The unifying purpose of this dissertation was to describe, model, and map
relationships between epiphvtic macrolichen communities and air quality in Ibrests of
northern and central California. First, multivariate analyses were used to subdivide the
large study area into three model areas with similar climate, topography, and lichen
communities: the...
Soil organic matter (SOM) is the terrestrial biosphere's largest pool of organic carbon (C) and is an integral part of C cycling globally. Soil organic matter composition typically can be traced directly back to the type of detrital inputs; however, the stabilization of SOM results as a combination of chemical...
Most plant toxicology tests developed in support of environmental laws use a single stress applied to an individual plant. While tests using individual species or stresses require fewer resources and are easier to interpret, they are under increasing criticism for being unrealistic and missing important ecological interactions. The objective of...
Arthropods are important food resources for birds. Forest management activities can influence shrub-dwelling arthropods by affecting the structure and composition of understory shrub communities. Changes in abundance and species composition of arthropod communities in turn may influence the distribution and abundance of insectivorous birds. I examined relationships among bird abundance,...
With the increased recognition of moss as a secondary forest product has come an increased concern for the ecological ramifications of moss harvest. Three issues of primary concern are (1) characterizing the epiphyte communities impacted by harvest, (2) assessing the host preferences of these epiphytes, and (3) describing the availability...
The U.S. Bureau of Fisheries (now National Marine Fisheries Service) conducted stream habitat surveys in the Upper Grande Ronde River Basin in 1941. This survey was part of an extensive inventory of stream habitat conditions for anadromous salmonids (Oncorhynchus spp.) throughout the Columbia River Basin. The survey systematically
inventoried 158...
Knowledge of how stream habitats change over time in natural and human-influenced ecosystems at large, regional scales is currently limited. A historical stream survey
(1934-1945) was compared to current surveys to assess changes in poo1 habitats in the Columbia River basin. Streams from across the basin, representing a wide range...
Before the arrival of Euro-Americans, the inland Pacific Northwest was settled by native
people whose frequent intentional burning of the landscape promoted open stands
dominated by large fire-resistant ponderosa pine. Fire suppression for nearly a century,
livestock grazing, and logging of the largest trees has resulted in forests characterized by...
The goal of this dissertation was to improve our understanding of the physiology and life-history of invasive plants and of the mechanisms underlying life-history trade-offs. I compared invasive and noninvasive species of Rubus (blackberry) that grow together in the Pacific Northwest. Three hypotheses were investigated: (1) Invasive Rubus have higher...