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Publications

Below is a list of WERC's peer-reviewed publications. If you are searching for a specific publication and cannot find it in this list, please contact werc_web@usgs.gov

Filter Total Items: 3617

Using presence of sign to measure habitats used by Roosevelt elk

tract Radiotelemetry and pellet-group surveys are methods used commonly to measure habi- tat use by large ungulates. However, telemetry can be expensive and analysis of data col- lected from pellet-group surveys is restricted to rank analysis. We explored the feasibil- ity of recording the presence of Roosevelt elk (Cervus elaphus roosevelti) sign to identify habitats used by elk. We surveyed stat
Authors
Floyd W. Weckerly, Mark A. Ricca

Inter-decadal change in diet and population of sea otters at Amchitka Island, Alaska

After having been hunted to near-extinction in the Pacific maritime fur trade, the sea otter population at Amchitka Island, Alaska increased from very low numbers in the early 1900s to near equilibrium density by the 1940s. The population persisted at or near equilibrium through the 1980s, but declined sharply in the 1990s in apparent response to increased killer whale predation. Sea otter diet an
Authors
J. Watt, D.B. Siniff, J. A. Estes

Forest gradient response in Sierran landscapes: the physical template

Vegetation pattern on landscapes is the manifestation of physical gradients, biotic response to these gradients, and disturbances. Here we focus on the physical template as it governs the distribution of mixed-conifer forests in California's Sierra Nevada. We extended a forest simulation model to examine montane environmental gradients, emphasizing factors affecting the water balance in these summ
Authors
Dean L. Urban, Carol Miller, Patrick N. Halpin, Nathan L. Stephenson

Predation on Corynorhinus townsendii by Rattus rattus

Corynorhinus townsendii (Townsend's big- eared bat) is a rare and declining species. Ex- tensive surveys for the coastal subspecies, C. t. townsendii, in California indicate that only 50% of historic maternity colonies are occu- pied currently (Pierson and Rainey, 1996). Three of the largest maternity colonies occur in Marin Co. Two of these have been moni- tored with evening exit counts on a reg
Authors
Gary M. Fellers

A Pacific spring migration route and breeding range expansion for greater white-fronted geese wintering in Japan

No abstract available.
Authors
John Y. Takekawa, Masayuki Kurechi, Dennis L. Orthmeyer, Yutaka Sabano, Sachiko Uemura, William M. Perry, Julie L. Yee

Estimated ages of some large giant sequoias: General Sherman keeps getting younger

During 1975-77, 168 bald eagles (Haliaeetus leucocephalus) found moribund or dead in 29 states were analyzed for organochlorine pesticides and polychlorinated biphenyls (PCBs); 32 specimens from 13 states were analyzed for polybrominated biphenyls (PBBs). PCBs were present in 166 bald eagle carcasses and DDE was found in 165. TDE and dieldrin were identified in 137 samples, trans-nonachlor in 118,
Authors
N.L. Stephenson

Variability of bed mobility in natural, gravel‐bed channels and adjustments to sediment load at local and reach scales

Local variations in boundary shear stress acting on bed‐surface particles control patterns of bed load transport and channel evolution during varying stream discharges. At the reach scale a channel adjusts to imposed water and sediment supply through mutual interactions among channel form, local grain size, and local flow dynamics that govern bed mobility. In order to explore these adjustments, we
Authors
Thomas E. Lisle, Jonathan M. Nelson, John Pitlick, Mary Ann Madej, Brent L. Barkett

Composition of Pteryxia terebinthina var. californica (Coult. and Rose) Mathias essential oils

β-Pinene (35.0%, 53.8%) was the major component of both the aerial parts and the root oils of Pteryxia terebinthina var. californica, respectively. β-Phellandrene (12.2%) was the other most abundant component of the oil from aeial parts while δ-3-carene (14.2%) was the second abundant component of the root oil.
Authors
Philip E. Beauchamp, Vasu Dev, Elsa Munevar-Mendoza, Peggy E. Moore

The use of fuel breaks in landscape fire management

Shaded fuelbreaks and larger landscape fuel treatments, such as prescribed fire, are receiving renewed interest as forest protection strategies in the western United States. The effectiveness of fuelbreaks remains a subject of debate because of differing fuelbreak objectives, prescriptions for creation and maintenance, and their placement in landscapes with differing fire regimes. A well-designed
Authors
James K. Agee, Berni Bahro, Mark A. Finney, Philip N. Omi, David B. Sapsis, Carl N. Skinner, Jan W. Van Wagtendonk, C. Phillip Weatherspoon

Tidal influence on spatial dynamics of leopard sharks, Triakis semifasciata, in Tomales Bay, California

We used ultrasonic telemetry to determine the movement directions and movement rates of leopard sharks, Triakis semifasciata, in Tomales Bay, California. To analyze tide and time of day effects, we surgically implanted transmitters in the peritoneal cavities of one male and five female leopard sharks, which we located during summer for three to five sampling sessions lasting 12 to 24 h each. All l
Authors
Joshua T. Ackerman, Matthew C. Kondratieff, Scott A. Matern, Joseph J. Jr. Cech

Predation: Hyla cadaverina

No abstract available.
Authors
E.L. Ervin, Robert N. Fisher, K. Madden