Butterfly responses to prairie restoration through fire and grazing
Jennifer A. Vogel, Diane M. Debinski, Rolf R. Koford, J.R. Miller
2007, Biological Conservation (140) 78-90
The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and...
Diel changes in water chemistry in an arsenic-rich stream and treatment-pond system
Christopher H. Gammons, T.M. Grant, David Nimick, S.R. Parker, M.D. DeGrandpre
2007, Science of the Total Environment (384) 433-451
Arsenic concentrations are elevated in surface waters of the Warm Springs Ponds Operable Unit (WSPOU), located at the head of the upper Clark Fork River Superfund site, Montana, USA. Arsenic is derived from historical deposition of smelter emissions (Mill and Willow Creeks) and historical mining and milling wastes (Silver Bow...
Testing ecological and behavioral correlates of nest predation
J.J. Fontaine, M. Martel, H.M. Markland, Alina M. Niklison, Karie L. Decker, T. E. Martin
2007, Oikos (116) 1887-1894
Variation in nest predation rates among bird species are assumed to reflect differences in risk that are specific to particular nest sites. Theoretical and empirical studies suggest that parental care behaviors can evolve in response to nest predation risk and thereby differ among ecological conditions that vary in inherent risk....
Formation and disruption of aquifers in southwestern Chryse Planitia, Mars
J.A.P. Rodriguez, K.L. Tanaka, J.S. Kargel, J. M. Dohm, R. Kuzmin, A.G. Fairen, S. Sasaki, G. Komatsu, Dirk Schulze-Makuch, Y. Jianguo
2007, Icarus (191) 545-567
We present geologic evidence suggesting that after the development of Mars' cryolithosphere, the formation of aquifers in southwestern Chryse Planitia and their subsequent disruption led to extensive regional resurfacing during the Late Hesperian, and perhaps even during the Amazonian. In our model, these aquifers formed preferentially along thrust faults associated...
A stand-replacing fire history in upper montane forests of the southern Rocky Mountains
E.Q. Margolis, T.W. Swetnam, Craig Allen
2007, Canadian Journal of Forest Research (37) 2227-2241
Dendroecological techniques were applied to reconstruct stand-replacing fire history in upper montane forests in northern New Mexico and southern Colorado. Fourteen stand-replacing fires were dated to 8 unique fire years (1842–1901) using four lines of evidence at each of 12 sites within the upper Rio Grande Basin. The four lines...
Field assessment of alternative bed-load transport estimators
G. Gaeuman, Robert B. Jacobson
2007, Journal of Hydraulic Engineering (133) 1319-1328
Measurement of near-bed sediment velocities with acoustic Doppler current profilers (ADCPs) is an emerging approach for quantifying bed-load sediment fluxes in rivers. Previous investigations of the technique have relied on conventional physical bed-load sampling to provide reference transport information with which to validate the ADCP measurements. However, physical samples are...
Habitat effects on condition of doe mule deer in arid mixed woodland-grassland
Louis C. Bender, L.A. Lomas, T. Kamienski
2007, Rangeland Ecology and Management (60) 277-284
Productivity of mule deer (Odocoileus hemionus Raf.) populations is closely linked to individual nutritional condition. We modeled body fat of individual does as a function of vegetation cover, composition, and water characteristics of their annual, summer, and winter home ranges in north-central New Mexico. We also modeled home range size...
Random forests for classification in ecology
D.R. Cutler, Thomas W.D. Edwards, K.H. Beard, A. Cutler, K.T. Hess, J. D. Gibson, J.J. Lawler
2007, Ecology (88) 2783-2792
Classification procedures are some of the most widely used statistical methods in ecology. Random forests (RF) is a new and powerful statistical classifier that is well established in other disciplines but is relatively unknown in ecology. Advantages of RF compared to other statistical classifiers include (1) very high classification accuracy;...
Individual dietary specialization and dive behaviour in the California sea otter: Using archival time-depth data to detect alternative foraging strategies
M. Tim Tinker, D.P. Costa, J.E. Estes, N. Wieringa
2007, Deep-Sea Research Part II: Topical Studies in Oceanography (54) 330-342
The existence of individual prey specializations has been reported for an ever-growing number of taxa, and has important ramifications for our understanding of predator-prey dynamics. We use the California sea otter population as a case study to validate the use of archival time-depth data to detect and measure differences in...
Remote sensing-based predictors improve distribution models of rare, early successional and broadleaf tree species in Utah
N.E. Zimmermann, Thomas W.D. Edwards, Gretchen G. Moisen, T.S. Frescino, J.A. Blackard
2007, Journal of Applied Ecology (44) 1057-1067
1. Compared to bioclimatic variables, remote sensing predictors are rarely used for predictive species modelling. When used, the predictors represent typically habitat classifications or filters rather than gradual spectral, surface or biophysical properties. Consequently, the full potential of remotely sensed predictors for modelling the spatial distribution of species remains unexplored....
Nitrous oxide fluxes from cultivated areas and rangeland: U.S. High Plains
Edwin P. Weeks, Peter B. McMahon
2007, Vadose Zone Journal (6) 496-510
Concentration profiles of N2O, a greenhouse gas, and the conservative trace gases SF6 and the chlorofluorocarbons CFC-11, CFC-12, CFC-113, and were measured periodically through thick vadose zones at nine sites in the U.S. High Plains. The CFC and SF6 measurements were used to calibrate a one-dimensional gas diffusion model, using...
The Penokean orogeny in the Lake Superior region
K. J. Schulz, William F. Cannon
2007, Precambrian Research (157) 4-25
The Penokean orogeny began at about 1880 Ma when an oceanic arc, now the Pembine-Wausau terrane, collided with the southern margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to...
Selection for rapid embryo development correlates with embryo exposure to maternal androgens among passerine birds
Hubert Schwabl, M.G. Palacios, T. E. Martin
2007, American Naturalist (170) 196-206
Greater offspring predation favors evolution of faster development among species. We hypothesized that greater offspring predation exerts selection on mothers to increase levels of anabolic androgens in egg yolks to achieve faster development. Here, we tested whether (1) concentrations of yolk androgens in passerine species were associated with offspring predation...
Recent records of alien anurans on the Pacific Island of Guam
M.T. Christy, C.S. Clark, D.E. Gee II, D. Vice, D.S. Vice, M.P. Warner, C.L. Tyrrell, G.H. Rodda, J. A. Savidge
2007, Pacific Science (61) 469-483
Eight anuran species were recorded for the first time in Guam in the period May 2003-December 2005, all apparently the result of arrivals to the island since 2000. Three of the eight species (Rana guentheri, Polypedates megacephalus, and Eleutherodactylus planirostris) had well-established breeding populations by 2005. A further three (Fejevarya...
Lack of association between ectoparasite intensities and rabies virus neutralizing antibody seroprevalence in wild big brown bats (Eptesicus fuscus), Fort Collins, Colorado
R.D. Pearce, Thomas J. O'Shea, V. Shankar, C. E. Rupprecht
2007, Vector-Borne and Zoonotic Diseases (7) 489-495
Recently, bat ectoparasites have been demonstrated to harbor pathogens of potential importance to humans. We evaluated antirabies antibody seroprevalence and the presence of ectoparasites in big brown bats (Eptesicus fuscus) sampled in 2002 and 2003 in Colorado to investigate if an association existed between ectoparasite intensity and exposure to rabies...
Regional dynamics of grassland change in the western Great Plains
M.A. Drummond
2007, Conference Paper, Great Plains Research
This paper examines the contemporary land-cover changes in two western Great Plains ecoregions between 1973 and 2000. Agriculture and other land uses can have a substantial effect on grassland cover that varies regionally depending on the primary driving forces of change. In order to better understand change, the rates, types,...
Recent results on the spatiotemporal modelling and comparative analysis of Black Death and bubonic plague epidemics
G. Christakos, Ricardo A. Olea, H.-L. Yu
2007, Public Health (121) 700-720
Background: This work demonstrates the importance of spatiotemporal stochastic modelling in constructing maps of major epidemics from fragmentary information, assessing population impacts, searching for possible etiologies, and performing comparative analysis of epidemics. Methods: Based on the theory previously published by the authors and incorporating new knowledge bases, informative maps of...
Characterizing dry deposition of mercury in urban runoff
Mark Fulkerson, F.N. Nnadi, L.S. Chasar
2007, Water, Air, & Soil Pollution (185) 21-32
Stormwater runoff from urban surfaces often contains elevated levels of toxic metals. When discharged directly into water bodies, these pollutants degrade water quality and impact aquatic life and human health. In this study, the composition of impervious surface runoff and associated rainfall was investigated for several storm events at an...
Distribution and sedimentary characteristics of tsunami deposits along the Cascadia margin of western North America
R. Peters, B. E. Jaffe, G. Gelfenbaum
2007, Sedimentary Geology (200) 372-386
Tsunami deposits have been found at more than 60 sites along the Cascadia margin of Western North America, and here we review and synthesize their distribution and sedimentary characteristics based on the published record. Cascadia tsunami deposits are best preserved, and most...
Heterogeneity of soil nutrients and subsurface biota in a dryland ecosystem
David C. Housman, C.M. Yeager, B.J. Darby, R.L. Sanford Jr., Cheryl R. Kuske, D.A. Neher, Jayne Belnap
2007, Soil Biology and Biochemistry (39) 2138-2149
Dryland ecosystems have long been considered to have a highly heterogeneous distribution of nutrients and soil biota, with greater concentrations of both in soils under plants relative to interspace soils. We examined the distribution of soil resources in two plant communities (dominated by either the shrub Coleogyne ramosissima or the...
Sulfur species behavior in soil organic matter during decomposition
A.W. Schroth, B.C. Bostick, M. Graham, James M. Kaste, M.J. Mitchell, A. J. Friedland
2007, Journal of Geophysical Research G: Biogeosciences (112)
Soil organic matter (SOM) is a primary re??servoir of terrestrial sulfur (S), but its role in the global S cycle remains poorly understood. We examine S speciation by X-ray absorption near-edge structure (XANES) spectroscopy to describe S species behavior during SOM decomposition. Sulfur species in SOM were best represented by...
Relation between mortality of prickly sculpin and diurnal extremes in water quality at Rodeo Lagoon, Marin County, California
B.A. Martin, M. K. Saiki, D. Fong
2007, California Fish and Game (93) 214-223
[No abstract available]...
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...
Scaling field data to calibrate and validate moderate spatial resolution remote sensing models
A. Baccini, M. A. Friedl, C. E. Woodcock, Z. Zhu
2007, Photogrammetric Engineering and Remote Sensing (73) 945-954
Validation and calibration are essential components of nearly all remote sensing-based studies. In both cases, ground measurements are collected and then related to the remote sensing observations or model results. In many situations, and particularly in studies that use moderate resolution remote sensing, a mismatch exists between the sensor’s field...
Intersex (Testicular Oocytes) in smallmouth bass from the Potomac River and selected nearby drainages
Vicki S. Blazer, Luke Iwanowicz, Deborah Iwanowicz, David R. Smith, John A. Young, J.D. Hedrick, S.W. Foster, S.J. Reeser
2007, Journal of Aquatic Animal Health (19) 242-253
Intersex, or the presence of characteristics of both sexes, in fishes that are normally gonochoristic has been used as an indicator of exposure to estrogenic compounds. In 2003, during health assessments conducted in response to kills and a high prevalence of skin lesions observed in smallmouth bass Micropterus dolomieu in...
