USGS Science⌕ Search

SEARCH · USGS Science

Results for “The R Journal”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources
USGS2011

Seasonal variation in nutritional characteristics of the diet of greater white-fronted geese

We studied diet and habitat use of greater white-fronted geese ( Anser albifrons ) from autumn through spring on their primary staging and wintering areas in the Pacific Flyway, 1979–1982. There have been few previous studies of resource use and forage quality of wintering greater white-fronted geese in North America, and as a consequence there has been little empirical support for management practices pertaining to habitat conservation of this broadly distributed species. Observations of >2,500 flocks of geese and collections of foraging birds revealed seasonal and geographic variation in resource use reflective of changes in habitat availability, selection, and fluctuating physiological demands. Autumn migrants from Alaska arrived first in the Klamath Basin of California and southern Oregon, where they fed on barley, oats, wheat, and potatoes. Geese migrated from the Klamath Basin into the Central Valley of California in late autumn where they exploited agricultural crops rich in soluble carbohydrates, with geese in the Sacramento Valley feeding almost exclusively on rice and birds on the Sacramento–San Joaquin Delta primarily utilizing corn. White-fronted geese began their northward migration in late winter, and by early spring most had returned to the Klamath Basin where 37% of flocks were found in fields of new growth cultivated and wild grasses. Cereal grains and potatoes ingested by geese were low in protein (7–14%) and high in soluble nutrients (17–47% neutral detergent fiber [NDF]), whereas grasses were low in available energy (47–49% NDF) but high in protein (26–42%). Greater white-fronted geese are generalist herbivores and can exploit a variety of carbohydrate-rich cultivated crops, likely making these geese less susceptible to winter food shortages than prior to the agriculturalization of the North American landscape. However, agricultural landscapes can be extremely dynamic and may be less predictable in the long-term than the historic environments to which geese are adapted. Thus far greater white-fronted geese have proved resilient to changes in land cover in the Pacific Flyway and by altering their migration regime have even been able to adapt to changes in the availability of suitable forage crops.

Pacific Flyway↗
USGS2016

Proximate influences on female dispersal in white-tailed deer

Ultimate causes of animal dispersal have been hypothesized to benefit the dispersing individual because dispersal reduces competition for local resources, potential for inbreeding, and competition for breeding partners. However, proximate cues influence important features of dispersal behavior, including when dispersal occurs, how long it lasts, and direction, straightness, and distance of the dispersal path. Therefore, proximate cues that affect dispersal influence ecological processes (e.g., population dynamics, disease transmission, gene flow). We captured and radio-marked 277 juvenile female white-tailed deer ( Odocoileus virginianus ), of which 27 dispersed, to evaluate dispersal behavior and to determine proximate cues that may influence dispersal behavior. Female dispersal largely occurred at 1 year of age and coincided with the fawning season. Dispersal paths varied but generally were non-linear and prolonged. Physical landscape features (i.e., roadways, rivers, residential areas) influenced dispersal path direction and where dispersal terminated. Additionally, forays outside of the natal range that did not result in dispersal occurred among 52% of global positioning system (GPS)-collared deer ( n = 25) during the dispersal period. Our results suggest intra-specific social interactions and physical landscape features influence dispersal behavior in female deer. Female dispersal behavior, particularly the lack of directionality, the semi-permeable nature of physical barriers, and the frequency of forays outside of the natal range, should be considered in regard to population management and controlling the spread of disease.

Pennsylvania↗
USGS2017

Shorebird stopover habitat decisions in a changing landscape

To examine how habitat use by sandpipers ( Calidris spp.; Baird's sandpipers, dunlin, least sandpipers, pectoral sandpipers, semipalmated sandpipers, stilt sandpipers, and white-rumped sandpipers) varies across a broad suite of environmental conditions, we conducted surveys at wetlands throughout the spring migratory period in 2013 and 2014 in 2 important stopover regions: the Rainwater Basin (RWB) in Nebraska, USA, and the Prairie Pothole Region (PPR) in South Dakota, USA. Because providing adequate energetic resources for migratory birds is a high priority for wetland management, we also measured invertebrate abundance at managed wetlands in the RWB to determine how food abundance influences the occupancy and abundance of sandpipers on wetlands throughout the migratory period. To quantify habitat use, we surveyed wetlands every 7–10 days in both regions and visually estimated wetland attributes. Our results indicate that invertebrate abundance predicted occupancy, but not abundance, of sandpipers at wetlands in the RWB. The wetland vegetation characteristics that predict sandpiper occupancy are similar in both regions, but wetlands in the PPR support a higher abundance of sandpipers than wetlands in the RWB. Our results suggest that sandpipers make stopover decisions that balance local and regional wetland conditions. Managers should maintain the cues (i.e., mudflat) and ecological conditions beyond invertebrate abundance that predict sandpiper habitat use to successfully provide resources for sandpipers during migratory stopover if that is a goal of wetland management. © 2017 The Wildlife Society.

Nebraska, South Dakota↗
USGS2018

Estimates of tidal-marsh bird densities using Bayesian networks

Conserving tidal-marsh bird communities requires strategies to address continuing pressures from human development to the effects of increasing rates of sea-level rise. Knowing tidal-marsh bird distributions and population sizes are important for developing these strategies. In the Northeast United States, where estimates of sea-level rise are 3 times higher than the global average, 5 bird species are tidal-marsh specialists: clapper rail (Rallus crepitans), willet (Tringa semipalmata), Nelson's sparrow (Ammospiza nelsoni), saltmarsh sparrow (A. caudacuta), and seaside sparrow (A. maritima). We used a regional marsh bird survey to develop Bayesian network models to identify factors that influence patch-scale species density and to estimate regional population sizes. We modeled species density as a function of habitat covariates at the patch, local, landscape, and regional spatial scales. Densities were most sensitive to patch location and dimension, patch geomorphic setting, indices of human development, and changes in mean sea level. We estimated 110,000 clapper rails (95% CI = 61,000–159,000), 111,000 willets (95% CI = 70,000–152,000), 7,000 Nelson's sparrows (95% CI = 4,000–10,000), 60,000 saltmarsh sparrows (95% CI = 40,000–80,000), and 234,000 seaside sparrows (95% CI = 112,000–356,000) from the United States–Canada border to, and including, the mouth of the Chesapeake Bay, Virginia, USA. Our abundance estimates can be used to identify priority conservation areas at multiple geographic scales and our models help identify key habitat and landscape components for tidal-marsh restoration and management to benefit tidal-marsh birds and can be modified for other species.

Maine, New Hampshire, Massachusetts, Rhode Island,↗
USGS2025

Weather, habitat area, connectivity, and number of patches influence breeding ecology of ring-necked pheasants

Understanding habitat selection is critical in habitat prioritization for species of conservation and management concern. Information on habitat selection is particularly important for grassland bird species whose populations have suffered steep declines over the last few decades. We assessed ring-necked pheasants' ( Phasianus colchicus ) habitat selection in a dynamic agricultural landscape. The population dynamics of pheasants are partially related to nest survival, which may be influenced by the quality of nesting habitat. Consequently, knowledge of vegetation composition and structural characteristics associated with the selection and survival of nests would help inform management decisions to improve nest success. We monitored nests from 103 radio-collared pheasants inhabiting an agricultural landscape in South Dakota, USA, from 2017–2019 to determine the effect of landscape composition and configuration on nest-site selection and nest survival. We explored nesting behavior at 2 orders of selection: resource selection within the home range (third order) and selection of specific resource items from a resource patch (fourth order). Proportion of row crop and connectivity of row crop was negatively associated with nest-site selection at the third order. At the fourth order, pheasants tended to select for taller vegetation and greater percent grass cover than at paired random sites. Pheasants also selected areas with more grasslands. A 1% increase in grass cover and proportion of grassland increased the odds of nest-site selection by 1% and 2%, respectively. Connectivity of row crop patches was negatively associated with daily nest survival. We also evaluated factors affecting pheasant brood-site selection. A 1-unit increase in grass cover and Hemiptera biomass increased the odds of brood-site selection by 4%. The probability of brood-site selection also increased with fewer row crop patches. Weather played a crucial role in driving nest survival. The consideration of local weather trends and regional variation in habitat can inform habitat management for pheasants. Pheasant populations may benefit from research that identifies thermal landscapes and land management techniques that promote cooler microclimates for nesting and brood-rearing activities.

South Dakota↗
USGS2025

Evaluation of the acute toxicity of the piscicide TFM to Burbot

Non-target animal sensitivity remains a concern when treating Laurentian Great Lakes streams with 4-nitro-3-(trifluoromethyl)phenol (TFM), the main pesticide used to control Sea Lamprey Petromyzon marinus as part of the bi-national Great Lakes Fishery Commission's Sea Lamprey Control Program. Populations of Burbot Lota lota , a historically and culturally important fish, inhabit some of the streams that are treated with TFM. While many species of fish inhabiting the Great Lakes streams have been assessed for sensitivity to TFM, we are not aware of previous research to assess the risk to Burbot. We assessed the sensitivity of Burbot to TFM using replicate 12-hour flow-through diluter toxicity tests. We found Burbot to have a median lethal concentration (LC 50 ) of 9.74 mg/L, while the minimum lethal concentration (LC 99.9 ) for Sea Lamprey was predicted to be 2.5 mg/L in similar waters. The resulting toxicity ratio (LC 50 of non-target organism/LC 99.9 of Sea Lamprey) of Burbot was 3.90, well above the toxicity ratios for known sensitive species. Our results suggest Burbot are not expected to be adversely affected during a typical TFM stream treatment.

Great Lakes↗
USGS2015

Species richness and distributions of boreal waterbirds in relation to nesting and brood-rearing habitats

Identification of ecological factors that drive animal distributions allows us to understand why distributions vary temporally and spatially, and to develop models to predict future changes to populations–vital tools for effective wildlife management and conservation. For waterbird broods in the boreal forest, distributions are likely driven by factors affecting quality of nesting and brood-rearing habitats, and the influence of these factors may extend beyond singles species, affecting the entire waterbird community. We used occupancy models to assess factors influencing species richness of waterbird broods on 72 boreal lakes, along with brood distributions of 3 species of conservation concern: lesser scaup ( Aythya affinis ), white-winged scoters ( Melanitta fusca ), and horned grebe ( Podiceps auritus ). Factors examined included abundance of invertebrate foods (Amphipoda, Diptera, Gastropoda, Hemiptera, Odonata), physical lake attributes (lake area, emergent vegetation), water chemistry (nitrogen, phosphorus, chlorophyll a concentrations), and nesting habitats (water edge, non-forest cover). Of the 5 invertebrates, only amphipod density was related to richness and occupancy, consistently having a large and positive relationship. Despite this importance to waterbirds, amphipods were the most patchily distributed invertebrate, with 17% of the study lakes containing 70% of collected amphipods. Lake area was the only other covariate that strongly and positively influenced species richness and occupancy of scaup, scoters, and grebes. All 3 water chemistry covariates, which provided alternative measures of lake productivity, were positively related to species richness but had little effect on scaup, scoter, and grebe occupancy. Conversely, emergent vegetation was negatively related to richness, reflecting avoidance of overgrown lakes by broods. Finally, nesting habitats had no influence on richness and occupancy, indicating that, at a broad spatial scale, brood distributions are largely driven by the presence of quality brood-rearing lakes, not nesting habitats. Our findings are relevant to generating conservation plans or management goals; specifically, boreal lakes with abundant amphipods and surface areas >25 ha are important habitat for waterbird broods and merit conservation, especially given the patchy distribution of amphipods. Moreover, these high quality brood-rearing lakes are much rarer, and thus more constraining, than are quality nesting habitats, which are likely abundant in the boreal.

Alaska↗
USGS1997

Succession of desert plants on debris flow terraces, Grand Canyon, Arizona, U.S.A.

Vegetation sampling on 11 debris flow terraces in Grand Canyon National Park, Arizona, U.S.A., showed that plant assemblages changed as age of surface increased. The terraces ranged in age from about 5 to about 3100 years. There were distinct differences among sites in the life history characteristics of the dominant plants. Young terraces (5-55 years) were dominated by short-lived plants that had high reproductive potential. Older surfaces were dominated by species with longer life-spans and lower reproductive potential. Density and cover of long-lived species increased with age of surface; for short-lived plants, density was inversely related to surface age. Species composition was also correlated with site age; however, location, exposure, and other factors ensured that no two debris flows supported identical mixtures of species. Succession on recent Grand Canyon debris flows is driven in part by life-history strategies, particularly life-span and seed dispersal traits, and also by climatic factors, especially those that control germination and establishment of the long-lived dominants.

Journal of Arid Environments↗
USGS1997

Molar heat capacity and entropy of calcium metal

The heat capacity of calcium has been measured at 85 mean temperatures between T ≈ 8 K and T ≈ 369 K using an adiabatically-shielded calorimeter in an intermittent heating mode. At T = 298.15 K, the recommended values for the molar heat capacity, molar entropy, and molar enthalpy increment referred to T = 0 are (25.77 ± 0.08) J·K −1 ·mol −1 , (42.90 ± 0.11) J·K −1 ·mol −1 , and (5811 ±12)J·mol −1 , respectively. The uncertainties are twice the standard deviation of the mean.

Journal of Chemical Thermodynamics↗
USGS2000

Distribution of metals during digestion by cutthroat trout fed benthic invertebrates contaminated in the Clark Fork River, Montana and the Coeur d'Alene River, Idaho, U.S.A., and fed artificially contaminated Artemia

The concentrations of essential amino acids in three, undigested invertebrate diets collected from the Clark Fork River (CFR) for cutthroat trout were similar to each other, but were c. 25–75% less than Artemia that were exposed to a mixture of arsenic, copper, cadmium, lead and zinc in the laboratory. The Artemia diet appeared less palatable and the texture, quantity and appearance of the intestinal contents differed between fish fed the Artemia and CFR diets. The Pb% in the fluid fraction of the intestinal contents was greater for the Artemia (29%) than for the CFR diets (10–17%), and the Cu% in the amino acid plus metal fraction of the intestinal contents was greater for the Artemia (78%) than for two of the three CFR diets (67% and 70%). Intestinal contents of fish fed invertebrate diets collected from various sites on the Coeur d'Alene River (CDA), Idaho, were similar in texture, quantity, and appearance. For fish fed the CDA diets, differences in the distribution of metals among fractions of the digestive fluids appeared to be related to concentrations of metals in the invertebrate diets. Pb% was lowest of all metals in the fluid portion of the intestinal contents. However, >80% of all metals in the hind gut were associated with the particulate fraction where they may still be available for uptake through pinocytosis.

Journal of Fish Biology↗
USGS1989

Late Quaternary paleolimnology of Walker Lake, Nevada

Diatoms, crustaceans, and pollen from sediment cores, in conjunction with dated shoreline tufas provide evidence for lake level and environmental fluctuations of Walker Lake in the late Quaternary. Large and rapid changes of lake chemistry and level apparently resulted from variations in the course and discharge of the Walker River. Paleolimnological evidence suggests that the basin contained a relatively deep and slightly saline to freshwater lake before ca. 30 000 years B.P. During the subsequent drawdown, the Walker River apparently shifted its course and flowed northward into the Carson Sink. As a result, Walker Lake shallowed and became saline. During the full glacial, cooler climates with more effective moisture supported a shallow brine lake in the basin even without the Walker River. As glacial climates waned after 15 000 years ago, Walker Lake became a playa. The Walker River returned to its basin 4700 years ago, filling it with fresh water in a few decades. Thereafter, salinity and depth increased as evaporation concentrated inflowing water, until by 3000 years ago Walker Lake was nearly 90 m deep, according to dated shoreline tufas. Lake levels fluctuated throughout this interval in response to variations in Sierra Nevada precipitation and local evaporation. A drought in the Sierras between 2400 and 2000 years ago reduced Walker Lake to a shallow, brine lake. Climate-controlled refilling of the lake beginning 2000 years ago required about one millennium to bring Walker lake near its historic level. Through time, lake basins in the complex Lake Lahontan system, fill and desiccate in response to climatic, tectonic and geomorphic events. Detailed, multidisciplinary paleolimnologic records from related subbasins are required to separate these processes before lake level history can be reliably used to interpret paleoclimatology. ?? 1989 Kluwer Academic Publishers.

Journal of Paleolimnology↗
USGS2017

Evaluation of diffuse and preferential flow pathways of infiltratedprecipitation and irrigation using oxygen and hydrogen isotopes

Subsurface-water flow pathways in three different land-use areas (non-irrigated grassland, poplar forest, and irrigated arable land) in the central North China Plain were investigated using oxygen ( 18 O) and hydrogen ( 2 H) isotopes in samples of precipitation, soils, and groundwater. Soil water in the top 10 cm was significantly affected by both evaporation and infiltration. Water at 10–40 cm depth in the grassland and arable land, and 10–60 cm in poplar forest, showed a relatively short residence time, as a substantial proportion of antecedent soil water was mixed with a 92-mm storm infiltration event, whereas below those depths (down to 150 cm), depleted δ 18 O spikes suggested that some storm water bypassed the shallow soil layers. Significant differences, in soil-water content and δ 18 O values, within a small area, suggested that the proportion of immobile soil water and water flowing in subsurface pathways varies depending on local vegetation cover, soil characteristics and irrigation applications. Soil-water δ 18 O values revealed that preferential flow and diffuse flow coexist. Preferential flow was active within the root zone, independent of antecedent soil-water content, in both poplar forest and arable land, whereas diffuse flow was observed in grassland. The depleted δ 18 O spikes at 20–50 cm depth in the arable land suggested the infiltration of irrigation water during the dry season. Temporal isotopic variations in precipitation were subdued in the shallow groundwater, suggesting more complete mixing of different input waters in the unsaturated zone before reaching the shallow groundwater.

Yellow Sea, Bohai Sea↗
USGS2012

A simulation-based approach for designing effective field-sampling programs to evaluate contamination risk of groundwater supplies

An approach to model discrimination and network design for evaluation of groundwater contamination risk is proposed and demonstrated by application to a site in a glaciofluvial aquifer in Sweden. The approach consists of first hypothesizing alternative conceptual models of hydrogeology at the site on the basis of both quantitative data and qualitative information. The conceptual models are then expressed as two-dimensional numerical models of groundwater flow and solute transport, and model attributes controlling risk to the water supply are determined by simulation. Model predictions of response to a specific field test are made with each model that affects risk. Regions for effective measurement networks are then identified. Effective networks are those that capture sufficient information to determine which of the hypothesized models best describes the system with a minimum of measurement points. For the example site in Sweden, the network is designed such that important system parameters may be accurately estimated at the same time as model discrimination is carried out.

Hydrogeology Journal↗
USGS2007

Head-bobbing behavior in walking whooping cranes ( Grus americana ) and sandhill cranes ( Grus canadensis )

Head-bobbing is a common and characteristic behavior of walking birds. While the activity could have a relatively minor biomechanical function, for balance and stabilization of gait, head-bobbing is thought to be primarily a visual behavior in which fixation of gaze alternates with a forward movement that generates visual flow. We studied head-bobbing in locomoting whooping cranes ( Grus americana ) and sandhill cranes ( Grus canadensis ), using food strewn on the ground to motivate them to walk or run. When the cranes walked, head-bobbing proceeded in a four-step sequence that was closely linked to the stepping cycle. The time available for gaze stabilization decreased with travel speed, and running cranes did not head-bob at all. As a crane extended its bill towards the ground for food, it also exhibited a series of short head-bobs that were not associated with forward travel. Head-bobbing is a flexible behavior that varies with gait and with visual search, most notably as the cranes prepare to strike with the bill.

Journal of Ornithology↗
USGS2021

Growth inhibition of the harmful alga Prymnesium parvum by plant-derived products and identification of ellipticine as highly potent allelochemical

Prymnesium parvum is a toxin-producing harmful alga that has caused ecological and economic damage worldwide. Effective methods to control blooms of this species in the field, however, are unavailable. This study examined five natural compounds present in the invasive plant Arundo donax and one synthetic derivative (5,6-dichlorogramine) for their effect on P. parvum growth. All compounds except one inhibited growth in the following order of potency: ellipticine > > 5,6-dichlorogramine > 1 H-indole = 2,4,6-trimethyl-benzonitrile > gramine. Ellipticine was by far the most potent inhibitor, with full algicidal activity at concentrations as low as 0.04 mg L −1 and 3- and 9-day IC 50 values of 0.012 and 0.007 mg L −1 , respectively. A reduction in chlorophyll content and swimming activity and an increase in length and volume (swelling) were documented in algal cells exposed to 0.01–0.02 mg ellipticine L −1 . These results show that ellipticine is among the most potent natural algicides identified to date. The sixth compound tested, oleamide, unexpectedly stimulated algal growth above control levels. Overall, these observations confirm the existence of highly potent anti- P. parvum allelochemicals in giant reed and demonstrate potential for using products derived from this plant in the development of natural, environmentally friendly methods to control harmful algal blooms.

Journal of Applied Phycology↗
USGS2010

Direct and indirect responses of tallgrass prairie butterflies to prescribed burning

Fire is an important tool in the conservation and restoration of tallgrass prairie ecosystems. We investigated how both the vegetation composition and butterfly community of tallgrass prairie remnants changed in relation to the elapsed time (in months) since prescribed fire. Butterfly richness and butterfly abundance were positively correlated with the time since burn. Habitat-specialist butterfly richness recovery time was greater than 70 months post-fire and habitat-specialist butterfly abundance recovery time was approximately 50 months post-fire. Thus, recovery times for butterfly populations after prescribed fires in our study were potentially longer than those previously reported. We used Path Analysis to evaluate the relative contributions of the direct effect of time since fire and the indirect effects of time since fire through changes in vegetation composition on butterfly abundance. Path models highlighted the importance of the indirect effects of fire on habitat features, such as increases in the cover of bare ground. Because fire return intervals on managed prairie remnants are often less than 5 years, information on recovery times for habitat-specialist insect species are of great importance. ?? 2010 Springer Science+Business Media B.V.

Journal of Insect Conservation↗
USGS2014

Uncertainty estimates in broadband seismometer sensitivities using microseisms

The midband sensitivity of a seismic instrument is one of the fundamental parameters used in published station metadata. Any errors in this value can compromise amplitude estimates in otherwise high-quality data. To estimate an upper bound in the uncertainty of the midband sensitivity for modern broadband instruments, we compare daily microseism (4- to 8-s period) amplitude ratios between the vertical components of colocated broadband sensors across the IRIS/USGS (network code IU) seismic network. We find that the mean of the 145,972 daily ratios used between 2002 and 2013 is 0.9895 with a standard deviation of 0.0231. This suggests that the ratio between instruments shows a small bias and considerable scatter. We also find that these ratios follow a standard normal distribution ( R 2  = 0.95442), which suggests that the midband sensitivity of an instrument has an error of no greater than ±6 % with a 99 % confidence interval. This gives an upper bound on the precision to which we know the sensitivity of a fielded instrument.

Journal of Seismology↗