Basal-topographic control of stationary ponds on a continuously moving landslide
J. A. Coe, J.P. McKenna, J. W. Godt, R.L. Baum
2009, Earth Surface Processes and Landforms (34) 264-279
The Slumgullion landslide in the San Juan Mountains of southwestern Colorado has been moving for at least the last few hundred years and has multiple ponds on its surface. We have studied eight ponds during 30 trips to the landslide between July 1998 and July 2007. During each trip, we...
Intercomparison, interpretation, and assessment of spring phenology in North America estimated from remote sensing for 1982-2006
M.A. White, K. M. de Beurs, K. Didan, D.W. Inouye, A.D. Richardson, O.P. Jensen, J. O'Keefe, G. Zhang, R.R. Nemani, Leeuwen W.J.D. van W.J.D., Jesslyn F. Brown, A. de Wit, M. Schaepman, X. Lin, M. Dettinger, A.S. Bailey, J. Kimball, M.D. Schwartz, D. D. Baldocchi, J.T. Lee, W.K. Lauenroth
2009, Global Change Biology (15) 2335-2359
Shifts in the timing of spring phenology are a central feature of global change research. Long-term observations of plant phenology have been used to track vegetation responses to climate variability but are often limited to particular species and locations and may not represent synoptic patterns. Satellite remote sensing is instead...
Gold and trace element zonation in pyrite using a laser imaging technique: Implications for the timing of gold in orogenic and carlin-style sediment-hosted deposits
R.R. Large, L. Danyushevsky, C. Hollit, V. Maslennikov, S. Meffre, S. Gilbert, S. Bull, R. Scott, P. Emsbo, H. Thomas, B. Singh, J. Foster
2009, Economic Geology (104) 635-668
Laser ablation ICP-MS imaging of gold and other trace elements in pyrite from four different sediment- hosted gold-arsenic deposits has revealed two distinct episodes of gold enrichment in each deposit: an early synsedimentary stage where invisible gold is concentrated in arsenian diagenetic pyrite along with other trace elements, in particular,...
Developing collaborative classifiers using an expert-based model
G. Mountrakis, R. Watts, L. Luo, Jingyuan Wang
2009, Photogrammetric Engineering and Remote Sensing (75) 831-843
This paper presents a hierarchical, multi-stage adaptive strategy for image classification. We iteratively apply various classification methods (e.g., decision trees, neural networks), identify regions of parametric and geographic space where accuracy is low, and in these regions, test and apply alternate methods repeating the process until the entire image is...
A grid-doubling finite-element technique for calculating dynamic three-dimensional spontaneous rupture on an earthquake fault
Michael Barall
2009, Geophysical Journal International (178) 845-859
We present a new finite-element technique for calculating dynamic 3-D spontaneous rupture on an earthquake fault, which can reduce the required computational resources by a factor of six or more, without loss of accuracy. The grid-doubling technique employs small cells in a thin layer surrounding the fault. The remainder of...
Interactive effects of fire, soil climate, and moss on CO2 fluxes in black spruce ecosystems of interior Alaska
J. A. O'Donnell, M.R. Turetsky, J.W. Harden, K.L. Manies, L.E. Pruett, G. Shetler, J. C. Neff
2009, Ecosystems (12) 57-72
Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana) ecosystems of...
Factors influencing densities of non-indigenous species in the ballast water of ships arriving at ports in Puget Sound, Washington, United States
J.R. Cordell, D. J. Lawrence, N.C. Ferm, L.M. Tear, S.S. Smith, R.P. Herwig
2009, Aquatic Conservation: Marine and Freshwater Ecosystems (19) 322-343
Oceanographic characteristics and the presence of international shipping in Puget Sound, Washington, USA contribute to its vulnerability to non-indigenous species (NIS) invasions. To evaluate NIS arriving in ballast water, zooplankton was sampled in 380 ballast tanks of ships after they entered Puget Sound. Taxa were classified into a higher risk...
Modeling haul-out behavior of walruses in Bering Sea ice
Mark S. Udevitz, Chadwick V. Jay, Anthony S. Fischbach, J. L. Garlich-Miller
2009, Canadian Journal of Zoology (87) 1111-1128
Understanding haul-out behavior of ice-associated pinnipeds is essential for designing and interpreting popula-tion surveys and for assessing effects of potential changes in their ice environments. We used satellite-linked transmitters to obtain sequential information about location and haul-out state for Pacific walruses, Odobenus rosmarus divergens (Il-liger, 1815), in the Bering Sea...
Climate alters response of an endemic island plant to removal of invasive herbivores
Mceachern A. Kathryn, D.M. Thomson, K.A. Chess
2009, Ecological Applications (19) 1574-1584
Islands experience higher rates of species extinction than mainland ecosystems, with biological invasions among the leading causes; they also serve as important model systems for testing ideas in basic and applied ecology. Invasive removal programs on islands are conservation efforts that can also be viewed as powerful manipulative experiments, but...
Surface complexation modeling of U(VI) adsorption by aquifer sediments from a former mill tailings site at Rifle, Colorado
S.P. Hyun, P.M. Fox, J.A. Davis, K.M. Campbell, K.F. Hayes, P.E. Long
2009, Environmental Science & Technology (43) 9368-9373
A study of U(VI) adsorption by aquifer sediment samples from a former uranium mill tailings site at Rifle, Colorado, was conducted under oxic conditions as a function of pH, U(VI), Ca, and dissolved carbonate concentration. Batch adsorption experiments were performed using <2mm size sediment fractions, a sand-sized fraction, and artificial...
Integration of MODIS-derived metrics to assess interannual variability in snowpack, lake ice, and NDVI in southwest Alaska
Bradley C. Reed, Michael E. Budde, Page Spencer, Amy E. Miller
2009, Remote Sensing of Environment (113) 1443-1452
Impacts of global climate change are expected to result in greater variation in the seasonality of snowpack, lake ice, and vegetation dynamics in southwest Alaska. All have wide-reaching physical and biological ecosystem effects in the region. We used Moderate Resolution Imaging Spectroradiometer (MODIS) calibrated radiance, snow cover extent, and vegetation...
A simulation of historic hydrology and salinity in Everglades National Park: Coupling paleoecologic assemblage data with regression models
Frank E. Marshall, G. Lynn Wingard, Patrick A. Pitts
2009, Estuaries and Coasts (32) 37-53
Restoration of Florida’s Everglades requires scientifically supportable hydrologic targets. This study establishes a restoration baseline by developing a method to simulate hydrologic and salinity conditions prior to anthropogenic changes. The method couples paleoecologic data on long-term historic ecosystem conditions with statistical models derived from observed meteorologic and hydrologic data that...
U.S. Geological Survey research in Handcart Gulch, Colorado—An alpine watershed with natural acid-rock drainage
Andrew H. Manning, Jonathan S. Caine, Philip L. Verplanck, Dana J. Bove, Katherine G. Kahn
2009, Conference Paper, Planning for an uncertain future - Monitoring, integration, and adaptation (SIR 2009-5049)
Handcart Gulch is an alpine watershed along the Continental Divide in the Colorado Rocky Mountain Front Range. It contains an unmined mineral deposit typical of many hydrothermal mineral deposits in the intermountain west, composed primarily of pyrite with trace metals including copper and molybdenum. Springs and the trunk stream have...
Climatic effects of 30 years of landscape change over the Greater Phoenix, Arizona, region: 1. Surface energy budget changes
M. Georgescu, G. Miguez-Macho, L. T. Steyaert, C.P. Weaver
2009, Journal of Geophysical Research D: Atmospheres (114)
This paper is part 1 of a two-part study that evaluates the climatic effects of recent landscape change for one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, Arizona, region. The region's landscape evolution over an approximate 30-year period since the early 1970s is documented on the...
Effects of simplifying fracture network representation on inert chemical migration in fracture-controlled aquifers
Tristan Wellman, Allen M. Shapiro, Mary C. Hill
2009, Water Resources Research (45)
[1] While it is widely recognized that highly permeable ‘large‐scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive ‘small‐scale’ fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes....
Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake
R. O. Hall Jr., J. L. Tank, D. J. Sobota, P. J. Mulholland, J. M. O’Brien, W. K. Dodds, J.R. Webster, H. M. Valett, G. C. Poole, B. J. Peterson, J.L. Meyer, W. H. McDowell, S. L. Johnson, S. K. Hamilton, N. B. Grimm, S.V. Gregory, Clifford N. Dahm, L. W. Cooper, L. R. Ashkenas, S. M. Thomas, R.W. Sheibley, J. D. Potter, B.R. Niederlehner, L. T. Johnson, A. M. Helton, C.M. Crenshaw, A. J. Burgin, M. J. Bernot, J. J. Beaulieu, C.P. Arangob
2009, Limnology and Oceanography (54) 653-665
We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural...
A combined telemetry - tag return approach to estimate fishing and natural mortality rates of an estuarine fish
N.M. Bacheler, J.A. Buckel, J.E. Hightower, L.M. Paramore, K. H. Pollock
2009, Canadian Journal of Fisheries and Aquatic Sciences (66) 1230-1244
A joint analysis of tag return and telemetry data should improve estimates of mortality rates for exploited fishes; however, the combined approach has thus far only been tested in terrestrial systems. We tagged subadult red drum (Sciaenops ocellatus) with conventional tags and ultrasonic transmitters over 3 years in coastal North...
Scaling the effects of moose browsing on forage distribution, from the geometry of plant canopies to landscapes
N. R. De Jager, J. Pastor, A.L. Hodgson
2009, Ecological Monographs (79) 281-297
Landscape heterogeneity influences large herbivores by altering their feeding rates, but as herbivores attempt to maximize feeding rates they also create spatial heterogeneity by altering plant growth. Herbivore feeding rates thus provide a quantitative link between the causes and consequences of spatial heterogeneity in herbivore-dominated ecosystems. The fractal geometry of...
Habitat-specific breeder survival of Florida Scrub-Jays: Inferences from multistate models
D.R. Breininger, J.D. Nichols, G.M. Carter, D.M. Oddy
2009, Ecology (90) 3180-3189
Quantifying habitat-specific survival and changes in habitat quality within disturbance-prone habitats is critical for understanding population dynamics and variation in fitness, and for managing degraded ecosystems. We used 18 years of color-banding data and multistate capture-recapture models to test whether habitat quality within territories influences survival and detection probability of...
Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts
R.B. Chandler, D.I. King, S. DeStefano
2009, The Auk (126) 186-197
Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter “beaver”) populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities....
Detecting declines in the abundance of a bull trout (Salvelinus confluentus) population: Understanding the accuracy, precision, and costs of our efforts
R. Al-Chokhachy, P. Budy, M. Conner
2009, Canadian Journal of Fisheries and Aquatic Sciences (66) 649-658
Using empirical field data for bull trout (Salvelinus confluentus), we evaluated the trade-off between power and sampling effort-cost using Monte Carlo simulations of commonly collected mark-recapture-resight and count data, and we estimated the power to detect changes in abundance across different time intervals. We also evaluated the effects of monitoring...
Feature pruning by upstream drainage area to support automated generalization of the United States National Hydrography Dataset
L.V. Stanislawski
2009, Computers, Environment and Urban Systems (33) 325-333
The United States Geological Survey has been researching generalization approaches to enable multiple-scale display and delivery of geographic data. This paper presents automated methods to prune network and polygon features of the United States high-resolution National Hydrography Dataset (NHD) to lower resolutions. Feature-pruning rules, data enrichment, and partitioning are derived...
Comparing stochastic point-source and finite-source ground-motion simulations: SMSIM and EXSIM
D.M. Boore
2009, Bulletin of the Seismological Society of America (99) 3202-3216
Comparisons of ground motions from two widely used point-source and finite-source ground-motion simulation programs (SMSIM and EXSIM) show that the following simple modifications in EXSIM will produce agreement in the motions from a small earthquake at a large distance for the two programs: (1) base the scaling of high frequencies...
Effect of time dependence on probabilistic seismic-hazard maps and deaggregation for the central Apennines, Italy
A. Akinci, F. Galadini, D. Pantosti, Mark D. Petersen, L. Malagnini, D. Perkins
2009, Bulletin of the Seismological Society of America (99) 585-610
We produce probabilistic seismic-hazard assessments for the central Apennines, Italy, using time-dependent models that are characterized using a Brownian passage time recurrence model. Using aperiodicity parameters, ?? of 0.3, 0.5, and 0.7, we examine the sensitivity of the probabilistic ground motion and its deaggregation to these parameters. For the seismic...
Anatomy of the dead sea transform from lithospheric to microscopic scale
M. Weber, K. Abu-Ayyash, A. Abueladas, A. Agnon, Z. Alasonati-Tasarova, H. Al-Zubi, A. Babeyko, Y. Bartov, K. Bauer, M. Becken, P. A. Bedrosian, Z. Ben-Avraham, G. Bock, M. Bohnhoff, J. Bribach, P. Dulski, J. Ebbing, R. El-Kelani, A. Forster, H.-J. Forster, U. Frieslander, Z. Garfunkel, H.J. Goetze, V. Haak, C. Haberland, M. Hassouneh, S. Helwig, A. Hofstetter, A. Hoffmann-Rotrie, K.H. Jackel, C. Janssen, D. Jaser, D. Kesten, M. Khatib, R. Kind, O. Koch, I. Koulakov, Gabi Laske, N. Maercklin, R. Masarweh, A. Masri, A. Matar, J. Mechie, N. Meqbel, B. Plessen, P. Moller, A. Mohsen, R. Oberhansli, S. Oreshin, A. Petrunin, I. Qabbani, I. Rabba, O. Ritter, R.L. Romer, G. Rumpker, M. Rybakov, T. Ryberg, J. Saul, F. Scherbaum, S. Schmidt, A. Schulze, S.V. Sobolev, M. Stiller, D. Stromeyer, K. Tarawneh, C. Trela, U. Weckmann, U. Wetzel, K. Wylegalla
2009, Reviews of Geophysics (47)
Fault zones are the locations where motion of tectonic plates, often associated with earthquakes, is accommodated. Despite a rapid increase in the understanding of faults in the last decades, our knowledge of their geometry, petrophysical properties, and controlling processes remains incomplete. The central questions addressed here in our study of...
