Recent formation of arroyos in the Little Missouri Badlands of southwestern North Dakota
M.A. Gonzalez
2001, Geomorphology (38) 63-84
In the Little Missouri Badlands of southwestern North Dakota, the channels of ephemeral streams are incised 2 to 10 m or more into mid-to-late Holocene alluvium. The objectives of this study were to determine the timing and cause(s) of the most recent episodes of fluvial incision and to develop a...
The Foraging Ecology of Royal and Sandwich Terns in North Carolina, USA
T.W. McGinnis, S.D. Emslie
2001, Waterbirds (24) 361-370
Population sizes of territorial male red-winged blackbirds (Agelaius phoeniceus) were determined with counts of territorial males (area count) and a Petersen-Lincoln Index method for roadsides (roadside estimate). Weather conditions and time of day did not influence either method. Combined roadside estimates had smaller error bounds than the individual...
Historical overfishing and the recent collapse of coastal ecosystems
J.B.C. Jackson, M.X. Kirby, W.H. Berger, K.A. Bjorndal, L.W. Botsford, B.J. Bourque, R. Bradbury, R. Cooke, J. Erlandson, J. A. Estes, T.P. Hughes, S. Kidwell, C.B. Lange, H.S. Lenihan, J.M. Pandolfi, C. H. Peterson, R.S. Steneck, M. J. Tegner, R. Warner
2001, Science (293) 629-638
A method for calculating parameters necessary to maintain stable populations is described and the management implications of the method are discussed. This method depends upon knowledge of the population mortality rate schedule, the age at which the species reaches maturity, and recruitment rates or age ratios in the population....
Standardized seawater rearing of chinook salmon smolts to evaluate hatchery practices showed low statistical power
Aldo N. Palmisano, N.E. Elder
2001, Transactions of the American Fisheries Society (130) 409-416
We examined, under standardized conditions, seawater survival of chinook salmon Oncorhynchus tshawytscha at the smolt stage to evaluate the experimental hatchery practices applied to their rearing. The experimental rearing practices included rearing fish at different densities; attempting to control bacterial kidney disease with broodstock segregation, erythromycin injection, and an experimental...
On incorporating fire into our thinking about natural ecosystems: A response to Saha and Howe
Jon E. Keeley, William J. Bond
2001, American Naturalist (158) 664-670
Ecologists long have had a fascination with fire impacts, although they have been slow to incorporate this ecological factor into serious thinking about the structure of communities and evolution of species (Bond and van Wilgen 1996). The remarks by Saha and Howe (2001, in this issue) illustrate some of the...
History and management of crown-fire ecosystems: A summary and response
Jon E. Keeley, C. J. Fotheringham
2001, Conservation Biology (15) 1561-1567
Some ecosystems, such as yellow pine forests, have had a long history of frequent surface fires, but because of fire suppression policy, fires have been largely excluded from them during the last century (Covington 2000). Unnatural fuel accumulation in these forests has increased the potential for large, catastrophic crown fires,...
Juxtaposition of Neoproterozoic units along the Baruda - Tulu Dimtu shear-belt in the East African Orogen of western Ethiopia
A. Braathen, Tor Grenne, M.G. Selassie, T. Worku
2001, Precambrian Research (107) 215-234
Amalgamation of East and West Gondwanaland during the Neoproterozoic East African Orogen is recorded by several shear-belts or 'suture zones', some of which are associated with ultramafic and mafic complexes that have been interpreted as ophiolite fragments. The Baruda shear-belt is a major structure of this type that belongs to...
Analysis of radiation-induced small Cu particle cluster formation in aqueous CuCl2
Sumedha Jayanetti, Robert A. Mayanovic, Alan J. Anderson, William A. Bassett, I.-M. Chou
2001, Journal of Chemical Physics (115) 954-962
Radition-induced small Cu particle cluster formation in aqueous CuCl2 was analyzed. It was noticed that nearest neighbor distance increased with the increase in the time of irradiation. This showed that the clusters approached the lattice dimension of bulk copper. As the average cluster size approached its bulk dimensions, an increase...
Survey protocol for assessment of endangered freshwater mussels the Allegheny River, Pennsylvania
D. R. Smith, R.F. Villella, D. P. Lemarie
2001, Journal of North American Benthological Society (20) 118-132
The United States Endangered Species Act (ESA) requires a biological assessment of any activity that is authorized, funded, or carried out by a federal agency and likely to affect a federally listed endangered species or its critical habitat. We developed a standardized survey protocol for biological assessments of the effects...
Release from parasites as natural enemies: increased performance of a globally introduced marine crab
Mark E. Torchin, Kevin D. Lafferty, Armand M. Kuris
2001, Biological Invasions (3) 333-345
Introduced species often seem to perform better than conspecifics in their native range. This is apparent in the high densities they may achieve or the larger individual sizes they attain. A prominent hypothesis explaining the success of introduced terrestrial species is that they are typically free of or are less...
Experimental repatriation of boreal toad (Bufo boreas) eggs, metamorphs, and adults in Rocky Mountain National Park
E. Muths, T. L. Johnson, P.S. Corn
2001, Southwestern Naturalist (46) 106-113
The boreal toad (Bufo boreas) is an endangered species in Colorado and is considered a candidate species for federal listing by the United States Fish and Wildlife Service. Boreal toads are absent from many areas of suitable habitat in the Southern Rocky Mountains of Colorado presumably due to a combination...
Recent growth of conifer species of western North America: Assessing spatial patterns of radial growth trends
D. McKenzie, Amy E. Hessl, D. L. Peterson
2001, Canadian Journal of Forest Research (31) 526-538
We explored spatial patterns of low-frequency variability in radial tree growth among western North American conifer species and identified predictors of the variability in these patterns. Using 185 sites from the International Tree-Ring Data Bank, each of which contained 10a??60 raw ring-width series, we rebuilt two chronologies for each site,...
Degradation of marine ecosystems and decline of fishery resources in marine protected areas in the US Virgin Islands
C.S. Rogers, J. Beets
2001, Environmental Conservation (28) 312-322
The large number of marine protected areas (MPAs) in the Caribbean (over 100) gives a misleading impression of the amount of protection the reefs and other marine resources in this region are receiving. This review synthesizes information on marine resources in two of the first MPAs established in the USA,...
Decline of disjunct green salamander (Aneides aeneus) populations in the southern appalachians
Jeffrey D. Corser
2001, Biological Conservation (97) 119-126
Coincident with other amphibians around the world Aneides aeneus, a terrestrial plethodontid salamander, suffered a population collapse in a disjunct portion of its range in the mid-late 1970s. Long-term monitoring of seven historical green salamander populations throughout the 1990s showed a 98% decline in relative abundance since 1970. Three out...
Utility of stable isotope analysis in studying foraging ecology of herbivores: Examples from moose and caribou
Merav Ben-David, Einav Shochat, Layne G. Adams
2001, Alces (37) 421-434
Recently, researchers emphasized that patterns of stable isotope ratios observed at the individual level are a result of an interaction between ecological, physiological, and biochemical processes. Isotopic models for herbivores provide additional complications because those mammals consume foods that have high variability in nitrogen concentrations. In addition, distribution of amino...
Historic fire regime in southern California shrublands
Jon E. Keeley, C. J. Fotheringham
2001, Conservation Biology (15) 1536-1548
Historical variability in fire regime is a conservative indicator of ecosystem sustainability, and thus understanding the natural role of fire in chaparral ecosystems is necessary for proper fire management. It has been suggested that the “natural” fire regime was one of frequent small fires that fragmented the landscape into a...
Diapause in copepods (Crustacea) from ephemeral habitats with different hydroperiods in Everglades National Park (Florida, U.S.A.)
M.C. Bruno, W.F. Loftus, J.W. Reid, S.A. Perry
2001, Conference Paper, Hydrobiologia
Water management practices in the Everglades have severely stressed the natural system, particularly by reducing the hydroperiods of much of the region. During the dry season of 1999, we investigated the influence of hydroperiod on the species composition and dormancy patterns of freshwater copepod communities in seasonal wetlands of Everglades...
A comparison of susceptibility to Myxobolus cerebralis among strains of rainbow trout and steelhead field and laboratory trials
Christine L. Densmore, V. S. Blazer, Deborah D. Cartwright, W. B. Schill, J. H. Schachte, C. J. Petrie, M.V. Batur, T.B. Waldrop, A. Mack, P.S. Pooler
2001, Journal of Aquatic Animal Health (13) 220-227
Three strains of rainbow trout and steelhead Oncorhynchus mykiss were evaluated for the presence of whirling disease in field and laboratory trials. In the field exposures, fingerling Salmon River steelhead and Cayuga Lake and Randolph strains of rainbow trout were placed in wire cages in an earthen, stream-fed pond in New York...
Chlorine-36, bromide, and the origin of spring water
S.N. Davis, L.D. Cecil, M. Zreda, S. Moysey
2001, Chemical Geology (179) 3-16
Natural ratios of chlorine-36 (36Cl) to stable chlorine (i.e., 36Cl/Cl ?? 10-15) vary in shallow groundwater of the United States from about 50 in coastal areas to about 1400 in the northern Rocky Mountains. Ratios lower than these indicate the presence of chloride (Cl-) that has been isolated from the...
Statistical self-similarity of hotspot seamount volumes modeled as self-similar criticality
S.F. Tebbens, S.M. Burroughs, C.C. Barton, D. F. Naar
2001, Geophysical Research Letters (28) 2711-2714
The processes responsible for hotspot seamount formation are complex, yet the cumulative frequency-volume distribution of hotspot seamounts in the Easter Island/Salas y Gomez Chain (ESC) is found to be well-described by an upper-truncated power law. We develop a model for hotspot seamount formation where uniform energy input produces events initiated...
From open to closed canopy: A century of change in Douglas-fir forest, Orcas Island, Washington
D. L. Peterson, R.D. Hammer
2001, Northwest Science (75) 262-269
During the past century, forest structure on south-facing slopes of Mount Constitution, Orcas Island, Washington, has changed from open-grown Douglas-fir (Pseudotsuga menziesii) mixed with prairie to primarily closed canopy forest. Density of open-grown Douglas-fir was approximately 7 stems/ha in the 19th century, while current density of trees in closed-canopy mature forest is 426 stems/ha....
New digital magnetic anomaly database for North America
C. A. Finn, M. Pilkington, A. Cuevas, I. Hernandez, Jaime Urrutia
2001, The Leading Edge (20) 870-872
The Geological Survey of Canada (GSC), U.S. Geological Survey (USGS), and Consejo de Recursos Minerales of Mexico (CRM) are compiling an upgraded digital magnetic anomaly database and map for North America. This trinational project is expected to be completed by late 2002....
Winter distributions of North American Plovers in the Laguna Madre regions of Tamaulipas, Mexico and Texas, USA
Todd J. Mabee, Jonathan H. Plissner, Susan M. Haig, J. P. Goossen
2001, Wader Study Group Bulletin (94) 39-43
To determine the distribution and abundance of wintering plovers in the Laguna Madre of Texas and Tamaulipas, surveys were conducted in December 1997 and February 1998, along a 160 km stretch of barrier islands in Mexico and- 40 km of shoreline on South Padre Island, Texas. Altogether, 5,673 individuals, representing...
Evolution of the December 14, 1989 precursory long-period event swarm at Redoubt volcano, Alaska
C.D. Stephens, B. A. Chouet
2001, Journal of Volcanology and Geothermal Research (109) 133-148
The intermittency pattern and evolution in waveforms of long-period (LP) seismic events during the intense, 23-h swarm that preceded the December 14, 1989 eruption of Redoubt volcano are investigated. Utilizing cross correlation to exploit the high degree of similarity among waveforms, a substantially more complete event catalog is generated than...
Dating the Vostok ice core record by importing the Devils Hole chronology
J.M. Landwehr, I.J. Winograd
2001, Journal of Geophysical Research D: Atmospheres (106) 31853-31861
The development of an accurate chronology for the Vostok record continues to be an open research question because these invaluable ice cores cannot be dated directly. Depth-to-age relationships have been developed using many different approaches, but published age estimates are inconsistent, even for major paleoclimatic events. We have developed a...
