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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: 1316

Conservation endocrinology: A noninvasive tool to understand relationships between carnivore colonization and ecological carrying capacity Conservation endocrinology: A noninvasive tool to understand relationships between carnivore colonization and ecological carrying capacity

Reproductive technology, especially the diagnosis of pregnancy by radioimmunoassay of fecal steroid metabolites, is an important component of captive propagation, but its role in our understanding of ecological interactions and in situ biological restoration has been more limited. Where large herbivores have been 'released' from predation by the extirpation of carnivores, controversy...
Authors
J. Berger, J.W. Testa, T. Roffe, S.L. Monfort

Estimating the effectiveness of further sampling inspecies inventories Estimating the effectiveness of further sampling inspecies inventories

Estimators of the number of additional species expected in the next Δn samples offer a potentially important tool for improving cost-effectiveness of species inventories but are largely untested. We used Monte Carlo methods to compare 11 such estimators, across a range of community structures and sampling regimes, and validated our results, where possible, using empirical data from...
Authors
Kim A. Keating, James F. Quinn, M.A. Ivie, L.L. Ivie

Assessing simulated ecosystem processes for climate variability research at Glacier National Park, USA Assessing simulated ecosystem processes for climate variability research at Glacier National Park, USA

Glacier National Park served as a test site for ecosystem analyses that involved a suite of integrated models embedded within a geographic information system. The goal of the exercise was to provide managers with maps that could illustrate probable shifts in vegetation, net primary production (NPP), and hydrologic responses associated with two selected climatic scenarios. The climatic...
Authors
Joseph D. White, Steven W. Running, Peter E. Thornton, Robert E. Keane, Kevin C. Ryan, Daniel B. Fagre, Carl H. Key

A female black bear denning habitat model using a geographic information system A female black bear denning habitat model using a geographic information system

We used the Mahalanobis distance statistic and a raster geographic information system (GIS) to model potential black bear (Ursus americanus) denning habitat in the Ouachita Mountains of Arkansas. The Mahalanobis distance statistic was used to represent the standard squared distance between sample variates in the GIS database (forest cover type, elevation, slope, aspect, distance to...
Authors
J. D. Clark, S.G. Hayes, J.M. Pledger

Estimating species richness: The Michaelis-Menten model revisited Estimating species richness: The Michaelis-Menten model revisited

The Michaelis-Menten model has been widely used to estimate the richness (S) of species pools, but is largely untested. We tested whether (1) species accumulation curves follow the form predicted by the model, (2) the model gives unbiased estimates (Ŝ and B̂, respectively) of S and of the sample size, B, needed to detect S/2 species, and (3) performance is robust to community structure
Authors
K.A. Keating, J.F. Quinn

Ecosystem dynamics of the Northern Rocky Mountains, USA Ecosystem dynamics of the Northern Rocky Mountains, USA

No abstract available.
Authors
D.B. Fagre, C.H. Key, J.D. White, S. W. Running, F. R. Hauer, R.E. Keane, K. C. Ryan

Imperiled mammalian fauna of aquatic ecosystems in the Southeast: A management perspective Imperiled mammalian fauna of aquatic ecosystems in the Southeast: A management perspective

Management of imperiled mammals associated with aquatic ecosystems in the southeastern United States ranges from almost no management for some species to intensive, high-profile programs for others. Aquatic mammals are notoriously difficult to census because they are often secretive, trap-wary, relatively rare, or have extensive movement patterns. As a result, conservation efforts aimed...
Authors
J. D. Clark, M. J. Harvey
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