Publications
Filter Total Items: 1994
PRAIRIEMAP: A GIS database for prairie grassland management in western North America
The USGS Forest and Rangeland Ecosystem Science Center, Snake River Field Station (SRFS) maintains a database of spatial information, called PRAIRIEMAP, which is needed to address the management of prairie grasslands in western North America. We identify and collect spatial data for the region encompassing the historical extent of prairie grasslands (Figure 1). State and federal agencies, the prim
Authors
Range-wide conservation assessment of Greater Sage-Grouse and sagebrush habitats
Declining numbers of Greater Sage-grouse (Centrocercus urophasianus) over the past three decades across most of their range accompanied by increasing habitat degradation and loss represent major conservation and management challenges. We are conducting a range-wide Conservation Assessment of Greater Sage-grouse and sagebrush habitats. This assessment is an interagency effort sponsored by the Weste
Authors
Native salamanders and introduced fish: Changing the nature of mountain lakes and ponds
During the last century, many fishless mountain lakes and ponds in the Pacific Northwest were stocked with non-native fish, such as brook trout, for recreational purposes. These introduced fish replaced long-toed and northwestern salamander larvae as the top aquatic vertebrate predator by preying on salamander larvae. This predatory interaction has been shown to reduce the abundances of larval sal
Authors
Gary L. Larson, Robert L. Hoffman
The Amphibian Research and Monitoring Initiative in the Pacific Northwest
Amphibians have been disappearing from many locations around the world with reports of declines increasing in recent decades. Some of the most dramatic declines have occurred in areas that were thought to be protected from human disturbance. For example, the once-common boreal toad has virtually disappeared from Rocky Mountain National Park in Colorado. Although there has been debate on whether th
Authors
M. J. Adams
Crater Lake: blue through time
Blue is the color of constancy, hence the term true blue. The unearthly blueness of Crater Lake reflects its pristine character and gives scientists a focal point for studying human impacts on aquatic environments over long periods of time.
Scientists with the U.S. Geological Survey (USGS), National Park Service, and Oregon State University have systematically studied the lake for the last two
Authors
Gary L. Larson, Mark Buktenica, Robert Collier
Estimating population trends with a linear model
We describe a simple and robust method for estimating trends in population size. The method may be used with Breeding Bird Survey data, aerial surveys, point counts, or any other program of repeated surveys at permanent locations. Surveys need not be made at each location during each survey period. The method differs from most existing methods in being design based, rather than model based. The on
Authors
Jonathan Bart, Brian D. Collins, R. I. G. Morrison
Fire and amphibians in North America
Information on amphibian responses to fire and fuel reduction practices is critically needed due to potential declines of species and the prevalence of new, more intensive fire management practices in North American forests. The goals of this review are to summarize the known and potential effects of fire and fuels management on amphibians and their aquatic habitats, and to identify information ga
Authors
D. S. Pilliod, R.B. Bury, E.J. Hyde, C.A. Pearl, P. S. Corn
Impacts of the Brown Tree Snake: Patterns of Decline and Species Persistence in Guam's Avifauna
Predation by brown tree snakes (Boiga irregularis ) devastated the avifauna of Guam in the Mariana Islands during the last half of the twentieth century, causing the extirpation or serious reduction of most of the island's 25 resident bird species. Past studies have provided qualitative descriptions of the decline of native forest birds but have not considered all species or presented quantitative
Authors
G.J. Wiles, J. Bart, R.E. Beck, C.F. Aguon
Effects of soil amendments on germination and emergence of downy brome (Bromus tectorum) and Hilaria jamesii
Downy brome is an introduced Mediterranean annual grass that now dominates millions of hectares of western U.S. rangelands. The presence of this grass has eliminated many native species and accelerated wildfire cycles. The objective of this study was to identify soil additives that allowed germination but inhibited emergence of downy brome, while not affecting germination or emergence of the nativ
Authors
J. Belnap, S. K. Sherrod, M. E. Miller
Management implications of the ecology of free-roaming horses in semiarid ecosystems of the western United States
Compared to other ungulates of North America, free-roaming horses (Equus caballus) possess a unique evolutionary history that has given rise to a distinct suite of behavioral, morphological, and physiological traits. Because of their unique combination of cecal digestion, an elongate head with flexible lips, and non-uniform use of the landscape, horses represent a unique disturbance agent in semi-
Authors
Erik Beever