Plagiobothrys hirtus (Boraginaceae) is a state and federally listed endangered plant found only in Douglas County, Oregon. This vernal pool endemic has historically been threatened by agricultural conversion of seasonal wetlands in the Sutherlin area, and is currently being eradicated as habitat is lost due to the rapid urban development...
With little previous research on Astragalus peckii (Fabaceae), a state-listed
Threatened species in Oregon, I investigated three facets of its biology which are
integral to the conservation and management of the species. First, a four-year
demographic study of two large populations revealed increasing population growth at
one site (Chiloquin) and...
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...
The phytopathogen Phytophthora ramorum (Werres, DeCock & Man in't Veld), causal agent of Sudden Oak Death (SOD) of oaks (Quercus spp.) and tanoaks (Notholithocarpus densiflorus syn. Lithocarpus densiflorus), is established in coastal forests of the western United States. Since the discovery of SOD in the Douglas-fir / tanoak forests of...
Total length and biomass of fungal mycelium in the soil of a young Douglas-fir stand in the central Oregon Coast Range were estimated over 27 months with the agar-film technique. In a second study, phenology and taxonomy of hypogeous (belowground) sporocarps were studied over 32 months in a nearby, young...
In the canyon grasslands of Garden Creek Ranch Preserve in Idaho, where the threatened plant Silene spaldingii occurs and invasion by the exotic species Centaurea solstitialis and Bromus tectorum is proceeding rapidly, I examined environmental and community patterns of site invasion, and evaluated the apparent influence of invasion on Silene...
Research on the population genetics of microbial organisms requires the use of specialized analyses designed for clonal organisms to avoid violating the assumptions of traditional population genetic models. The tools necessary for performing these analyses existed as a set of unrelated software with non-overlapping capabilities and did not cover all...
The purpose of this study was to develope a plant community classification
within the Siskiyou mountains, a small range within the Klamath
geological province well known for its geologic and floristic diversity.
Forest land managers have expressed the need for identification of
basic Land classes that will aid in the...
Montane forest vegetation as it occurs on the east flank of the
central Oregon Cascades has provided excellent conditions for a
"natural experiment" in the use of various methodologies in studying
vegetational distribution. This "experiment" has reflected on some
theory and practice for the discipline of plant synecology. Detailed
descriptions,...
Lichens are an important part of the biota in western Oregon forests, where
they perform valuable ecological roles and contribute significantly to biodiversity.
Lichens in western Oregon are threatened by a number of factors including air
pollution and land use practices. If we wish to maintain the persistence of lichens...