Holocene environmental and parasequence development of the St. Jones Estuary, Delaware (USA): Foraminiferal proxies of natural climatic and anthropogenic change
E. Leorri, R. Martin, P. McLaughlin
2006, Palaeogeography, Palaeoclimatology, Palaeoecology (241) 590-607
The benthic foraminiferal record of marshes located along western Delaware Bay (St. Jones Estuary, USA) reflects the response of estuaries to sea-level and paleoclimate change during the Holocene. System tracts are recognized and within them parasequences based on sedimentological and foraminiferal assemblages identification. The parasequences defined by foraminiferal assemblages appear...
Oil resources - Estimates and uncertainties
D. L. Gautier
2006, Conference Paper, Society of Petroleum Engineers, 68th European Association of Geoscientists and Engineers Conference and Exhibition, incorporating SPE EUROPEC 2006, EAGE 2006: Opportunities in Mature Areas
Oil reserves are reasonably well known, but they are not a reliable indicator of longterm supply. Future oil availability will depend upon reserve additions, which are highly uncertain. New reserves will come from three sources: 1) new field discoveries, 2) growth of reserves in existing fields, and 3) development of...
Pigs on the plains: Institutional analysis of a Colorado water quality initiative
D. King, N. Burkardt, Lamb B. Lee
2006, International Journal of Public Administration (29) 1411-1430
We used the Legal-Institutional Analysis Model (LIAM) and Advocacy Coalition Framework (ACF) to analyze the campaign over passage of the Colorado Hogs Rule, an initiative passed by the voters in 1998 to require regulation of swine production facilities in Colorado. Used in tandem, LIAM and ACF provided an opportunity to...
Response of Tridens flavus (L.) A. S. Hitchc. to soil nutrients and disturbance in an early successional old field
Y. A. K. Honu, D.J. Gibson, B.A. Middleton
2006, Journal of the Torrey Botanical Society (133) 421-428
Soil nutrients and disturbance are two of the main abiotic factors that influence plant dominance (canopy cover), density, and fecundity in early successional old field plant communities. The manner in which the dominant species in old field successional systems respond to the interaction of nutrients and disturbance is poorly known....
Examination of the watershed-wide distribution of Escherichia coli along southern Lake Michigan: An integrated approach
R.L. Whitman, M.B. Nevers, M.N. Byappanahalli
2006, Applied and Environmental Microbiology (72) 7301-7310
Recent research has highlighted the occurrence of Escherichia coli in natural habitats not directly influenced by sewage inputs. Most studies on E. coli in recreational water typically focus on discernible sources (e.g., effluent discharge and runoff) and fall short of integrating riparian, nearshore, onshore, and outfall sources. An integrated “beachshed” approach that links E. coli inputs...
Modeling post-fledging survival of lark buntings in response to ecological and biological factors
A. A. Yackel Adams, S. K. Skagen, J. A. Savidge
2006, Ecology (87) 178-188
We evaluated the influences of several ecological, biological, and methodological factors on post-fledging survival of a shortgrass prairie bird, the Lark Bunting (Calamospiza melanocorys). We estimated daily post-fledging survival (n = 206, 82 broods) using radiotelemetry and color bands to track fledglings. Daily survival probabilities were best explained by...
Novel ecosystems: Theoretical and management aspects of the new ecological world order
R.J. Hobbs, S. Arico, J. Aronson, Jill Baron, P. Bridgewater, V.A. Cramer, P.R. Epstein, J.J. Ewel, C.A. Klink, A.E. Lugo, D. Norton, D. Ojima, D.M. Richardson, E.W. Sanderson, F. Valladares, M. Vila, R. Zamora, M. Zobel
2006, Global Ecology and Biogeography (15) 1-7
We explore the issues relevant to those types of ecosystems containing new combinations of species that arise through human action, environmental change, and the impacts of the deliberate and inadvertent introduction of species from other regions. Novel ecosystems (also termed ‘emerging ecosystems’) result when species occur in combinations and relative...
Flood pattern and weather determine Populus leaf litter breakdown and nitrogen dynamics on a cold desert floodplain
D.C. Andersen, S. M. Nelson
2006, Journal of Arid Environments (64) 626-650
Patterns and processes involved in litter breakdown on desert river floodplains are not well understood. We used leafpacks containing Fremont cottonwood (Populus deltoides subsp. wislizenii) leaf litter to investigate the roles of weather and microclimate, flooding (immersion), and macroinvertebrates on litter organic matter (OM) and nitrogen (N) loss on a...
A permutation test for quantile regression
Brian S. Cade, Jon D. Richards
2006, Journal of Agricultural, Biological, and Environmental Statistics (11) 106-126
A drop in dispersion, F-ratio like, permutation test (D) for linear quantile regression estimates (0≤τ≤1) had relative power ≥1 compared to quantile rank score tests (T) for hypotheses on parameters other than the intercept. Power was compared for combinations of sample sizes (<i class="EmphasisTypeItalic...
Hindcasting nitrogen deposition to determine an ecological critical load
Jill Baron
2006, Ecological Applications (16) 433-439
Using an estimated background nitrogen (N) deposition value of 0.5 kg N·ha−1·yr−1 in 1900, and a 19-year record of measured values from Loch Vale (Colorado, USA; NADP site CO98), I reconstructed an N-deposition history using exponential equations that correlated well with EPA-reported NOx emissions from Colorado and from the sum...
Forest reproduction along a climatic gradient in the Sierra Nevada, California
Phillip J. van Mantgem, Nathan L. Stephenson, Jon E. Keeley
2006, Forest Ecology and Management (225) 391-399
To elucidate broad-scale environmental controls of coniferous forest reproduction in the Sierra Nevada, California, we monitored reproduction for 5 years in 47 plots arrayed across a steep elevational (climatic) gradient. We found that both absolute seedling densities (stems < 1.37 m) and seedling densities relative to overstory parent tree basal area declined sharply...
Evaluating redband trout habitat in sagebrush desert basins in southwestern Idaho
B.W. Zoellick, B.S. Cade
2006, North American Journal of Fisheries Management (26) 268-281
We estimated abundance quantiles of redband trout Oncorhynchus mykiss gairdneri relative to five site-specific habitat variables (stream shading, bank cover, bank stability, fine sediment in the stream substrate, and cover for adults) and one landscape variable (distance from stream headwaters) on 30 streams in southwestern Idaho during 1993–1998. In addition,...
Palaeomagnetic intensities from 14C-dated lava flows on the Big Island, Hawaii: 0-21 kyr
Nicola Pressling, Carlo Laj, Catherie Kissel, Duane E. Champion, David Gubbins
2006, Earth and Planetary Science Letters (247) 26-40
Thellier–Thellier experiments were carried out on 216 lava samples collected by the USGS on the Big Island. 35 individual flows from the Kilauea, Mauna Loa and Hualalai volcanoes are represented and independent radiocarbon dating of the flows yields absolute ages ranging from 290 to 20,240 yrs old. The palaeomagnetic analysis was...
Prediction and discovery of new geothermal resources in the Great Basin: Multiple evidence of a large undiscovered resource base
M.F. Coolbaugh, G. L. Raines, R. E. Zehner, L. Shevenell, C.F. Williams
2006, Conference Paper, Transactions - Geothermal Resources Council
Geothermal potential maps by themselves cannot directly be used to estimate undiscovered resources. To address the undiscovered resource base in the Great Basin, a new and relatively quantitative methodology is presented. The methodology involves three steps, the first being the construction of a data-driven probabilistic model of the location of...
Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario
W.E. Adams Jr., L.W. Kallemeyn, D.W. Willis
2006, Journal of Applied Ichthyology (22) 97-102
Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted...
A trait-based test for habitat filtering: Convex hull volume
W.K. Cornwell, D.W. Schwilk, D. D. Ackerly
2006, Ecology (87) 1465-1471
Community assembly theory suggests that two processes affect the distribution of trait values within communities: competition and habitat filtering. Within a local community, competition leads to ecological differentiation of coexisting species, while habitat filtering reduces the spread of trait values, reflecting shared ecological tolerances. Many statistical tests for the effects...
Effects of human recreation on the incubation behavior of American Oystercatchers
C.P. McGowan, T.R. Simons
2006, Wilson Journal of Ornithology (118) 485-493
Human recreational disturbance and its effects on wildlife demographics and behavior is an increasingly important area of research. We monitored the nesting success of American Oystercatchers (Haematopus palliatus) in coastal North Carolina in 2002 and 2003. We also used video monitoring at nests to measure the response of incubating birds...
Decay of aftershock density with distance indicates triggering by dynamic stress
K.R. Felzer, E. E. Brodsky
2006, Nature (441) 735-738
The majority of earthquakes are aftershocks, yet aftershock physics is not well understood. Many studies suggest that static stress changes trigger aftershocks, but recent work suggests that shaking (dynamic stresses) may also play a role. Here we measure the decay of aftershocks as a function of distance from magnitude 2-6...
Perchlorate in pleistocene and holocene groundwater in North-Central New Mexico
Niel Plummer, J.K. Böhlke, M. W. Doughten
2006, Environmental Science & Technology (40) 1757-1763
Groundwater from remote parts of the Middle Rio Grande Basin in north-central New Mexico has perchlorate (ClO4-) concentrations of 0.12−1.8 μg/L. Because the water samples are mostly preanthropogenic in age (0−28 000 years) and there are no industrial sources in the study area, a natural source of the...
Recharge processes drive sulfate reduction in an alluvial aquifer contaminated with landfill leachate
M. A. Scholl, I.M. Cozzarelli, S. C. Christenson
2006, Journal of Contaminant Hydrology (86) 239-261
Natural attenuation of contaminants in groundwater depends on an adequate supply of electron acceptors to stimulate biodegradation. In an alluvial aquifer contaminated with leachate from an unlined municipal landfill, the mechanism of recharge infiltration was investigated as a source of electron acceptors. Water samples were collected monthly at closely spaced intervals...
CO2 jets formed by sublimation beneath translucent slab ice in Mars' seasonal south polar ice cap
Hugh H. Kieffer, Phillip R. Christensen, Timothy N. Titus
2006, Nature (442) 793-796
The martian polar caps are among the most dynamic regions on Mars, growing substantially in winter as a significant fraction of the atmosphere freezes out in the form of CO2 ice. Unusual dark spots, fans and blotches form as the south-polar seasonal CO2 ice cap retreats during spring and summer....
Carryover aquatic effects on survival of metamorphic frogs during pond emigration
N.D. Chelgren, D.K. Rosenberg, S.S. Heppell, A.I. Gitelman
2006, Ecological Applications (16) 250-261
In organisms with complex life cycles, physiological stressors during early life stages may have fitness-level impacts that are delayed into later stages or habitats. We tested the hypothesis that body size and date of metamorphosis, which are highly responsive to aquatic stressors, influence post-metamorphic survival and movement patterns in the...
Lesser scaup winter foraging and nutrient reserve acquisition in east-central Florida
G. Herring, J.A. Collazo
2006, Journal of Wildlife Management (70) 1682-1689
Lesser scaup (Aythya affinis) populations have been declining since the late 1970s. One of the explanations to account for this decline, the spring-condition hypothesis (SCH), is based on the premise that scaup are limited by their ability to acquire or maintain nutrient reserves during migration to the breeding grounds, leading...
Associations of breeding birds with fire-influenced and riparian-upland gradients in a longleaf pine ecosystem
J. C. Allen, S.M. Krieger, J. R. Walters, J.A. Collazo
2006, The Auk (123) 1110-1128
We determined the effects of fire history and a riparian-upland gradient on the breeding bird community at Fort Bragg Military Installation in North Carolina, one of the largest remnant areas of the endangered longleaf pine (Pinus palustris) ecosystem. Study sites were classified into two treatments: fire-intense (areas experiencing growing-season burns)...
Seismic response and damage detection analyses of an instrumented steel moment-framed building
J.E. Rodgers, M. Çelebi
2006, Journal of Structural Engineering (132) 1543-1552
The seismic performance of steel moment-framed buildings has been of particular interest since brittle fractures were discovered at the beam-column connections in a number of buildings following the M 6.7 Northridge earthquake of January 17, 1994. A case study of the seismic behavior of an extensively instrumented 13-story steel moment...
