The objective of my study was to examine differences in riparian tree and shrub composition associated with adult aquatic emergence and implications for terrestrial spiders in these sites. Seasonal abundance and biomass of adult emergent aquatic insects, riparian arthropod abundances and spider densities were compared between conifer- and hardwood-dominated sites...
Craneflies of the genus Lipsothrix inhabit decomposing wood in
streams. The life cycles and ecological relationships of L. nigrilinea
(Doane) and L. fenderi Alexander were investigated to determine how they
exploit and respond to the wood habitat and their role in degradation of
woody debris in western Oregon. Surveys of...
Potato (Solanum tuberosum L.) is the fourth largest food crop in the world following rice (Oryza sativa L.), wheat (Triticum spp.), and maize (Zea mays subs. mays). Potatoes arrived in the United States in the early 1600s and over the following centuries, the crop was subsequently cultivated across the country...
Four key aspects of the relationship between predatory hoverflies and the aphid pest Brevicoryne brassicae L. on broccoli were investigated in the Willamette Valley, Oregon USA: 1) the relationship between aphid density and hoverfly oviposition, 2) the larval voracity of key hoverfly species, 3) the preferences of hoverflies and broccoli...
Weed management in sustainable farming systems often requires the integration of several different pest management techniques. Cultural, biological, and chemical pest control efforts can be utilized to contribute to the common goal of reducing weeds in vegetable row crop systems. This research addresses how common disturbances such as tillage and...
Two of the most powerful ways in which humans have altered ecosystems are by increasing productivity and changing the densities of important consumers. The bottom-up effects of productivity and the top-down effects of consumers have been identified as primary determinants of biological diversity, though the links between them remain unclear....
The omnivorous ground beetle, Pterostichus melanarius Illager (Coleoptera: Carabidae), is a ubiquitous inhabitant of western Oregon crop land. Because it is often the most abundant ground beetle, and attains densities that could lead to serious impacts on its prey sources, I sought to understand the overall diet composition, and specifically...
The black vine weevil (BVW), Otiorhynchus sulcatus (F.) (Coleoptera:
Curculionidae) is a persistent pest of nursery operations in the United States,
feeding on over 140 species of plants. The goals of this research were to 1) assess
the behavioral response of BVW to a commonly employed insecticide bifenthrin
(Talstar 0.2G®)...
Careful analysis and thoughtful synthesis will be necessary for expanding the envelope of
ecological understanding. This work is my attempt at communicating both of these, in relation
to three questions about our understanding of the structure and dynamics of biological diversity.
These questions focus on a) advancing our understanding of...
The relationship between nutrients and community structure is poorly understood in open-coast habitats. I created a system of artificial tidepools, of identical age and physical dimensions, at two sites that differed in wave exposure, and manipulated nutrient levels and the abundance of herbivores. Using these unique field mesocosms, I explored...