Palynological composition of a Lower Cretaceous South American tropical sequence: Climatic implications and diversity comparisons with other latitudes.
Paula J. Mejia-Velasquez, David L. Dilcher, Carlos A. Jaramillo, Lucas B. Fortini, Steven R. Manchester
2012, American Journal of Botany (99) 1819-1827
Premise of the study: Reconstruction of floristic patterns during the early diversification of angiosperms is impeded by the scarce fossil record, especially in tropical latitudes. Here we collected quantitative palynological data from a stratigraphic sequence in tropical South America to provide floristic and climatic insights into such tropical environments during...
Simulation of groundwater flow in the shallow aquifer system of the Delmarva Peninsula, Maryland and Delaware
Ward E. Sanford, Jason P. Pope, David L. Selnick, Ryan F. Stumvoll
2012, Open-File Report 2012-1140
Estimating future loadings of nitrogen to the Chesapeake Bay requires knowledge about the groundwater flow system and the traveltime of water and chemicals between recharge at the water table and the discharge to streams and directly to the bay. The Delmarva Peninsula has a relatively large proportion of its land...
Ash3d: A finite-volume, conservative numerical model for ash transport and tephra deposition
Hans F. Schwaiger, Roger P. Denlinger, Larry G. Mastin
2012, Journal of Geophysical Research (117)
We develop a transient, 3-D Eulerian model (Ash3d) to predict airborne volcanic ash concentration and tephra deposition during volcanic eruptions. This model simulates downwind advection, turbulent diffusion, and settling of ash injected into the atmosphere by a volcanic eruption column. Ash advection is calculated using time-varying pre-existing wind data and...
Carbon stocks across a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands
Matthew D. Powers, Randall K. Kolka, John B. Bradford, Brian J. Palik, Shawn Fraver, Martin F. Jurgensen
2012, Ecological Applications (22) 1297-1307
Forests function as a major global C sink, and forest management strategies that maximize C stocks offer one possible means of mitigating the impacts of increasing anthropogenic CO2 emissions. We studied the effects of thinning, a common management technique in many forest types, on age-related trends in C stocks using...
Extension of the spatial autocorrelation (SPAC) method to mixed-component correlations of surface waves
Matthew M. Haney, T. Dylan Mikesell, Kasper van Wijk, Hisashi Nakahara
2012, Geophysical Journal International (191) 189-206
Using ambient seismic noise for imaging subsurface structure dates back to the development of the spatial autocorrelation (SPAC) method in the 1950s. We present a theoretical analysis of the SPAC method for multicomponent recordings of surface waves to determine the complete 3 × 3 matrix of correlations between all pairs...
Determination and uncertainty of moment tensors for microearthquakes at Okmok Volcano, Alaska
J. D. Pesicek, J. Sileny, S. G. Prejean, C.H. Thurber
2012, Geophysical Journal International (190) 1689-1709
Efforts to determine general moment tensors (MTs) for microearthquakes in volcanic areas are often hampered by small seismic networks, which can lead to poorly constrained hypocentres and inadequate modelling of seismic velocity heterogeneity. In addition, noisy seismic signals can make it difficult to identify phase arrivals correctly for small magnitude...
Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters
Timothy B. Grabowski, Kevin M. Boswell, Bruce J. McAdam, R. J. David Wells, Gudrun Marteinsdottir
2012, PLoS ONE (7)
The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations...
Temporal analysis of mtDNA variation reveals decreased genetic diversity in least terns
Hope M. Draheim, Patricia Baird, Susan M. Haig
2012, The Condor (114) 145-154
The Least Tern (Sternula antillarum) has undergone large population declines over the last century as a result of direct and indirect anthropogenic factors. The genetic implications of these declines are unknown. We used historical museum specimens (pre-1960) and contemporary (2001–2005) samples to examine range-wide phylogeographic patterns and investigate potential loss...
Do bioclimate variables improve performance of climate envelope models?
James I. Watling, Stephanie S. Romañach, David N. Bucklin, Carolina Speroterra, Laura A. Brandt, Leonard G. Pearlstine, Frank J. Mazzotti
2012, Ecological Modelling (246) 79-85
Climate envelope models are widely used to forecast potential effects of climate change on species distributions. A key issue in climate envelope modeling is the selection of predictor variables that most directly influence species. To determine whether model performance and spatial predictions were related to the selection of predictor variables,...
Along-shelf current variability on the Catalan inner-shelf (NW Mediterranean)
Manel Grifoll, Alfredo L. Aretxabaleta, Manuel Espino, John C. Warner
2012, Journal of Geophysical Research (117)
We examine the circulation over the inner shelf of the Catalan Sea using observations of currents obtained from three ADCPs within the inner-shelf (24 and 50 m depth) during March-April 2011. The along-shelf current fluctuations during that period are mainly controlled by the local wind stress on short time scales...
Body condition of Morelet’s Crocodiles (Crocodylus moreletii) from northern Belize
Frank J. Mazzotti, Michael S. Cherkiss, Laura A. Brandt, Ikuko Fujisaki, Kristen Hart, Brian Jeffery, Scott T. McMurry, Steven G. Platt, Thomas R. Rainwater, Joy Vinci
2012, Journal of Herpetology (46) 356-362
Body condition factors have been used as an indicator of health and well-being of crocodilians. We evaluated body condition of Morelet's Crocodiles (Crocodylus moreletii) in northern Belize in relation to biotic (size, sex, and habitat) and abiotic (location, water level, and air temperature) factors. We also tested the hypothesis that...
Ballistic blocks around Kīlauea Caldera: Their vent locations and number of eruptions in the late 18th century
Donald A. Swanson, Scott P. Zolkos, Ben Haravitch
2012, Journal of Volcanology and Geothermal Research (231-232) 1-11
Thousands of ballistic blocks occur around Kīlauea Caldera and record part of the latest major period of explosive activity on the volcano, in late 1790 or within a few years thereafter. The sizes of the blocks – the largest of which is more than 2 m in nominal diameter –...
Status and trends of land change in the United States--1973 to 2000
Water Resources Division, U.S. Geological Survey
2012, Professional Paper 1794
Summary U.S. Geological Survey (USGS) Professional Paper 1794 is a four-volume series on the status and trends of the Nation’s land use and land cover, providing an assessment of the rates and causes of land-use and land-cover change in the United States between 1973 and 2000. Volumes A, B, C, and...
Flood-inundation maps for a nine-mile reach of the Des Plaines River from Riverwoods to Mettawa, Illinois
Elizabeth A. Murphy, David T. Soong, Jennifer B. Sharpe
2012, Scientific Investigations Report 2012-5227
Digital flood-inundation maps for a 9-mile reach of the Des Plaines River from Riverwoods to Mettawa, Illinois, were created by the U.S. Geological Survey (USGS) in cooperation with the Lake County Stormwater Management Commission and the Villages of Lincolnshire and Riverwoods. The inundation maps, which can be accessed through the...
Revolutionary land use change in the 21st century: Is (rangeland) science relevant?
J. E. Herrick, J.R. Brown, B.T. Bestelmeyer, S.S. Andrews, G. Baldi, J. Davies, M. Duniway, K. M. Havstad, J.W. Karl, D.L. Karlen, Debra P. C. Peters, J.N. Quinton, C. Riginos, P.L. Shaver, D. Steinaker, S. Twomlow
2012, Rangeland Ecology and Management (65) 590-598
Rapidly increasing demand for food, fiber, and fuel together with new technologies and the mobility of global capital are driving revolutionary changes in land use throughout the world. Efforts to increase land productivity include conversion of millions of hectares of rangelands to crop production, including many marginal lands with low...
Net Ecosystem Production (NEP) of the Great Plains, United States
Daniel Howard, Tagir Gilmanov, Yingxin Gu, Bruce Wylie, Li Zhang
2012, Fact Sheet 2012-3134
Gross primary production (GPP) and ecosystem respiration (Re) are the fundamental environmental characteristics that promote carbon exchanges with the atmosphere (Chapin and others, 2009), although other exchanges of carbon, such as direct oxidation (Lovett and others, 2006), can modify net ecosystem production (NEP). The accumulation of carbon in terrestrial ecosystems...
The state of amphibians in the United States
E. Muths, M.J. Adams, E.H.C. Grant, Dick Miller, P.S. Corn, L.C. Ball
2012, Fact Sheet 2012-3092
More than 25 years ago, scientists began to identify unexplained declines in amphibian populations around the world. Much has been learned since then, but amphibian declines have not abated and the interactions among the various threats to amphibians are not clear. Amphibian decline is a problem of local, national, and...
Ohio River backwater flood-inundation maps for the Saline and Wabash Rivers in southern Illinois
Elizabeth A. Murphy, Jennifer B. Sharpe, David T. Soong
2012, Scientific Investigations Report 2012-5212
Digital flood-inundation maps for the Saline and Wabash Rivers referenced to elevations on the Ohio River in southern Illinois were created by the U.S. Geological Survey (USGS). The inundation maps, accessible through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent of flooding...
Effect of brook trout removal from a spawning stream on an adfluvial population of Lahontan cutthroat trout
G. Gary Scoppettone, Peter H. Rissler, Sean P. Shea, William Somer
2012, North American Journal of Fisheries Management (32) 586-596
Independence Lake (Nevada and Sierra counties, California) harbors the only extant native population of Lahontan cutthroat trout Oncorhynchus clarkii henshawi in the Truckee River system and one of two extant adfluvial populations in the Lahontan basin. The persistence of this population has been precarious for more than 50 years, with...
Downstream movement of fall Chinook salmon juveniles in the lower Snake River reservoirs during winter and early spring
Kenneth F. Tiffan, Tobias J. Kock, William P. Connor, Frank Mullins, R. Kirk Steinhorst
2012, Transactions of the American Fisheries Society (141) 285-293
We conducted a 3-year radiotelemetry study in the lower Snake River to (1) determine whether juvenile fall Chinook salmon Oncorhynchus tshawytscha pass dams during winter, when bypass systems and structures designed to prevent mortality are not operated; (2) determine whether downstream movement rate varies annually, seasonally, and from reservoir to...
Wetland fire remote sensing research--The Greater Everglades example
John W. Jones
2012, Fact Sheet 2012-3133
Fire is a major factor in the Everglades ecosystem. For thousands of years, lightning-strike fires from summer thunderstorms have helped create and maintain a dynamic landscape suited both to withstand fire and recover quickly in the wake of frequent fires. Today, managers in the Everglades National Park are implementing controlled...
Effects of hydroperiod duration on survival, developmental rate, and size at metamorphosis in boreal chorus frog tadpoles (Pseudacris maculata)
Staci Amburgey, W. Chris Funk, Melanie Murphy, Erin Muths
2012, Herpetologica (68) 456-467
Understanding the relationship between climate-driven habitat conditions and survival is key to preserving biodiversity in the face of rapid climate change. Hydroperiod—the length of time water is in a wetland—is a critical limiting habitat variable for amphibians as larvae must metamorphose before ponds dry. Changes in precipitation and temperature patterns...
Variability in expression of anadromy by female Oncorhynchus mykiss within a river network
Justin S. Mills, Jason B. Dunham, Gordon H. Reeves, John R. McMillan, Christian E. Zimmerman, Chris E. Jordan
2012, Environmental Biology of Fishes (93) 505-517
We described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss in the John Day River watershed, Oregon. We collected 149 juvenile O. mykiss across 72 sites and identified locations used by anadromous females by assigning maternal origin (anadromous versus non-anadromous) to each juvenile. These assignments used...
Residence time, chemical and isotopic analysis of nitrate in the groundwater and surface water of a small agricultural watershed in the Coastal Plain, Bucks Branch, Sussex County, Delaware
John W. Clune, Judith M. Denver
2012, Scientific Investigations Report 2012-5235
Nitrate is a common contaminant in groundwater and surface water throughout the Nation, and water-resource managers need more detailed small-scale watershed research to guide conservation efforts aimed at improving water quality. Concentrations of nitrate in Bucks Branch are among the highest in the state of Delaware and a scientific investigation...
Streamflow statistics for selected streams in North Dakota, Minnesota, Manitoba, and Saskatchewan
Tara Williams-Sether
2012, Open-File Report 2012-1147
Statistical summaries of streamflow data for the periods of record through water year 2009 for selected active and discontinued U.S. Geological Survey streamflow-gaging stations in North Dakota, Minnesota, Manitoba, and Saskatchewan were compiled. The summaries for each streamflow-gaging station include a brief station description, a graph of the annual peak...
