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Articles 3361 - 3390 of 3635

Full-Text Articles in Other Environmental Sciences

Domestic Well Water Quality In Rural Nebraska: Focus On Nitrate-Nitrogen, Pesticides And Coliform Bacteria, D. C. Gosselin, J. Headrick, R. Tremblay, X. H. Chen, S. E. Summerside Jan 1997

Domestic Well Water Quality In Rural Nebraska: Focus On Nitrate-Nitrogen, Pesticides And Coliform Bacteria, D. C. Gosselin, J. Headrick, R. Tremblay, X. H. Chen, S. E. Summerside

School of Natural Resources: Faculty Publications

No abstract provided.


Back-Calculated Length-At-Age Estimates From Two Scale Radii, Keith L. Hurley, Kevin L. Pope, David W. Willis Jan 1997

Back-Calculated Length-At-Age Estimates From Two Scale Radii, Keith L. Hurley, Kevin L. Pope, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Variability in length-at-age estimates back-calculated from scales continues to be of concern to fishery scientists. Measurement transects used to back-calculate length at age have been recommended; however, specific scale and annuli radius measurements have not been evaluated for variability between different radii. Thus, the purpose of our study was to compare back-calculated length-at-age estimates determined from two different scale radii: one horizontally from the focus to the anterior-median edge and one diagonally from the focus to the anterior-lateral corner of the scale. No significant differences (P = 0.13 - 0.58 and P = 0.24 - 0.87) in backcalculated length-at-age estimates …


Radiation And Gas Exchange Of Understory Species At Boreas: Research Annual Performance Report For Period June 15, 1997- June 14, 1998, E. A. Walter-Shea, T. J. Arkebauer Jan 1997

Radiation And Gas Exchange Of Understory Species At Boreas: Research Annual Performance Report For Period June 15, 1997- June 14, 1998, E. A. Walter-Shea, T. J. Arkebauer

School of Natural Resources: Documents and Reviews

No abstract provided.


Effects Of Red Imported Fire Ants On Recruitment Of White-Tailed Deer Fawns, Craig R. Allen, Stephen Demarais, R. Scott Lutz Jan 1997

Effects Of Red Imported Fire Ants On Recruitment Of White-Tailed Deer Fawns, Craig R. Allen, Stephen Demarais, R. Scott Lutz

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We investigated the effect of red imported fire ants (RIFA; Solenopsis invicta) on an index of whitetailed deer (Odocoileus virginianus) fawn recruitment (doe:fawn ratio) on 10 200-ha plots in the Texas Coastal Prairie during 1991-93. Five of the plots received treatments of the fire ant bait AMDRO© (Am. Cyanamid Co., Wayne, N.].) during April and October 1991 and May 1992 to reduce RIFA populations. The remaining 5 plots served as untreated comparison areas. Populations of RIFA were reduced (P < 0.10) on treated study areas during deer fawning periods in 1991-92. Fawn recruitment was higher on treated areas during 1991 (P = 0.037) and 1992 (P = 0.069), with recruitment about twice as high on treated areas. In 1993, after 1 year of RIFA reinfestation, fawn recruitment did not differ between treated and untreated plots (P = 0.443). We conclude that high density RIFA infestations reduced white-tailed deer fawn recruitment.


Effect Of Red Imported Fire Ant Envenomization On Neonatal American Alligators, Craig R. Allen, Kenneth G. Rice, Daniel P. Wojcik, H. Franklin Percival Jan 1997

Effect Of Red Imported Fire Ant Envenomization On Neonatal American Alligators, Craig R. Allen, Kenneth G. Rice, Daniel P. Wojcik, H. Franklin Percival

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Alligator populations in the southeastern United States have substantially recovered since the late 1960s when they were placed on the federal Endangered Species List (Joanen and McNease, 1987). In Florida, both early age class and adult animals currently are harvested for commercial and recreational purposes (Hines and Abercrombie, 1987). In addition, the alligator is ecologically important as a keystone species and as an indicator of wetland health (Mazzotti and Brandt, 1994). Recently, the nonnative ant Solenopsis invicta (the red imported fire ant) has surfaced as a potential threat to alligator populations. Solenopsis invicta is a relatively new (approx. 65 yr) …


Environmental Characteristics Of Black Crappie (Pomoxis Nigromaculatus) Nesting Sites In Two South Dakota Waters, K. L. Pope, D. W. Willis Jan 1997

Environmental Characteristics Of Black Crappie (Pomoxis Nigromaculatus) Nesting Sites In Two South Dakota Waters, K. L. Pope, D. W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

A biotelemetry study was undertaken during spring 1995 to identify black crappie (Pomoxis nigromaculatus) nesting sites in two South Dakota water bodies. Individually coded ultrasonic transmitters were implanted into the body cavity of 15 adult male black crappie in each water body prior to spawning. Available habitat characteristics were recorded at 75 randomly selected sites within each water body, and habitat characteristics at nesting sites were recorded for each male black crappie believed to be nesting. Of the habitat characteristics analyzed, only substrate firmness did not differ (P=0.79) between water bodies. In Richmond Lake, black crappie selected nesting …


Oxytetracycline Marking Efficacy For Yellow Perch Fingerlings And Temporal Assays Of Tissue Residues, Eric G. Unkenholz, Michael L. Brown, Kevin L. Pope Jan 1997

Oxytetracycline Marking Efficacy For Yellow Perch Fingerlings And Temporal Assays Of Tissue Residues, Eric G. Unkenholz, Michael L. Brown, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Differentiating between hatchery and naturally reproduced fishes is difficult because of the lack of appropriate marking techniques. Chemical immersion techniques can be a practical method for mass marking juvenile fishes. The objectives of this study were to determine the concentration of oxytetracycline (OTC) hydrochloride needed to effectively mark age-0 yellow perch Perca flavescens to observe the retention lime of the mark, and to measure the persistence of OTC in body tissues. Fish were immersed in 309, 534, and 748 mg OTC/L for 12 h. Initial fish collections were made weekly, and monthly collections began 1 month postmarking for tissue and …


Nearly Synchronous Climate Change In The Northern Hemisphere During The Last Glacial Termination, Larry V. Benson, James Burdett, Steve Lund, Michaele Kashgarian, Scott Mensing Jan 1997

Nearly Synchronous Climate Change In The Northern Hemisphere During The Last Glacial Termination, Larry V. Benson, James Burdett, Steve Lund, Michaele Kashgarian, Scott Mensing

United States Geological Survey: Staff Publications

The climate of the North Atlantic region underwent a series of abrupt cold/warm oscillations when the ice sheets of the Northern Hemisphere retreated during the last glacial termination (17,700–11,500 years ago). Evidence for these oscillations, which are recorded in European terrestrial sediments as the Oldest Dryas/Bølling/ Older Dryas/Allerød/Younger Dryas vegetational sequence, has been found in Greenland ice cores. The geographical extent of many of these oscillations is not well known, but the last major cold event (the Younger Dryas) seems to have been global in extent. Here we present evidence of four major oscillations in the hydrological balance of the …


Correlation Of Late-Pleistocene Lake-Level Oscillations In Mono Lake, California, With North Atlantic Climate Events, Larry Benson, Steve P. Lund, James W. Burdett, Michaele Kashgarian, Timothy P. Rose, Joseph P. Smoot, Martha Schwartz Jan 1997

Correlation Of Late-Pleistocene Lake-Level Oscillations In Mono Lake, California, With North Atlantic Climate Events, Larry Benson, Steve P. Lund, James W. Burdett, Michaele Kashgarian, Timothy P. Rose, Joseph P. Smoot, Martha Schwartz

United States Geological Survey: Staff Publications

Oxygen-18 (18O) values of sediment from the Wilson Creek Formation, Mono Basin, California, indicate three scales of temporal variation (Dansgaard-Oeschger, Heinrich, and Milankovitch) in the hydrologic balance of Mono Lake between 35,400 and 12,900 14C yr B.P. During this interval, Mono Lake experienced four lowstands each lasting from 1000 to 2000 yr. The youngest low stand, which occurred between 15,500 and 14,000 14C yr B.P., was nearly synchronous with a desiccation of Owens Lake, California. Paleomagnetic secular variation (PSV) data indicate that three of four persistent low stands occurred at the same times as Heinrich events …


Histomorphological Responses Of Red Shiner (Cyprinella Lutrensis) To Atrazine, Terbufos, And Their Mixture, Ibrahim A. Messaad Dec 1996

Histomorphological Responses Of Red Shiner (Cyprinella Lutrensis) To Atrazine, Terbufos, And Their Mixture, Ibrahim A. Messaad

School of Natural Resources: Dissertations, Theses, and Student Research

Alterations of normal histomorphology of fish tissues, behavior, and thermal tolerance are recognized by environmental toxicologists and fish biologists as powerful tools indicating diverse biochemical and physiological changes. Toxicity of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), terbufos (S-(((1,1-dimethyl-ethyl)thio)methyl)O,O-diethyl phosphorodithioate), and their mixture to red shiner (Cyprinella lutrensis) at 23$\sp\circ$C and 30$\sp\circ$C was investigated in 14-d bioassays after 14-d acclimation. During the bioassays, fish behavior, indications of toxicosis, and external anomalies were observed. After the bioassays, the critical thermal maximum (CTM) was determined. Fish also were preserved for examinations of gill, liver, and kidney tissues using scanning electron microscopy (SEM) and light microscopy (LM). SEM …


The Effects Of Wet Meadow Fragmentation On Grassland Birds, Christopher J. Helzer Dec 1996

The Effects Of Wet Meadow Fragmentation On Grassland Birds, Christopher J. Helzer

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Propagation Of Juniperus For Conservation Plantings In The Great Plains, Scott Allen Lee Aug 1996

Propagation Of Juniperus For Conservation Plantings In The Great Plains, Scott Allen Lee

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


The Biology Of Alewife Alosa Pseudoharengus In Lake Ogallala, Nebraska, Eric A. Laux Aug 1996

The Biology Of Alewife Alosa Pseudoharengus In Lake Ogallala, Nebraska, Eric A. Laux

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Improving The Validation Of Model-Simulated Crop Yield Response To Climate Change: An Application To The Epic Model* Jour. Ser. No. 11339 Nebraska Ag. Res. Div., William E. Easterling, Xiafen Chen, Cynthia Hays, James R, Brandle, Hehui Zang Jun 1996

Improving The Validation Of Model-Simulated Crop Yield Response To Climate Change: An Application To The Epic Model* Jour. Ser. No. 11339 Nebraska Ag. Res. Div., William E. Easterling, Xiafen Chen, Cynthia Hays, James R, Brandle, Hehui Zang

School of Natural Resources: Faculty Publications

Crop models have been used extensively to simulate yield response to various scenarios of climate change. Such simulations have been inadequately validated, limiting their utility in policy analysis. In this research, it is argued that the performance of crop models during recent years of extreme weather conditions relative to current normals may give a better indication of the validity of model simulations of crop yields in response to climate change than performance during the full range of climate conditions (as is done now). Twenty years of the climate record (1971-1990) are separated into different growing season temperature and precipitation classes …


Growth And Yield Of Snap Beans (Phaseolus Vulgaris L.) As Affected By Shelterbelts And Planting Dates, Mohd Nazip Suratman May 1996

Growth And Yield Of Snap Beans (Phaseolus Vulgaris L.) As Affected By Shelterbelts And Planting Dates, Mohd Nazip Suratman

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Thermal Tolerances Of Platte River Fishes: Field And Laboratory Studies, Brett P. Fessell May 1996

Thermal Tolerances Of Platte River Fishes: Field And Laboratory Studies, Brett P. Fessell

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Chronic Effects Of Baseflow Levels Of Atrazine On Platte River Algae, Karen J. Nelson May 1996

Chronic Effects Of Baseflow Levels Of Atrazine On Platte River Algae, Karen J. Nelson

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Influence Of Prey Availability On Walleye (Stizostedion Vitreum), Mark T. Porath May 1996

Influence Of Prey Availability On Walleye (Stizostedion Vitreum), Mark T. Porath

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Surface Exchange Of Water Vapour Between An Open Sphagnum Fen And The Atmosphere, S. B. Verma Jan 1996

Surface Exchange Of Water Vapour Between An Open Sphagnum Fen And The Atmosphere, S. B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.


Conifer Shoot Bidirectional Scattering: Methodology And Preliminary Results, E.A. Walter-Shea, M.A. Mesarch Jan 1996

Conifer Shoot Bidirectional Scattering: Methodology And Preliminary Results, E.A. Walter-Shea, M.A. Mesarch

School of Natural Resources: Faculty Publications

No abstract provided.


The Local Effect Of Intermittency On The Inertial Subrange Energy Spectrum Of The Atmospheric Surface Layer, Jozsef Szilagyi, Gabriel G. Katul, Marc B. Parlange, John D. Albertson, Anthony T. Cahill Jan 1996

The Local Effect Of Intermittency On The Inertial Subrange Energy Spectrum Of The Atmospheric Surface Layer, Jozsef Szilagyi, Gabriel G. Katul, Marc B. Parlange, John D. Albertson, Anthony T. Cahill

School of Natural Resources: Faculty Publications

No abstract provided.


An Assessment Of Burbot (Lota Iota) Weight - Length Data From North American Populations, Shannon J. Fisher, David W. Willis, Kevin L. Pope Jan 1996

An Assessment Of Burbot (Lota Iota) Weight - Length Data From North American Populations, Shannon J. Fisher, David W. Willis, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Declining buroot (Lola lola) abundance across some portions of North America has prompted a search for additional evaluation tools, including a measure of condition. Weight - length data were compiled for 10293 burbot from 79 North American populations. These data were used to develop a 75th percentile standard weight (W,) equation using the regression-line-percentile technique. The proposed equation is log10 W3 = - 4.868 + 2.898 log10 TL, where Ws is the standard weight in grams, and TL is the maximum total length in millimetres. The equation is valid for burbot ≥20 cm and …


Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais Jan 1996

Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Populations of red imported fire ants (RIFA; Solenopsis invtcta) have spread rapidly throughout the southeastern United States. RIFA, directly or indirectly, negatively affect many wildlife species, and northern bobwhite (Colinus virginianus) appear to be particularly susceptible. We examined the effect of exposure to different numbers of RIFA for 15 and 60 seconds on body mass and survival of captive northern bobwhite chicks. Compared to unexposed birds, survival of chicks was reduced with exposure to as few as 50 RIFA for 60 seconds, or 200 RIFA for 15 seconds, and body mass was lower in chicks exposed to …


Egg Development In A High-Density Black Crappie (Pomoxis Nigromacuiatus) Population, Kevin L. Pope, Wade T. Geraets, David W. Willis Jan 1996

Egg Development In A High-Density Black Crappie (Pomoxis Nigromacuiatus) Population, Kevin L. Pope, Wade T. Geraets, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Female black crappie (Pomoxis nigromaculatus) were collected from Richmond Lake, South Dakota" and egg-diameter frequencies were examined to document spawning strategy during 1994. Two hundred and sixteen adult females [mean total length (TL) ±SE = 204 ± 1 mm] were collected and 85,572 egg diameters were measured. Female black crappie gonadosomatic-index (GSI) values exceeded 8% from 18 May to 22 June 1994, and the density of larval black crappie caught with an ichthyoplankton net peaked on 8 June 1994. The GSI values and larval catches indicated that the population, as a whole, had a single extended spawn from …


Csrees Department Of Forestry, Fisheries & Wildlife Comprehensive Review, University Of Nebraska - Lincoln Jan 1996

Csrees Department Of Forestry, Fisheries & Wildlife Comprehensive Review, University Of Nebraska - Lincoln

School of Natural Resources: Documents and Reviews

No abstract provided.


Seasonal Influences On Freshwater Fisheries Sampling Data, Kevin L. Pope, David W. Willis Jan 1996

Seasonal Influences On Freshwater Fisheries Sampling Data, Kevin L. Pope, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Fisheries managers often assess fish populations using catch per unit effort (CPUE), size and age structure, growth, and condition. For many freshwater fishes and common sampling gears, CPUE, size and age structure, and condition are highest in the spring and fall, while growth commonly is fastest during the summer growing season. However, there are exceptions to these general trends, especially in populations with erratic recruitment, growth, or mortality. At the least, CPUE, size and age structure, growth, and condition of fish should be expected to change with season, given the effects of variable recruitment, growth, and mortality. However, if recruitment, …


Scale Issues In Soil Moisture Modelling: Problems And Prospects, Rezaul Mahmood Jan 1996

Scale Issues In Soil Moisture Modelling: Problems And Prospects, Rezaul Mahmood

School of Natural Resources: Faculty Publications

Soil moisture storage is an important component of the hydrological cycle and plays a key role in land-surface-atmosphere interaction. The soil-moisture storage equation in this study considers precipitation as an input and soil moisture as a residual term for runoff and evapotranspiration. A number of models have been developed to estimate soil moisture storage and the components of the soil-moisture storage equation. A detailed discussion of the implication of the scale of application of these models reports that it is not possible to extrapolate processes and their estimates from the small to the large scale. It is also noted that …


Climatic And Hydrologic Oscillations In The Owens Lake Basin And Adjacent Sierra Nevada, California, Larry Benson, James W. Burdett, Michaele Kashgarian, Steve Lund, Fred Phillips, Robert O. Rye Jan 1996

Climatic And Hydrologic Oscillations In The Owens Lake Basin And Adjacent Sierra Nevada, California, Larry Benson, James W. Burdett, Michaele Kashgarian, Steve Lund, Fred Phillips, Robert O. Rye

United States Geological Survey: Staff Publications

Oxygen isotope and total inorganic carbon values of cored sediments from the Owens Lake basin, California, indicate that Owens Lake overflowed most of the time between 52,500 and 12,500 carbon-14 (14C) years before present (B.P.). Owens Lake desicated during or after Heinrich event H1 and was hydrologically closed during Heinrich event H2. The magnetic susceptibility and organiz carbon content of cored sediments indicate that about 19 Sierra Nevada glaciations occurred between 52,500 and 23,500 14C years B.P.


Origin Of The Late Quaternary Dune Fields Of Northeastern Colorado, Daniel R. Muhs, Thomas W. Stafford, Scott D. Cowherd, Shannon A. Mahan, Rolf Kihl, Paula B. Maat, Charles A. Bush, Jennifer Nehring Jan 1996

Origin Of The Late Quaternary Dune Fields Of Northeastern Colorado, Daniel R. Muhs, Thomas W. Stafford, Scott D. Cowherd, Shannon A. Mahan, Rolf Kihl, Paula B. Maat, Charles A. Bush, Jennifer Nehring

United States Geological Survey: Staff Publications

Stabilized eolian deposits, mostly parabolic dunes and sand sheets, cover much of the landscape of northeastern Colorado and adjacent parts of southwestern Nebraska in four geographically distinct dune fields. Stratigraphic and soil-geomorphic relations and accelerator radiocarbon dating indicate that at least three episodes of eolian sand movement occurred between 27 ka and 11 ka. possibly between 11 ka and 4 ka. and within the past 1.5 ka. Thus, eolian sand deposition took place under both glacial and interglacial climatic conditions. In the youngest episodes of eolian sand movement. Holocene parabolic dunes partially buried Pleistocene sand sheet deposits.

Late Holocene sands …


Department Of Agricultural Meteorology Csrees Comprehensive Review Sep 1995

Department Of Agricultural Meteorology Csrees Comprehensive Review

School of Natural Resources: Documents and Reviews

No abstract provided.