No consistent effect of plant diversity on productivity
M.A. Huston, L.W. Aarssen, M.P. Austin, B.S. Cade, J.D. Fridley, E. Garnier, J.P. Grime, J. Hodgson, W.K. Lauenroth, K. Thompson, J.H. Vandermeer, D.A. Wardle
2000, Science (289)
Hector et al. (1) reported on BIODEPTH, a major international experiment on the response of plant productivity to variation in the number of plant species. They found “an overall log-linear reduction of average aboveground biomass with loss of species,” leading to what the accompanying Perspective (2) described as “a rule...
Population estimates of Nearctic shorebirds
R. I. G. Morrison, Robert E. Gill Jr., B. A. Harrington, S. K. Skagen, G. W. Page, C. L. Gratto-Trevor, S. M. Haig
2000, Waterbirds (23) 337-352
Estimates are presented for the population sizes of 53 species of Nearctic shorebirds occurring regularly in North America, plus four species that breed occasionally. Shorebird population sizes were derived from data obtained by a variety of methods from breeding, migration and wintering areas, and formal assessments of accuracy of counts...
Linkage of bioaccumulation and biological effects to changes in pollutant loads in south San Francisco Bay
Michelle I. Hornberger, S. N. Luoma, D.J. Cain, F. Parchaso, C. L. Brown, R. M. Bouse, C. Wellise, J.K. Thompson
2000, Environmental Science & Technology (34) 2401-2409
The developed world has invested billions of dollars in waste treatment since the 1970s; however, changes in ecological or biological responses are rarely associated with reductions in metal pollutants. Here we present a novel, 23-yr time series of environmental change from a San Francisco Bay mudflat located...
REE speciation in low-temperature acidic waters and the competitive effects of aluminum
Serrano M.J. Gimeno, Sanz L.F. Auque, D. Kirk Nordstrom
2000, Chemical Geology (165) 167-180
The effect of simultaneous competitive speciation of dissolved rare earth elements (REEs) in acidic waters (pH 3.3 to 5.2) has been evaluated by applying the PHREEQE code to the speciation of water analyses from Spain, Brazil, USA, and Canada. The main ions that might affect REE are Al3+, F-, SO42-,...
Composition of fish communities in relation to stream acidification and habitat in the Neversink River, New York
Barry P. Baldigo, G.B. Lawrence
2000, Transactions of the American Fisheries Society (129) 60-76
The effects of acidification in lotic systems are not well documented. Spatial and temporal variability of habitat and water quality complicate the evaluation of acidification effects in streams and rivers. The Neversink River in the Catskill Mountains of southeastern New York, the tributaries of which vary from well buffered to...
Alunite-jarosite crystallography, thermodynamics, and geochronology
R.E. Stoffregen, Charles N. Alpers, J.L. Jambor
2000, Reviews in Mineralogy and Geochemistry (40) 453-479
The alunite supergroup consists of more than 40 mineral species that have in common the general formula DG3(TO4)2(OH,H2O)6. The D sites are occupied by monovalent (e.g. K, Na, NH4, Ag, Tl, H3O), divalent (e.g. Ca, Sr, Ba, Pb), trivalent (e.g. Bi, REE) or more rarely quadrivalent (Th) ions; G is Al or Fe3+ or rarely Ga...
Trace element geochemistry of altered volcanic ash layers (tonsteins) in late Permian coal-bearing formations of eastern Yunnan and western Guizhou Provinces, China
Y. Zhou, B.F. Bohor, Y. Ren
2000, International Journal of Coal Geology (44) 305-324
Trace element compositions were determined (by instrumental neutron activation analysis; INAA) in 30 samples of synsedimentary volcanic ash-derived tonsteins and detrital claystones from coal seams within the late Permian coal-bearing formation of eastern Yunnan and western Guizhou Provinces, China. The characteristics of trace-element geochemistry in the tonsteins can be distinguished...
Microscopic character of marine sediment containing disseminated gas hydrate. Examples from the Blake Ridge and the Middle America Trench
T.D. Lorenson
2000, Conference Paper, Annals of the New York Academy of Sciences
The presence of disseminated gas hydrate was inferred based on pore fluid geochemistry and downhole logging data, but was rarely observed at Ocean Drilling Program (ODP) Leg 164 (Blake Ridge), and Leg 170 (Middle America Trench, offshore from Costa Rica) drilling sites. Gas hydrate nucleation is likely to occur first...
Correlates to colonizations of new patches by translocated populations of bighorn sheep
F. J. Singer, M.E. Moses, S. Bellew, W. Sloan
2000, Restoration Ecology (8) 66-74
By 1950, bighorn sheep were extirpated from large areas of their range. Most extant populations of bighorn sheep (Ovis canadensis) in the Intermountain West consist of <100 individuals occurring in a fragmented distribution across the landscape. Dispersal and successful colonizations of unoccupied habitat patches has been rarely reported, and, in...
U-Th dating of single zircons from young granitoid xenoliths: New tools for understanding volcanic processes
J. B. Lowenstern, H.M. Persing, J. L. Wooden, M. Lanphere, J. Donnelly-Nolan, T.L. Grove
2000, Earth and Planetary Science Letters (183) 291-302
Multiple U-Th isotopic analyses of individual zircon crystals by ion microprobe define isochrons that discriminate between different crystallization ages of granitoid xenoliths in lavas erupted 1065 and 2000 years ago from Medicine Lake volcano, CA, USA. Zircon ages indicate at least two intrusive episodes, ~ 25 and ~ 90 ka,...
Nesting habitat and reproductive success of southwestern riparian birds
B.F. Powell, R.J. Steidl
2000, Condor (102) 823-831
Vegetation structure and floristic composition strongly influence the structure of bird communities. To assess the influence of vegetation and other environmental characteristics on songbirds, we quantified nest-site characteristics and reproductive success of a riparian songbird community in Arizona. Although we found interspecific variation in characteristics associated with nest sites, we...
Vegetation associations in a rare community type - Coastal tallgrass prairie
James B. Grace, Larry K. Allain, Charles Allen
2000, Plant Ecology (147) 105-115
The coastal prairie ecoregion is located along the northwestern coastal plain of the Gulf of Mexico in North America. Because of agricultural and urban development, less than 1% of the original 3.4 million ha of this ecosystem type remains in native condition, making it one of the most endangered ecosystems...
Predicting broad-scale occurrences of vertebrates in patchy landscapes
R.B. Boone, W.B. Krohn
2000, Landscape Ecology (15) 63-74
Spatially explicit landscape-scale models that predict species distributions, where patches of habitat are shown as having potential to be occupied or unoccupied, are increasingly common. To successfully use such data, one should understand how these predicted distributions are created and how their relative accuracies are assessed. Geographic ranges, defined upon...
Clostridium perfringens in Long Island Sound sediments: An urban sedimentary record
Marilyn R. Buchholtz ten Brink, E.L. Mecray, E.L. Galvin
2000, Journal of Coastal Research (16) 591-612
Clostridium perfringens is a conservative tracer and an indicator of sewage-derived pollution in the marine environment. The distribution of Clostridium perfringens spores was measured in sediments from Long Island Sound, USA, as part of a regional study designed to: (1) map the distribution of contaminated sediments; (2) determine transport and...
Determination of geochemical affinities of granitic rocks from the Aue-Schwarzenberg zone (Erzgebirge, Germany) by multivariate statistics
H.-J. Forster, J.C. Davis
2000, Neues Jahrbuch fur Mineralogie, Monatshefte (12) 529-542
Variscan granites of the Erzgebirge region can be effectively classified into five genetically distinct major groups by canonical analysis of geochemical variables. The same classification procedure, when applied to small plutons in the Aue-Schwarzenberg granite zone (ASGZ), shows that all ASGZ granites have compositional affinities to low-F biotite or low-F...
Unsaturated‐zone wedge beneath a large, natural lake
Donald O. Rosenberry
2000, Water Resources Research (36) 3401-3409
Lake Belle Taine (480 ha) in north central Minnesota receives on average 76,000 m3 d−1 of water from Little Sand Creek but has no outlet. Water seeps out of the lake, flows through glacial outwash, and discharges into three nearby lakes with stages 13–14 m lower than Belle Taine. Seepage‐meter data indicate...
Metal-sulfate salts from sulfide mineral oxidation
J.L. Jambor, D. Kirk Nordstrom, Charles N. Alpers
2000, Reviews in Mineralogy and Geochemistry (40) 302-350
The observation of “efflorescences,” or the flowering of salts, associated with periods of dryness in soils, in closed-basin lakes, in rock outcrops, and in mines and mine wastes has been noted since early antiquity. The formation of metal-sulfate salts, in connection with the mining of metals, was a phenomenon well...
Stratigraphy, geochemistry and tectonic significance of the Oligocene magmatic rocks of western Oaxaca, southern Mexico
B. Martiny, R. G. Martinez-Serrano, D. J. Moran-Zenteno, C. MacIas-Romo, R. A. Ayuso
2000, Conference Paper, Tectonophysics
In Western Oaxaca, Tertiary magmatic activity is represented by extensive plutons along the continental margin and volcanic sequences in the inland region. K-Ar age determinations reported previously and in the present work indicate that these rocks correspond to a relatively broad arc in this region that was active mainly during...
Silurian K-bentonites of the Dnestr Basin, Podolia, Ukraine
W.D. Huff, Stig M. Bergstrom, Dennis R. Kolata
2000, Journal of the Geological Society (157) 493-504
The Dnestr Basin of Podolia, Ukraine, is an epicratonic basin consisting of neritic carbonate and calcareous mudstone facies including a nearly complete Silurian sequence ranging from late Llandovery to late Pridoli in age. The Silurian section has served as a standard for regional and interregional studies as a consequence of...
Regional interdisciplinary paleoflood approach to assess extreme flood potential
Robert D. Jarrett, Edward M. Tomlinson
2000, Water Resources Research (36) 2957-2984
In the past decade, there has been a growing interest of dam safety officials to incorporate a risk‐based analysis for design‐flood hydrology. Extreme or rare floods, with probabilities in the range of about 10−3 to 10−7 chance of occurrence per year, are of continuing interest to the hydrologic and engineering communities for...
Volcanic history of El Chichon Volcano (Chiapas, Mexico) during the Holocene, and its impact on human activity
J.M. Espindola, J.L. Macias, R.I. Tilling, M.F. Sheridan
2000, Bulletin of Volcanology (62) 90-104
Before its devastating eruption in 1982, El Chichon Volcano was little known and did not appear on any listings of hazardous volcanoes. Subsequent geologic studies, based on stratigraphic and radiocarbon investigations, showed that at least three explosive eruptions had occurred previously at this volcano. In this paper, we present the...
Effects of management practices on grassland birds: Horned Lark
Meghan F. Dinkins, Amy L. Zimmerman, Jill A. Dechant, Barry D. Parkin, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Betty R. Euliss
2000, Report, Effects of management practices on grassland birds
Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds...
Effects of management practices on grassland birds: Vesper Sparrow
Jill A. Dechant, Meghan F. Dinkins, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Betty R. Euliss
2000, Report, Effects of management practices on grassland birds
Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds...
Effects of management practices on grassland birds: Swainson's Hawk
Jill A. Dechant, Meghan F. Dinkins, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Betty R. Euliss
2000, Report, Effects of management practices on grassland birds
Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds...
Recolonization and possible recovery of burrowing mayflies (Ephemeroptera: Ephemeridae: Hexagenia spp.) in Lake Erie of the Laurentian Great Lakes
Don W. Schloesser, Kenneth A. Krieger, Jan J.H. Ciborowski, Lynda D. Corkum
2000, Journal of Aquatic Ecosystem Stress and Recovery (8) 125-141
Burrowing mayflies of the genus Hexagenia spp. were widely distributed (ca. 80% of sites) and abundant (ca. 160 nymphs/m2) in the western basin of Lake Erie of the Laurentian Great Lakes in 1929–1930, prior to a period of anoxia in the mid 1950s. Nymphs were absent or rare...
