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
Sagebrush ecosystems: current status and trends.
The sagebrush (Artemisia spp.) biome has changed since settlement by Europeans. The current distribution, composition and dynamics, and disturbance regimes of sagebrush ecosystems have been altered by interactions among disturbance, land use, and invasion of exotic plants. In this chapter, we present the dominant factors that have influenced habitats across the sagebrush biome. Using a large-scale
Authors
E.A. Beever, J.W. Connelly, S.T. Knick, M.A. Schroeder, S. J. Stiver
Pattern detection in stream networks: Quantifying spatial variability in fish distribution
Biological and physical properties of rivers and streams are inherently difficult to sample and visualize at the resolution and extent necessary to detect fine-scale distributional patterns over large areas. Satellite imagery and broad-scale fish survey methods are effective for quantifying spatial variability in biological and physical variables over a range of scales in marine environments but a
Authors
Christian E. Torgersen, Robert E. Gresswell, Douglas S. Bateman
Geospatial techniques for developing a sampling frame of watersheds across a region
Current land-management decisions that affect the persistence of native salmonids are often influenced by studies of individual sites that are selected based on judgment and convenience. Although this approach is useful for some purposes, extrapolating results to areas that were not sampled is statistically inappropriate because the sampling design is usually biased. Therefore, in recent investiga
Authors
Robert E. Gresswell, Douglas S. Bateman, George Lienkaemper, T.J. Guy
Nutritional ecology of ursids: A review of newer methods and management implications
The capability to understand the nutritional ecology of free-ranging bears has increased dramatically in the last 20 years. Advancements have occurred because (1) managers and biologists recognized the need to link habitat quality, productivity, and variability with bear movements, home ranges, and demographic parameters like reproductive output, survival, and population growth, and (2) several re
Authors
Charles T. Robbins, Charles C. Schwartz, L.A. Felicetti
Importance of salmon to wildlife: Implications for integrated management
Salmon (Oncorhynchuss pp.) are an important resource for terrestrial wildlife. However, the salmon requirements of wildlife populations and the role wildlife play in nutrient transport across ecosystems are largely ignored in salmon and habitat management. Any activity that reduces the availability of or access to salmon by wildlife may adversely affect wildlife populations and, potentially, ecosy
Authors
Grant V. Hilderbrand, Sean D. Farley, Charles C. Schwartz, Charles T. Robbins
Natural avalanches and transportation: A case study from Glacier National Park, Montana, USA
In January 2004, two natural avalanches (destructive class 3) derailed a freight train in John F. Stevens Canyon, on the southern boundary of Glacier National Park. The railroad tracks were closed for 29 hours due to cleanup and lingering avalanche hazard, backing up 112km of trains and shutting down Amtrak’s passenger service. The incident marked the fourth time in three winters that natural aval
Authors
B.A. Reardon, Daniel B. Fagre, R.W. Steiner
USA: Glacier National Park, Biosphere Reserve and GLORIA Site
The National Park Service of the United States has 388 designated protected areas and parks that include historic and cultural sites as well as ‘natural resource’ parks set aside for their unique and outstanding natural features. Early efforts to create parks were focused on areas of beauty or unusual features but later efforts increasingly aimed to protect biodiversity and intact ecosystems. Prot
Authors
Daniel B. Fagre
Yellowstone grizzly bear investigations: Annual report of the Interagency Grizzly Bear Study Team, 2003
The contents of this Annual Report summarize results of monitoring and research from the 2003 field season. The report also contains a summary of nuisance grizzly bear (Ursus arctos horribilis) management actions.
The study team continues to work on issues associated with counts of unduplicated females with cubs-of-the-year (COY). These counts are used to establish a minimum population size, which
Forecasting for natural avalanches during spring opening of Going-to-the-Sun Road, Glacier National Park, Montana, USA
The annual spring opening of the Going-to-the-Sun Road in Glacier National Park presents a unique avalanche forecasting challenge. The highway traverses dozens of avalanche paths mid-track in a 23-kilometer section that crosses the Continental Divide. Workers removing seasonal snow and avalanche debris are exposed to paths that can produce avalanches of destructive class 4. The starting zones for
Authors
Blase Reardon, Chris Lundy
Modeling survival: application of the Andersen-Gill model to Yellowstone grizzly bears
Wildlife ecologists often use the Kaplan-Meier procedure or Cox proportional hazards model to estimate survival rates, distributions, and magnitude of risk factors. The Andersen-Gill formulation (A-G) of the Cox proportional hazards model has seen limited application to mark-resight data but has a number of advantages, including the ability to accommodate left-censored data, time-varying covariat
Authors
Christopher J. Johnson, Mark S. Boyce, Charles C. Schwartz, Mark A. Haroldson
What limits the Serengeti zebra population?
The populations of the ecologically dominant ungulates in the Serengeti ecosystem (zebra, wildebeest and buffalo) have shown markedly different trends since the 1960s: the two ruminants both irrupted after the elimination of rinderpest in 1960, while the zebras have remained stable. The ruminants are resource limited (though parts of the buffalo population have been limited by poaching since the 1
Authors
Sophie Grange, Patrick Duncan, Jean-Michel Gaillard, Anthony R.E. Sinclair, Peter J. Gogan, Craig Packer, Heribert Hofer, East Marion