Publications

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We report results from shorebird surveys in the North American Arctic, defined here as Bird Conservation Regions 2 and 3 of the North American Bird Conservation Initiative (http://www.nabci.net/International/English/bcrmap.html). The surveys estimate population size and trend, and provide information on habitat relationships, at the regional and Arctic-wide scale (Table 1, Fig 1). Of the...

Recent studies have demonstrated the geomorphic complexity and wide range of hydrologic regimes found in alpine headwater channels that provide complex habitats for aquatic taxa. These geohydrologic elements are fundamental to better understand patterns in species assemblages and indicator taxa and are necessary to aquatic monitoring protocols that aim to track changes in physical...

This brief chapter addresses two related issues: how effort should be allocated to different parts of the sampling plan and, given optimal allocation, how large a sample will be required to achieve the PRISM accuracy target. Simulations based on data collected to date showed that 2 plots per cluster on rapid surveys, 2 intensive camps per field crew-year, 2-4 intensive plots per...

Detecting declines in population size is one of the highest priorities of the shorebird initiatives in Canada and the United States. The quantitative goal is 80% power to detect a 50% decline, occurring during no more than 20 years, with a significance level of 0.15, using a two-tailed test, and incorporating effects of potential bias into the estimator. The Arctic PRISM program was...

Large-scale commercial thinning of young forests in the Pacific Northwest is currently promoted on public lands to accelerate the development of late-seral forest structure for the benefit of wildlife species such as northern spotted owls (Strix occidentalis caurina) and their prey, including the northern flying squirrel (Glaucomys sabrinus). Attempts to measure the impact of commercial...

Each year shorebirds from North and South America migrate thousands of miles to spend the summer in the Arctic. There they feed in shoreline marshes and estuaries along some of the most productive and pristine coasts anywhere. With so much available food they are able to reproduce almost explosively; and as winter approaches, they retreat south along with their offspring, to return to...

Snags (standing dead trees) are an essential structural component of forests. Because wildlife use of snags depends on size and decay stage, snag density estimation without any information about snag quality attributes is of little value for wildlife management decision makers. Little work has been done to develop models that allow multivariate estimation of snag density by snag quality...

When habitat becomes fragmented, populations of species may become increasingly isolated. In the absence of habitat corridors, genetic structure may develop and populations risk reductions in genetic diversity from increased genetic drift and inbreeding. Deforestation of the Cerrado biome of Brazil, particularly of the dry forests within the Parana˜ River Basin, has incrementally...

This chapter summarizes results in previous chapters by providing estimated densities and population sizes, in the areas we have surveyed, for Alaska, Canada, and both regions combined. A total of 1,554 rapid plots, covering 232 km2, and 83 intensive plots were surveyed during the study. The monograph presents >600 density estimates and >200 estimated population sizes. Densities for all...

Biological soil crusts (biocrusts) are critical components of arid and semi-arid ecosystems that contribute significantly to carbon (C) and nitrogen (N) fixation, water retention, soil stability, and seedling recruitment. While dry-land ecosystems face a number of environmental changes, our understanding of how biocrusts may respond to such perturbation remains notably poor. To determine...

We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through...