Stochastic Ground Water Flow Simulation with a Fracture Zone Continuum Model
C.D. Langevin
2003, Ground Water (41) 587-601
A method is presented for incorporating the hydraulic effects of vertical fracture zones into two-dimensional cell-based continuum models of ground water flow and particle tracking. High hydraulic conductivity features are used in the model to represent fracture zones. For fracture zones that are not coincident with model rows or columns,...
Statistical sampling to characterize recent United States land-cover change
S.V. Stehman, Terry L. Sohl, Thomas R. Loveland
2003, Remote Sensing of Environment (86) 517-529
The U.S. Geological Survey, in conjunction with the U.S. Environmental Protection Agency, is conducting a study focused on developing methods for estimating changes in land-cover and landscape pattern for the conterminous United States from 1973 to 2000. Eleven land-cover and land-use classes are interpreted from Landsat imagery for five sampling...
Catastrophic rock-ice collapse and rapid shove of the Kukurtli glacier (Elbrus Volcano, Northern Caucasus) in first and second centuries
O.A. Bogatikov, I.V. Melekestsev, D.K. Miller, A.G. Gurbanov, P. W. Lipman, J.B. Lovenstern, L.D. Sulerzhitskii, A.V. Shevchenko
2003, Doklady Earth Sciences (391) 627-630
No abstract available....
Oxygen isotopes in nitrate: New reference materials for 18O:17O:16O measurements and observations on nitrate-water equilibration
J.K. Böhlke, S.J. Mroczkowski, T.B. Coplen
2003, Rapid Communications in Mass Spectrometry (17) 1835-1846
Despite a rapidly growing literature on analytical methods and field applications of O isotope-ratio measurements of NO3− in environmental studies, there is evidence that the reported data may not be comparable because reference materials with widely varying δ18O values have not been readily available. To address this problem, we prepared...
Causes of hot-spot wetland loss in the Mississippi delta plain
R.A. Morton, G. Tiling, N.F. Ferina
2003, Environmental Geosciences (10) 71-80
Field surveys and sediment cores were used to estimate marsh erosion and land subsidence at Madison Bay, a well-known wetland loss hot spot in coastal Louisiana. Former marshes of Madison Bay are under about 1 m of water. Nearly two-thirds of the permanent flooding was caused by rapid subsidence...
Studies of the environmental fate and effect of aircraft deicing fluids: Detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas)
Devon A. Cancilla, J.C. Baird, S.W. Geis, Steven R. Corsi
2003, Environmental Toxicology and Chemistry (22) 134-140
This paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent...
Sand ridges off Sarasota, Florida: A complex facies boundary on a low-energy inner shelf environment
D. Twichell, Gillian L. Brooks, G. Gelfenbaum, V. Paskevich, Brian Donahue
2003, Marine Geology (200) 243-262
The innermost shelf off Sarasota, Florida was mapped using sidescan-sonar imagery, seismic-reflection profiles, surface sediment samples, and short cores to define the transition between an onshore siliciclastic sand province and an offshore carbonate province and to identify the processes controlling the distribution of these distinctive facies. The transition between these...
Annual survival and population estimates of Mountain Plovers in Southern Phillips County, Montana
S.J. Dinsmore, Gary C. White, F.L. Knopf
2003, Ecological Applications (13) 1013-1026
Information about the demography of declining species is especially relevant to their conservation and future recovery. Knowledge of survival rates and population size can be used to assess long-term viability and population trends, both of which are of interest to conservation biologists. We used capture–recapture techniques to study the demography...
Beaver (Castor canadensis) in heavily browsed environments
Bruce W. Baker
2003, Lutra (46) 173-181
Beaver (Castor canadensis) populations have declined or failed to recover in heavily browsed environments. I suggest that intense browsing by livestock or ungulates can disrupt beaver-willow (Salix spp.) mutualisms that likely evolved under relatively low herbivory in a more predator-rich environment, and that this interaction may explain beaver and willow...
The rich get richer: Patterns of plant invasions in the United States
T.J. Stohlgren, D.T. Barnett, J.T. Kartesz
2003, Frontiers in Ecology and the Environment (1) 11-14
Observations from islands, small-scale experiments, and mathematical models have generally supported the paradigm that habitats of low plant diversity are more vulnerable to plant invasions than areas of high plant diversity. We summarize two independent data sets to show exactly the opposite pattern at multiple spatial scales. More significant, and...
Isotopic study of sulfate sources and residence times in a subalpine watershed
C.L. Kester, Jill Baron, J.T. Turk
2003, Environmental Geology (43) 606-613
Stable sulfur and oxygen isotope ratios and naturally occurring 35SSO4 activities were used to examine sulfate sources, address the role of sulfur dynamics, and estimate residence times of atmospherically derived sulfate in Loch Vale Watershed, Colorado. In 1996, surface water samples from small streams flowing through talus, forest, and wetland...
Isolation and characterization of microsatellite loci in Greater Sage-Grouse (Centlocerus urophasianus)
S.E. Taylor, S.J. Oyler-McCance, T.W. Quinn
2003, Molecular Ecology Notes (3) 262-264
Primers for five polymorphic microsatellite loci were developed for Greater Sage-Grouse (Centrocercus urophasianus) using an enrichment/detection protocol. The high level of polymorphism (nine to 33 alleles) suggests that these loci will be applicable for investigating mating systems and paternity analysis as well as population genetics. Cross-species amplification was successful for...
Monitoring the shorebirds of North America: Towards a unified approach
S. K. Skagen, J. Bart, B. Andres, S. Brown, G. Donaldson, B. Harrington, V. Johnston, S.L. Jones, R. I. G. Morrison
2003, Wader Study Group Bulletin (100) 102-104
The Program for Regional and International Shorebird Monitoring (PRISM) has recently developed a single blueprint for monitoring shorebirds in Canada and the United States in response to needs identified by recent shorebird conservation plans. The goals of PRISM are to: (1) estimate the size of breeding populations of 74 shorebird...
Do ungulates accelerate or decelerate nitrogen cycling?
F. J. Singer, K.A. Schoenecker
2003, Forest Ecology and Management (181) 189-204
Nitrogen (N) is an essential nutrient for plants and animals, and N may be limiting in many western US grassland and shrubland ungulate winter ranges. Ungulates may influence N pools and they may alter N inputs and outputs (losses) to the ecosystem in a number of ways. In this paper...
Biology, ecology and management of Elaeagnus angustifolia L. (Russian olive) in western North America
G.L. Katz, P.B. Shafroth
2003, Wetlands (23) 763-777
Elaeagnus angustifolia (Russian olive) is an alien tree that is increasingly common in riparian habitats of western North America. This paper reviews the pertinent scientific literature in order to determine the status of E. angustifolia as a riparian invader and to suggest ecological reasons for its success. Elaeagnus angustifolia meets...
Recent ecological and biogeochemical changes in alpine lakes of Rocky Mountain National Park (Colorado, USA): A response to anthropogenic nitrogen deposition
A.P. Wolfe, A.C. Van Gorp, Jill Baron
2003, Geobiology (1) 153-168
Dated sediment cores from five alpine lakes (>3200 m asl) in Rocky Mountain National Park (Colorado Front Range, USA) record near-synchronous stratigraphic changes that are believed to reflect ecological and biogeochemical responses to enhanced nitrogen deposition from anthropogenic sources. Changes in sediment proxies include progressive increases in the frequencies of mesotrophic...
Isotope variations in white-tailed kites from various habitats in California: Possible limitations in assessing prey utilization and population dynamics
W.M. Iko, C.L. Kester, C.R. Bern, Rey C. Stendell, R. O. Rye
2003, Isotopes in Environmental and Health Studies (39) 159-167
White-tailed kite (Elanus leucurus) populations in the 1930s were close to extirpation in the United States. But by the 1940s, an upward trend towards recovery was apparent and continued to their current stable population levels. These dramatic fluctuations in kite numbers may have been related to changes in rodent prey...
The high-elevation population of Mountain Plovers in Colorado
Michael B. Wunder, F.L. Knopf, C.A. Pague
2003, The Condor (105) 654-662
We surveyed a discrete population of Mountain Plovers (Charadrius montanus) in South Park, Park County, Colorado, to determine the size and relative contribution of this geographically isolated area to the global population of plovers. First, we mapped potential plover habitat within South Park based on landform and vegetation descriptors. Second,...
Relating geomorphic change and grazing to avian communities in riparian forests
M. L. Scott, S. K. Skagen, M.F. Merligliano
2003, Conservation Biology (17) 284-296
Avian conservation in riparian or bottomland forests requires an understanding of the physical and biotic factors that sustain the structural complexity of riparian vegetation. Riparian forests of western North America are dependent upon flow-related geomorphic processes necessary for establishment of new cottonwood and willow patches. In June 1995, we examined...
Immune function and hematology of male cotton rats (Sigmodon hispidus) in response to food supplementation and methionine
R.E. Webb, David M. Leslie Jr., R.L. Lochmiller, R.E. Masters
2003, Comparative Biochemistry and Physiology, Part A: Molecular & Integrative Physiology (136) 577-589
We examined effects of supplementation of food quantity and quality (=enhanced methionine) on hematologic and immunologic parameters of wild, but enclosed, adult male cotton rats (Sigmodon hispidus) in north-central Oklahoma. Sheet metal enclosures were stocked with a high density of wild-caught cotton rats (160 animals/ha) and randomly assigned a treatment...
Modeling tritium transport through a deep unsaturated zone, Amargosa Desert Research Site, Nye County, Nevada
C.J. Mayers
2003, Thesis
No abstract available....
Continuous monitoring of suspended sediment discharge in rivers by use of optical backscatterance sensors
D. H. Schoellhamer, S.A. Wright
2003, Book chapter, Erosion and sediment transport measurement: Technological and methodological advances: International Association for Hydrological Science Publication 283
No abstract available....
A bathymetry system for measuring sediment accumulation in tidal marsh restoration projects
John Y. Takekawa, S. Demers, I. Woo, N.D. Athearn, N. Ganju, G.G. Shellenbarger, D. Schoellhamer, W.M. Perry
2003, Conference Paper, Proceedings of the 6th biennial State-of-the-Estuary Conference
No abstract available....
Sediment dynamics drive contaminant dynamics
David H. Schoellhamer, Gregory Shellenbarger, Neil K. Ganju, Jay A. Davis, Lester J. McKee
2003, Pulse of the Estuary 2003
Many contaminants of greatest concern in San Francisco Bay, including mercury and PCBs, are primarily associated with sediment particles rather than dissolved in water. Therefore, the movement and fate of sediment determines the movement and fate of many contaminants in the Bay. Because of this close association, the RMP monitors...
Gunbarrel mafic magmatic event: A key 780 Ma time marker for Rodinia plate reconstructions
S. S. Harlan, L. Heaman, A.N. LeCheminant, W. R. Premo
2003, Geology (31) 1053-1056
Precise U-Pb baddeleyite dating of mafic igneous rocks provides evidence for a widespread and synchronous magmatic event that extended for >2400 km along the western margin of the Neoproterozoic Laurentian craton. U-Pb baddeleyite analyses for eight intrusions from seven localities ranging from the northern Canadian Shield to northwestern Wyoming-southwestern Montana...
