Deep mixing events in the ocean’s surface layer act as physical drivers of carbon export by detraining dissolved and particulate organic matter, including surface phytoplankton communities, to depth. Once removed from the sunlit surface ocean environment, phytoplankton accumulation rates are dependent on the relative contributions of loss processes, such as...
Managers of forest and plantation ecosystems are encountering growing problems involving plant pathogens and the expanding geographic ranges of these pathogens. Historically unexposed stands are exceptionally vulnerable when a non-native pathogen is introduced because these pathogens can cause devastating disease in a host population that lacks co-evolved resistance mechanisms. One...
Photoacclimation is the process by which plants and phytoplankton adjust the concentration and composition of their photosynthetic machinery (i.e. their photoacclimation state) in response to changes in their light or nutrient environment. The purpose of photoacclimation is to balance the rate at which light energy is absorbed with the energetic...
One goal of this environmental education curriculum is that students will gain an appreciation of Willamette Valley wetland prairies, a threatened ecosystem, and will gain an understanding of the importance of protecting these wetlands. A second goal is that students will see first-hand the processes involved in conducting scientific field...
We report first-year results from two field experiments evaluating the effectiveness of various techniques for the control of pest plants in Fender's blue butterfly habitat. In the woody-plant study, we monitored the effects of mowing, mowing and herbicides, and burning on woody plants and key native and non-native grasses and...
Erigeron decumbens var. decumbens, the Willamette daisy, is known only from the Willamette Valley of Oregon. Herbarium records, from the 1800's until 1934, indicate that the Willamette daisy was once common and widely distributed throughout the Willamette Valley (Clark et al. 1993). However, between 1934 and 1980, this taxon was...
Erigeron decumbens var. decumbens, the Willamette Daisy, is endemic to the Willamette Valley of Oregon. This taxon is a Category 1 Candidate for listing under the federal Endangered Species Act (U.S. Fish and Wildlife Service 1990) and is listed as Endangered under Oregon state law. Herbarium records indicate that E....
Seed size, abundance, viability, dormancy, and germination requirements strongly influence plant establishment and therefore are important considerations in restoration of native vegetation. These characteristics provide criteria for selection of suitable species, development of collection and pretreatment methods, and determination of seeding densities. The first set of objectives of this study...
Native prairies, which once dominated the landscape of the Willamette Valley, are considered among the rarest of Oregon's ecosystems. Even though only remnants remain today, they harbor rare and endangered species such as the Fender's blue butterfly (Icaricia icariodes fenderi) and its preferred host plant, Kincaid's lupine (Lupinus sulphureus ssp....
We report results from a field experiment evaluating the effectiveness of mowing, mowing and herbicides, and burning on woody plants, key native and non-native grasses and forbs, and the Fender's blue butterfly. The goal was to find a technique that controlled woody pest plants without harming native species or promoting...