The vegetation of the Oregon coast is characterized by a
variety of stages of plant succession which are repeated widely
throughout the sand dune area. During the years from 1960 to 1963
the gradation of upland sand dune succession was studied on 48 plots
within a 150 mile section of...
Mycorrhizal fungi in arid and semiarid rangelands have received little study in southwest Asia and north Africa, although they are important in food production and rangeland productivity. The desert truffles of the genera Terfezia and Tirmania form fruiting-bodies and mycorrhizae with rangeland plants. This thesis treats the taxonomy and the...
The semi-arid sagebrush steppe ecosystem is one of the largest biomes in
North America. The steppe provides critical habitat and forage for wildlife and is
economically important to recreation and livestock industries. However, the ecosystem
is threatened primarily due to several negative effects associated with expansion of the
exotic annual...
• Premise of the study: Seed longevity and persistence in soil seed banks may be especially important for population persistence in ecosystems where opportunities for seedling establishment and disturbance are unpredictable. The fire regime, an important driver of population dynamics in sagebrush steppe ecosystems, has been altered by exotic annual...
Sediment samples were collected from eight sampling sites
along the Yaquina Estuary, Oregon from Yaquina Bay to Elk City near
the head of the estuary. Samples were collected in November 1973,
February 1974, May 1974 and August 1974 from two or three intertidal
levels depending on the magnitude of the...
Field plots of cv. Russet Burbank potatoes from a
single seedlot were established at four sites over two
seasons (1985-86) in two locations in Oregon to determine
the role of water-borne inoculum of Erwinia carotovora in
plant infection. One site at each location was irrigated
from a surface-water source and...
Eight species of Lathvrus (Fabaceae, Faboideae) endemic to the
Pacific Coast of North America were the subject of a systematic
investigation. Taxa studied included Lathvrus vestitus, Nutt. ex T.
& G., L. laetif lorus Greene, L.. iepsonii Greene, £,. splendens
Kellogg, L. polvphvllus, Nutt. ex T. & G., L. holochlorus...
Nitrogen-fixing lichens (cyanolichens) are an important source of nitrogen (N) in Pacific Northwest forests, but limitation of lichen growth by elements essential for N fixation is poorly understood. To investigate how nutrient limitation may affect cyanolichen growth rates, we fertilized a tripartite cyanobacterial lichen (Lobaria pulmonaria) and a green algal...
Conservation conflicts may develop on restoration sites with multiple species recovery objectives. For example, on Pacific Northwest prairies, the co-planting of the diploid cytotype of the common native wildflower Castilleja hispida with the endangered wildflower C. levisecta has resulted in putative Castilleja hybrids on restoration sites, prompting fears that genetic...