Physical Sciences and Mathematics Commons^™

Numerical Validation Of A Diurnal Streamflow-Pattern-Based Evapotranspiration Estimation Method, Zoltan Gribovszki, Peter Kalicz, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Comment On Interference Of River Level Changes On Riparian Zone Evapotranspiration Estimates From Diurnal Groundwater Level Fluctuations By Zhu Et Al., Jozsef Szilagyi, Zoltan Gribovszki, Peter Kalicz

School of Natural Resources: Faculty Publications

No abstract provided.

Discovering Native Bees, Alison P. Stevens

School of Natural Resources: Faculty Publications

NATURAL SYSTEMS PROVIDE humans with a variety of services essential to our survival. Ecosystem services such as climate regulation, water purification, oxygen production, waste treatment and detoxification, flood prevention, and pollination are provided at no cost, yet their true value is immeasurable. In our economydriven world, these systems are often taken for granted, and as a consequence many are in peril. Understanding their role is a critical first step towards ensuring that they endure. Pollination, the process of moving pollen grains from one flower to another to stimulate fruit and seed production, is among the easiest of these services to …

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 …

Landscape Structure, Groundwater Dynamics, And Soil Water Content Influence Soil Respiration Across Riparian–Hillslope Transitions In The Tenderfoot Creek Experimental Forest, Montana, Vincent J. Pacific, Diego Andrés Riveros-Iregui, Daniel L. Welsch, Howard E. Epstein

School of Natural Resources: Faculty Publications

Variability in soil respiration at various spatial and temporal scales has been the focus of much research over the last decade aimed to improve our understanding and parameterization of physical and environmental controls on this flux. However, few studies have assessed the control of landscape position and groundwater table dynamics on the spatiotemporal variability of soil respiration. We investigated growing season soil respiration in a ~393 ha subalpine watershed in Montana across eight riparian–hillslope transitions that differed in slope, upslope accumulated area (UAA), aspect, and groundwater table dynamics. We collected daily-to-weekly measurements of soil water content (SWC), soil temperature, soil …

An Interannual Assessment Of The Relationship Between The Stable Carbon Isotopic Composition Of Ecosystem Respiration And Climate In A High‐Elevation Subalpine Forest, Diego Andrés Riveros-Iregui, Jia Hu, Sean Burns, David R. Bowling, Russell K. Monson

School of Natural Resources: Faculty Publications

We measured the carbon isotopic composition (δ¹³C) of ecosystem respiration (δ¹³C_R) in a subalpine forest across four growing seasons to examine whether patterns in δ¹³C_R were consistent with those expected based on leaf‐level gas‐exchange theory, and in agreement with past studies of the relation between δ¹³C_R and climate conducted across broad geographic regions. Conventional trends (i.e., less negative δ¹³C_R with increased vapor pressure deficit (VPD) and air temperature (TAIR), and decreased soil moisture (θ)) were observed when we focused on the driest portions …

Integrating Info-Gap Decision Theory With Robust Population Management: A Case Study Using The Mountain Plover, Max Post Van Der Burg, Andrew J. Tyre

School of Natural Resources: Faculty Publications

Wildlife managers often make decisions under considerable uncertainty. In the most extreme case, a complete lack of data leads to uncertainty that is unquantifiable.Information-gap decision theory deals with assessing management decisions under extreme uncertainty, but it is not widely used in wildlife management. So too, robust population management methods were developed to deal with uncertainties in multiple-model parameters.However, the two methods have not, as yet, been used in tandem to assess population management decisions. We provide a novel combination of the robust population management approach for matrix models with the information-gap decision theory framework for making conservation decisions under extreme …

Confronting Socially Generated Uncertainty In Adaptive Management, Andrew J. Tyre, Sarah Michaels

School of Natural Resources: Faculty Publications

As more and more organizations with responsibility for natural resource management adopt adaptive management as the rubric in which they wish to operate, it becomes increasingly important to consider the sources of uncertainty inherent in their endeavors. Without recognizing that uncertainty originates both in the natural world and in human undertakings, efforts to manage adaptively at the least will prove frustrating and at the worst will prove damaging to the very natural resources that are the management targets. There will be more surprises and those surprises potentially may prove at the very least unwanted and at the worst devastating. We …

Evaluating The Efficacy Of Adaptive Management Approaches: Is There A Formula For Success?, Jamie E. Mcfadden, Tim L. Hiller, Andrew J. Tyre

School of Natural Resources: Faculty Publications

Within the field of natural-resources management, the application of adaptive management is appropriate for complex problems high in uncertainty. Adaptive management is becoming an increasingly popular management-decision tool within the scientific community and has developed into two primary schools of thought: the Resilience-Experimentalist School (with high emphasis on stakeholder involvement, resilience, and highly complex models) and the Decision-Theoretic School (which results in relatively simple models through emphasizing stakeholder involvement for identifying management objectives). Because of these differences, adaptive management plans implemented under each of these schools may yield varying levels of success. We evaluated peer-reviewed literature focused on incorporation of …

Review Of Mammalogy, 5th Edition By T. A. Vaughan, J. M. Ryan, And N. J. Czaplewski, Patricia W. Freeman

School of Natural Resources: Faculty Publications

Last summer I spent time with old friends. Terry Vaughan and company have significantly updated their text, Mammalogy, for the 5th edition (2011). The book is 62% larger than the 1st edition in 1972 (Vaughan 1972). Vaughan, Ryan, and Czaplewski skewer topics with a simplicity derived from years of mammalian research and teaching, and it is a pure pleasure to read. The synthetic nature of Mammalogy (2011) and exceptional clarity in writing make this edition an ideal book that is not just for class. Because much new research has been integrated into each chapter, all mammalogists will appreciate new …

Review Of Mammalian Teeth: Origin, Evolution, And Diversity By Peter S. Ungar, Patricia W. Freeman

School of Natural Resources: Faculty Publications

Peter Ungar has written a book on mammalian teeth, a topic close to the heart of mammalogy itself and most mammalogists. His distillation of the massive literature on teeth into a succinct whole will appeal to scientists and professionals across disciplines. With paleontological and extant dental research in one place I no longer have to search these areas separately to find what I want. Ungar’s broad background includes physical anthropology, anatomy, and paleontology. Further, he has been one of the pioneers using dental microwear to analyze diets in primates and geographic information systems (GISs) on a microscale to study cusps …

Estimating Daily Gross Primary Production Of Maize Based Only On Modis Wdrvi And Shortwave Radiation Data, Toshihiro Sakamoto, Anatoly Gitelson, Brian D. Wardlow, Shashi Verma, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Accurate assessment of temporal changes in gross primary production (GPP) is important for carbon budget assessments and evaluating the impact of climate change on crop productivity. The objective of this study was to devise a simple remote sensing- based GPP model to quantify daily GPP of maize. In the model, (1) daily shortwave radiation (SW), derived from the reanalysis data (North American Land Data Assimilation System; NLDAS-2) and (2) smoothed Wide Dynamic Range Vegetation Index (WDRVI) data, derived from Moderate Resolution Imaging Spectroradiometer (MODIS) 250-m observations were used as proxy variables of the incident photosynthetically active radiation (PAR) and the …

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 …

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

School of Natural Resources: Faculty Publications

No abstract provided.