Scale-dependent factors affecting North American river otter distribution in the midwest
Mackenzie R. Jeffress, Craig P. Paukert, Joanna B. Whittier, B. K. Sandercock, P. S. Gipson
2011, American Midland Naturalist (166) 177-193
The North American river otter (Lontra canadensis) is recovering from near extirpation throughout much of its range. Although reintroductions, trapping regulations and habitat improvements have led to the reestablishment of river otters in the Midwest, little is known about how their distribution is influenced by local- and landscape-scale habitat....
Development of soil properties and nitrogen cycling in created wetlands
K.L. Wolf, C. Ahn, G.B. Noe
2011, Wetlands (31) 699-712
Mitigation wetlands are expected to compensate for the loss of structure and function of natural wetlands within 5–10 years of creation; however, the age-based trajectory of development in wetlands is unclear. This study investigates the development of coupled structural (soil properties) and functional (nitrogen cycling) attributes of created non-tidal freshwater...
Volcanic plume height measured by seismic waves based on a mechanical model
Stephanie G. Prejean, Emily E. Brodsky
2011, Journal of Geophysical Research B: Solid Earth (116) B01306
In August 2008 an unmonitored, largely unstudied Aleutian volcano, Kasatochi, erupted catastrophically. Here we use seismic data to infer the height of large eruptive columns such as those of Kasatochi based on a combination of existing fluid and solid mechanical models. In so doing, we propose a connection between a...
Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California
O. W. Purvis, J. P. Bennett, J. Spratt
2011, Lichenologist (43) 165-173
An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its...
Ant-nest ichnofossils in honeycomb calcretes, Neogene Ogallala Formation, High Plains region of western Kansas, U.S.A.
J.J. Smith, B.F. Platt, Greg A. Ludvigson, J.R. Thomasson
2011, Palaeogeography, Palaeoclimatology, Palaeoecology (308) 383-394
Two new ant-nest trace fossils are described from calcic sandy paleosols of the Neogene Ogallala Formation in western Kansas. The ichnofossils are preserved within and below calcrete beds weathering in positive relief as carbonate-filled casts or as cavities in negative relief. Daimoniobarax ichnogenus nov. is established for burrow systems composed of...
Whole-edifice ice volume change A.D. 1970 to 2007/2008 at Mount Rainier, Washington, based on LiDAR surveying
T. W. Sisson, J.E. Robinson, D.D. Swinney
2011, Geology (39) 639-642
Net changes in thickness and volume of glacial ice and perennial snow at Mount Rainier, Washington State, have been mapped over the entire edifice by differencing between a highresolution LiDAR (light detection and ranging) topographic survey of September-October 2007/2008 and the 10 m lateral resolution U.S. Geological Survey digital elevation...
Challenges in identifying sites climatically matched to the native ranges of animal invaders
G.H. Rodda, C. S. Jarnevich, R.N. Reed
2011, PLoS ONE (6)
Background: Species distribution models are often used to characterize a species' native range climate, so as to identify sites elsewhere in the world that may be climatically similar and therefore at risk of invasion by the species. This endeavor provoked intense public controversy over recent attempts to model areas at...
Post-breeding bird responses to canopy tree retention, stand size, and edge in regenerating Appalachian hardwood stands
Molly E. McDermott, Petra B. Wood
2011, Forest Ecology and Management (262) 547-554
Avian use of even-aged timber harvests is likely affected by stand attributes such as size, amount of edge, and retained basal area, all characteristics that can easily be manipulated in timber harvesting plans. However, few studies have examined their effects during the post-breeding period. We studied the impacts of clearcut,...
Understanding the role of fog in forest hydrology: Stable isotopes as tools for determining input and partitioning of cloud water in montane forests
Martha A. Scholl, W. Eugster, R. Burkard
2011, Hydrological Processes (25) 353-366
Understanding the hydrology of tropical montane cloud forests (TMCF) has become essential as deforestation of mountain areas proceeds at an increased rate worldwide. Passive and active cloud‐water collectors, throughfall and stemflow collectors, visibility or droplet size measurements, and micrometeorological sensors are typically used to measure the fog water inputs to...
Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers
A.D. Dybowska, Marie Noele Croteau, S.K. Misra, D. Berhanu, Samuel N. Luoma, P. Christian, P. O'Brien, E. Valsami-Jones
2011, Environmental Pollution (159) 266-273
Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically...
Coexistence in streams: Do source-sink dynamics allow salamanders to persist with fish predators?
Adam J. Sepulveda, W.H. Lowe
2011, Oecologia (166) 1043-1054
Theory suggests that source–sink dynamics can allow coexistence of intraguild predators and prey, but empirical evidence for this coexistence mechanism is limited. We used capture–mark–recapture, genetic methods, and stable isotopes to test whether source–sink dynamics promote coexistence between stream fishes, the intraguild predator, and stream salamanders (Dicamptodon aterrimus), the intraguild...
Sulfur in the South Florida ecosystem: Distribution, sources, biogeochemistry, impacts, and management for restoration
William H. Orem, C. Gilmour, D. Axelrad, David P. Krabbenhoft, D. Scheidt, P. Kalla, P. McCormick, M. Gabriel, George Aiken
2011, Critical Reviews in Environmental Science and Technology (41) 249-288
Sulfur is broadly recognized as a water quality issue of significance for the freshwater Florida Everglades. Roughly 60% of the remnant Everglades has surface water sulfate concentrations above 1 mg l-1, a restoration performance measure based on present sulfate levels in unenriched areas. Highly enriched marshes in the northern Everglades...
Cougar survival and source-sink structure on Greater Yellowstone's Northern Range
T.K. Ruth, M.A. Haroldson, K.M. Murphy, P.C. Buotte, M.G. Hornocker, H.B. Quigley
2011, Journal of Wildlife Management (75) 1381-1398
We studied survival and causes of mortality of radiocollared cougars (Puma concolor) on the Greater Yellowstone Northern Range (GYNR) prior to (1987–1994) and after wolf (Canis lupus) reintroduction (1998–2005) and evaluated temporal, spatial, and environmental factors that explain variation in adult, subadult, and kitten survival. Using Program MARK and multimodel...
A counter-intuitive approach to calculating non-exchangeable 2H isotopic composition of hair: treating the molar exchange fraction fE as a process-related rather than compound-specific variable
J.M. Landwehr, W. Meier-Augenstein, H.F. Kemp
2011, Rapid Communications in Mass Spectrometry (25) 301-306
Hair is a keratinous tissue that incorporates hydrogen from material that an animal consumes but it is metabolically inert following synthesis. The stable hydrogen isotope composition of hair has been used in ecological studies to track migrations of mammals as well as for forensic and archaeological purposes to determine the...
Neoarchean paleoweathering of tonalite and metabasalt: Implications for reconstructions of 2.69Ga early terrestrial ecosystems and paleoatmospheric chemistry
S.G. Driese, M.A. Jirsa, M. Ren, S.L. Brantley, N.D. Sheldon, Dana C. Parker, M. Schmitz
2011, Precambrian Research (189) 1-17
Field and laboratory investigations of a 2690.83 Ma (207Pb/206Pb age of Saganaga Tonalite) unconformity exposed in outcrop in northeastern Minnesota, USA, reveal evidence for development of a deep paleoweathering profile with geochemical biosignatures consistent with the presence of microbial communities and weakly oxygenated conditions. Weathering profiles are characterized by a 5–50 m...
Watershed morphology of highland and mountain ecoregions in eastern Oklahoma
D. K. Splinter, Daniel C. Dauwalter, R. A. Marston, William Fisher
2011, Professional Geographer (63) 131-143
The fluvial system represents a nested hierarchy that reflects the relationship among different spatial and temporal scales. Within the hierarchy, larger scale variables influence the characteristics of the next lower nested scale. Ecoregions represent one of the largest scales in the fluvial hierarchy and are defined by recurring patterns of...
Origin of a rhyolite that intruded a geothermal well while drilling at the Krafla volcano, Iceland
W.A. Elders, G.O. Fridleifsson, R.A. Zierenberg, E.C. Pope, A.K. Mortensen, A. Gudmundsson, Jacob B. Lowenstern, N.E. Marks, L. Owens, D.K. Bird, M. Reed, N.J. Olsen, Peter Schiffmant
2011, Geology (39) 231-234
Magma flowed into an exploratory geothermal well at 2.1 km depth being drilled in the Krafla central volcano in Iceland, creating a unique opportunity to study rhyolite magma in situ in a basaltic environment. The quenched magma is a partly vesicular, sparsely phyric, glass containing ∼1.8% of dissolved volatiles. Based...
An analysis of modern pollen rain from the Maya lowlands of northern Belize
T. Bhattacharya, T. Beach, David B. Wahl
2011, Review of Palaeobotany and Palynology (164) 109-120
In the lowland Maya area, pollen records provide important insights into the impact of past human populations and climate change on tropical ecosystems. Despite a long history of regional paleoecological research, few studies have characterized the palynological signatures of lowland ecosystems, a fact which lowers confidence in ecological inferences made...
Fire, grazing history, lichen abundance, and winter distribution of caribou in Alaska's taiga
William B. Collins, Bruce W. Dale, Layne G. Adams, Darien E. McElwain, Kyle Joly
2011, Journal of Wildlife Management (75) 369-377
In the early 1990s the Nelchina Caribou (Rangifer tarandus) Herd (NCH) began a dramatic shift to its current winter range, migrating at least an additional 100 km beyond its historic range. We evaluated the impacts of fire and grazing history on lichen abundance and subsequent use and distribution by the NCH....
Empirical critical loads of atmospheric nitrogen deposition for nutrient enrichment and acidification of sensitive US lakes
Jill Baron, C. T. Driscoll, J.L. Stoddard, E.E. Richer
2011, BioScience (61) 602-613
The ecological effects of elevated atmospheric nitrogen (N) deposition on high-elevation lakes of the western and northeastern United States include nutrient enrichment and acidification. The nutrient enrichment critical load for western lakes ranged from 1.0 to 3.0 kilograms (kg) of N per hectare (ha) per year, reflecting the nearly nonexistent...
King eider foraging effort during the pre-breeding period in Alaska
Steffen Oppel, Abby N. Powell, Malcolm G. Butler
2011, The Condor (113) 52-60
For reproduction, many arctic-nesting migratory birds rely on nutrients obtained on the breeding grounds, so they devote sufficient time to foraging immediately prior to nesting. However, little is known about the increase in foraging effort necessary to meet the energetic requirements of reproduction. In early June 2006 and 2008, we...
Permafrost-associated natural gas hydrate occurrences on the Alaska North Slope
Timothy S. Collett, Myung W. Lee, Warren F. Agena, John J. Miller, Kristen A. Lewis, M.V. Zyrianova, R. Boswell, T.L. Inks
2011, Marine and Petroleum Geology (28) 279-294
In the 1960s Russian scientists made what was then a bold assertion that gas hydrates should occur in abundance in nature. Since this early start, the scientific foundation has been built for the realization that gas hydrates are a global phenomenon,...
Downhole well log and core montages from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope
Timothy S. Collett, R.E. Lewis, William J. Winters, Myung W. Lee, K.K. Rose, R.M. Boswell
2011, Marine and Petroleum Geology (28) 561-577
The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was an integral part of an ongoing project to determine the future energy resource potential of gas hydrates on the Alaska North Slope. As part of this effort, the Mount Elbert well included an advanced downhole geophysical logging program. Because gas...
Direction of unsaturated flow in a homogeneous and isotropic hillslope
N. Lu, B.S. Kaya, J. W. Godt
2011, Water Resources Research (47)
The distribution of soil moisture in a homogeneous and isotropic hillslope is a transient, variably saturated physical process controlled by rainfall characteristics, hillslope geometry, and the hydrological properties of the hillslope materials. The major driving mechanisms for moisture movement are gravity and gradients in matric potential. The latter is solely...
Position of the Triassic-Jurassic boundary and timing of the end-Triassic extinctions on land: Data from the Moenave Formation on the southern Colorado Plateau, USA
S. G. Lucas, L.H. Tanner, L. Donohoo-Hurley, J. W. Geissman, H. W. Kozur, A.B. Heckert, Robert E. Weems
2011, Palaeogeography, Palaeoclimatology, Palaeoecology (302) 194-205
Strata of the Moenave Formation on and adjacent to the southern Colorado Plateau in Utah–Arizona, U.S.A., represent one of the best known and most stratigraphically continuous, complete and fossiliferous terrestrial sections across the Triassic–Jurassic boundary. We present a synthesis of new biostratigraphic and magnetostratigraphic data collected from across the Moenave...
