The causes of natural mortality and disease in free ranging black bears, Ursus americanus, in California, Oregon, and Washington are poorly known. Life history components, such as scavenging and overlapping habitat with many species of carnivores, potentially expose bears to a wide range of infectious disease agents. To date, no...
Leaf surface area present on black cottonwood (Populus trichocarpa) and Douglas hawthorn (Crataegus douglasi) was measured indirectly using a point frame, photographs, and a canopy analyzer. Each was compared to directly measured leaf surface area. Six black cottonwood and 3 Douglas hawthorn shrubs were selected in 1996 and 9 black...
As a key factor contributing to slope stability, in-stream habitat for aquatic species (e.g., salmonids), nutrient cycling, and corridors for upland species, riparian vegetation and its maintenance is of critical conservation importance. Subsequently, the chronic degradation of aquatic and riparian ecosystems in the semi-arid and arid landscapes of the western...
Black Brant (Branta bernicla nigricans) had two different seasonal patterns of occurrence at Yaquina Estuary. At embayment areas with eelgrass (Zostera marina), Brant typically arrived between October 22 and November 4, Brant numbers progressively climbed in November, Brant abundance in December-January was relatively constant, and Brant numbers often fluctuated greatly...
Seasonal trends in forage production and environmental parameters
for five plant community types within a northeastern Oregon riparian zone
were described and modeled using correlation and path analysis. Wet
meadows produced the greatest amount of herbage biomass, followed by moist
bluegrass meadows, gravel bars, forests and dry bluegrass meadows. Trends...
From 1987-1997, Oregon State University conducted studies at Hart Mountain National Antelope Refuge (HMNAR) to better understand the relationship between grouse productivity and key habitat components. Early studies indicated sage grouse habitat preference and reproductive success were related to particular forbs (including legumes and milky juice composites) and structural characters...