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Publications

Below is a list of available NOROCK peer reviewed and published science. If you are in search of a specific publication and cannot find it below or through a search, please contact twojtowicz@usgs.gov.

Filter Total Items: 1197

Mechanisms for an ∼7‐kyr climate and sea‐level oscillation during marine isotope stage 3

No abstract available.
Authors
Peter U. Clark, Steven W. Hostetler, N. G. Pisias, Andreas Schmittner, K. J. Meissner

Yellowstone grizzly bear investigations: Annual report of the Interagency Grizzly Bear Study Team, 2006

The contents of this Annual Report summarize results of monitoring and research from the 2006 field season. The report also contains a summary of nuisance grizzly bear (Ursus arctos horribilis) management actions. The Interagency Grizzly Bear Study Team (IGBST) continues to work on issues associated with counts of unduplicated females with cubs-of- the-year (COY). These counts are used to establis

A comparison of protocols and observer precision for measuring physical stream attributes

Stream monitoring programs commonly measure physical attributes to assess the effect of land management on stream habitat. Variability associated with the measurement of these attributes has been linked to a number of factors, but few studies have evaluated variability due to differences in protocols. We compared six protocols, five used by the U.S. Department of Agriculture Forest Service and one
Authors
H.W. Whitacre, B.B. Roper, J. L. Kershner

Use of a wetland index to evaluate changes in riparian vegetation after livestock exclusion

A method was developed to characterize ecological integrity of riparian sites based on the abundance of hydric species. This wetland index can be calculated with species data, or with community type data as performed here. Classified riparian community types were used to describe vegetation at 14 livestock exclosures and adjacent grazed areas. Community type wetland index values were generated and
Authors
M. C. Coles-Ritchie, D.W. Roberts, J. L. Kershner, R.C. Henderson

The impact of time and field conditions on brown bear (Ursus arctos) faecal DNA amplification

To establish longevity of faecal DNA samples under varying summer field conditions, we collected 53 faeces from captive brown bears (Ursus arctos) on a restricted vegetation diet. Each faeces was divided, and one half was placed on a warm, dry field site while the other half was placed on a cool, wet field site on Moscow Mountain, Idaho, USA. Temperature, relative humidity, and dew point data were
Authors
M.A. Murphy, K.C. Kendall, A. Robinson, L.P. Waits

Population growth of Yellowstone grizzly bears: Uncertainty and future monitoring

Grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem of the US Rocky Mountains have recently increased in numbers, but remain vulnerable due to isolation from other populations and predicted reductions in favored food resources. Harris et al. (2006) projected how this population might fare in the future under alternative survival rates, and in doing so estimated the rate of population
Authors
R.B. Harris, Gary C. White, C.C. Schwartz, M.A. Haroldson

Rapid assessment of postfire plant invasions in coniferous forests of the western United States

Fire is a natural part of most forest ecosystems in the western United States, but its effects on nonnative plant invasion have only recently been studied. Also, forest managers are engaging in fuel reduction projects to lessen fire severity, often without considering potential negative ecological consequences such as nonnative plant species introductions. Increased availability of light, nutrient
Authors
J.P. Freeman, T.J. Stohlgren, M.E. Hunter, Philip N. Omi, E.J. Martinson, G.W. Chong, C. S. Brown

Influences of geomorphology and geology on alpine treeline in the American West - More important than climatic influences?

The spatial distribution and pattern of alpine treeline in the American West reflect the overarching influences of geological history, lithology and structure, and geomorphic processes and landforms, and geologic and geomorphic factors—both forms and processes—can control the spatiotemporal response of the ecotone to climate change. These influences occur at spatial scales ranging from the contine
Authors
D.R. Butler, G.P. Malanson, S. J. Walsh, D.B. Fagre

Utility of R0 as a predictor of disease invasion in structured populations

Early theoretical work on disease invasion typically assumed large and well-mixed host populations. Many human and wildlife systems, however, have small groups with limited movement among groups. In these situations, the basic reproductive number, R0, is likely to be a poor predictor of a disease pandemic because it typically does not account for group structure and movement of individuals among g
Authors
Paul C. Cross, Philip L. Johnson, James O. Lloyd-Smith, Wayne M. Getz

Testing a Mahalanobis distance model of black bear habitat use in the Ouachita Mountains of Oklahoma

Regional wildlife–habitat models are commonly developed but rarely tested with truly independent data. We tested a published habitat model for black bears (Ursus americanus) with new data collected in a different site in the same ecological region (i.e., Ouachita Mountains of Arkansas and Oklahoma, USA). We used a Mahalanobis distance model developed from relocations of black bears in Arkansas to
Authors
E. C. Hellgren, S.L. Bales, M.S. Gregory, David M. Leslie, J. D. Clark

Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem

Every winter, government agencies feed ∼6000 metric tons (6 × 106 kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed t
Authors
P.C. Cross, W.H. Edwards, B.M. Scurlock, E.J. Maichak, J.D. Rogerson

The role of natural vegetative disturbance in determining stream reach characteristics in central Idaho and western Montana

We evaluated the relationship between natural vegetative disturbance and changes in stream habitat and macroinvertebrate metrics within 33 randomly selected minimally managed watersheds in central Idaho and western Montana. Changes in stream reach conditions were related to vegetative disturbance for the time periods from 1985 to 1993 and 1993 to 2000, respectively, at the following three spatial
Authors
B.B. Roper, B. Jarvis, J. L. Kershner