A greater than 10-fold increase in Canada goose (Branta canadensis) populations over the past several years has resulted in concerns over grazing impacts on grass seed production in the mid-Willamette Valley, Oregon. This study was designed to develop methods to quantify and statistically analyze goose-grazing impacts on seed yields of...
Numbers of wild Canada geese (Branta canadensis) have increased dramatically during the past 30 years in the lower Columbia and Willamette Valley systems. The damage they cause by grazing and trampling plants can be substantial.
The objectives of this research were to:
1) Develop methods that provide reliable estimates of...
Despite the importance of fodder shrubs to small ruminant diets and production in arid and semi-arid ecosystems, they are often not considered when quantifying grazing land potential. This oversight is mainly due to the time consuming and costly traditional techniques used to estimate shrub biomass. The shrub fodder component should...
Slickspots are soil inclusions with unique loamy soils that provide habitats for many endemic plants worldwide, including those within sagebrush steppe. Sagebrush-dominated communities are declining and require restoration, but restoration techniques commonly used may impact negatively some intermixed communities found on soil inclusions including those on slickspot soils. Slickspot soils...
Medusahead [Taeniatherum caput-medusae (L.) Nevski], a non-native, winter-annual grass (Poaceae), has
invaded rangelands throughout the western USA. Medusahead is an aggressive competitor that crowds out native plants
and reduces forage for wildlife and livestock. Sulfometuron methyl is a sulfonylurea herbicide used to control medusahead,
but its effect on non-target native...
Direct seeding techniques often result in unsatisfactory outcomes in rangeland rehabilitation, primarily because of low seedling emergence and poor establishment. Seed processing techniques aimed at improving seedling emergence have gained interest by pasture managers. The purpose of this study was to investigate the combined effects of bracteole removal and seeding...
Invasive plant species are expanding and transforming vegetative communities across Oregon and throughout the United States. Over the past three decades remote sensing, geographic information system (GIS), and Global Positioning System (GPS) technologies have been integrated to detect and map the distribution of noxious rangeland plants. This study developed low-cost...
Published June 2009. 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
Autonomous vehicles bring great societal benefits but also potential impact and disruption to road safety, traffic congestion, and driving behaviors. One important technology that is indispensable to the success of such systems is vehicular networks. Vehicular networks provide the backbone for ensuring communication and connectivity among vehicles, all crucial to...
Weeping alkaligrass (Puccinellia distans) and Nuttall’s alkaligrass (Puccinellia
nuttalliana) infest Kentucky bluegrass seed fields of eastern Oregon. Weeping
alkaligrass is an introduced species from Eurasia, whereas Nuttall’s alkaligrass is
native to semi arid environments of western North America. These species are often
referred to collectively as ‘alkaligrass’; however, for farmers...
Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that...
Full Text:
-Philippe L�egar�e139,
Susan G. Letcher140, Nick A. Littlewood141, Carlos A. L�opez-Quintero142, Mounir
In some practical systems, most of the errors are of 1 → 0 type and 0 → 1
errors occur very rarely. In this thesis, first, the capacity of the asymmetric
channel is derived. The capacity of the binary symmetric channel (BSC) and the
Z-channel can be derived from this...
Since the 1930's, many fields on the Crooked River National grasslands have been seeded to crested wheatgrass (Agropyron desertorum). While some of these fields remain dominated by crested wheatgrass others had a greater presence of deep rooted native perennial grasses such as bluebunch wheatgrass (Pseudoroegneria spicata). Twenty eight fields previously...
This study identified new compounds with pest control activities. The two sources of candidates that were followed here were the main heartwood extract of Alaska Yellow Cedar (AYC) constituents and several semi-synthetic counterparts. Five compounds were isolated and identified for the first time in AYC heartwood in this research: two...
Remote sensing and Geographic Information Systems (GIS) are well known tools for the study of time change analysis in natural systems. However, long-term studies of riparian systems using large-scale aerial photography are less common. The purpose of this project was to combine large scale aerial photography, GIS, Global Positioning Systems...
Western juniper has rapidly expanded into sagebrush steppe communities in the Intermountain West during the past 120 years. This expansion has occurred across a wide range of soil types and topographic positions. These plant communities, however, are typically treated in current peer-reviewed literature generically. The focus of this research is...