Publications
Filter Total Items: 2002
Long-term patterns of diameter and basal area growth of old-growth Douglas-fir trees in western Oregon
Diameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100a??300 years. The diameters of the trees at ages 100a??300 years
Authors
Nathan Poage, J. C. Tappeiner
Ascaphus trueii (Tailed frog). Albinism
No abstract available.
Authors
Christopher A. Pearl, D.J. Major, R. Bruce Bury
Growth responses of subalpine fir to climatic variability in the Pacific Northwest
We studied regional variation in growth-limiting factors and responses to climatic variability in subalpine forests by analyzing growth patterns for 28 tree-ring growth chronologies from subalpine fir (Abies lasiocarpa (Hook.) Nutt.) stands in the Cascade and Olympic Mountains (Washington and Oregon, U.S.A.). Factor analysis identified four distinct time series of common growth patterns; the domin
Authors
David W. Peterson, David L. Peterson, Gregory J. Ettl
Nineteenth century mercury: Hazard to wading birds and cormorants of the Carson River, Nevada
Contemporary mercury interest relates to atmospheric deposition, contaminated fish stocks and exposed fish-eating wildlife. The focus is on methylmercury (MeHg) even though most contamination is of inorganic (IoHg) origin. However, IoHg is readily methylated in aquatic systems to become more hazardous to vertebrates. In response to a classic episode of historical (1859a??1890) IoHg contamination,
Residency and movement patterns of wintering Dunlin in the Willamette Valley of Oregon
In the winters of 1998-1999 and 1999-2000, we tracked 67 radio-marked Dunlin (Calidris alpina) throughout the complex agricultural landscape of the Willamette Valley of Oregon. Individual birds were tracked across 8-week sampling periods and indicated a high degree of regional fidelity throughout the three winter sampling periods. Birds exhibited varied degrees of fidelity to specific wetland site
Authors
P.M. Sanzenbacher, S. M. Haig
Space use, migratory connectivity, and population segregation among Willets breeding in the western Great Basin
Western Willets (Catoptrophorus semipalmatus inornatus) were banded (n = 146 breeding adults and chicks) and radio-marked (n = 68 adults) at three western Great Basin wetland complexes to determine inter- and intraseasonal space use and movement patterns (primarily in 1998 and 1999). Birds were then tracked to overwintering sites where migratory connectivity and local movements were documented. Wi
Authors
S. M. Haig, L.W. Oring, P.M. Sanzenbacher, O.W. Taft
Persistence of pikas in two low-elevation national monuments in the western United States
[No abstract available]
Authors
E.A. Beever
Double sampling to estimate density and population trends in birds
We present a method for estimating density of nesting birds based on double sampling. The approach involves surveying a large sample of plots using a rapid method such as uncorrected point counts, variable circular plot counts, or the recently suggested double-observer method. A subsample of those plots is also surveyed using intensive methods to determine actual density. The ratio of the mean cou
Authors
Jonathan Bart, Susan L. Earnst
Born of fire - restoring sagebrush steppe
Fire is a natural feature of sagebrush grasslands in the Great Basin. The invasion of exotic annual grasses, such as Bromus tectorum (cheatgrass), has changed the environment in these ecosystems. Invasive annual grasses provide a dense and continuous source of fuel that extends the season for fires and increases the frequency of fires in the region. Frequent fires eventually eliminate the native s
Authors
David A. Pyke
Assessing rangelands
It is important for land managers and technical assistance specialists to be able to assess the health of rangelands in order to know where to focus management efforts. The complexity of ecological processes, and the inherent expense of directly measuring site integrity, suggests a need for an evaluation process that focuses instead on biological and physical attributes.
In a collaborative effo
Authors
David A. Pyke
SAGEMAP: A web-based spatial dataset for sage grouse and sagebrush steppe management in the Intermountain West
The Snake River Field Station of the Forest and Rangeland Ecosystem Science Center has developed and now maintains a database of the spatial information
needed to address management of sage grouse and sagebrush steppe habitats in the western United States. The SAGEMAP project identifies and collects infor-mation for the region encompassing the historical extent of sage grouse distribution. State
Authors
Steven T. Knick, Linda Schueck
Effects of shrubland changes on birds in the Intermountain West
We are integrating field surveys with information obtained from satellite imagery to determine how birds respond to the habitat changes in shrubland regions in the Intermountain West. Our objectives are to determine the primary causes that change shrubland habitats, the spatial and temporal scales at which shrubland landscapes change, and the mechanisms by which distribution and abundance of bird
Authors
Steven T. Knick, Thomas R. Loveland