Overcompensatory response of a smallmouth bass (Micropterus dolomieu) population to harvest: Release from competition?
E.F. Zipkin, P.J. Sullivan, E.G. Cooch, C.E. Kraft, B.J. Shuter, B.C. Weidel
2008, Canadian Journal of Fisheries and Aquatic Sciences (65) 2279-2292
An intensive seven-year removal of adult, juvenile, and young-of-the-year smallmouth bass (Micropterus dolomieu) from a north temperate lake (Little Moose Lake, New York, USA) resulted in an increase in overall population abundance, primarily due to increased abundance of immature individuals. We developed a density-dependent, stage-structured model to examine conditions under...
Tectonic and magmatic evolution of the northwestern Basin and Range and its transition to unextended volcanic plateaus: Black Rock Range, Nevada
D.W. Lerch, E. Miller, M. McWilliams, J. Colgan
2008, Geological Society of America Bulletin (120) 300-311
The seismically active eastern and western margins of the northern Basin and Range have been extensively studied, yet the northwestern margin of the province remains incompletely understood. The Black Rock Range of northwestern Nevada straddles the transition from the Basin and Range province to the south and east, and flat-lying...
Quantitative estimation of bioclimatic parameters from presence/absence vegetation data in North America by the modern analog technique
R.S. Thompson, K. H. Anderson, P. J. Bartlein
2008, Quaternary Science Reviews (27) 1234-1254
The method of modern analogs is widely used to obtain estimates of past climatic conditions from paleobiological assemblages, and despite its frequent use, this method involved so-far untested assumptions. We applied four analog approaches to a continental-scale set of bioclimatic and plant-distribution presence/absence data for North America to assess how...
Analysis of an unconfined aquifer subject to asynchronous dual-tide propagation
K. Rotzoll, A. I. El-Kadi, S. B. Gingerich
2008, Ground Water (46) 239-250
Most published solutions for aquifer responses to ocean tides focus on the one-sided attenuation of the signal as it propagates inland. However, island aquifers experience periodic forcing from the entire coast, which can lead to integrated effects of different tidal signals, especially on narrow high-permeability islands. In general, studies disregard...
Modeling unobserved sources of heterogeneity in animal abundance using a Dirichlet process prior
R.M. Dorazio, B. Mukherjee, L. Zhang, M. Ghosh, H.L. Jelks, F. Jordan
2008, Biometrics (64) 635-644
In surveys of natural populations of animals, a sampling protocol is often spatially replicated to collect a representative sample of the population. In these surveys, differences in abundance of animals among sample locations may induce spatial heterogeneity in the counts associated with a particular sampling protocol. For some species, the...
Spatial patterns of ecohydrologic properties on a hillslope-alluvial fan transect, central New Mexico
D. R. Bedford, E.E. Small
2008, Catena (73) 34-48
Spatial patterns of soil properties are linked to patchy vegetation in arid and semi-arid landscapes. The patterns of soil properties are generally assumed to be linked to the ecohydrological functioning of patchy dryland vegetation ecosystems. We studied the effects of vegetation canopy, its spatial pattern, and landforms on soil properties...
Utilizing geochemical, hydrologic, and boron isotopic data to assess the success of a salinity and selenium remediation project, Upper Colorado River Basin, Utah
D. L. Naftz, T.D. Bullen, Bernard J. Stolp, C.D. Wilkowske
2008, Science of the Total Environment (392) 1-11
Stream discharge and geochemical data were collected at two sites along lower Ashley Creek, Utah, from 1999 to 2003, to assess the success of a site specific salinity and Se remediation project. The remediation project involved the replacement of a leaking sewage lagoon system that was interacting with Mancos Shale...
A review of the endemic Hawaiian Drosophilidae and their host plants
K.N. Magnacca, D. Foote, P. M. O’Grady
2008, Zootaxa 1-58
The Hawaiian Drosophilidae is one of the best examples of rapid speciation in nature. Nearly 1,000 species of endemic drosophilids have evolved in situ in Hawaii since a single colonist arrived over 25 million years ago. A number of mechanisms, including ecological adaptation, sexual selection, and geographic isolation, have been...
Movements of wintering surf scoters: Predator responses to different prey landscapes
M. Kirk, Daniel Esler, S. A. Iverson, W. S. Boyd
2008, Oecologia (155) 859-867
The distribution of predators is widely recognized to be intimately linked to the distribution of their prey. Foraging theory suggests that predators will modify their behaviors, including movements, to optimize net energy intake when faced with variation in prey attributes or abundance. While many studies have documented changes in movement...
Use of a 15 k gene microarray to determine gene expression changes in response to acute and chronic methylmercury exposure in the fathead minnow Pimephales promelas Rafinesque
R. Klaper, Barbara J. Carter, C.A. Richter, P.E. Drevnick, M.B. Sandheinrich, D. E. Tillitt
2008, Journal of Fish Biology (72) 2207-2280
This study describes the use of a 15 000 gene microarray developed for the toxicological model species, Pimephales promelas, in investigating the impact of acute and chronic methylmercury exposures in male gonad and liver tissues. The results show significant differences in the individual genes that were differentially expressed in response...
Short-term monitoring of aridland lichen cover and biomass using photography and fatty acids
M. A. Bowker, N.C. Johnson, J. Belnap, G.W. Koch
2008, Journal of Arid Environments (72) 869-878
Biological soil crust (BSC) communities (composed of lichens, bryophytes, and cyanobacteria) may be more dynamic on short-time scales than previously thought, requiring new and informative short-term monitoring techniques. We used repeat digital photography and image analysis, which revealed a change in area of a dominant BSC lichen, Collema tenax. The...
Desert bird associations with broad-scale boundary length: Applications in avian conservation
K.J. Gutzwiller, W.C. Barrow Jr.
2008, Journal of Applied Ecology (45) 873-882
1. Current understanding regarding the effects of boundaries on bird communities has originated largely from studies of forest-non-forest boundaries in mesic systems. To assess whether broad-scale boundary length can affect bird community structure in deserts, and to identify patterns and predictors of species' associations useful in avian conservation, we studied...
Efficient implementation of the Metropolis-Hastings algorithm, with application to the Cormack-Jolly-Seber model
W.A. Link, R. J. Barker
2008, Conference Paper, Environmental and Ecological Statistics
Judicious choice of candidate generating distributions improves efficiency of the Metropolis-Hastings algorithm. In Bayesian applications, it is sometimes possible to identify an approximation to the target posterior distribution; this approximate posterior distribution is a good choice for candidate generation. These observations are applied to analysis of the Cormack-Jolly-Seber model and...
Use of an annular chamber for testing thermal preference of westslope cutthroat trout and rainbow trout
T.E. McMahon, E.A. Bear, A.V. Zale
2008, Journal of Freshwater Ecology (23) 55-63
Remaining populations of westslope cutthroat trout (Oncorhynchus clarkii lewisi) in western North America are primarily confined to cold headwaters whereas nonnative rainbow trout (Oncorhynchus mykiss) predominate in warmer, lower elevation stream sections historically occupied by westslope cutthroat trout. We tested whether differing thermal preferences could account for the spatial segregation...
Middle UV to near-IR spectrum of electron-excited SO2
J.M. Ajello, A. Aguilar, R.S. Mangina, G.K. James, P. Geissler, L. Trafton
2008, Journal of Geophysical Research E: Planets (113)
We investigated the electron impact–induced fluorescence spectrum of SO2 to provide excitation cross sections for modeling Io's emission spectrum and analyzing Cassini Imaging Science Subsystem observations. The electron-excited middle-ultraviolet visible optical near-infrared (VOIR) emission spectrum of SO2 gas was generated in the laboratory and studied from 2000 to 11,000 Å at a...
Soil nutrient-landscape relationships in a lowland tropical rainforest in Panama
F.K. Barthold, R.F. Stallard, H. Elsenbeer
2008, Forest Ecology and Management (255) 1135-1148
Soils play a crucial role in biogeochemical cycles as spatially distributed sources and sinks of nutrients. Any spatial patterns depend on soil forming processes, our understanding of which is still limited, especially in regards to tropical rainforests. The objective of our study was to investigate the effects of landscape properties,...
Storm-driven sediment transport in Massachusetts Bay
J.C. Warner, B. Butman, P.S. Dalyander
2008, Continental Shelf Research (28) 257-282
Massachusetts Bay is a semi-enclosed embayment in the western Gulf of Maine about 50 km wide and 100 km long. Bottom sediment resuspension is controlled predominately by storm-induced surface waves and transport by the tidal- and wind-driven circulation. Because the Bay is open to the northeast, winds from the northeast...
Limited occurrence of denitrification in four shallow aquifers in agricultural areas of the United States
C.T. Green, L.J. Puckett, J.K. Böhlke, B.A. Bekins, S.P. Phillips, L. J. Kauffman, J. M. Denver, H.M. Johnson
2008, Journal of Environmental Quality (37) 994-1009
The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin...
Processes of coastal bluff erosion in weakly lithified sands, Pacifica, California, USA
B.D. Collins, N. Sitar
2008, Geomorphology (97) 483-501
Coastal bluff erosion and landsliding are currently the major geomorphic processes sculpting much of the marine terrace dominated coastline of northern California. In this study, we identify the spatial and temporal processes responsible for erosion and landsliding in an area of weakly lithified sand coastal bluffs located south of San...
Eruption dynamics at Mount St. Helens imaged from broadband seismic waveforms: Interaction of the shallow magmatic and hydrothermal systems
G.P. Waite, B. A. Chouet, P.B. Dawson
2008, Journal of Geophysical Research B: Solid Earth (113)
The current eruption at Mount St. Helens is characterized by dome building and shallow, repetitive, long-period (LP) earthquakes. Waveform cross-correlation reveals remarkable similarity for a majority of the earthquakes over periods of several weeks. Stacked spectra of these events display multiple peaks between 0.5 and 2 Hz that are common...
Sensitivity of summer climate to anthropogenic land-cover change over the Greater Phoenix, AZ, region
M. Georgescu, G. Miguez-Macho, L. T. Steyaert, C.P. Weaver
2008, Journal of Arid Environments (72) 1358-1373
This work evaluates the first-order effect of land-use/land-cover change (LULCC) on the summer climate of one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, AZ, region. High-resolution-2-km grid spacing-Regional Atmospheric Modeling System (RAMS) simulations of three "wet" and three "dry" summers were carried out for two different...
Regularized joint inverse estimation of extreme rainfall amounts in ungauged coastal basins of El Salvador
M.J. Friedel
2008, Natural Hazards (46) 15-34
A regularized joint inverse procedure is presented and used to estimate the magnitude of extreme rainfall events in ungauged coastal river basins of El Salvador: Paz, Jiboa, Grande de San Miguel, and Goascoran. Since streamflow measurements reflect temporal and spatial rainfall information, peak-flow discharge is hypothesized to represent a similarity...
Characterization of the shallow groundwater system in an alpine watershed: Handcart Gulch, Colorado, USA
Katherine G. Kahn, Shemin Ge, Jonathan S. Caine, A. Manning
2008, Hydrogeology Journal (16) 103-121
Water-table elevation measurements and aquifer parameter estimates are rare in alpine settings because few wells exist in these environments. Alpine groundwater systems may be a primary source of recharge to regional groundwater flow systems. Handcart Gulch is an alpine watershed in Colorado, USA comprised of highly fractured Proterozoic metamorphic and...
Fluctuating Arctic Sea ice thickness changes estimated by an in situ learned and empirically forced neural network model
G. I. Belchansky, David C. Douglas, Nikita G. Platonov
2008, Journal of Climate (21) 716-729
Sea ice thickness (SIT) is a key parameter of scientific interest because understanding the natural spatiotemporal variability of ice thickness is critical for improving global climate models. In this paper, changes in Arctic SIT during 1982-2003 are examined using a neural network (NN) algorithm trained with in situ submarine ice...
Stand-level forest structure and avian habitat: Scale dependencies in predicting occurrence in a heterogeneous forest
K.M. Smith, W.S. Keeton, T.M. Donovan, B. Mitchell
2008, Forest Science (54) 36-46
We explored the role of stand-level forest structure and spatial extent of forest sampling in models of avian occurrence in northern hardwood-conifer forests for two species: black-throated blue warbler (Dendroica caerulescens) and ovenbird (Seiurus aurocapillus). We estimated site occupancy from point counts at 20 sites and characterized the forest structure...
