Comparative investigations based on volcanic morphology suffer from the lack of a large terrestrial baseline for comparison. To fill this gap, the Lava Flow Morphology Database (LAMDA) was proposed as a GIS based central clearinghouse for remote and field investigations of volcanic morphology. This study presents an analysis of LAMDA’S...
The marine environment is under increasing pressure from human activities worldwide, particularly in coastal waters, creating a need to better understand fine-scale distributions of highly mobile species that occur in the area, as they are frequently most threatened. Harbor porpoise (Phocoena phocoena) occur frequently in Oregon’s nearshore habitat, but due...
This study examined the distribution and behavior of adult spring chinook salmon
(Oncorhynchus tshawytscha) related to patterns of stream temperature and physical
habitat at channel unit, reach, and basin-wide spatial scales in both a wilderness stream
and a disturbed stream in the John Day River basin in northeastern Oregon. Thermal...
Volcanic hazard maps inform the public on the nature and extent of the hazards that threaten them, but these maps are often challenging for those who are not trained in map use or geology. The maps in this study focus on lahars, a dangerous, fast, and far-reaching volcanic hazard that...
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...
Warming of the terrestrial biosphere due to the anthropogenic addition of carbon dioxide to the earth’s atmosphere is becoming a major focus of scientific inquiry. Predictions of the extent of this warming are hampered by uncertainty in the ability of the earth’s ecosystems to counteract this effect by sequestering carbon...
Population trends and patterns in species distributions are the major currencies used to examine responses by biodiversity to changing environments. Effective conservation recommendations require that models of both distribution dynamics and population trends accurately reflect reality. However, identification of the appropriate temporal and spatial scales of animal response, and then...
This dissertation focuses on the evolutionary forces of genetic drift and gene flow in frog populations. The balance of these two forces and the force of mutation largely determine the amount of neutral genetic variation within populations as well as the degree of genetic similarity among populations. The stochastic evolutionary...
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...