Epichloë typhina (Ascomycetes: Clavicipitaceae) is an endophytic fungus that
infects perennial Pooid grasses and is the causal agent of choke disease. It is endemic
to Europe and was inadvertently introduced into orchardgrass seed production fields in
western Oregon. Choke disease, which was first recorded in Oregon in 1996, currently
infects...
This thesis explored the distributions and life histories of dragonflies and damselflies (Insecta: Odonata) of the riverine wetlands of the Willamette Valley in western Oregon, USA. Odonate species distributions were characterized over two seasons in the autumn of 2000 and the spring of 2001-at twenty-seven wetlands located throughout the valley....
Little research has been directed toward determining the status and ecological role of riparian areas in agricultural landscapes of the Willamette Valley, Oregon. A research project has been designed to contribute to the development and evaluation of alternative future scenarios and to improve the basic understanding of the role of...
Prairie-oak ecosystems in the Willamette Valley, Oregon have experienced habitat loss and degradation; most of these ecosystems are fragmented into smaller patches. Prairie-oak butterfly species, in the Willamette Valley, have decreased dramatically due to loss or degradation of habitat. More research is needed on sustaining the populations of butterflies in...
Quercus garryana dominated plant communities are found in
the interior coastal valleys and on foothills from southeastern
Vancouver Island, British Columbia, south to San Francisco,
California. They occur as savannas, intermixed with a variety of
conifers, and in almost pure stands. The diversity of habitats
occupied by the species and...
The Oregon Long-Term Soil Quality Project was initiated to identify soil
properties that respond rapidly to alternative management practices. Such practices
included winter cover cropping, which was implemented at two experimental research
stations and several grower fields throughout the Willamette Valley. The goal of this
thesis was to identify the...
Relatively little is known about wintering bird communities in lowlands of the Pacific Northwest, yet, the condition of winter habitats potentially can pose a major constraint on bird populations. I initiated a study to determine: (1) Which avian species use lowland riparian and wetland habitats in the Willamette Valley during...
Understanding how wetland birds use habitat is pivotal to developing successful and
beneficial conservation strategies. Although it has been an ardent topic in forest
research for some time, how species interact with the spatial patterning of habitat
across a landscape (i.e., landscape structure) has been more or less neglected in...
Over one third of the earth’s land surface has been modified to some extent for agricultural purposes. The large global footprint of agriculture, combined with the knowledge that existing reserve networks are likely insufficient for long-term conservation of native biodiversity, has necessitated that agricultural systems contribute to conservation of native...
In the last 200 years there have been significant declines in the amount and structural complexity of oak-dominated forests and savannahs in the Pacific Northwest. Restoring oak systems often involves selectively thinning stands of oaks in order to reduce competition for sunlight. In choosing which trees to cut, land managers...
Native plants provide many ecosystem services while also having great beauty and are a valuable component of the landscape. As use of these plants in habitat restoration, agricultural insectary plantings, and home landscapes increases so does demand for information on the basic biology of a group of species that have...
Many agricultural sustainability issues are related to biological processes which are central to the ecological function of soils. Soil physical properties are the architecture in which these processes are carried out. Cover crops hold promise as one of the techniques which can ameliorate poor soil structure and improve bulk density...
The nature and extent of niparian vegetation change from 1972 to
1981 in the Willamette River Greenway in Benton and Linn Counties,
Oregon was quantitatively investigated. The study was primarily by
aerial imagery analysis and associated field verification. A classification
of vegetation and land cover within the study area was...
In ecological restoration, species that are sown to increase the native plant
diversity range in establishment ability. Some species readily establish, while others
rarely do. This study set out to investigate some of the potential processes influencing
species establishment, as well as the traits that are associated with the success...
Birds perform valuable ecological functions and are useful environmental indicators. Avian distributions and diversity are predicted to change over the next 50 years. Little information exists on the role of local and regional conditions in fluctuations of avian communities over time. Historic datasets present a legacy of information that helps...
Invasive species are a major threat to global biodiversity. Understanding the mechanisms underlying successful invasions is imperative for developing effective management strategies. Plasticity in physiological, morphological, and behavioral traits could be an indicator of invasion potential in non-native species. The invasive American bullfrog (Lithobates catesbeianus) has recently been observed breeding...
I examined hydrological and plant community changes associated with the implementation of a restoration management plan in two riparian meadows located within an agricultural landscape of the central Willamette Valley, Oregon. I established exclosure fencing (a form of passive restoration) in one agricultural field and established fencing and plugged a...
Invasion by exotic species can pose a major challenge for developing native
plant communities in wetland restoration projects. Often native plant communities
do not develop as anticipated in restored wetlands due to colonization by exotic
species that dominate the native plant community. Despite the time and expense to
restore wetlands,...
The importance of pollinators in native and managed landscapes is well known, and recent interest is directed towards investigating the role of native bees as providers of pollination ecosystem services. Uncertainty about bee populations at global and local scales has prompted research and general interest in conservation of bee diversity....
Prior to European settlement, native prairie dominated the landscape of the
Willamette Valley. Today, due to urbanization, agriculture, and the cessation of
burning, only isolated remnants of these grasslands still exist. In response to
conservation concerns, there has been a move to restore the remaining prairies in the
Willamette Valley,...
Fires set by Native Americans were important in shaping and maintaining Willamette Valley prairie plant communities. With fire exclusion after Euro-American settlement in the 1840's, composition of the remaining prairies shifted toward shrub and tree dominance with a concomitant decline in endemic prairie plant populations. I hypothesize that by restoring...
Small remnants of 'natural' habitats exist today throughout much of the world. Upland prairies in the Willamette Valley, Oregon have been nearly eliminated by conversion to agriculture and other uses. As a result, very few prairies remain and at least four butterfly species that require this habitat appear to be...
Recognizing the importance of native black cottonwood-dominated riparian
forests is especially important to preserve, protect, and manage for biodiversity in
the Willamette River Valley. Species composition, structure, and biomass along a
successional gradient from stand initiation to late succession of black cottonwood
(Populus balsamfera L. subsp. trichocarpa (T. & G.)...
The relation of nutria (Myocastor coypus) feeding to total abundance, species composition, and seasonal use of the marsh flora on
the William L. Finley National Wildlife Refuge was studied during
1969 and 1970. Nutria numbers were estimated by livetrapping. Food
habits data were compiled from observations of feeding nutria. Phenology,...
The Willamette Valley (Oregon) Prairie Plant Trait Dataset is a compilation of plant traits of species important in upland prairies, wetland prairies, vernal pools, and emergent wetlands, and in the restoration of prairies and wetlands of the Willamette Valley of Oregon. These species are also found widely throughout the Pacific...
The vast majority of terrestrial plant species live in symbiosis with arbuscular mycorrhizal fungi (AMF). AMF and plants live in complex networks, with roots of individual plants hosting multiple AMF, and single AMF colonizing multiple plants concurrently. Through the exchange of resources, the two partners of this symbiosis can have...
Identifying mechanisms that determine who lives and dies is the first step in developing successful restoration techniques for rare species and endangered habitats. We studied interactions that affect establishment of native plant forbs of conservation concern at the seedling stage to support the theoretical basis for restoration activities in Pacific...
An estimated 99% of native wet prairie has been lost in the Willamette Valley, Oregon, but a large number of seasonal wetlands remain on private lands dedicated to grass seed production within the historical wet prairie landscape. Because agriculture is known to alter physical and chemical wetland conditions, I investigated...
Habitat loss causes a reduction in available resources for wildlife, alters the configuration of remaining habitat, and may isolate wildlife populations. White-breasted nuthatches (Sitta carolinensis) are experiencing long-term population declines in the Willamette Valley of Oregon, where they are historically associated with oak woodlands. As secondary cavity-nesters, white-breasted nuthatches may...
Biological invasions are the second largest threat to biodiversity following habitat loss, and studying invasions has been a focus of ecological the past two decades. Despite the intense research, many basic questions remain empirically unanswered, particularly in the realm of behavior. The purpose of this research was to explore the...
This thesis is a documentation of a selected number of nineteenth century quilts studied by the investigator in the Willamette Valley.
The quilts were located in museums and in individual's homes. A questionnaire, that was developed for this study of quilts, was
filled out as each quilt was examined. Slides...
The future expansion of agricultural production in the Willamette
Valley will depend to a large degree upon the feasibility of introducing
irrigated agriculture on the poorly drained soils in the Valley. A
r earch program has been initiated to investigate the feasibility of
rigation on poorly drained soils with the...
Permeability, effects of age, and water table fluctuations were
studied for nine drainfields in five soil types ranging from well to
poorly drained. Three sites were in Willamette, one in Woodburn,
two in Amity, two in Concord, and one in Dayton soils. Before
permeability of drainfields could be evaluated, methods...
A Willamette sandy shot loam was treated with ZnC1₂, CdC1₂, or sewage sludge to determine the chemical fate of added Cd and Zn in the soil and their influence on the growth of corn and wheat seedlings. Cadmium was added as CdC1₂ at rates of 0, 5, 20, or 80...
The wetlands are distinguished from other lands of the Mid-Willamette Valley by excessive soil moisture. The wetlands, as defined for this study, consist of 20 soil series (in 22 soil mapping units) which are classified by the Soil Conservation Service as having excessive wetness as the major factor limiting their...
Relationships among the surface wind, horizontal synoptic-scale
pressure gradient and topography are studied in the Willamette Valley
in western Oregon. Terrain features alter the standard surface wind-pressure
gradient relationship such that the angle between the surface
wind and the surface geostrophic wind is most frequently 60°.
In winter the surface...
Published April 1981. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published February 1961. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published March 1936. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published April 1935. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published March 1925. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog