Temperature-profile methods for estimating percolation rates in arid environments
Jim Constantz, Scott W. Tyler, Edward Kwicklis
2003, Vadose Zone Journal (2) 12-24
Percolation rates are estimated using vertical temperature profiles from sequentially deeper vadose environments, progressing from sediments beneath stream channels, to expansive basin-fill materials, and finally to deep fractured bedrock underlying mountainous terrain. Beneath stream channels, vertical temperature profiles vary over time in response to downward heat transport, which is generally...
Measurements of thermal updraft intensity over complex terrain using American white pelicans and a simple boundary-layer forecast model
H.D. Shannon, G.S. Young, M. Yates, Mark R. Fuller, W. Seegar
2003, Boundary-Layer Meteorology (104) 167-199
An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of...
How should environmental stress affect the population dynamics of disease?
Kevin D. Lafferty, Robert D. Holt
2003, Ecology Letters (6) 654-664
We modelled how stress affects the population dynamics of infectious disease. We were specifically concerned with stress that increased susceptibility of uninfected hosts when exposed to infection. If such stresses also reduced resources, fecundity and/or survivorship, there was a reduction in the host carrying capacity. This lowered the contact between...
Characterization of the time-dependent strain field at seismogenic depths using first-motion focal mechanisms: Observations of large-scale decadal variations in stress along the San Andrea fault system
S.A. Sipkin, P.G. Silver
2003, Journal of Geophysical Research B: Solid Earth (108)
We present a method for summing moment tensors derived from first-motion focal mechanisms to study temporal dependence in features of the subsurface regional strain field. Time-dependent processes are inferred by comparing mechanisms summed over differing time periods. We apply this methodology to seismogenic zones in central and southern California using...
Bark heat resistance of small trees in Californian mixed conifer forests: Testing some model assumptions
Phillip J. van Mantgem, Mark Schwartz
2003, Forest Ecology and Management (178) 341-352
An essential component to models of fire-caused tree mortality is an assessment of cambial damage. Cambial heat resistance has been traditionally measured in large overstory trees with thick bark, although small trees have thinner bark and thus are more sensitive to fire. We undertook this study to determine if...
Modeling species-abundance relationships in multi-species collections
S. Peng, Z. Yin, H. Ren, Q. Guo
2003, Acta Ecologica Sinica (23) 1590-1605
Species-abundance relationship is one of the most fundamental aspects of community ecology. Since Motomura first developed the geometric series model to describe the feature of community structure, ecologists have developed many other models to fit the species-abundance data in communities. These models can be classified into empirical and theoretical ones,...
Growth rate predicts mortality of Abies concolor in both burned and unburned stands
Phillip J. van Mantgem, Nathan L. Stephenson, Linda S. Mutch, Veronica G. Johnson, Annie M. Esperanza, David J. Parsons
2003, Canadian Journal of Forest Research (33) 1029-1038
Tree mortality is often the result of both long-term and short-term stress. Growth rate, an indicator of long-term stress, is often used to estimate probability of death in unburned stands. In contrast, probability of death in burned stands is modeled as a function of short-term disturbance severity. We sought to...
The economics of protecting tiger populations: Linking household behavior to poaching and prey depletion
R. Damania, R. Stringer, K. U. Karanth, B. Stith
2003, Land Economics (79) 198-216
The tiger (Panthera tigris) is classified as endangered and populations continue to decline. This paper presents a formal economic analysis of the two most imminent threats to the survival of wild tigers: poaching tigers and hunting their prey. A model is developed to examine interactions between tigers and farm households...
Temporal species richness-biomass relationships along successional gradients
Q. Guo
2003, Journal of Vegetation Science (14) 121-128
Diversity-biomass relationships are frequently reported to be hump-shaped over space at a given time. However, it is not yet clear how diversity and biomass change simultaneously and how they are related to each other over time (e.g. in succession) at one locality. This study develops a temporal model based on...
Managed forest reserves: preserving diversity
John Tappeiner, Nathan Poage, Janet L. Erickson
2003, Fact Sheet 034-03
<span data-sheets-value="{"1":2,"2":"Background\n\nAs part of the Northwest Forest Plan, large areas have been designated on many federal forests in western Oregon to provide critical habitat for plants and animals that are associated with old-growth habitat. Some of the structural characteristics often considered typical of old forests include large-diameter overstory trees, large...
Visible/near-infrared spectra of experimentally shocked plagioclase feldspars
J. R. Johnson, F. Horz
2003, Journal of Geophysical Research E: Planets (108) 6-1
High shock pressures cause structural changes in plagioclase feldspars such as mechanical fracturing and disaggregation of the crystal lattice at submicron scales, the formation of diaplectic glass (maskelynite), and genuine melting. Past studies of visible/ near-infrared spectra of shocked feldspars demonstrated few spectral variations with pressure except for a decrease...
Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands
Jon E. Keeley
2003, Diversity and Distributions (9) 253-259
Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands...
Kinetic dissolution of carbonates and Mn oxides in acidic water: Measurement of in situ field rates and reactive transport modeling
J. G. Brown, P. D. Glynn
2003, Applied Geochemistry (18) 1225-1239
The kinetics of carbonate and Mn oxide dissolution under acidic conditions were examined through the in situ exposure of pure phase samples to acidic ground water in Pinal Creek Basin, Arizona. The average long-term calculated in situ dissolution rates for calcite and dolomite were 1.65??10-7 and 3.64??10-10 mmol/(cm2 s), respectively,...
Wetlands: Crop freezes and land-use change in Florida
C. H. Marshall, R.A. Pielke Sr., L. T. Steyaert
2003, Nature (426) 29-30
South Florida experienced a significant change in land usage during the twentieth century, including the conversion of natural wetlands into agricultural land for the cultivation of winter vegetable, sugar cane and citrus crops. This movement of agriculture from more northerly areas was intended partly...
Exposure and effects of chemical contaminants on tree swallows nesting along the Housatonic River, Berkshire County, Massachusetts, USA, 1998-2000
Christine M. Custer, T. W. Custer, P.M. Dummer, K.L. Munney
2003, Environmental Toxicology and Chemistry (22) 1605-1621
Hatching success of tree swallows (Tachycineta bicolor) was assessed for three years in relation to chemical contamination along the Housatonic River, Berkshire County (MA, USA), in 1998, 1999, and 2000. Nest boxes were erected at five sites along the Housatonic River and its tributaries and at one reference location. Concentrations...
A 16,000 14C yr B.P. packrat midden series from the USA-Mexico Borderlands
C.A. Holmgren, M.C. Penalba, K.A. Rylander, J.L. Betancourt
2003, Quaternary Research (60) 319-329
A new packrat midden chronology from Playas Valley, southwestern New Mexico, is the first installment of an ongoing effort to reconstruct paleovegetation and paleoclimate in the U.S.A.-Mexico Borderlands. Playas Valley and neighboring basins supported pluvial lakes during full and/or late glacial times. Plant macrofossil and pollen assemblages from nine middens...
Patterns and sources of multidecadal oscillations in drought-sensitive tree-ring records from the central and southern Rocky Mountains
S.J. Gray, J.L. Betancourt, C.L. Fastie, S.T. Jackson
2003, Geophysical Research Letters (30) 49-1
Tree-ring records spanning the past seven centuries from the central and southern Rocky Mountains were studied using wavelet analysis to examine multidecadal (>30-70 yr) patterns of drought variation. Fifteen tree-ring series were grouped into five regional composite chronologies based on shared low-frequency behavior. Strong multidecadal phasing of moisture variation was...
The typological approach to submarine groundwater discharge (SGD)
H. Bokuniewicz, R. Buddemeier, B. Maxwell, C. Smith
2003, Biogeochemistry (66) 145-158
Coastal zone managers need to factor submarine groundwater discharge (SGD) in their integration. SGD provides a pathway for the transfer of freshwater, and its dissolved chemical burden, from the land to the coastal ocean. SGD reduces salinities and provides nutrients to specialized coastal habitats. It also can be a pollutant...
Modeling radium and radon transport through soil and vegetation
J.A. Kozak, H. W. Reeves, B.A. Lewis
2003, Journal of Contaminant Hydrology (66) 179-200
A one-dimensional flow and transport model was developed to describe the movement of two fluid phases, gas and water, within a porous medium and the transport of 226Ra and 222Rn within and between these two phases. Included in this model is the vegetative uptake of water and aqueous 226Ra and...
Sediment transport and deposition processes near ocean outfalls in southern California
H.J. Lee, M.A. Noble, J. Xu
Locat J.Galvez-Cloutier R.Chaney R.Demars K., editor(s)
2003, Conference Paper, ASTM Special Technical Publication
An urbanized coastal ocean that has complex topography and large-scale atmospheric and oceanographic forcing can contain a variety of sediment and pollutant distribution patterns. For example, the central southern California Bight has two large embayments, Santa Monica and San Pedro Bays, that are connected by a short, very narrow shelf...
Movement and habitat use by radio-tagged paddlefish in the upper Mississippi River and tributaries
S. J. Zigler, M. R. Dewey, B.C. Knights, A.L. Runstrom, M.T. Steingraeber
2003, North American Journal of Fisheries Management (23) 189-205
We used radio telemetry to evaluate the movement and habitat use of paddlefish Polyodon spathula in the upper Mississippi River and two tributary rivers. Radio transmitters were surgically implanted into 71 paddlefish in Navigation Pools 5A and 8 of the upper Mississippi River, the Chippewa River, and the Wisconsin River...
Bottom-current and wind-pattern changes as indicated by Late Glacial and Holocene sediments from western Lake Geneva (Switzerland)
S. Girardclos, I. Baster, W. Wildi, A. Pugin, A. #NAME? Rachoud-Schneider
2003, Ecologae Geologicae Helvetiae (96)
The Late-Glacial and Holocene sedimentary history of the Hauts-Monts area (western Lake Geneva, Switzerland) is reconstructed combining high resolution seismic stratigraphy and well-dated sedimentary cores. Six reflections and seismic units are defined and represented by individual isopach maps, which are further combined to obtain a three-dimensional age-depth model. Slumps, blank...
Global occurrence of tellurium-rich ferromanganese crusts and a model for the enrichment of tellurium
J.R. Hein, A. Koschinsky, A. N. Halliday
2003, Geochimica et Cosmochimica Acta (67) 1117-1127
Hydrogenetic ferromanganese oxyhydroxide crusts (Fe-Mn crusts) precipitate out of cold ambient ocean water onto hard-rock surfaces (seamounts, plateaus, ridges) at water depths of about 400 to 4000 m throughout the ocean basins. The slow-growing (mm/Ma) Fe-Mn crusts concentrate most elements above their mean...
Comparison of heat and bromide as ground-water tracers near streams
J. Constantz, M.H. Cox, G.W. Su
2003, Ground Water (41) 647-656
Heat and bromide were compared as tracers for examining stream/ground water exchanges along the middle reaches of the Santa Clara River, California, during a 10-hour surface water sodium bromide injection test. Three cross sections that comprise six shallow (<1 m) piezometers were installed at the upper, middle, and lower sections...
Effects of lampricide exposure on the survival, growth, and behavior of the unionid mussels Elliptio complanata and Pyganadon cataracta
D. L. Waller, T.D. Bills, M.A. Boogaard, D.A. Johnson, T.C.J. Doolittle
2003, Conference Paper, Journal of Great Lakes Research
The effects of a 12-h exposure to the lampricide 3-trifluoromethyl-4- nitrophenol (TFM) and a combination of TFM and 1% niclosamide (active ingredient in Bayluscide 70% wettable powder) on the short and long-term (10 mo post exposure) survival and behavior of two unionid freshwater mussel species Elliptio complanata and Pyganadon cataracta...
