Human influence on California fire regimes
A.D. Syphard, V. C. Radeloff, Jon E. Keeley, T. J. Hawbaker, M.K. Clayton, S. I. Stewart, R. B. Hammer
2007, Ecological Applications (17) 1388-1402
Periodic wildfire maintains the integrity and species composition of many ecosystems, including the mediterranean-climate shrublands of California. However, human activities alter natural fire regimes, which can lead to cascading ecological effects. Increased human ignitions at the wildland-urban interface (WUI) have recently gained attention, but fire activity and risk are typically...
Modeling grain size variations of aeolian gypsum deposits at White Sands, New Mexico, using AVIRIS imagery
H.A. Ghrefat, P.C. Goodell, B.E. Hubbard, R.P. Langford, R.E. Aldouri
2007, Geomorphology (88) 57-68
Visible and Near-Infrared (VNIR) through Short Wavelength Infrared (SWIR) (0.4-2.5????m) AVIRIS data, along with laboratory spectral measurements and analyses of field samples, were used to characterize grain size variations in aeolian gypsum deposits across barchan-transverse, parabolic, and barchan dunes at White Sands, New Mexico, USA. All field samples contained a...
Concentration, UV-spectroscopic characteristics and fractionation of DOC in stormflow from an urban stream, Southern California, USA
John A. Izbicki, Isabel Pimentel, Russell Johnson, George R. Aiken, Jerry Leenheer
2007, Environmental Chemistry (4) 35-48
The composition of dissolved organic carbon (DOC) in stormflow from urban areas has been greatly altered, both directly and indirectly, by human activities and there is concern that there may be public health issues associated with DOC, which has unknown composition from different sources within urban watersheds. This...
Sandhill crane abundance and nesting ecology at Grays Lake, Idaho
J. E. Austin, A.R. Henry, I.J. Ball
2007, Journal of Wildlife Management (71) 1067-1079
We examined population size and factors influencing nest survival of greater sandhill cranes (Grus canadensis tabida) at Grays Lake National Wildlife Refuge, Idaho, USA, during 1997-2000. Average local population of cranes from late April to early May, 1998-2000, was 735 cranes, 34% higher than that reported for May 1970-1971. We...
Biodegradation of organic chemicals in soil/water microcosms system: Model development
L. Liu, J.A. Tindall, M.J. Friedel, W. Zhang
2007, Water, Air, & Soil Pollution (178) 131-143
The chemical interactions of hydrophobic organic contaminants with soils and sediments may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints. In order to illustrate the recalcitrance of chemical to degradation on sites, a sorption mechanism of intraparticle sequestration was postulated to operate...
Brown-headed cowbird, Molothrus ater, parasitism and abundance in the northern Great Plains
L.D. Igl, Douglas H. Johnson
2007, Canadian Field-Naturalist (121) 239-255
The Brown-headed Cowbird (Molothrus ater) reaches its highest abundance in the northern Great Plains, but much of our understanding of cowbird ecology and host-parasite interactions comes from areas outside of this region. We examine cowbird brood parasitism and densities during two studies of breeding birds in the northern Great Plains...
Relationships between reef fish communities and remotely sensed rugosity measurements in Biscayne National Park, Florida, USA
Ilsa B. Kuffner, John Brock, Rikki Grober-Dunsmore, Victor E. Bonito, T. Donald Hickey, C. Wayne Wright
2007, Environmental Biology of Fishes (78) 71-82
The realization that coral reef ecosystem management must occur across multiple spatial scales and habitat types has led scientists and resource managers to seek variables that are easily measured over large areas and correlate well with reef resources. Here we investigate the utility of new technology in airborne laser surveying...
Physically based estimation of soil water retention from textural data: General framework, new models, and streamlined existing models
John R. Nimmo, William N. Herkelrath, Luna Laguna
2007, Vadose Zone Journal (6) 766-773
Numerous models are in widespread use for the estimation of soil water retention from more easily measured textural data. Improved models are needed for better prediction and wider applicability. We developed a basic framework from which new and existing models can be derived to facilitate improvements. Starting from the assumption...
Effects of earlier sea ice breakup on survival and population size of polar bears in western Hudson Bay
E.V. Regehr, N.J. Lunn, Steven C. Amstrup, I. Stirling
2007, Journal of Wildlife Management (71) 2673-2683
Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult...
In situ time-series measurements of subseafloor sediment properties
R. A. Wheatcroft, A.W. Stevens, R.V. Johnson
2007, IEEE Journal of Oceanic Engineering (32) 862-871
The capabilities and diversity of subsurface sediment sensors lags significantly from what is available for the water column, thereby limiting progress in understanding time-dependent seabed exchange and high-frequency acoustics. To help redress this imbalance, a new instrument, the autonomous sediment profiler (ASP), is described herein....
Geology of the Yucca Mountain site area, southwestern Nevada
W. R. Keefer, J.W. Whitney, D.C. Buesch
2007, Memoir of the Geological Society of America (199) 53-103
Yucca Mountain in southwestern Nevada is a prominent, irregularly shaped upland formed by a thick apron of Miocene pyroclastic-flow and fallout tephra deposits, with minor lava flows, that was segmented by through-going, large-displacement normal faults into a series of north-trending, eastwardly tilted structural blocks. The principal volcanic-rock units are the...
Putting it all together: Exhumation histories from a formal combination of heat flow and a suite of thermochronometers
M. A. d'Alessio, C.F. Williams
2007, Journal of Geophysical Research B: Solid Earth (112)
A suite of new techniques in thermochronometry allow analysis of the thermal history of a sample over a broad range of temperature sensitivities. New analysis tools must be developed that fully and formally integrate these techniques, allowing a single geologic interpretation of the rate and timing of exhumation and burial...
Larval feeding behavior and ant association in frosted elfin, Callophrys irus (Lycaenidae)
G. Albanese, M.W. Nelson, P.D. Vickery, P.R. Sievert
2007, Journal of the Lepidopterists' Society (61) 61-66
Callophrys irus is a rare and declining lycaenid found in the eastern U.S., inhabiting xeric and open habitats maintained by disturbance. Populations are localized and monophagous. We document a previously undescribed larval feeding behavior in both field and lab reared larvae in which late instar larvae girdled the main stem...
Fatty acid signatures of stomach oil and adipose tissue of northern fulmars (Fulmarus glacialis) in Alaska: Implications for diet analysis of Procellariiform birds
S.W. Wang, S.J. Iverson, A.M. Springer, Scott A. Hatch
2007, Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology (177) 893-903
Procellariiforms are unique among seabirds in storing dietary lipids in both adipose tissue and stomach oil. Thus, both lipid sources are potentially useful for trophic studies using fatty acid (FA) signatures. However, little is known about the relationship between FA signatures in stomach oil and adipose tissue of individuals or...
Movement patterns of armado, Pterodoras granulosus, in the Paraná River Basin
M.C. Makrakis, L.E. Miranda, S. Makrakis, D.R. Fernandez, J.O. Garcia, J.H.P. Dias
2007, Ecology of Freshwater Fish (16) 410-416
We studied the migratory behaviour of armado, Pterodoras granulosus, in the Paraná River Basin of Brazil, Paraguay and Argentina, during 1997–2005. This species invaded the Upper Paraná River after upstream dispersal was facilitated when Itaipu Reservoir inundated a natural barrier. Fish were tagged (N = 8051) in the mainstems of the Yacyreta and...
Influence of in-stream diel concentration cycles of dissolved trace metals on acute toxicity to one-year-old cutthroat trout (Oncorhynchus clarki lewisi)
David A. Nimick, David D. Harper, Aida Farag, Tom Cleasby, Elizabeth MacConnell, D. Skaar
2007, Environmental Toxicology and Chemistry (26) 2667-2678
Extrapolating results of laboratory bioassays to streams is difficult, because conditions such as temperature and dissolved metal concentrations can change substantially on diel time scales. Field bioassays conducted for 96 h in two mining‐affected streams compared the survival of hatchery‐raised, metal‐näive westslope cutthroat trout (Oncorhynchus clarki lewisi) exposed to dissolved...
Hazard assessment of the Tidal Inlet landslide and potential subsequent tsunami, Glacier Bay National Park, Alaska
G. F. Wieczorek, E.L. Geist, R.J. Motyka, M. Jakob
2007, Landslides (4) 205-215
An unstable rock slump, estimated at 5 to 10 × 106 m3, lies perched above the northern shore of Tidal Inlet in Glacier Bay National Park, Alaska. This landslide mass has the potential to rapidly move into Tidal Inlet and generate large, long-period-impulse tsunami waves. Field and photographic examination...
The USGS national geothermal resource assessment: An update
C.F. Williams, M.J. Reed, S.P. Galanis Jr., J. DeAngelo
2007, Conference Paper, Transactions - Geothermal Resources Council
The U. S. Geological Survey (USGS) is working with the Department of Energy's (DOE) Geothermal Technologies Program and other geothermal organizations on a three-year effort to produce an updated assessment of available geothermal resources. The new assessment will introduce significant changes in the models for geothermal energy recovery factors, estimates...
Influence of groundwater pumping on streamflow restoration following upstream dam removal
James E. Constantz, Hedeff I. Essaid
2007, Hydrological Processes (21) 2823-2834
We compared streamflow in basins under the combined impacts of an upland dam and groundwater pumping withdrawals, by examining streamflow in the presence and absence of each impact. As a qualitative analysis, inter-watershed streamflow comparisons were performed for several rivers flowing into the east side...
A critical assessment of the Burning Index in Los Angeles County, California
F.P. Schoenberg, H.-C. Chang, Jon E. Keeley, J. Pompa, J. Woods, H. Xu
2007, International Journal of Wildland Fire (16) 473-483
The Burning Index (BI) is commonly used as a predictor of wildfire activity. An examination of data on the BI and wildfires in Los Angeles County, California, from January 1976 to December 2000 reveals that although the BI is positively associated with wildfire occurrence, its predictive value is quite limited....
The case for infrasound as the long-range map cue in avian navigation
J.T. Hagstrum
2007, Conference Paper, Proceedings of the Annual Meeting - Institute of Navigation
Of the various 'map' and 'compass' components of Kramer's avian navigational model, the long-range map component is the least well understood. In this paper atmospheric infrasounds are proposed as the elusive longrange cues constituting the avian navigational map. Although infrasounds were considered a viable candidate for the avian map in...
Genetic analysis confirms first record of polygyny in Cooper's Hawks
Robert N. Rosenfield, Timothy G. Driscoll, R.P. Franckowiak, Laura J. Rosenfield, Brian L. Sloss, Michael A. Bozek
2007, Journal of Raptor Research (41) 230-234
[No abstract available]...
Regional disconformities in Turonian and Coniacian (Upper Cretaceous) strata in Colorado, Wyoming, and adjoining states - Biochronological evidence
E. Allen Merewether, William A. Cobban, John D. Obradovich
2007, Rocky Mountain Geology (42) 95-122
Siliciclastic and calcareous sedimentary rocks of early Late Cretaceous age in the Western Interior of the United States have been assigned to, in ascending order, the Graneros Shale, Greenhorn Formation, Carlile Shale, Niobrara Formation, and their lateral equivalents (including members of the Frontier Formation and overlying formations). This sequence of...
THEMIS observes possible cave skylights on Mars
Glen Cushing, Timothy N. Titus, J. Judson Wynne, P. R. Christensen
2007, Geophysical Research Letters (34)
Seven possible skylight entrances into Martian caves were observed on and around the flanks of Arsia Mons by the Mars Odyssey Thermal Emission Imaging System (THEMIS). Distinct from impact craters, collapse pits or any other surface feature on Mars, these candidates appear to be deep dark holes at visible wavelengths...
Ground motion issues for seismic analysis of tall buildings: A status report
Y. Bozorgnia, K.W. Campbell, N. Luco, J.P. Moehle, F. Naeim, P. Somerville, T.Y. Yang
2007, Structural Design of Tall and Special Buildings (16) 665-674
The Pacific Earthquake Engineering Research Center (PEER) is coordinating a major multidisciplinary programme, the Tall Buildings Initiative (TBI), to address critical technical issues related to the design and analysis of new tall buildings located in coastal California. The authors of this paper, listed alphabetically, are involved in various research studies...
