Skip to main content
USGS - science for a changing world
Advanced Search

Filters: Types: Journal Citation (X)

3,237 results (10ms)   

View Results as: JSON ATOM CSV
Microtus richardsoni, the water vole, was listed as a sensitive species in Region 2 of the USDA Forest Service in 1994. Historical records indicate water voles were found in the Big Horn Mountains, but little was known about their current status. The purpose of this study was to locate water voles in the Big Horn Mountains of Wyoming, develop a habitat profile, and evaluate the extent to which livestock grazing affects them. Accessible creeks with habitat requirements for water voles were surveyed. Water voles were not captured below 2440 m. Grazed and ungrazed sites occupied by water voles were matched and analyzed for percent plant cover, dry weight biomass, riparian classification, mean stream depth, channel...
thumbnail
We revised distribution maps of potential presettlement habitat and current populations for Greater Sage-Grouse (Centrocercus urophasianus) and Gunnison Sage-Grouse (C. minimus) in North America. The revised map of potential presettlement habitat included some areas omitted from previously published maps such as the San Luis Valley of Colorado and Jackson area of Wyoming. Areas excluded from the revised maps were those dominated by barren, alpine, and forest habitats. The resulting presettlement distribution of potential habitat for Greater Sage-Grouse encompassed 1 200 483 km(2), With the species' current range 668 412 km(2). The distribution of potential Gunnison Sage-Grouse habitat encompassed 46 521 km(2), with...
Areas occupied by white-tailed prairie dogs (WTPD; Cynomys leucurus) and Gunnison's prairie dogs (GPD; C. gunnisoni) are not well-known in Colorado (USA) and elsewhere. Suitable methodology for monitoring changes in populations of WTPD and GPD over broad areas also has not been well established. We evaluated occupancy modeling methodology to establish baseline occupancy rates for WTPD and GPD in Colorado. We estimated that WTPD occupied 24.1% (SE = 12.8) of 47,710 0.25-km2 plots and GPD occupied 7.5% (SE = 1.3) of 158,225 0.25-km2 plots in Colorado during 2004 and 2005. Areas reported as colonies in the Colorado Division of Wildlife's database were not good predictors of WTPD and GPD occupancy. Occupancy rates were...
A science agenda for the Greater Yellowstone Area: Responding to landscape impacts from climate change, land use change, and invasive species, credited to Bischke, S., published in 2010. Published in Yellowstone Science, volume 18, on pages 14 - 22, in 2010.
Seasonal snowpack chemistry data from the Rocky Mountain region of the US was examined to identify long-term trends in concentration and chemical deposition in snow and in snow-water equivalent. For the period 1993?2004, comparisons of trends were made between 54 Rocky Mountain Snowpack sites and 16 National Atmospheric Deposition Program wetfall sites located nearby in the region. The region was divided into three subregions: Northern, Central, and Southern. A non-parametric correlation method known as the Regional Kendall Test was used. This technique collectively computed the slope, direction, and probability of trend for several sites at once in each of the Northern, Central, and Southern Rockies subregions....
Sediment production and infiltration rates were measured in conjunction with an analysis of burning and grazing treatments in a chained pinyon-juniper study in southeastern Utah. While high natural variability was present among sites, no significant changes in sediment production were detected following our prescribed burning or grazing treatments. Following treatment, however, both the burned and grazed sites exhibited significantly depressed infiltration rates during certain time intervals in comparison to the ?undisturbed, natural? woodland control location. Published in Journal of Range Management, volume 29, issue 1, on pages 83 - 85, in 1976.
An increase in quarrying, open-cast mining and road traffic suggest that dust deposition onto vegetation may be increasing. This review describes the physical and chemical characters of a range of dust types. The effects of dust on crops, grasslands, heathlands, trees and woodlands, arctic bryophyte and lichen communities are identified. Dust may affect photosynthesis, respiration, transpiration and allow the penetration of phytotoxic gaseous pollutants. Visible injury symptoms may occur and generally there is decreased productivity. Most of the plant communities are affected by dust deposition so that community structure is altered. Epiphytic lichen and Sphagnum dominated communities are the most sensitive of those...
Cheatgrass brome, also known as "downy chess", "downy brome", "broncograss", "Mormon oats" and "Junegrass", is an annual grass that has become widely established on western ranges since its introduction from Europe. It presents complex problems which for years have complicated the management of the ranges it inhabits. In 1959 a cooperative research program on the management of cheatgrass ranges was started in southern Idaho by the Intermountain Forest and Range Experiment Station and the Bureau of Land Management. The beginning of these studies was necessarily preceded by a careful review and analysis of the literature on cheatgrass. This paper reviews that literature about this important western range plant. The...
Dissolved salts (salinity) adversely affect numerous urban and agriculatural users of Colorado River water in California and Arizona. Congress in 1974 authorized a major salinity control program. Studies of general economic benefits from salinity abatement and the cost per unit of salinity reduction expected from specific proposed projects have been developed by the responsible federal agencies, but no project-by-project evaluation has been published. We find a conceptual basis for a substantial downward revision of prospective economic benefits of salinity abatement. Revised benefits are compared with estimated costs, and only for five of the nineteen projects do economic benefits appear to exceed costs. Published...
thumbnail
Social organization of the Gunnison's prairie dog, Cynomys gunnisoni, was studied in two populations in south-central Colorado. Gunnison's prairie dogs live in complex, interactive societies fitting current definitions of highly social ground squirrels. Members of harems (‘coteries’) cooperatively use and defend a common territory. Spatial overlap is extensive between the adult male(s) and adult females, and among adult females within the harem through the active season. Amicable behavioral interactions are frequent within the harem, whereas interactions between members of different harems are primarily agonistic and spatial overlap is minimal. Although their behavioral repertoire is more limited, social organization...
Microbial crusts are present on surfaces of soils throughout the world. A key feature of these crusts in arid zones is the abundance of filamentous sheath-forming and polysaccharide-excreting cyanobacteria. Several isolates of cyanobacteria were prepared from crust samples (Nizzana sand dunes, north-western Negev Desert, Israel). Optimal growth conditions for two such isolates of Microcoleus sp. were defined, and the role of the excreted polysaccharides in affecting the hydrological properties of crust-covered sand dunes was studied. Experiments with the native crust microbial population demonstrated the possibility of net primary productivity at both high relative air humidities and low moisture content. Published...
The ecology and phytosociology of a virgin grassland community (Virginia Park, Canyonlands National Park, Utah) have been investigated. Based on the use of C × F index, Hilaria jamesii and Stipa comata are the most abundant of the four major perennial grasses. Oryzopsis hymenoides and Sporobolus cryptandrus are less abundant in decreasing order. The sites dominated by Hilaria are characterized by soils with finer texture, slightly warmer average temperature and higher surface K+ and organic matter compared to sites dominated by Stipa comata. In addition, frequency of both vascular and cryptogamic species is greater on sites dominated by Hilaria. Published in Journal of Range Management, volume 30, issue 4, on pages...
Male boreal toads (Bufo boreas) are thought to return to the breeding site every year but, if absent in a particular year, will be more likely to return the following year. Using Pollock's robust design we estimated temporary emigration (the probability a male toad is absent from a breeding site in a given year) at three locations in Colorado, USA: two in Rocky Mountain National Park and one in Chaffee County. We present data that suggest that not all male toads return to the breeding site every year. Our analyses indicate that temporary emigration varies by site and time (for example, from 1992 to 1998, the probability of temporary emigration ranged from 10% to 29% and from 3% to 95% at Lost Lake and Kettle Tarn,...
Double fertilization and the associated formation of endosperm have long been considered unique and defining characters (autapomorphies) of the angiosperms. During normal fertilization in Ephedra nevadensis, a nonflowering seed plant, fusion of a second sperm nucleus with the ventral canal nucleus occurs regularly within the egg cytoplasm. The occurrence of double fertilization in Ephedra assumes added significance in light of its critical phylogenetic position as a basal member of the most closely related extant group of seed plants (Gnetales) to angiosperms. Thus, double fertilization in angiosperms and Ephedra may represent an evolutionary homology. Published in Science, volume 547, issue 4945, on pages 951 -...
Categories: Publication; Types: Citation, Journal Citation; Tags: Science
thumbnail
First paragraph of introduction: On 20 July 2004 a single Asian tapeworm (Bothriocephalus acheilognathi) was collected from the intestine of a roundtail chub (Gila robusta) in the Yampa River in Dinosaur National Monument in northwestern Colorado. This fish (274 mm TL) was collected at river mile 24 and dissected in the field. A single tapeworm was removed from the intestine and preserved in ethanol. The tapeworm was later identified in the laboratory as B. acheilognathi by its characteristic arrow-shaped scolex (Poole et al. 1984). This is the 1st recorded incidence of Asian tapeworm infecting fish in the Yampa River drainage. Published in Western North American Naturalist, volume 65, issue 3, on pages 403 - 404,...
Change in alpine meadow greenness and wetness over a 25-year period in the Sierra Nevada (In preparation), credited to Soulard, Chris, published in 2011.
Categories: Publication; Types: Citation, Journal Citation
The invasion of woody vegetation into deserts, grasslands and savannas is generally thought to lead to an increase in the amount of carbon stored in those ecosystems. For this reason, shrub and forest expansion (for example, into grasslands) is also suggested to be a substantial, if uncertain, component of the terrestrial carbon sink. Here we investigate woody plant invasion along a precipitation gradient (200 to 1,100 mm yr(-1)) by comparing carbon and nitrogen budgets and soil delta(13)C profiles between six pairs of adjacent grasslands, in which one of each pair was invaded by woody species 30 to 100 years ago. We found a clear negative relationship between precipitation and changes in soil organic carbon and...
Categories: Publication; Types: Citation, Journal Citation; Tags: Nature
Some ecological characteristics of 25 white-tailed (Cynomys leucurus) and 21 black-tailed (Cynomys ludovicianus) prairie dog colinies in Wyoming were compared. The size of the colonies and density of burrow openings were similar for the two species, but the number of white-tailed prairie dogs per 100 km2 and the number of hectares occupied by white-tails per 100 km 2 were 3.7 and 4.6 times greater, respectively, than for black-tails. Sixty-four vertebrate species (22 mammals, 33 birds, five reptiles, and four amphibians) were found on prairie dog colonies. The ecological relationships between prairie dogs and associated vertebrate predator species and the history of prairie dog control in Wyoming are discussed.
Black-footed ferrets (Mustela nigripes) excavate subsoil from black-tailed prairie dog (Cynomys ludovicianus) burrows and deposit it in unique piles. Black-tailed prairie dogs tend to fill in or "plug" burrows visited or occupied by ferrets (Hillman 1968, Henderson et al. 1969, Fortenbery 1972). In this paper, we describe the configuration, rate of production, persistence, and seasonality of ferret diggings and rate of burrow plugging by prairie dogs within white-tailed prairie dog (C. leucurus) colonies. Published in Journal of Wildlife Management, volume 48, issue 4, on pages 1441 - 1444, in 1984.
The Crystal Geyser Dinosaur Quarry, near Green River, Utah, is located at the base of the Lower Cretaceous (Barremian) Yellow Cat Member of the Cedar Mountain Formation. The quarry preserves a nearly monospecific accumulation of a new basal therizinosauroid, Falcarius utahensis. We used field descriptions and petrographic analysis to determine the depositional environment and development of the quarry strata. Results of these analyses suggest that the quarry represents multiple episodes of bone accumulation buried by spring and overbank flood deposits. Evidence for these previously undescribed spring deposits includes calcite macroscopic structures within the quarry strata—such as pisolites and travertine fragments—and...
Categories: Publication; Types: Citation, Journal Citation; Tags: PALAIOS


map background search result map search result map Social organization and space-use in Gunnison's prairie dog Collection of Asian tapeworm ( Bothriocephalus acheilognathi ) from the Yampa River, Colorado Distribution of Sage-Grouse in North America Collection of Asian tapeworm ( Bothriocephalus acheilognathi ) from the Yampa River, Colorado Distribution of Sage-Grouse in North America