Physical Sciences and Mathematics Commons^™

Seasonal Energy And Water Balance Of A Phragmites Australis-Dominated Wetland In The Republican River Basin Of South-Central Nebraska (Usa), John D. Lenters, Gregory J. Cutrell, Erkan Istanbulluoglu, Durelle T. Scott, Kyle S. Herrman, Dean E. Eisenhauer

School of Natural Resources: Faculty Publications

energy and water balance, especially in dry climatic regions, can have a significant impact on local water availability and, therefore, water resource management. The purpose of this study is to quantify the energy and water balance of a riparian wetland in a subhumid region of the central US, as well as the role of seasonal climate variability and vegetation phenology. The site is located in the Republican River basin in south-central Nebraska, where decreases in streamflow have been observed in recent decades. In an effort to reduce consumptive water use from evapotranspiration (ET), and thereby reclaim surface water, invasive species …

Assessing Net Ecosystem Carbon Exchange Of U.S. Terrestrial Ecosystems By Integrating Eddy Covariance Flux Measurements And Satellite Observations, Jingfeng Xiao, Qianlai Zhuang, Beverly E. Law, Dennis D. Baldocchi, Jiquan Chen, Andrew D. Richardson, Jerry M. Melillo, Kenneth J. Davis, David Y. Hollinger, Sonia Wharton, Ram Oren, Asko Noormets, Marc L. Fischer, Shashi Verma, David R. Cook, Ge Sun, Steve Mcnulty, Steven C. Wofsy, Paul V. Bolstad, Sean P. Burns, Peter S. Curtis, Bert G. Drake, Matthias Falk, David R. Foster, Lianhong Gu, Julian L. Hadley, Gabriel G. Katul, Marcy Litvak, Siyan Ma, Timothy A. Martin, Roser Matamala, Tilden P. Meyers, Russell K. Monson, J. William Munger, Walter C. Oechel, U. Kyaw Tha Paw, Hans Peter Schmid, Russell L. Scott, Gregory Starr, Andrew E. Suyker, Margaret S. Torn

School of Natural Resources: Faculty Publications

More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr⁻¹ with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and …

Comparison And Analysis Of Empirical Equations For Soil Heat Flux For Different Cropping Systems And Irrigation Methods, Ayse Kilic, R. K. Singh, Elizabeth A. Walter-Shea, Shashi Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center‐pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (R_n) ratio (G/R_n) and the normalized difference …

Farmer Perceptions Of Sustainable Agriculture Practices And Drought Risk Reduction In Nebraska, Usa, Cody L. Knutson, Tonya Haigh, Michael J. Hayes, Melissa Widhalm, J. Nothwehr, M. Kleinschmidt, L. Graf

School of Natural Resources: Faculty Publications

Social factors, such as farming methods, have an impact on farm vulnerability to drought, but have received little research or policy attention. Some researchers and advocates have argued that sustainable agriculture systems are less vulnerable to climate risk than conventional systems because sustainable agriculture requires producers to have skills promoting adaptability. In this paper, we investigate producers’ perceptions on the use of sustainable agriculture in reducing drought risk, and what they believe would help them better adapt to drought. We surveyed and interviewed farmer members of two sustainable agriculture organizations in Nebraska, USA, during a multi-year drought period from 1999 …

Adaptive Harvest Management And Harvest Mortality Of Greater Prairie-Chickens, Larkin A. Powell, J. Scott Taylor, Ty W. Matthews

School of Natural Resources: Faculty Publications

Adaptive harvest management (AHM) can assist biologists with decisions made under uncertainty. There have been few applications of AHM to manage wildlife at the state level, and we provide a theoretical exercise using AHM in the context of Greater Prairie-Chicken harvest in southeast Nebraska. Our goals were to develop and evaluate an AHM framework for a state specific harvest decision, and to use the AHM process to evaluate uncertainties associated with harvest mortality for Greater Prairie-Chickens in Nebraska. Harvest of prairie chickens in southeast Nebraska was restarted 2000, using a special limited permit system, and was controversial with respect to …

Estimating Nest Density When Detectability Is Incomplete: Variation In Nest Attendance And Response To Disturbance By Western Meadowlarks, Matthew D. Giovanni, Max Post Van Der Burg, Lars C. Anderson, Larkin A. Powell, Walter H. Schacht, Andrew J. Tyre

School of Natural Resources: Faculty Publications

Researchers commonly model nest density as a function of ecological variables, but nests, like birds, can be undetected while present. In the Nebraska Sandhills in 2007, we used the rope-drag method on previously located Western Meadowlark (Sturnella neglecta) nests to model nest-detection error and nest density. Detecting nests by rope dragging (commonly used for nests of grassland birds) is conditional on two primary sources of nest availability, adults attending nests and adults flushing from nests in response to disturbance from the rope, the behavioral cue necessary for nest detection. On the basis of our trials with rope dragging, …

Chapter Thirteen- Habitat Selection And Brood Survival Of Greater Prairie-Chickens, Ty W. Matthews, Andrew J. Tyre, J. Scott Taylor, Jeffery J. Lusk, Larkin A. Powell

School of Natural Resources: Faculty Publications

The Greater Prairie-Chicken (Tympanuchus cupido pinnatus) is a species that may benefit from conversion of crop ground to grassland through the Conservation Reserve Program (CRP). CRP grasslands could provide nesting and brood-rearing habitat, an important component of population persistence. Managers and policymakers currently lack evidence of CRP’s relative contribution to populations of Greater Prairie-Chicken. We used radiotelemetry to mark females (n =100) in southeast Nebraska, in a landscape which had >15% of land area enrolled in CRP. We examined macrohabitat and microhabitat selection of brood-rearing females (n=36) using discrete choice models, and examined the variability in brood survival …

Nest Survival Of Long-Billed Curlew In Nebraska, Cory J. Gregory, Stephen J. Dinsmore, Larkin A. Powell, Joel G. Jorgensen

School of Natural Resources: Faculty Publications

Long-billed Curlew Numenius americanus is an imperiled shorebird of western North America. Populations have declined dramatically in the last 150 years from the conversion of prairie to agriculture and it is now listed as a “Tier I at-risk” species in Nebraska. We undertook a 3-year project (2008–2010) to study the nest survival of Long-billed Curlews in Nebraska. We measured vegetation characteristics at each nest site (n = 14 nests) on two different spatial scales and used program MARK to model nest survival as a function of multiple covariates. Apparent nest survival was 29% (n = 4 successful nests) and our …

Fluctuation Of Hyporheic Zone Thickness Due To Inflow And Outflow Across The Water-Sediment Interface, Xunhong Chen

School of Natural Resources: Faculty Publications

Determination of hyporheic zone thickness in streams is an important step for study of stream-aquifer interactions. Knowledge about hyporheic zone thickness is useful in stream restoration. However, because there is a lack of standard techniques for such study, evaluation of the hyporheic zone thickness for a given stream reach remains a challenge task for researchers. This paper presents Galerkin finite element flow and stream function models that can simulate the hyporheic zone thickness. The flow and stream function equations are solved for 2-D profile domains that can be across a stream or parallel to a stream. The numeral schemes for …

Post-Disaster Assessment Of Northeastern Coastal Region For The 2011 Sendai Earthquake And Tsunami, Ruopu Li, Shishi Liu, Qingfeng Guan, Yi Peng

School of Natural Resources: Faculty Publications

The 2011 Sendai Earthquake has hit the north-east of Japan triggering a destructive tsunami that has caused extensive damage. A fast and effective post-disaster assessment is highly imperative for the recovery of this region. This study modeled the tsunami-affected areas of coastal Fukushima Prefecture using Landsat-7 ETM+ data and terrain analysis. The result shows that most of the coastal areas were significantly affected by the tsunami. The low-lying plains along the coast are particularly vulnerable to the tsunami.

Understanding Weather, Climate, And Birthweight: Findings From The U.S. Natility Data Files 1969-78, Ge Lin, Song Feng

School of Natural Resources: Faculty Publications

Weather and extreme weather events are thought to be related to low birth weight. If this relation is held, it will have a wide range of public health impacts as birth weight is a key indicator of many life course health outcomes, and climate change increases the intensity of extreme weather events. The current study examines the relationship between birth weight and weather variables during the birth month while controlling other known risk factors. While the preliminary results seem to suggest a relationship between birth weight and extreme hot temperature, the result does not hold when individual and other risk …

A Review Of Interior Least Tern And Piping Plover Management, Conservation, And Recovery On The Lower Platte River, Nebraska, Mary Bomberger Brown, Joel G. Jorgensen, Sonya E. Steckler, Melissa J. Panella, W. Ross Silcock

School of Natural Resources: Faculty Publications

SUMMARY

The Lower Platte River in eastern Nebraska provides many resources for wildlife and a variety of stakeholders. This river and its major tributaries contain important nesting habitat for two state and federally-listed bird species, the Interior Least Tern (endangered; Sternula antillarum athalassos) and the Northern Great Plains Piping Plover (threatened; Charadrius melodus). Both species nest on bare or sparsely-vegetated expanses of sand in natural and human-created habitat, which occur in and along river channels; the Lower Platte River system is critical for the survival and recovery of both species.

The Lower Platte River in eastern Nebraska provides …

Variations In North American Summer Precipitation Driven By The Atlantic Multidecadal Oscillation, Qi Hu, Song Feng, Robert J. Oglesby

School of Natural Resources: Faculty Publications

Understanding the development and variation of the atmospheric circulation regimes driven by the Atlantic multidecadal oscillation (AMO) is essential because these circulations interactwith other forcings on decadal and interannual time scales. Collectively, they determine the summer (June, July, and August) precipitation variations for NorthAmerica. In this study, a general circulation model (GCM) is used to obtain such understanding, with a focus on physical processes connecting the AMO and the summertime precipitation regime change in NorthAmerica. Two experimental runs are conducted with sea surface temperature (SST) anomalies imposed in the North Atlantic Ocean that represent the warm and cold phases of …

Spectral Data-Based Estimation Of Soil Heat Flux, Ramesh K. Singh, Ayse Kilic, Elizabeth Walter-Shea, Shashi B. Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Numerous existing spectral‐based soil heat flux (G) models have shown wide variation in performance for maize and soybean cropping systems in Nebraska, indicating the need for localized calibration and model development. The objectives of this article are to develop a semi‐empirical model to estimate G from a normalized difference vegetation index (NDVI) and net radiation (R_n) for maize (Zea mays L.) and soybean (Glycine max L.) fields in the Great Plains, and present the suitability of the developed model to estimate G under similar and different soil and management conditions. Soil heat fluxes measured in both …

2011 Interior Least Tern And Piping Plover Monitoring, Research, Management, And Outreach Report For The Lower Platte River, Nebraska, Mary Bomberger Brown, Joel G. Jorgensen, Lauren R. Dinan

School of Natural Resources: Faculty Publications

This document reports on our monitoring, research, management, and outreach activities during the past 12 months (2011). We prepared it to inform our partners, cooperating agencies, funding sources, and other interested parties of our activities and to provide a preliminary summary of our results.

The Tern and Plover Conservation Partnership (TPCP), based at the University of Nebraska School of Natural Resources, and the Nongame Bird Program (NBP), based at the Nebraska Game and Parks Commission (NGPC), work cooperatively on Interior Least Tern and Piping Plover monitoring, research, management, and outreach in Nebraska. While the focus of our work is the …

Modeling Gross Primary Production Of Irrigated And Rain-Fed Maize Using Modis Imagery And Co2 Flux Tower Data, Joshua L. Kalfas, Xiangming Xiao, Diana X. Vanegas, Shashi B. Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Abstract

Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO₂ between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation …

Long-Term Rice-Based Cropping System Effects On Near-Surface Soil Compaction, J. M. Motschenbacher, K. R. Brye, M. M. Anders

School of Natural Resources: Faculty Publications

No abstract provided.

Discovering Native Bees, Alison P. Stevens

School of Natural Resources: Faculty Publications

No abstract provided.

Chapter 18- Chick Survival Of Greater Prairie-Chickens, Adam C. Schole, Ty W. Matthews, Larkin A. Powell, Jeffrey J. Lusk, J. Scott Taylor

School of Natural Resources: Faculty Publications

Chick survival during the first three weeks of life is a critical stage in the demography of Greater Prairie-Chickens (Tympanuchus cupido), but little information is available. Biologists often estimate brood success using periodic flushes of radio-marked females, but it is impossible to determine mortality factors if chicks are not radio-marked. We used sutures to attach 0.5-g transmitters to 1- to 2-day-old chicks in Johnson County, Nebraska, during 2008. Our objectives were to (1) assess causes of mortality of 0- to 21-day-old chicks, (2) estimate daily survival probability for 0- to 21-day-old chicks, and (3) evaluate the effect of applying …

Intense Natural Selection On Morphology Of Cliff Swallows (Petrochelidon Pyrrhonota) A Decade Later: Did The Population Move Between Adaptive Peaks? Sélection Naturelle Intensive Sur La Morphologie De Petrochelidon Pyrrhonota Une Décennie Plus Tard: La Population S’Est-Elle Déplacée Entre Deux Pics Adaptatifs?, Mary Bomberger Brown, Charles R. Brown

School of Natural Resources: Faculty Publications

Unusual climatic events often lead to intense natural selection on organisms. Whether episodic selection events result in permanent microevolutionary changes or are reversed by opposing selection pressures at a later time is rarely known, because most studies do not last long enough to witness rare events and document their aftermath. In 1996, unusually cold and wet weather in southwestern Nebraska led to the deaths of thousands of Cliff Swallows (Petrochelidon pyrrhonota) over a 6-day period. Survivors were skeletally larger, with shorter wings and tails, and had less asymmetry in wing length than those that died. We determined trajectories of morphological …

A Review Of Ethical Concepts And Moral Reasoning Integration Into Climate Change Curriculum, J. M. Dauer, C. Lettero, M. Ocana

School of Natural Resources: Faculty Publications

No abstract provided.

Tracking Plant Physiological Properties From Multi-Angular Tower-Based Remote Sensing, Thomas Hilker, Anatoly A. Gitelson, Nicholas C. Coops, Forrest G. Hall, T. Andrew Black

School of Natural Resources: Faculty Publications

Imaging spectroscopy is a powerful technique for monitoring the biochemical constituents of vegetation and is critical for understanding the fluxes of carbon and water between the land surface and the atmosphere. However, spectral observations are subject to the sun-observer geometry and canopy structure which impose confounding effects on spectral estimates of leaf pigments. For instance, the sun-observer geometry influences the spectral brightness measured by the sensor. Likewise, when considering pigment distribution at the stand level scale, the pigment content observed from single view angles may not necessarily be representative of stand-level conditions as some constituents vary as a function of …

Influence Of Atlantic Sea Surface Temperatures On Persistent Drought In North America, Song Feng, Qi Hu, Robert Oglesby

School of Natural Resources: Faculty Publications

This study investigates the relationship between North Atlantic sea surface temperatures (SST) and persistent drought in North America using modern observations, proxy paleodata, and simulations from multiple climate models. The observational results show that persistent droughts in the Great Plains and the southwest North America are closely related to multidecadal variations of North Atlantic SST (Atlantic Multidecadal Oscillations, AMO). During the AMO warm (cold) phases, most of North America is dry (wet). This relationship is persistent since at least 1567 AD, as based on proxy SST for the North Atlantic and the reconstructed drought index for North America. On centennial …

Sensitivity Of Planetary Boundary Layer Atmosphere To Historical And Future Changes Of Land Use/Land Cover, Vegetation Fraction, And Soil Moisture In Western Kentucky, Usa, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Impacts Of Irrigation On Dry Season Precipitation In India, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Land Use/Land Cover Changes And Climate: Modeling Analysis And Observational Evidence, Roger A. Pielke Sr., Andy Pitman, Dev Niyogi, Rezaul Mahmood, Clive Mcalpine, Faisal Hossain, Kees Klein Goldewijk, Udaysankar S. Nair, Richard Betts, Souleymane Fall, Markus Reichstein, Pavel Kabat, Nathalie De Noblet

School of Natural Resources: Faculty Publications

This article summarizes the changes in landscape structure because of human land management over the last several centuries, and using observed and modeled data, documents how these changes have altered biogeophysical and biogeochemical surface fluxes on the local, mesoscale, and regional scales. Remaining research issues are presented including whether these landscape changes alter large-scale atmospheric circulation patterns far from where the land use and land cover changes occur. We conclude that existing climate assessments have not yet adequately factored in this climate forcing. For those regions that have undergone intensive human landscape change, or would undergo intensive change in the …

Estimates Of Duck Breeding Populations In The Nebraska Sandhills Using Double Observer Methodology, Mark P. Vrtiska, Larkin A. Powell

School of Natural Resources: Faculty Publications

The Nebraska Sandhills are an important area for breeding ducks in the Great Plains, but reliable estimates of breeding populations are unavailable. Double-observer methodology was used to estimate abundance of breeding duck populations in the Nebraska Sandhills. Aerial transect surveys were conducted using methodology similar to the cooperative Waterfowl Breeding Population and Habitat Survey conducted by the U.S. Fish and Wildlife Service and Canadian Wildlife Service. Observations by two front-seat observers and one rear-seat observer were used to account for incomplete detectability. Transect-specific population size and detection probabilities were estimated using program SURVIV; estimates were species-specific by type of social …

Soil Moisture: A Central And Unifying Theme In Physical Geography, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Heat Flux Measurements And Modeling Of Malodorous Compounds Above An Anaerobic Swine Lagoon, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Remote Estimation Of Gross Primary Production In Maize, Yi Peng, Anatoly A. Gitelson, Galina Keydan, Donald C. Rundquist, Bryan Leavitt, Shashi B. Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

There is a growing interest in the estimation of gross primary productivity (GPP) in crops due to its importance in regional and global studies of carbon balance. We have found that crop GPP was closely related to its total chlorophyll content, and thus chlorophyll can be used as a proxy of GPP in crops. In this study, we tested the performance of various vegetation indices for estimating GPP. The indices were derived from spectral data collected remotely but at close-range over a period of eight years, from 2001 through 2008. The results show that chlorophyll indices, based on near infrared …