In 1988 the Tualatin River was designated 'water quality limited' by the Oregon Department of Environmental Quality. Three sources of pollution: urban point source, forestry non-point source and agricultural non-point source pollution were considered to contribute unacceptable levels of nutrients (phosphates and ammonium nitrates) to the river. Since a significant...
For the last fifty years, meadow foxtail (Alopecurus pratensis L.) has been invading native flood meadows throughout the Harney Basin in southeastern Oregon. The expansion of this grass species has been the result of its broad climatic requirements and ability to withstand drought while thriving in saturated soil conditions for...
The Bureau of Land Managements (BLM) Emergency Fire Rehabilitation (EFR) policy was developed in 1985 to encourage protection of sites from soil erosion and to minimize potential changes in vegetation communities that may result from the dominance of weedy species. To achieve the goals of EFR policy, managers often used...
Current research indicates that the expansion of
western juniper can inhibit soil water retention, storage
and prolonged releases from watersheds. This phenomenon
is of great importance in eastern Oregon, as western
juniper is encroaching into sagebrush/grass communities
with a correlated reduction in herbaceous ground cover,
resulting in reduced infiltration rates...
Small herds of cows were observed and spatially mapped over continuous twenty-four hour periods. Treatments were implemented that investigated the effect of water site and supplementation on animal distribution patterns. A series of six observation periods constituted each observation series. Observation series were repeated winter (January) and summer (July) for...
The influence of streambank location and timing of herbivory on success of planted Booth's willow (Salix boothii Dorn) cuttings along a Rosgen C5-type stream in an eastern Oregon meadow was determined. Willow cuttings were planted on two morphological locations (i.e. point bar and floodplain) in May of 2002 and 2003....
Two studies were conducted to determine the factors influencing distribution of cattle on northeastern Oregon mixed-conifer forested rangelands. The objective of the first study was the quantification of differences in distribution of cattle of different ages. Beginning in 1991, and continuing through 2001, radio telemetry collars were placed on a...
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...
The purpose of this research was to determine whether hybridization between Amelanchier denticulata. (H.B.K.) Koch and Amelanchier nervosa (Decaisne) StandL occurs in Oaxaca, Mexico, and to evaluate components of yield and germination characteristics and seed dormancy of Amelanchier denticulata. Amelanchier nervosa and Amelanchier denticulata samples and morphological characters were used...
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...
Since European American settlement of the Intermountain Region, dramatic changes in vegetation composition and structure have occurred in the sagebrush steppe ecosystem. Western juniper (Juniperus occidentalis spp. occidentalis Vasek), although indigenous to the Intermountain Region, has increased since the late 1800s. Considerable work has been done documenting juniper woodland expansion...
Yellow starthistle (Centaurea solstitialis L.) is an introduced Asteraceae that has become established on 10 million acres in the Pacific Northwest and California. This weed functions as an annual or short-lived perennial and depends on seeds for reproduction. Strategies of control that reduce plant fitness or lower seed production or...
Because forage quality of cool season grasses declines to sub-maintenance levels for ruminants late in the growing season in the northern Great Basin, there is a need to elevate protein levels and digestibility of grasses for both wild and domestic ruminants in late summer. Anderson and Scherzinger (1975) proposed using...
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...
The effect of temperature on cattle behavior and distribution was studied in the foothills of California. To accurately understand changes in livestock behavior and distribution, five seasonal trials, each spanning three to four weeks were conducted beginning spring 2004 and ending spring 2005. The two spring trials and the fall...
Vegetation diversity in the Wyoming big sagebrush/Thurber needlegrass (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young/Achnatherum thurberianum (Piper) Barkworth. syn. Stipa thurberiana Piper) plant association was studied across a condition class gradient in southeastern Oregon. All observable vascular plant species were counted during 6 seasons and 2 years and diversity...
A documented case history of riparian grazing at Oregon State University's Soap Creek Ranch was conducted from 1999 to 2001. Impacts of four different riparian grazing treatments were evaluated. Emphasis was placed on investigating the relationship between riparian cattle use and water quality. Through a series of carefully designed and...
This paper was written as a book chapter on the ecology and biology of sage grouse. Because the book was never fully developed, we chose to publish the information with the OSU Agricultural Experiment Station.
A case study examining the relationship between stream temperatures and the thermal environment through which streams flow was conducted on the headwaters of 4 tributaries of the Burnt River (Barney, Elk, Greenhorn, and Stevens Creeks) in northeastern Oregon during July through August 1998 and 1999. Barney Creek and Stevens Creek...
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...
