columbia River Basalt, initiated with the eruption of the most mafic member, the Steens Basalt (~16.9 Ma). The Steens Basalt is exposed in southeast Oregon, southwest...
The primary goal of this study is to assess the impact of a subduction component
added to the mantle wedge beneath the Oregon Cascades to the composition and fO2 of
primitive Cascade basalts. Olivine-hosted melt inclusions from compositionally diverse
basalts across the Cascade arc (~100 km) are utilized in an...
Full Text:
provided by Rick Conrey and Dave Sherrod. In
addition, Carl Thornber’s help with the Mount St. Helens
Understanding continental crust formation and modification is a fundamental and longstanding geologic problem. Influx of mantle-derived basaltic magma and partial melting of the crust are two ways to drive crustal differentiation. This process results in a low density upper crust and denser, more refractory lower crust, creating significant and vastly...
Full Text:
great insight into the results. Rick Conrey
(Washington State University) was essential in obtaining
Volcanic and sedimentary deposits of the Mount Jefferson area (MJA) record a fourmillion-year
history of arc-related volcanism related to the subduction of the Juan de Fuca plate
beneath North America. 171 mapped stratigraphic units over an area of 150 km² reveal four
periods of volcanic activity resulting in diverse composition...
Full Text:
geochemical investigation of Mount Jefferson on which this study is based. Rick has been
constantly
The "old-growth controversy" in the Pacific Northwest recognized thinning as the
primary silvicultural practice for land managers to produce wildlife habitat while
continuing to produce timber. For the foreseeable future, forest stands will be harvested to
produce forest gaps and a patchwork of trees of different ages. In order to...
Senecio jacobaea (tansy ragwort) is a common weed in the
Pacific Northwest that contains toxic pyrrolizidine alkaloids
(PAs). Jacobine, the major PA in Senecio jacobaea, was incubated
with rat liver microsomes and metabolites were isolated by high
performance liquid chromatography (HPLC) and identified by mass
spectrometric analysis. Metabolites included a...
This study is an effort to characterize the magma sources, plumbing system, and eruptive behavior of Mount Hood, a low-explosivity recharge-dominated volcano in the Oregon Cascades. The three manuscripts in this dissertation make use of melt inclusion data, phenocryst compositions, and whole rock petrology and geochemistry to build a schematic...
The purpose of this thesis is to analyze an abrupt case of climate change in the past as a means to understand the mechanisms that force climate change. By looking to past analogs of climate change, we hopefully will gain an understanding of these events, which could be used to...
I focus on addressing knowledge gaps relating to management of cryptogams in Oregon's public lands in Pseudotsuga menziesii-Tsuga heterophylla forests on the west side of the Cascade Range and dryland steppe in the Cascade Range's rainshadow.
While a great deal of research has illustrated the importance of late-successional forests for...