Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates
John Crusius, Timothy C. Kenna
2007, Estuarine, Coastal and Shelf Science (71) 537-544
Sedimentary records of naturally occurring and fallout-derived radionuclides are widely used as tools for estimating both the ages of recent sediments and rates of sedimentation and bioturbation. Developing these records to the point of data interpretation requires careful sample collection, processing, analysis and data modeling. In this work, we document...
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....
Estimating biomass of submersed vegetation using a simple rake sampling technique
K.P. Kenow, J.E. Lyon, R. K. Hines, A. Elfessi
2007, Hydrobiologia (575) 447-454
We evaluated the use of a simple rake sampling technique for predicting the biomass of submersed aquatic vegetation. Vegetation sampled from impounded areas of the Mississippi River using a rake sampling technique, was compared with vegetation harvested from 0.33-m2 quadrats. The resulting data were used to model the relationship between...
On the choice of statistical models for estimating occurrence and extinction from animal surveys
R.M. Dorazio
2007, Ecology (88) 2773-2782
In surveys of natural animal populations the number of animals that are present and available to be detected at a sample location is often low, resulting in few or no detections. Low detection frequencies are especially common in surveys of imperiled species; however, the choice of sampling method and protocol...
Predicting wetland plant community responses to proposed water-level-regulation plans for Lake Ontario: GIS-based modeling
D.A. Wilcox, Y. Xie
2007, Journal of Great Lakes Research (33) 751-773
Integrated, GIS-based, wetland predictive models were constructed to assist in predicting the responses of wetland plant communities to proposed new water-level regulation plans for Lake Ontario. The modeling exercise consisted of four major components: 1) building individual site wetland geometric models; 2) constructing generalized wetland geometric models representing specific types...
Evaluating planetary digital terrain models-The HRSC DTM test
C. Heipke, J. Oberst, J. Albertz, M. Attwenger, P. Dorninger, E. Dorrer, M. Ewe, S. Gehrke, K. Gwinner, H. Hirschmuller, J.R. Kim, Randolph L. Kirk, H. Mayer, Jan-Peter Muller, R. Rengarajan, M. Rentsch, R. Schmidt, F. Scholten, J. Shan, M. Spiegel, M. Wahlisch, G. Neukum
2007, Planetary and Space Science (55) 2173-2191
The High Resolution Stereo Camera (HRSC) has been orbiting the planet Mars since January 2004 onboard the European Space Agency (ESA) Mars Express mission and delivers imagery which is being used for topographic mapping of the planet. The HRSC team has conducted a systematic inter-comparison of different alternatives for the...
Characterization of post-fire surface cover, soils, and burn severity at the Cerro Grande Fire, New Mexico, using hyperspectral and multispectral remote sensing
R.F. Kokaly, B.W. Rockwell, S.L. Haire, T. V. V. King
2007, Remote Sensing of Environment (106) 305-325
Forest fires leave behind a changed ecosystem with a patchwork of surface cover that includes ash, charred organic matter, soils and soil minerals, and dead, damaged, and living vegetation. The distributions of these materials affect post-fire processes of erosion, nutrient cycling, and vegetation regrowth. We analyzed high spatial resolution (2.4??m...
Weirs: Counting and sampling adult salmonids in streams and rivers
Christian E. Zimmerman, Laura M. Zabkar
2007, Book chapter, Salmonid field protocols handbook: techniques for assessing status and trends in salmon and trout populations.
Weirs—which function as porous barriers built across stream—have long been used to capture migrating fish in flowing waters. For example, the Netsilik peoples of northern Canada used V-shaped weirs constructed of river rocks gathered onsite to capture migrating Arctic char Salvelinus alpinus (Balikci 1970). Similarly, fences constructed of stakes and...
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...
Imprint of oaks on nitrogen availability and δ15N in California grassland-savanna: A case of enhanced N inputs?
S.S. Perakis, C.H. Kellogg
2007, Plant Ecology (191) 209-220
Woody vegetation is distributed patchily in many arid and semi-arid ecosystems, where it is often associated with elevated nitrogen (N) pools and availability in islands of fertility. We measured N availability and δ15N in paired blue-oak versus annual grass dominated patches to characterize the causes and consequences of spatial variation...
Sediment compaction rates and subsidence in deltaic plains: Numerical constraints and stratigraphic influences
T.A. Meckel, Uri S. ten Brink, S.J. Williams
2007, Basin Research (19) 19-31
Natural sediment compaction in deltaic plains influences subsidence rates and the evolution of deltaic morphology. Determining compaction rates requires detailed knowledge of subsurface geotechnical properties and depositional history, neither of which is often readily available. To overcome this lack of knowledge, we numerically forward model the incremental sedimentation and compaction...
The relationship between tree growth patterns and likelihood of mortality: A study of two tree species in the Sierra Nevada
A.J. Das, J. J. Battles, N.L. Stephenson, P. J. van Mantgem
2007, Canadian Journal of Forest Research (37) 580-597
We examined mortality of Abies concolor (Gord. & Glend.) Lindl. (white fir) and Pinus lambertiana Dougl. (sugar pine) by developing logistic models using three growth indices obtained from tree rings: average growth, growth trend, and count of abrupt growth declines. For P. lambertiana, models with average growth, growth trend, and count...
Persistent chlordane concentrations in long island sound sediment: Implications from chlordane, 210Pb, and 137Cs profiles
L. Yang, X. Li, John Crusius, U. Jans, M.E. Melcer, P. Zhang
2007, Environmental Science & Technology (41) 7723-7729
Concentrations of chlordane, a banned termiticide and pesticide, were examined in recently collected surficial sediment (10 sites) and sediment cores (4 sites) in Long Island Sound (LIS).The highest chlordane concentrations were observed in western LIS, near highly urbanized areas. Chlordane concentrations did not decrease significantly in the past decade when...
Role of burning season on initial understory vegetation response to prescribed fire in a mixed conifer forest
E. E. Knapp, D.W. Schwilk, J.M. Kane, Jon E. Keeley
2007, Canadian Journal of Forest Research (37) 11-22
Although the majority of fires in the western United States historically occurred during the late summer or early fall when fuels were dry and plants were dormant or nearly so, early-season prescribed burns are often ignited when fuels are still moist and plants are actively growing. The purpose of this...
Evaluation of the status of anurans on a refuge in suburban Maryland
S.M. Brander, J. Andrew Royle, M. Eames
2007, Journal of Herpetology (41) 52-60
Because many anurans have well-defined breeding seasons and male anurans produce loud advertisement calls, surveys of these breeding choruses are believed to provide a dependable means of monitoring population trends. The Patuxent Research Refuge initiated such a calling survey in the spring of 1997, which uses volunteers to collect anuran...
Local and regional factors affecting atmospheric mercury speciation at a remote location
H. Manolopoulos, J.J. Schauer, M.D. Purcell, T.M. Rudolph, Mark L. Olson, B. Rodger, David P. Krabbenhoft
2007, Journal of Environmental Engineering and Science (6) 491-501
Atmospheric concentrations of elemental (Hg0), reactive gaseous (RGM), and particulate (PHg) mercury were measured at two remote sites in the midwestern United States. Concurrent measurements of Hg0, PHg, and RGM obtained at Devil's Lake and Mt. Horeb, located approximately 65 km apart, showed that Hg0 and PHg concentrations were affected...
Distinguishing centrarchid genera by use of lateral line scales
N.M. Roberts, C.F. Rabeni, J.S. Stanovick
2007, North American Journal of Fisheries Management (27) 215-219
Predator-prey relations involving fishes are often evaluated using scales remaining in gut contents or feces. While several reliable keys help identify North American freshwater fish scales to the family level, none attempt to separate the family Centrarchidae to the genus level. Centrarchidae is of particular concern in the midwestern United...
Ecological linkages between headwaters and downstream ecosystems: Transport of organic matter, invertebrates, and wood down headwater channels
M.S. Wipfli, J.S. Richardson, R.J. Naiman
2007, Journal of the American Water Resources Association (43) 72-85
Headwater streams make up a large proportion of the total length and watershed area of fluvial networks, and are partially characterized by the large volume of organic matter (large wood, detritus, and dissolved organic matter) and invertebrate inputs from the riparian forest, relative to stream size. Much of those inputs...
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...
Earthquake likelihood model testing
D. Schorlemmer, M.C. Gerstenberger, S. Wiemer, D.D. Jackson, D.A. Rhoades
2007, Seismological Research Letters (78) 17-29
INTRODUCTIONThe Regional Earthquake Likelihood Models (RELM) project aims to produce and evaluate alternate models of earthquake potential (probability per unit volume, magnitude, and time) for California. Based on differing assumptions, these models are produced to test the validity of their assumptions and to explore which models should be incorporated...
Estimating fishing mortality, natural mortality, and selectivity using recoveries from tagging young fish
H. Jiang, C. Brownie, J.E. Hightower, K. H. Pollock
2007, North American Journal of Fisheries Management (27) 773-781
Current methods for estimation of age- and year-specific instantaneous mortality rates based on multiyear, multiple-age tagging studies assume that it is feasible to tag fish in a wide range of ages. For some species, however, only the youngest one or two age-classes are readily available for tagging. Given the practical...
Effects of sea-level rise on ground water flow in a coastal aquifer system
John P. Masterson, S. P. Garabedian
2007, Ground Water (45) 209-217
The effects of sea-level rise on the depth to the fresh water/salt water interface were simulated by using a density-dependent, three-dimensional numerical ground water flow model for a simplified hypothetical fresh water lens that is similar to shallow, coastal aquifers found along the Atlantic coast of the United States. Simulations...
Natural landscape and stream segment attributes influencing the distribution and relative abundance of riverine smallmouth bass in Missouri
S.K. Brewer, C.F. Rabeni, S.P. Sowa, G. Annis
2007, North American Journal of Fisheries Management (27) 326-341
Protecting and restoring fish populations on a regional basis are most effective if the multiscale factors responsible for the relative quality of a fishery are known. We spatially linked Missouri's statewide historical fish collections to environmental features in a geographic information system, which was used as a basis for modeling...
Petrology and tectonics of Phanerozoic continent formation: From island arcs to accretion and continental arc magmatism
C.-T.A. Lee, D. M. Morton, R. W. Kistler, A. K. Baird
2007, Earth and Planetary Science Letters (263) 370-387
Mesozoic continental arcs in the North American Cordillera were examined here to establish a baseline model for Phanerozoic continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of...
Evidence for a physical linkage between galactic cosmic rays and regional climate time series
C. A. Perry
2007, Advances in Space Research (40) 353-364
The effects of solar variability on regional climate time series were examined using a sequence of physical connections between total solar irradiance (TSI) modulated by galactic cosmic rays (GCRs), and ocean and atmospheric patterns that affect precipitation and streamflow. The solar energy reaching the Earth's surface and its oceans is...
