Introduced predators transform subarctic islands from grassland to tundra
D.A. Croll, J.L. Maron, J. A. Estes, E.M. Danner, G.V. Byrd
2005, Science (307) 1959-1961
Top predators often have powerful direct effects on prey populations, but whether these direct effects propagate to the base of terrestrial food webs is debated. There are few examples of trophic cascades strong enough to alter the abundance and composition of entire plant communities. We show that the introduction of...
Relation of baseflow to row crop intensity in Iowa
K. E. Schilling
2005, Agriculture, Ecosystems and Environment (105) 433-438
Increasing baseflow and baseflow percentage over the second half of the 20th century in Iowa has contributed to increasing nitrate-nitrogen concentrations measured in Iowa rivers because nitrate is primarily delivered to streams as baseflow and tile drainage. The relation of baseflow and baseflow percentage to row crop land use was...
The severity of Whirling disease among wild trout corresponds to the differences in genetic composition of tubifex tubifex populations in Central Colorado
K.A. Beauchamp, G.O. Kelley, R.B. Nehring, R.P. Hedrick
2005, Journal of Parasitology (91) 53-60
We analyzed the geographic distribution of Tubifex tubifex from various river drainages in central Colorado by genetic screening with specific mitochondrial 16S ribosomal DNA (mt 16S rDNA) markers. Four distinct mt 16S rDNA lineages are evident. The sites varied with respect to land- and water-use practices. All sites represented habitats...
Physiological response of wild rainbow trout to angling: Impact of angling duration, fish size, body condition, and temperature
Julie M. Meka, S. D. McCormick
2005, Fisheries Research (72) 311-322
This study evaluated the immediate physiological response of wild rainbow trout to catch-and-release angling in the Alagnak River, southwest Alaska. Information was recorded on individual rainbow trout (n = 415) captured by angling including landing time and the time required to remove hooks (angling duration), the time to anesthetize fish...
Influence of the Atchafalaya River on recent evolution of the chenier-plain inner continental shelf, northern Gulf of Mexico
A.E. Draut, G.C. Kineke, D.W. Velasco, M. A. Allison, R.J. Prime
2005, Continental Shelf Research (25) 91-112
This study examines the influence of the Atchafalaya River, a major distributary of the Mississippi River, on stratigraphic evolution of the inner continental shelf in the northern Gulf of Mexico. Sedimentary, geochemical, and shallow acoustic data are used to identify the western limit of the distal Atchafalaya subaqueous delta, and...
Earthquakes: Predicting the unpredictable?
Susan E. Hough
2005, Geotimes (50)
The earthquake prediction pendulum has swung from optimism in the 1970s to rather extreme pessimism in the 1990s. Earlier work revealed evidence of possible earthquake precursors: physical changes in the planet that signal that a large earthquake is on the way. Some respected earthquake scientists argued that earthquakes are likewise...
Factors affecting chick provisioning by Caspian Terns nesting in the Columbia River estuary
Scott K. Anderson, D.D. Roby, Donald E. Lyons, K. Collis
2005, Waterbirds (28) 95-105
We investigated factors affecting chick provisioning by radio-tagged Caspian Terns (Sterna caspia) nesting in a large colony on East Sand Island in the Columbia River estuary during 2001. Caspian Tern predation on juvenile salmonids (Oncorhynchus spp.) in the estuary prompted resource managers to relocate ca. 9,000 pairs of terns nesting...
Primary production in an impounded baldcypress swamp (Taxodium distichum) at the northern limit of the range
B.A. Middleton, K.L. McKee
2005, Conference Paper, Wetlands Ecology and Management
The ability of baldcypress (Taxodium distichum)swamps to maintain themselves near the northern limit of their range depends on their levels of production, which is not only are response to climate but also to local environmental factors(e.g., impoundment). We asked if primary production was reduced under impounded conditions and if species'...
Ecohydrological control of deep drainage in arid and semiarid regions
M.S. Seyfried, S. Schwinning, Michelle Ann Walvoord, W. T. Pockman, B.D. Newman, R.B. Jackson, F. M. Phillips
2005, Ecology (86) 277-287
The amount and spatial distribution of deep drainage (downward movement of water across the bottom of the root zone) and groundwater recharge affect the quantity and quality of increasingly limited groundwater in arid and semiarid regions. We synthesize research from the fields of ecology and hydrology to address the issue...
Dating offset fans along the Mojave section of the San Andreas fault using cosmogenic 26Al and 10Be
A. Matmon, David P. Schwartz, R. Finkel, S. Clemmens, T. Hanks
2005, Geological Society of America Bulletin (117) 795-807
Analysis of cosmogenic 10Be and 26Al in samples collected from exposed boulders (n = 20) and from buried sediment (n = 3) from offset fans along the San Andreas fault near Little Rock, California, yielded ages, ranging from 16 to 413 ka, which increase with distance from their source at...
Variability in vegetation effects on density and nesting success of grassland birds
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer
2005, Journal of Wildlife Management (69) 185-197
The structure of vegetation in grassland systems, unlike that in forest systems, varies dramatically among years on the same sites, and among regions with similar vegetation. The role of this variation in vegetation structure on bird density and nesting success of grassland birds is poorly understood, primarily because few studies...
Forest cover influences dispersal distance of white-tailed deer
E.S. Long, Duane R. Diefenbach, C.S. Rosenberry, B.D. Wallingford, M.D. Grund
2005, Journal of Mammalogy (86) 623-629
Animal dispersal patterns influence gene flow, disease spread, population dynamics, spread of invasive species, and establishment of rare or endangered species. Although differences in dispersal distances among taxa have been reported, few studies have described plasticity of dispersal distance among populations of a single species. In 2002-2003, we radiomarked 308...
Mercury burdens in Chinese mitten crabs (Eriocheir sinensis) in three tributaries of southern San Francisco Bay, California, USA
C. A. Hui, D. Rudnick, E. Williams
2005, Environmental Pollution (133) 481-487
Chinese mitten crabs (Eriocheir sinensis), endemic to Asia, were first reported in the San Francisco Bay in 1992. They are now established in nearly all San Francisco Bay tributaries. These crabs accumulate more metals, such as mercury, than crustaceans living in the water column. Because their predators include fish, birds,...
LogCauchy, log-sech and lognormal distributions of species abundances in forest communities
Z.-Y. Yin, S.-L. Peng, H. Ren, Q. Guo, Z.-H. Chen
2005, Ecological Modelling (184) 329-340
Species-abundance (SA) pattern is one of the most fundamental aspects of biological community structure, providing important information regarding species richness, species-area relation and succession. To better describe the SA distribution (SAD) in a community, based on the widely used lognormal (LN) distribution model with exp(-x2) roll-off on Preston's octave scale,...
Host population persistence in the face of introduced vector-borne diseases: Hawaii amakihi and avian malaria
B.L. Woodworth, C. T. Atkinson, D.A. Lapointe, P.J. Hart, C.S. Spiegel, E.J. Tweed, C. Henneman, J. LeBrun, T. Denette, R. DeMots, K.L. Kozar, D. Triglia, Dan Lease, A. Gregor, T. Smith, D. Duffy
2005, Proceedings of the National Academy of Sciences of the United States of America (102) 1531-1536
The past quarter century has seen an unprecedented increase in the number of new and emerging infectious diseases throughout the world, with serious implications for human and wildlife populations. We examined host persistence in the face of introduced vector-borne diseases in Hawaii, where introduced avian malaria and introduced vectors have...
Major and trace element composition of copiapite-group minerals and coexisting water from the Richmond mine, Iron Mountain, California
H.E. Jamieson, C. Robinson, Charles N. Alpers, R. Blaine McCleskey, D. Kirk Nordstrom, Ronald C. Peterson
2005, Chemical Geology (215) 387-405
Copiapite-group minerals of the general formula AR4(SO4)6(OH)2·nH2O, where A is predominantly Mg, Fe2+, or 0.67Al3+, R is predominantly Fe3+, and n is typically 20, are among several secondary hydrous Fe sulfates occurring in the inactive mine workings of the massive sulfide deposit at Iron Mountain, CA, a USEPA Superfund site...
Thermal state and complex geology of a heterogeneous salty crust of Jupiter's satellite, Europa
O. Prieto-Ballesteros, J.S. Kargel
2005, Icarus (173) 212-221
The complex geology of Europa is evidenced by many tectonic and cryomagmatic resurfacing structures, some of which are "painted" into a more visible expression by exogenic alteration processes acting on the principal endogenic cryopetrology. The surface materials emplaced and affected by this activity are mainly composed of water ice in...
A statistical approach to estimate the 3D size distribution of spheres from 2D size distributions
M. Kong, R.N. Bhattacharya, C. James, A. Basu
2005, Geological Society of America Bulletin (117) 244-249
Size distribution of rigidly embedded spheres in a groundmass is usually determined from measurements of the radii of the two-dimensional (2D) circular cross sections of the spheres in random flat planes of a sample, such as in thin sections or polished slabs. Several methods have been devised to find a...
Early marine life history of juvenile Pacific salmon in two regions of Puget Sound
E.J. Duffy, D.A. Beauchamp, R.M. Buckley
2005, Conference Paper, Estuarine, Coastal and Shelf Science
Puget Sound could differentially represent either a simple migration corridor or an important rearing environment during the potentially critical early marine residence period for different species of Pacific salmon. Recent declines in various stocks of Puget Sound salmon could reflect degraded rearing conditions or changes in temporal-spatial utilization patterns by...
Serosurvey of selected zoonotic agents in polar bears (Ursus maritimus)
H. Rah, B.B. Chomel, Erich H. Follmann, R.W. Kasten, C.H. Hew, T.B. Farver, G.W. Garner, Steven C. Amstrup
2005, Veterinary Record (156) 7-13
Between 1982 and 1999 blood samples were collected from 500 polar bears (Ursus maritimus) captured in the Beaufort and Chukchi seas, to determine the seroprevalence of Brucella species, Toxoplasma gondii, and Trichinella species infections. The bears were classified into four age groups, cubs, yearlings, subadults and adults. Brucella and Toxoplasma...
Fuel reduction and coarse woody debris dynamics with early season and late season prescribed fire in a Sierra Nevada mixed conifer forest
E. E. Knapp, Jon E. Keeley, E. A. Ballenger, T. J. Brennan
2005, Forest Ecology and Management (208) 383-397
Fire exclusion has led to an unnatural accumulation and greater spatial continuity of organic material on the ground in many forests. This material serves both as potential fuel for forest fires and habitat for a large array of forest species. Managers must balance fuel reduction to reduce wildfire hazard with...
Subduction-zone magnetic anomalies and implications for hydrated forearc mantle
R.J. Blakely, T.M. Brocher, R.E. Wells
2005, Geology (33) 445-448
Continental mantle in subduction zones is hydrated by release of water from the underlying oceanic plate. Magnetite is a significant byproduct of mantle hydration, and forearc mantle, cooled by subduction, should contribute to long-wavelength magnetic anomalies above subduction zones. We test this hypothesis with a quantitative model of the Cascadia...
Mineralogical and geochemical consequences of the long-term presence of CO2 in natural reservoirs: An example from the Springerville-St. Johns Field, Arizona, and New Mexico, U.S.A
Jeff Moore, M. Adams, R. Allis, S. Lutz, S. Rauzi
2005, Chemical Geology (217) 365-385
The Springerville-St. Johns CO2 field in eastern Arizona and western New Mexico is one of more than a dozen gas fields developed within the Colorado Plateau and Southern Rocky Mountain region. Extensive travertine (CaCO3) deposits record a long history of CO2 migration and leakage to the atmosphere. The oldest travertine...
Determination of goslarite-bianchite equilibria by the humidity-buffer technique at 0.1 MPa
I.-M. Chou, R.R. Seal II
2005, Chemical Geology (215) 517-523
Goslarite-bianchite equilibria were determined along four humidity-buffer curves at 0.1 MPa and between 27 and 36 ??C. Results, based on tight reversals along each humidity buffer, can be represented by ln K (??0.005)=19.643-7015.38/T, where K is the equilibrium constant and T is temperature in K. Our data are in excellent...
Retreating glacier fronts on the Antarctic Peninsula over the past half-century
A.J. Cook, A.J. Fox, D.G. Vaughan, J.G. Ferrigno
2005, Science (308) 541-544
The continued retreat of ice shelves on the Antarctic Peninsula has been widely attributed to recent atmospheric warming, but there is little published work describing changes in glacier margin positions. We present trends in 244 marine glacier fronts on the peninsula and associated islands over the past 61 years. Of...
