Field experiments were done to test the relative
effectiveness of single and multiple biological control
agents in reducing weed populations using two insects, the
cinnabar moth, Tvria iacobaeae (L.), and the ragwort flea
beetle, Lonqitarsus iacobaeae (Waterhouse). These two
insects were released for biological control of the biennial weed tansy...
The effect of solution nitrogen (N) and phosphorus
(P) concentrations on biomass production and N₂ fixation
of red alder (Alnus rubra Bong.) seedlings grown in
perlite-filled pots in a climate controlled growth room
were studied. Nodulated seedlings were subjected to 12
different nutrient solution combinations of nitrogen and
phosphorus and...
This study characterized the nature and dynamics of interference in mixed red alder
(Alnus rubra Bong.)/Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands in the Pacific Northwest, USA. Long-term spatial and tree measurements from the Cascade Head (CH) and H.J. Andrews (HJA) Experimental Forests in western Oregon and Delezene Creek (DC), Washington...
Kincaid's lupine (Lupinus sulphureus ssp. kincaidii [Smith] Phillips) is a federally listed Threatened plant of Willamette Valley prairies. Both low reproduction, due to seed coat dormancy, and competition from invasive plants may threaten the longterm viability of this species. In separate studies, I investigated seed germination and an invasive species...
Stream systems in the Pacific Northwest have come to be understood in the absence of beaver (Castor canadensis). To understand the effect of beaver upon riparian plant communities, four basins in the lower Alsea drainage were examined to determine the effect of beaver and their impoundments on streamside herbaceous/shrub and...
The internship I performed was with Rural Community Development Program (RCDP), a domestic non-governmental organization in the country of Nepal. This organization focuses on community development goals in rural communities, utilizing the efforts of volunteers within the context of environmental conservation ideals. I primarily worked with the associated community plant...
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Committee Member: Dr. MarkWilson
I understand that my final report will become part of the
The feeding ecology of a common temperate mesoherbivore, the oligophagous sea slug Placida dendritica (Gastropoda: Opisthobranchia: Ascoglossa), was examined from April 1985 to June 1989. Along the central coast of Oregon, Placida consumed three host species: the low intertidal green algae Codium setchellii, C. fragile, and Bryopsis corticulans. Individual slugs...
Phacelia capitata Rruckeberg is a member of the
Phacelia magellanica polyploid complex (species group
Magellanicae), a group of wide-ranging, polymorphic
perennials in western North America related to the South
American P. secunda (= P. magellanica). The purpose of
this project was to determine, to the extent possible, the
interrelationships of...
This thesis consists of four chapters. Literature is
reviewed in Chapter 1. Chapter 2 describes an addition
series experiment to determine the influence of species
density and proportion on vegetative and reproductive yield
of spring wheat and Lolium multiflorum. Chapter 3 consists
of a growth analysis experiment to determine whether...