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Environmental Sciences

2009

University of Nebraska - Lincoln

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Articles 1 - 30 of 386

Full-Text Articles in Physical Sciences and Mathematics

The Effect Of Consumerism And Regulation On Household Solid Waste Management In The United States And Germany: A Comparative Study, Amir Vafa Dec 2009

The Effect Of Consumerism And Regulation On Household Solid Waste Management In The United States And Germany: A Comparative Study, Amir Vafa

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

Private household recycling is a significant aspect of consumerism in economically developed countries and the inevitable question of household waste management has gained more importance among municipalities in recent years. The present study examined the effect of regulation on household solid waste management. Within a comparative, qualitative framework, the study explored and evaluated the pro-regulatory effects in Germany and the anti-regulatory policies in the United States by means of comparing two similar communities, Lincoln, Nebraska and Augsburg, Germany. By examining the present legislations, official documents, legal and operational procedures, and other relevant artifacts, laws, regulations and the degree of their …


Nest And Brood Survival And Habitat Selection Of Ring-Necked Pheasants And Greater Prairie-Chickens In Nebraska, Ty Matthews Dec 2009

Nest And Brood Survival And Habitat Selection Of Ring-Necked Pheasants And Greater Prairie-Chickens In Nebraska, Ty Matthews

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

Ring-Necked Pheasant (Phasianus colchicus) and Greater Prairie-chicken (Tympanuchus cupido pinnatus) populations have declined in the Midwest since the 1960’s. Research has suggested decreased nest and brood survival are the major causes of this decline due to the lack of suitable habitat. Habitat degradation has been attributed to the shift to larger crop fields, lower diversity of crops, and more intensive pesticide and herbicide use. A primary goal of the Conservation Reserve Program (CRP) is to mitigate the loss of wildlife habitat. Early research found that CRP increased the amount of suitable nesting and brood rearing cover …


Development Of The Mask Scentometer, A Comparison Of Ambient Odor Assessment Methods, And Their Application In Ground Truthing Atmospheric Dispersion Models, Christopher G. Henry Dec 2009

Development Of The Mask Scentometer, A Comparison Of Ambient Odor Assessment Methods, And Their Application In Ground Truthing Atmospheric Dispersion Models, Christopher G. Henry

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

This dissertation is organized as four stand-alone papers. Paper No. 1 describes the development of the Mask Scentometer and reports dilution ratios measured during use by twelve different people. Dilution ratios at the Mask Scentometer’s five dilution-to-threshold (D/T) settings were found to be 0.35, 1, 2, 4.5 and 18. In Paper No.’s 2 and 4, ambient odor assessment methods were compared in both controlled laboratory conditions and in the field. Laboratory analysis of ambient air samples using dynamic triangular forced-choice olfactometry (DTFCO) did not correlate well with any of the ambient odor assessment methods. Average intensity-predicted D/T was roughly five …


Satellite-Based Estimation Of Chlorophyll-A Concentration In Turbid Productive Waters, Wesley Moses Dec 2009

Satellite-Based Estimation Of Chlorophyll-A Concentration In Turbid Productive Waters, Wesley Moses

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

Inland, coastal, and estuarine waters, which are often turbid and biologically productive, play a crucial role in maintaining global bio-diversity and are of immense value to aquatic life as well as human-beings. Concentration of chlorophyll-a (chl-a) is a key indicator of the trophic status of these waters, which should be regularly monitored to ensure that their ecological balance is not disturbed. Remote sensing is a powerful tool for this.

Due to the optical complexity of turbid productive waters, standard algorithms that use blue and green reflectances are unreliable for estimating chl-a concentration. Algorithms based on red and near-infrared (NIR) reflectances …


Observations Of Badgers Preying On Black-Tailed Prairie Dogs, Daniel S. Licht Dec 2009

Observations Of Badgers Preying On Black-Tailed Prairie Dogs, Daniel S. Licht

The Prairie Naturalist

American badgers (Taxidea taxus) often visit black-tailed prairie dog (Cynomys ludovicianus) colonies, most likely in search of prey (Lomolino and Smith 2004, Shaughnessy and Cifelli 2004). Badgers are well suited to hunting fossorial prey such as prairie dogs by excavating burrows and capturing individuals belowground (Lindzey 2003). However, the ecological literature is sparse regarding details of how badgers hunt and capture prairie dogs underground. Eads and Biggins (2008) documented three occurrences of a badger excavating prairie dogs. That badger (apparently the same individual) had a den within the prairie dog town where captures occurred. This note …


Mortality Of Cranes (Gruidae) Associated With Powerlines Over A Major Roost On The Platte River, Nebraska, Gregory D. Wright, Timothy J. Smith, Robert K. Murphy, Jeffery T. Runge, Robert R. Harms Dec 2009

Mortality Of Cranes (Gruidae) Associated With Powerlines Over A Major Roost On The Platte River, Nebraska, Gregory D. Wright, Timothy J. Smith, Robert K. Murphy, Jeffery T. Runge, Robert R. Harms

The Prairie Naturalist

Two 69-kilovolt powerlines spanning the Platte River in south central Nebraska are suspected to cause substantial mortality to sandhill cranes (Grus canadensis) and pose a threat to endangered whooping cranes (G. americana) that roost overnight on the river during spring and fall migrations. Most studies of crane collisions with powerlines in the region have focused on counts of carcasses away from night roosts on the river and none have accounted for potential biases in detecting carcasses. We found 61 carcasses of sandhill cranes below over-river segments of the two powerlines during 4 March to 7 April …


Long Distance Molt Migration By A Giant Canada Goose From Eastern South Dakota, Bobby J. Anderson, Charles D. Dieter Dec 2009

Long Distance Molt Migration By A Giant Canada Goose From Eastern South Dakota, Bobby J. Anderson, Charles D. Dieter

The Prairie Naturalist

To reduce crop damage by resident giant Canada geese (Schaible et al. 2005), the South Dakota Department of Game, Fish and Parks (SDGFP) initiated a program to reduce goose nesting success in eastern South Dakota. One management tool used by SDGFP personnel was the destruction of giant Canada goose nests. When a giant Canada goose has its nest destroyed, they are known to initiate a molt migration (Mykut 2002, Luukkonen et aI. 2008). We attached Platform Transmitting Terminals (PTT; model ST -19) to document and describe molt migrations of giant Canada geese following nest destruction. We captured 3 adult nesting …


Noteworthy Winter Prey Of Short-Eared Owls In Southern Texas: A Case Study, Damon Williford, Marc C. Woodin, Mary Kay Skoruppa Dec 2009

Noteworthy Winter Prey Of Short-Eared Owls In Southern Texas: A Case Study, Damon Williford, Marc C. Woodin, Mary Kay Skoruppa

The Prairie Naturalist

The winter range of North American short-eared owls (Asio flammeus) encompasses much of the United States, including southern Texas, where it is a common winter resident (Oberholser 1974, Rappole and Blacklock 1985). Winter food habits of short-eared owls are relatively weJl documented, but the majority of investigations have been conducted in eastern Canada and northeastern U.S. (Clark 1975, Holt 1993); midwestern U.S. (Colvin and Spaulding 1983); and British Columbia and Pacific northwestern U.S. (Bogiatto et al. 2001). The short-eared owl has a narrow trophic niche, generally preying on small mammals, with voles (Microtus spp.) and deer mice …


Patterns Of Bison Hair Use In Nests Of Tallgrass Prairie Birds, Bryan R. Coppedge Dec 2009

Patterns Of Bison Hair Use In Nests Of Tallgrass Prairie Birds, Bryan R. Coppedge

The Prairie Naturalist

I examined patterns of bison (Bison bison L.) hair use by passerine birds nesting in the Tallgrass Prairie Preserve, Osage County, Oklahoma, 2002-2004. I collected and dissected 103 nests of 15 species into their constituent components. Nests were predominately composed of herbaceous material such as grass stems and leaves. Woody material and mud were rarely used. Bison hair was the most prominent zoological material used in nests, with lesser amounts and occurrence of arthropod silk, snake skin, feathers, jack rabbit (Lepus californicus Oray) fur, and man-made materials such as cellophane and string. At least one nest of 13 …


Monitoring Meadows With A Modified Robel Pole In The Northern Black Hills, South Dakota, Daniel W, Uresk, Daryl E. Mergen, Ted A. Benzon Dec 2009

Monitoring Meadows With A Modified Robel Pole In The Northern Black Hills, South Dakota, Daniel W, Uresk, Daryl E. Mergen, Ted A. Benzon

The Prairie Naturalist

We used a modified Robel pole to measure vegetation for a study conducted in the northern Black Hills, South Dakota. Objectives were to determine the relationship between visual obstruction readings and clipped standing herbage, and develop guidelines for monitoring standing herbage. The relationship between visual obstruction readings and standing herbage was linear and regression coefficients were significant (P≤ 0.001). Herbage ranged from 140 to 3313 kg· ha-1 with a mean of 1386 kg· ha-1 (SE = 320 kg· ha-1) for 123 transects. Visual obstruction readings (VOR) ranged from 0.6 to 30.4 (number of 1.27 cm bands …


Review Of The Evidence Used In The Description Of Currently Recognized Cetacean Subspecies, William F. Perrin, James G. Mead, Robert L. Brownell Jr. Dec 2009

Review Of The Evidence Used In The Description Of Currently Recognized Cetacean Subspecies, William F. Perrin, James G. Mead, Robert L. Brownell Jr.

United States Department of Commerce: Staff Publications

We reviewed the subspecies listed by Rice (1998) and those described since (a total of 49, in 19 species), assessing them against the criteria recommended by the recent Workshop on Shortcomings of Cetacean Taxonomy in Relation to Needs of Conservation and Management (Reeves et al., 2004). The workshop suggested that the subspecies concept can be construed to cover two types of entities: a) lineages diverging but not quite far along the continuum of divergence (still having significant gene flow with another lineage or lineages) to be judged as species, and b) lineages that may well be species but for which …


Bed Site Selection Of Fawn Pronghorn In Custer State Park, South Dakota, Chad P. Lehman, Jamin D. Hartland, Barbara J. Keller, Joshua J. Millspaugh, Gary C. Brundige Dec 2009

Bed Site Selection Of Fawn Pronghorn In Custer State Park, South Dakota, Chad P. Lehman, Jamin D. Hartland, Barbara J. Keller, Joshua J. Millspaugh, Gary C. Brundige

The Prairie Naturalist

We evaluated pronghorn (Antilocapra americana) fawn bedding site characteristics on a prairie and ponderosa pine (Pinus ponderosa) landscape interface in Custer State Park, South Dakota. We radio-marked 16 adult female pronghorn and collected bed site information from their fawns during 2007~2008. We compared bed site selection with random sites (n = 74) during 2 periods; the early hiding phase when fawns were 1 ~28 days of age (n = 23 bed sites) and the later group phase when fawns were 29~60 days of age (n = 52 bed sites). During the hiding phase fawns selected dry …


A Partial Inventory Of Islands In North Dakota: Potential For Breeding Waterfowl Management, Michael L. Szymanski Dec 2009

A Partial Inventory Of Islands In North Dakota: Potential For Breeding Waterfowl Management, Michael L. Szymanski

The Prairie Naturalist

Islands can provide secure nesting habitat for ducks and other waterbirds, especially in agriculturally dominated landscapes. I inventoried natural and man-made islands in the portion of North Dakota covered by the Prairie Pothole Joint Venture (PPJV). I mapped 1,305 islands in this area; up to 46% of which could provide enhanced nest success with management (e.g., predator removal or establishment of brushy cover). Management of islands for breeding ducks may be an important method for achieving desired reproductive rates in the PP JV as substantial areas of perennial grass cover are lost from federal conservation programs, primarily the Conservation Reserve …


Relating Fires Affect On Forest Succession And Forest's Effect On Fire Severity In One Burned And Unburned Environment, Tyler Jay Seiboldt Dec 2009

Relating Fires Affect On Forest Succession And Forest's Effect On Fire Severity In One Burned And Unburned Environment, Tyler Jay Seiboldt

Department of Environmental Studies: Undergraduate Student Theses

Wildfires are a natural part of many forest ecosystems and play a vital role in maintaining their health. Wildfires can have a critical influence on a landscapes plant community through their relative frequency, seasonality, and severity. One of the most heavily influenced regions by wildfire disturbance is the Klamath Mountain region of California. I looked at the affect a wildfires severity had on the Whiskey creek valley within the Whiskeytown National Recreation Area. 8 tree species and 4 flower species were examined on both the burned and unburned regions within this valley nearly a year after the wildfire (May 17-23 …


Water Current, Volume 41, No. 4, Fall 2009 Nov 2009

Water Current, Volume 41, No. 4, Fall 2009

Water Current Newsletter

Meet the Faculty, Sara Michaels and Ron Yoder
Water Tour to North and South Platte Basins
Dvorak Named Interim Director
Featured Partner: Nebraska Well Drillers Association
Irrigation and Water Photos From Nebraska’s Past
Emerging Contaminants in a Flat World
River City Roundup Features Nebraska Water Issues
Platte River BasinScience and Resource Management Symposium, Oct. 14-15, Kearney
New UNL Spreadsheet Helps Irrigators Evaluate Efficiency
Water Center Events
Our Water Supply, Down the Drain
WRAP Ranks Priorities, Spurs Proposal Development


Provenance Signatures Of The Antarctic Ice Sheets In The Ross Embayment During The Late Miocene To Early Pliocene: The Andrill And-1b Core Record, Franco M. Talarico, Sonia Sandroni Nov 2009

Provenance Signatures Of The Antarctic Ice Sheets In The Ross Embayment During The Late Miocene To Early Pliocene: The Andrill And-1b Core Record, Franco M. Talarico, Sonia Sandroni

ANDRILL Research and Publications

Significant down-core modal and compositional variations are described for granule- to cobble-sized clasts in the Early Pliocene to Middle/Late Miocene sedimentary cycles of the AND-1B drill core at the NW edge of the Ross Ice Shelf (McMurdo Sound).

Long-term shifts in compositional patterns outline an evolving provenance which is interpreted as reflecting the combined effects and complex interactions among variations in ice volume, ice flow patterns and paleogeographic changes linked to the local tectonic and volcanic activity. High-frequency variations and the petrological features of the basement clast fraction provide direct information about the potential source regions during both glacial maxima …


Refuge Update – November/December 2009, Volume 6, Number 6 Nov 2009

Refuge Update – November/December 2009, Volume 6, Number 6

RefugeUpdate (USFWS-NWRS)

Table of Contents:

Tufted Puffin Released A rehabilitated puffin gingerly tests freedom at Oregon Islands National Wildlife Refuge.

FOCUS: Stories of Hope From cemeteries to woodpeckers, to newspaper columns and support at the ballot box, refuges represent stories of hope as they pursue their mission.

Bats in the Barn Scientists and volunteers wrap a barn in plastic and count the bats inside.

Sense of Wonder Award Jim Burkhart shares the joy and mysteries of the natural world with visitors to Okefenokee National Wildlife Refuge, GA.


Forensic Bird-Strike Identification Techniques Used In An Accident Investigation At Wiley Post Airport, Oklahoma, 2008, Carla J. Dove, Nor Faridah Dahlan, Marcy Heacker Oct 2009

Forensic Bird-Strike Identification Techniques Used In An Accident Investigation At Wiley Post Airport, Oklahoma, 2008, Carla J. Dove, Nor Faridah Dahlan, Marcy Heacker

Human–Wildlife Interactions

On March 4, 2008, a Cessna Citation 1 (Model 500) crashed in a wooded area near Wiley Post Airport, Oklahoma, killing all 5 people on board. This paper describes the detailed forensic methods and expertise used by the Smithsonian Institution’s Feather Identification Lab to identify the bird that caused this bird-strike incident. We used standard methods of whole-feather analysis, microscopic examination, and DNA barcoding in this case to identify American white pelican (Pelecanus erythrorhynchos) as the bird species involved in this fatal crash. We also report the importance of proper field investigation and evidence collection for accurate results, …


Using Wedelia As Ground Cover On Tropical Airports To Reduce Bird Activity, Michael A. Linnell, Michael R. Conover, Tim J. Ohashi Oct 2009

Using Wedelia As Ground Cover On Tropical Airports To Reduce Bird Activity, Michael A. Linnell, Michael R. Conover, Tim J. Ohashi

Human–Wildlife Interactions

aircraft collisions (i.e., bird strikes) are a major problem at airports worldwide, often because birds are attracted to airfields to feed on seeds, insects, or rodents that abound in the grassy areas near runways and taxiways. We compared an alternative ground cover, wedelia (Wedelia trilobata), to existing vegetation (control plots) on the airfield at Lihue Airport, Kauai, Hawaii, to determine if bird populations on the airport could be reduced by eliminating their forage base. We studied wedalia because it is a low-growing plant that did not need mowing, was easily established in plots, and out-competed other plants, resulting …


Satellite Estimation Of Chlorophyll-A Concentration Using The Red And Nir Bands Of Meris—The Azov Sea Case Study, Wesley J. Moses, Anatoly A. Gitelson, Sergey Berdnikov, Vasiliy Povazhnyy Oct 2009

Satellite Estimation Of Chlorophyll-A Concentration Using The Red And Nir Bands Of Meris—The Azov Sea Case Study, Wesley J. Moses, Anatoly A. Gitelson, Sergey Berdnikov, Vasiliy Povazhnyy

School of Natural Resources: Faculty Publications

We present here the results of calibrating and validating a three-band model and, its special case, a two-band model, which use MEdium Resolution Imaging Spectrometer (MERIS) reflectances in the red and near-infrared spectral regions for estimating chlorophyll-a (chl-a) concentration in inland, estuarine, and coastal turbid productive waters. During four data collection campaigns in 2008 and one campaign in 2009 in the Taganrog Bay and the Azov Sea, Russia, water samples were collected, and concentrations of chl-a and total suspended solids were measured in the laboratory. The data collected in 2008 were used for model calibration, and the …


Corrections To “Satellite Estimation Of Chlorophyll-A Concentration Using The Red And Nir Bands Of Meris—The Azov Sea Case Study”, Wesley J. Moses, Anatoly A. Gitelson, Sergey Berdnikov, Vasiliy Povazhnyy Oct 2009

Corrections To “Satellite Estimation Of Chlorophyll-A Concentration Using The Red And Nir Bands Of Meris—The Azov Sea Case Study”, Wesley J. Moses, Anatoly A. Gitelson, Sergey Berdnikov, Vasiliy Povazhnyy

School of Natural Resources: Faculty Publications

We correct here some errors that appear in our paper: W.J. Moses, A.A. Gitelson, S. Berdnikov, and V. Povazhnyy, “Satellite estimation of chlorophyll-a concentration using the red and NIR bands of MERIS—The Azov Sea case study,” IEEE Geoscience and Remote Sensing Letters, volume 6, number 4, pp. 845–849, October 2009.


Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi Oct 2009

Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi

School of Natural Resources: Faculty Publications

We present and discuss here the results of our work using MODIS (moderate resolution imaging spectroradiometer) and MERIS (medium resolution imaging spectrometer) satellite data to estimate the concentration of chlorophyll-a (chl-a) in reservoirs of the Dnieper River and the Sea of Azov, which are typical case II waters, i.e., turbid and productive. Our objective was to test the potential of satellite remote sensing as a tool for near-real-time monitoring of chl-a distribution in these water bodies. We tested the performance of a recently developed three-band model, and its special case, a two-band model, which use the reflectance at red and …


Droughtscape- Fall 2009, Kelly Smith Oct 2009

Droughtscape- Fall 2009, Kelly Smith

Droughtscape, Quarterly Newsletter of NDMC, 2007-

Drought Monitor Forum to be in Austin, Oct. 7-8

El Niño Likely to Bring More Needed Precipitation

NDMC Welcomes Visiting Chinese Scientist

TX, CA Feeling Worst of Impacts

Grant to Bring Climate Change Ed to Teachers

Speaking of Drought ...

NDMC Takes Message Across Nebraska and World


In The News, Joe N. Caudell Oct 2009

In The News, Joe N. Caudell

Human–Wildlife Interactions

Bird dogs of a different feather-- A report from the website of 10 Connect News of Tampa, Florida, reported that a bird-chasing border collie, a breed of dog, is being used to harass birds at airports. The dog is just 1 part of MacDill Airforce Base’s safety management program to reduce damage at airfields.

Recent bird strikes from around the world--Bucharest, Romania, Denver, Colorado, Rome, Italy

Pilot lands plane in Hudson River--One of the most widely-reported recent birdstrike disasters occurred on January 15, 2009, in New York City. The incident involved US Airways Flight 1549 with 155 people on board. …


Survival And Productivity Of A Low-Density Black Bear Population In Rocky Mountain National Park, Colorado, Roger A. Baldwin, Louis C. Bender Oct 2009

Survival And Productivity Of A Low-Density Black Bear Population In Rocky Mountain National Park, Colorado, Roger A. Baldwin, Louis C. Bender

Human–Wildlife Interactions

Rocky Mountain National Park (RMNP) has supported a small black bear (Ursus americanus) population of low productivity. Increased visitor use of the park and development around its periphery could lead to a reduction in population viability of RMNP’s bear population or could increase the potential for human–bear conflict. Therefore, we investigated contemporary survival and productivity parameters for RMNP’s black bear population from 2003 to 2006 and compared these values to historic levels (1984–1991) and population means throughout the western United States to clarify the current status of RMNP’s bear population. The contemporary black bear population showed signs of …


Molt Migration By Giant Canada Geese In Eastern South Dakota, Charles D. Dieter, Bobby J. Anderson Oct 2009

Molt Migration By Giant Canada Geese In Eastern South Dakota, Charles D. Dieter, Bobby J. Anderson

Human–Wildlife Interactions

We captured giant Canada geese (Branta canadensis maxima) in 7 counties in eastern South Dakota during the summer molting period, 2000–2003. We attached very high frequency (VHF) transmitters to 150 adult female geese with brood patches, and leg bands to 3,839 geese. We documented molt migrations using VHF telemetry and indirect band recovery at locations north of South Dakota. Telemetry of radio-collared female geese during the breeding season indicated that 56% of nonbreeders, 81% of unsuccessful breeders, and 19% of successful female breeders embarked on a molt migration. Five of 34 geese that underwent molt migrations moved to …


Developing Bird-Strike Risk Assessment Models For Open-Water Restorations, Justin D. Hart, Alison Colyer, John R. Allan Oct 2009

Developing Bird-Strike Risk Assessment Models For Open-Water Restorations, Justin D. Hart, Alison Colyer, John R. Allan

Human–Wildlife Interactions

Mineral extraction sites that are restored to open water can increase bird-strike risk if they are planned near airports. This can generate conflict between the minerals industry and safeguarding authorities. To help resolve this potential conflict, it would be useful to predict how new restorations affect local water-bird populations so that mineral deposits can be exploited and restored in safeguarded zones without compromising flight safety. Bird abundances and movements at new restorations can be estimated with statistical models that use the environmental characteristics of restoration schemes as predictor variables. These models can improve guidance in safeguarding, provided that they comprise …


Impacts Of Meteorological Factors On Modis-Observed Fire Activity In The North American Boreal Forest: The Role Of Lightning, David A. Peterson Oct 2009

Impacts Of Meteorological Factors On Modis-Observed Fire Activity In The North American Boreal Forest: The Role Of Lightning, David A. Peterson

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The meteorological impact on wildfire activity in the North American boreal forest during the fire seasons of 2000 – 2006 is statistically analyzed through an integration of the following data sets: the MODerate Resolution Imaging Spectroradiometer (MODIS) level 2 fire products, the 3-hourly 32-km gridded meteorological data from North American Regional Reanalysis (NARR), the instantaneous lightning data collected by the Canadian Lightning Detection Network (CLDN), and the Alaska Lightning Detection Network (ALDN). Positive anomalies of the 500 hpa geopotential height field, convective available potential energy (CAPE), number of cloud-to-ground lightning strikes, and the number of consecutive dry days are found …


Scwds Briefs: Volume 25, Number 3 (October 2009), Gary L. Doster , Editor, Scwds Briefs, Michael J. Yabsley Oct 2009

Scwds Briefs: Volume 25, Number 3 (October 2009), Gary L. Doster , Editor, Scwds Briefs, Michael J. Yabsley

Southeastern Cooperative Wildlife Disease Study: Publications

Table of Contents:

Clams & AI Virus

SCWDS Funded to Study WNS

USDA Program Changes Proposed

TB in Captive Cervids

CWD Prions in Deer Feces

TWS Position Statement on Lead

WDA Awards For SCWDS Staff

New Brochure for Hog Hunters


Crop Yield Gaps: Their Importance, Magnitudes, And Causes, David B. Lobell, Kenneth G. Cassman, Christopher B. Field Oct 2009

Crop Yield Gaps: Their Importance, Magnitudes, And Causes, David B. Lobell, Kenneth G. Cassman, Christopher B. Field

Nebraska Center for Energy Sciences Research: Publications

Future trajectories of food prices, food security, and cropland expansion are closely linked to future average crop yields in the major agricultural regions of the world. Because the maximum possible yields achieved in farmers’ fields might level off or even decline in many regions over the next few decades, reducing the gap between average and potential yields is critical. In most major irrigated wheat, rice, and maize systems, yields appear to be at or near 80% of yield potential, with no evidence for yields having exceeded this threshold to date. A fundamental constraint in these systems appears to be uncertainty …