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...
Many streams in eastern Oregon are listed as water quality impaired on the basis of water temperature. However, it is often difficult to predict water temperature for these streams even if there are no anthropogenic impacts. We measured air and water temperature and stream characteristics on three Type C and...
Crested wheatgrass (Agropyron cristatum [L] Gaertm), an introduced bunchgrass, has been seeded on over 5 million hectares of degraded rangeland in western North America because it establishes more readily than native bunchgrasses. Because crested wheatgrass stands are associated with native species displacement and low biological diversity, there is substantial interest...
Since the late 1880's western juniper has expanded in range and
increased in density in sagebrush-bunchgrass, riparian, and forested plant
communities of the Pacific Northwest. Succession to western juniper
woodland has been shown to reduce the productivity and diversity of the
understory component, result in concentration of soil nutrients beneath...
In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus occidentalis) is encroaching into aspen stands. This study determined the timing, extent, and some of the effects of this expansion. Aspen stands below 2,133...
Water potential, leaf conductance, growth, nitrogen
content, and seedling survival of Wyoming Big Sagebrush
(Artemisia tridentata ssp. wyomingensis) following
defoliation of the herbaceous understory were assessed
during two growing seasons. Precipitation was 107% and 63%
of the long-term mean (283 mm) in 1989 and 1990,
respectively, which presented an opportunity...
Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems' resilience to disturbance and invasion by Bromus tectorum (cheatgrass). The role of the foundational shrub Artemisia as a driver of herbaceous community structure and...
A study was conducted to determine effects of year and season on diet quality of beef cattle grazing northern Great Basin rangelands from 1990 to 1993. Forage quality was high early in the growing season, then declined as seasons progressed (P<.05). Plant chemical composition was higher early in the growing...
Frost injury is one of the major factors limiting potato production in many parts
of the world. It would be desirable to transfer the frost-tolerance traits from the hardy
relatives to the cultivated potato, however, progress has been very slow. Since Solanum
commersonii has been the major source of frost...