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 tamarisk habitat suitability map for the continental US
J.T. Morisette, C. S. Jarnevich, A. Ullah, W. Cai, J.A. Pedelty, J.E. Gentle, T.J. Stohlgren, J.L. Schnase
2006, Frontiers in Ecology and the Environment (4) 11-17
This paper presents a national-scale map of habitat suitability for tamarisk (Tamarix spp, salt cedar), a high-priority invasive species. We successfully integrate satellite data and tens of thousands of field sampling points through logistic regression modeling to create a habitat suitability map that is 90% accurate. This interagency effort...
History of the Fort Collins Science Center, U.S. Geological Survey
Thomas J. (compiler) O'Shea
2006, Open-File Report 2006-1336
The U.S. Geological Survey’s Fort Collins Science Center ("the Center") has been a nucleus of research, technology development, and associated scientific activities within the Department of the Interior for more than 30 years. The Center’s historical activities are deeply rooted in federal biological resources research and its supporting disciplines, particularly...
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...
2005 annual progress report: Elk and bison grazing ecology in the Great Sand Dunes complex of lands
Kate A. Schoenecker, Bruce C. Lubow, Linda Zeigenfuss, Julie Mao
2006, Open-File Report 2006-1267
In 2000 the U.S. Congress authorized the expansion of the former Great Sand Dunes National Monument by establishing a new Great Sand Dunes National Park and Preserve in its place, and establishing the Baca National Wildlife Refuge. The establishment of Great Sand Dunes National Park and Preserve and the new...
Field responses of Prunus serotina and Asclepias syriaca to ozone around southern Lake Michigan
J. P. Bennett, E.A. Jepsen, J.A. Roth
2006, Environmental Pollution (142) 354-366
Higher ozone concentrations east of southern Lake Michigan compared to west of the lake were used to test hypotheses about injury and growth effects on two plant species. We measured approximately 1000 black cherry trees and over 3000 milkweed stems from 1999 to 2001 for this purpose. Black cherry branch...
West Nile virus antibody prevalence in wild mammals, southern Wisconsin
Douglas E. Docherty, Michael D. Samuel, C.A. Nolden, Kristina F. Egstad, Kathryn M. Griffin
2006, Emerging Infectious Diseases (12) 1982-1984
Twenty percent prevalence of West Nile virus antibody was found in free-ranging medium-sized Wisconsin mammals. No significant differences were noted in antibody prevalence with regard to sex, age, month of collection, or species. Our results suggest a similar route of infection in these mammals....
USGS National Wildlife Health Center's Quarterly Wildlife Mortality Report
R. Sohn, K. A. Converse, G. McLaughlin
2006, Supplement to the Journal of Wildlife Diseases (42)
USGS National Wildlife Health Center's Quartlerly Wildlife Mortality Report
K. A. Converse, G. McLaughlin, Lori Steckervetz
2006, Supplement to the Journal of Wildlife Diseases (42)
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...
Increased levels of IgE and autoreactive, polyreactive IgG in wild rodents: implications for the hygiene hypothesis
A.P. Devalapalli, A. Lesher, K. Shieh, J.S. Solow, M.L. Everett, A.S. Edala, P. Whitt, Renee R. Long, N. Newton, W. Parker
2006, Scandinavian Journal of Immunology (64) 125-136
To probe the potential role of Th1 versus Th2 reactivity underlying the hygiene hypothesis, intrinsic levels of Th1-associated and Th2-associated antibodies in the serum of wild rodents were compared with that in various strains of laboratory rodents. Studies using rat lung antigens as a target indicated that wild rats have...
USGS/National Wildlife Health Center's Quarterly Wildlife Mortality Report
R. Sohn, K. A. Converse, G. McLaughlin
2006, Supplement to the Journal of Wildlife Diseases (42)
Importance of spatial autocorrelation in modeling bird distributions at a continental scale
V. Bahn, R.J. O’Connor, W.B. Krohn
2006, Ecography (29) 835-844
Spatial autocorrelation in species' distributions has been recognized as inflating the probability of a type I error in hypotheses tests, causing biases in variable selection, and violating the assumption of independence of error terms in models such as correlation or regression. However, it remains unclear whether these problems occur at...
Effects of feral horses in Great Basin landscapes on soils and ants: Direct and indirect mechanisms
E.A. Beever, J. E. Herrick
2006, Journal of Arid Environments (66) 96-112
We compared soil-surface penetration resistance and abundance of ant mounds at 12 western Great Basin sites (composed of 19 plots) either grazed by feral horses (Equus caballus) or having had horses removed for the last 10–14 years. Across this broad spatial domain (3.03 million ha), we minimized confounding due to abiotic...
Evaluation of eelgrass beds mapping using a high-resolution airborne multispectral scanner
H. Su, D. Karna, E. Fraim, M. Fitzgerald, J. S. Myers, R. Dominguez, B. Coffland, Lawrence R. Handley, T. Mace
2006, Photogrammetric Engineering and Remote Sensing (72) 789-797
Eelgrass (Zostera marina) can provide vital ecological functions in stabilizing sediments, influencing current dynamics, and contributing significant amounts of biomass to numerous food webs in coastal ecosystems. Mapping eelgrass beds is important for coastal water and nearshore estuarine monitoring, management, and planning. This study demonstrated the possible use of high...
Factors influencing the incidence of cowbird parasitism of least Bell's vireos
B.L. Sharp, B.E. Kus
2006, Journal of Wildlife Management (70) 682-690
Least Bell's vireo (Vireo bellii pusillus) is a federally endangered subspecies of Bell's vireo subject to high levels of brood parasitism by brown-headed cowbirds (Molothrus ater). Brood parasitism greatly reduces the reproductive success of the vireo. We examined the relationship of vegetation structure surrounding nests and of activity near the...
Titan Radar Mapper observations from Cassini's T3 fly-by
C. Elachi, S. Wall, M. Janssen, E. Stofan, R. Lopes, Randolph L. Kirk, R. Lorenz, J. Lunine, F. Paganelli, Laurence A. Soderblom, C. Wood, L. Wye, H. Zebker, Y. Anderson, S. Ostro, M. Allison, R. Boehmer, P. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, W. Johnson, K. Kelleher, D. Muhleman, G. Picardi, F. Posa, L. Roth, R. Seu, S. Shaffer, B. Stiles, S. Vetrella, R. West
2006, Nature (441) 709-713
Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark...
Occurrence and fate of organic contaminants during onsite wastewater treatment
K.E. Conn, L. B. Barber, G.K. Brown, R.L. Siegrist
2006, Environmental Science & Technology (40) 7358-7366
Onsite wastewater treatment systems serve approximately 25% of the U.S. population. However, little is known regarding the occurrence and fate of organic wastewater contaminants (OWCs), including endocrine disrupting compounds, during onsite treatment. A range of OWCs including surfactant metabolites, steroids, stimulants, metal-chelating agents, disinfectants, antimicrobial agents, and...
Longitudinal hydraulic analysis of river‐aquifer exchanges
C.P. Konrad
2006, Water Resources Research (42)
A longitudinal analysis of transient flow between a river and an underlying aquifer is developed to calculate flow rates between the river and the aquifer and the location of groundwater seepage into the river as it changes over time. Two flow domains are defined in the analysis: an upstream domain...
Grassland songbirds in a dynamic management landscape: Behavioral responses and management strategies
N.G. Perlut, A.M. Strong, T.M. Donovan, N. J. Buckley
2006, Ecological Applications (16) 2235-2247
In recent decades, earlier and more frequent harvests of agricultural grasslands have been implicated as a major cause of population declines in grassland songbirds. From 2002 to 2005, in the Champlain Valley of Vermont and New York, USA, we studied the reproductive success of Savannah Sparrows (Passerculus sandwichensis) and Bobolinks...
Volcanic history and 40Ar/39Ar and 14C geochronology of Terceira Island, Azores, Portugal
Andrew T. Calvert, Richard B. Moore, John P. McGeehin, Antonio Rodrigues da Silva
2006, Journal of Volcanology and Geothermal Research (156) 103-115
Seven new 40Ar/39Ar and 23 new radiocarbon ages of eruptive units, in support of new geologic mapping, improve the known chronology of Middle to Late Pleistocene and Holocene volcanic activity on the island of Terceira, Azores and define an east-to-west progression in stratovolcano growth. The argon ages indicate that Cinco Picos...
An agreement coefficient for image comparison
Lei Ji, Kevin Gallo
2006, Photogrammetric Engineering and Remote Sensing (72) 823-833
Combination of datasets acquired from different sensor systems is necessary to construct a long time-series dataset for remotely sensed land-surface variables. Assessment of the agreement of the data derived from various sources is an important issue in understanding the data continuity through the time-series. Some traditional measures, including correlation coefficient,...
Mixed-grass prairie passerines exhibit weak and variable responses to patch size
S.K. Davis, R.M. Brigham, T.L. Shaffer, P.C. James
2006, The Auk (123) 807-821
Much of our current understanding of the demographic effects of habitat fragmentation on bird populations is derived from studies of passerines in forests and tallgrass prairie surrounded by woody vegetation. We quantified grassland bird density, nest survival, and productivity in 41 native mixed-grass prairie pastures during 1997-2000 in southern Saskatchewan,...
Two models for evaluating landslide hazards
J.C. Davis, C.-J. Chung, G.C. Ohlmacher
2006, Computers & Geosciences (32) 1120-1127
Two alternative procedures for estimating landslide hazards were evaluated using data on topographic digital elevation models (DEMs) and bedrock lithologies in an area adjacent to the Missouri River in Atchison County, Kansas, USA. The two procedures are based on the likelihood ratio model but utilize different assumptions. The empirical likelihood...
Mapping of Titan: Results from the first Titan radar passes
E. R. Stofan, J. I. Lunine, R. Lopes, F. Paganelli, R. D. Lorenz, C. A. Wood, Randolph L. Kirk, S. Wall, C. Elachi, Laurence A. Soderblom, S. Ostro, M. Janssen, J. Radebaugh, L. Wye, H. Zebker, Y. Anderson, M. Allison, R. Boehmer, P. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, W.T.K. Johnson, K. Kelleher, D. Muhleman, G. Picardi, F. Posa, L. Roth, R. Seu, S. Shaffer, B. Stiles, S. Vetrella, R. West
2006, Icarus (185) 443-456
The first two swaths collected by Cassini's Titan Radar Mapper were obtained in October of 2004 (Ta) and February of 2005 (T3). The Ta swath provides evidence for cryovolcanic processes, the possible occurrence of fluvial channels and lakes, and some tectonic activity. The T3 swath has extensive areas of dunes...
