Digital Commons Network^™

Development Of A Benchmark Eddy Flux Evapotranspiration Dataset For Evaluation Of Satellite-Driven Evapotranspiration Models Over The Conus, John M. Volk, Justin Huntington, Forrest S. Melton, Richard Allen, Martha C. Anderson, Joshua B. Fisher, Ayse Kilic, Gabriel Senay, Gregory Halverson, Kyla Knipper, Blake Minor, Christopher Pearson, Tianxin Wang, Yun Yang, Steven Evett, Andrew N. French, Richard Jasoni, William Kustas

School of Natural Resources: Faculty Publications

A large sample of ground-based evapotranspiration (ET) measurements made in the United States, primarily from eddy covariance systems, were post-processed to produce a benchmark ET dataset. The dataset was produced primarily to support the intercomparison and evaluation of the OpenET satellite-based remote sensing ET (RSET) models and could also be used to evaluate ET data from other models and approaches. OpenET is a web-based service that makes field-delineated and pixel-level ET estimates from well-established RSET models readily available to water managers, agricultural producers, and the public. The benchmark dataset is composed of flux and meteorological data from a variety of …

Role Of Social Determinants Of Health In Differential Respiratory Exposure And Health Outcomes Among Children, Jagadeesh Puvvula, Jill A. Poole, Yeongjin Gwon, Eleanor G. Rogan, Jesse E. Bell

School of Natural Resources: Faculty Publications

Background Attributes defining the Social Determinants of Health (SDoH) are associated with disproportionate exposures to environmental hazards and differential health outcomes among communities. The dynamics between SDoH, disproportionate environmental exposures, and differential health outcomes are often specific to micro-geographic areas.

Methods This study focused on children less than 20 years of age who lived in Douglas County, Nebraska, during 2016–2019. To assess the role of SDoH in differential exposures, we evaluated the association between SDoH metrics and criteria pollutant concentrations and the association between SDoH and pediatric asthma exacerbations to quantify the role of SDoH in differential pediatric asthma outcomes. …

Panarchy Theory For Convergence, Shana M. Sundstrom, David G. Angeler, Jesse Bell, Michael J. Hayes, Jennifer Hodbod, Babak Jalalzadeh‑Fard, Rezaul Mahmood, Elizabeth Vanwormer, Craig R. Allen

School of Natural Resources: Faculty Publications

Coping with surprise and uncertainty resulting from the emergence of undesired and unexpected novelty or the sudden reorganization of systems at multiple spatiotemporal scales requires both a scientific process that can incorporate diverse expertise and viewpoints, and a scientific framework that can account for the structure and dynamics of interacting social-ecological systems (SES) and the inherent uncertainty of what might emerge in the future. We argue that combining a convergence scientific process with a panarchy framework provides a pathway for improving our understanding of, and response to, emergence. Emergent phenomena are often unexpected (e.g., pandemics, regime shifts) and can be …

Drought Influences Annual Survival Of Painted Turtles In Western Nebraska, Allyson N. Beard, Larkin Powell

School of Natural Resources: Faculty Publications

Aquatic habitats in the Great Plains of North America have increased risk of droughts under climate forecasts. Droughts have the potential to influence the population dynamics of pond turtles, and long-term studies are useful to assess the impact of climatic variation on turtles. We compiled twelve years of mark-recapture data for painted turtles (Chrysemys picta) captured in a pond in Keith County, Nebraska during 2005–2016 that included two periods of drought. We used a robust design analysis to investigate influences on population size, annual survival, temporary immigration, and capture probability. Estimates of the annual population size ranged from 92 (CI: …

Changing Blow Fly (Diptera: Calliphoridae) Populations In Orlando, Florida, United States, Amanda Roe, Russell J. Barnes, Leon G. Higley, Neal H. Haskell

School of Natural Resources: Faculty Publications

Blow flies (Diptera: Calliphoridae) were collected from various carrion baits in Orlando, Florida over 2 periods: Jun 2009 to Sep 2009 and Apr 2010 to Oct 2010. In a previous study conducted from 2002 to 2004 the dominant blow fly in Orlando, Florida, was Lucilia coeruleiviridis Macquart (Gruner et al. 2007). This collection documents a shift to Chrysomya megacephala Fabricius, as the most dominant blow fly species found in Orlando, Florida in 2009 to 2010. These field results have potential forensic implications, particularly in the analysis of cold cases.

Changing Blowfly (Diptera: Calliphoridae) Populations In Orlando, Florida, United States, A. Roe, R. J. Barnes, Leon G. Higley, N. H. Haskell

School of Natural Resources: Faculty Publications

No abstract provided.

Remotely Detected Aboveground Plant Function Predicts Belowground Processes In Two Prairie Diversity Experiments, Jeannine Cavender-Bares, Anna K. Schweiger, John Gamon, Hamed Gholizadeh, Kimberly Helzer, Cathleen Lapadat, Michael D. Madritch, Philip A. Townsend, Zhihui Wang, Sarah E. Hobbie

School of Natural Resources: Faculty Publications

Imaging spectroscopy provides the opportunity to incorporate leaf and canopy optical data into ecological studies, but the extent to which remote sensing of vegetation can enhance the study of belowground processes is not well understood. In terrestrial systems, aboveground and belowground vegetation quantity and quality are coupled, and both influence belowground microbial processes and nutrient cycling. We hypothesized that ecosystem productivity, and the chemical, structural and phylogenetic-functional composition of plant communities would be detectable with remote sensing and could be used to predict belowground plant and soil processes in two grassland biodiversity experiments: the BioDIV experiment at Cedar Creek Ecosystem …

The Role Of Rare Avian Species For Spatial Resilience Of Shifting Biomes In The Great Plains Of North America, D. Angeler, C. Roberts, D. Twidwell Jr., C. Allen

School of Natural Resources: Faculty Publications

No abstract provided.

Mapping Heat Vulnerability Index Based On Different Urbanization Levels In Nebraska, Usa, Babak J. Fard, Rezaul Mahmood, Michael Hayes, Clinton M. Rowe, Azar M Abadi, Martha Shulski, Sharon Medcalf, Rachel Lookadoo, Jesse E. Bell

School of Natural Resources: Faculty Publications

Despite similar incidence rates, Heat Vulnerability Index (HVI) in rural areas is under- studied in comparison to urban areas. • The environmental vulnerability variables in rural areas are dissimilar to urban areas, so we applied different variables to calculate them. • We found different organization of socioeconomic variables in calculated HVIs, suggesting separate heat strategies for urbanization levels.

Heatwaves cause excess mortality and physiological impacts on humans throughout the world, and climate change will intensify and increase the frequency of heat events. Many adaptation and mitigation studies use spatial distribution of highly vulnerable local populations to inform heat reduction and …

Ecophysio-Optical Traits Of Semiarid Nebraska Grasslands Under Different Juniperus Virginiana And Pinus Ponderosa Canopy Covers, Anastasios Mazis, Julie A. Fowler, Jeremy Hiller, Yuzhen Zhou, Brian Wardlow, David A. Wedin, Tala Awada

School of Natural Resources: Faculty Publications

Despite conservation efforts in the U.S. Great Plains, woody species have continued to expand at an unprecedented rate, threatening key ecosystem services and resilience. Cross-scale monitoring of these grasslands is key to successful integrative management strategies. In this study we measured plant optical traits derived from hyperspectral proximal sensing techniques with a field spectrometer, coupled with field-based measurements, including fluorescence and chlorophyll content, to determine the impacts of Juniperus virginiana and Pinus ponderosa expansion on grasslands health in Nebraska Sandhills, and investigated the use of optical-based approaches as indicators of successful monitoring of grasslands. Our results showed that higher woody …

Remotely Detected Plant Function In Two Midwestern Prairie Grassland Experiments Reveals Belowground Processes, J. Cavender-Bares, A. Schweiger, J. Gamon, H. Gholizadeh, K. Helzer, C. Lapadat, M. Madritch, P. Townsend, Z. Wang, S. Hobbie

School of Natural Resources: Faculty Publications

No abstract provided.

Nutrient Cycling In Forage Production Systems, David A. Wedin, Michael P. Russelle

School of Natural Resources: Faculty Publications

In most forage production systems, the nutrients needed for plant growth are provided by the microbially-mediated breakdown and release of plant-available mineral nutrients from dead plant tissues, livestock excreta, soil organic matter, and geochemically-bound mineral forms. Even in fertilized forage systems, determining appropriate fertilizer or manure application rates requires a “systems” approach on the part of the manager (Rotz et al. 2005; Wood et al. 2012). Fertilizer additions are simply one input in the system of inputs, outputs, pools, and fluxes that characterize nutrient cycling in a particular ecosystem.

Discontinuity Analysis Reveals Alternative Community Regimes During Phytoplankton Succession, David G. Angeler, Craig R. Allen, Dirac L. Twidwell Jr., Monika Winder

School of Natural Resources: Faculty Publications

It is well-recognized in plankton ecology that phytoplankton development can lead to distinct peaks (i.e., blooms) during spring and summer. We used a 5-year (2007–2011) phytoplankton data set and utilized discontinuity analysis to assess resilience attributes of spring and summer blooms based on the cross-scale resilience model. Using the size structure (i.e., cross-scale structure as an indicator of resilience) in the sampled plankton data, we assessed whether spring and summer blooms differ substantially between but not within blooms; that is, whether they comprise alternative community regimes. Our exploratory study supported this expectation and more broadly resilience theory, which posits that …

Early Warnings For State Transitions, Caleb P. Roberts, Dirac Twidwell, Jessica L. Burnett, Victoria M. Donovan, Carissa L. Wonkka, Christine L. Bielski, Ahjond S. Garmestani, David G. Angeler, Tarsha Eason, Brady W. Allred, Matthew O. Jones, David E. Naugle, Shana M. Sundstrom, Craig R. Allen

School of Natural Resources: Faculty Publications

New concepts have emerged in theoretical ecology with the intent to quantify complexities in ecological change that are unaccounted for in state-and-transition models and to provide applied ecologists with statistical early warning metrics able to predict and prevent state transitions. With its rich history of furthering ecological theory and its robust and broad-scale monitoring frameworks, the rangeland discipline is poised to empirically assess these newly proposed ideas while also serving as early adopters of novel statistical metrics that provide advanced warning of a pending shift to an alternative ecological regime. We review multivariate early warning and regime shift detection metrics, …

Present And Future Thermal Environments Available To Sharp-Tailed Grouse In An Intact Grassland, Edward J. Raynor, Larkin Powell, Walter H. Schacht

School of Natural Resources: Faculty Publications

Better understanding animal ecology in terms of thermal habitat use has become a focus of ecological studies, in large part due to the predicted temperature increases associated with global climate change. To further our knowledge on how ground-nesting endotherms respond to thermal landscapes, we examined the thermal ecology of Sharp-tailed Grouse (Tympanuchus phasianellus) during the nesting period. We measured site-specific iButton temperatures (TiB) and vegetation characteristics at nest sites, nearby random sites, and landscape sites to assess thermal patterns at scales relevant to nesting birds. We asked if microhabitat vegetation characteristics at nest sites matched the characteristics that directed macrohabitat …

Effects Of Patch Size And Basal Area On Avian Taxonomic And Functional Diversity In Pine Forests: Implication For The Influence Of Habitat Quality On The Species–Area Relationship, Myung-Bok Lee, John P. Carroll

School of Natural Resources: Faculty Publications

Relationships between avian diversity and habitat area are assumed to be positive; however, often little attention has given to how these relationships can be influenced by the habitat structure or quality. In addition, other components of biodiversity, such as functional diversity, are often overlooked in assessing habitat patch value. In the Sandhills Ecoregion of Georgia, USA, we investigated the relationship between avian species richness and functional diversity, forest basal area, and patch size in pine forests using basal area as a surrogate for overstory structure which in turn impacts vegetation structure and determines habitat quality within a patch. We conducted …

Common Carp Disrupt Ecosystem Structure And Function Through Middle-Out Effects, Mark A. Kaemingk, Jeffrey C. Jolley, Craig P. Paukert, David W. Willis, Kjetil Henderson, Richard S. Holland, Greg A. Wanner, Mark L. Lindvall

School of Natural Resources: Faculty Publications

Middle-out effects or a combination of top-down and bottom-up processes create many theoretical and empirical challenges in the realm of trophic ecology. We propose using specific autecology or species trait (i.e. behavioural) information to help explain and understand trophic dynamics that may involve complicated and nonunidirectional trophic interactions. The common carp (Cyprinus carpio) served as our model species for whole-lake observational and experimental studies; four trophic levels were measured to assess common carp-mediated middle-out effects across multiple lakes. We hypothesised that common carp could influence aquatic ecosystems through multiple pathways (i.e. abiotic and biotic foraging, early life feeding, nutrient). Both …

Eastern Wild Turkey Nest Site Selection In Two Frequently Burned Pine Savannas, Andrew R. Little, Nathan P. Nibbelink, Michael J. Chamberlain, L. Mike Conner, Robert J. Warren

School of Natural Resources: Faculty Publications

Introduction: Reproductive success is a critical factor affecting avian demographics and can be influenced by many factors including nesting chronology, predation risk, and fine-scale nest site selection.

Methods: We modeled the relative influences of habitat-related covariates at six spatial scales (nest site: 15-, 40-, 80-, 120-, 160-, and 200-m radii) on Eastern wild turkey (Meleagris gallopavo silvestris) nest site selection in two pine savannas managed by frequent prescribed fire (≤3 years) in southwestern Georgia during 2011–2013.

Results: Nest site (15-m scale) habitat metrics (mean visual obstruction [cm] and canopy closure [%]) had the greatest influence on nest site …

Development Modeling Of Lucilia Sericata (Diptera: Calliphoridae), Amanda Roe, Leon G. Higley

School of Natural Resources: Faculty Publications

The relationship between insect development and temperature has been well established and has a wide range of uses, including the use of blow flies for postmortem (PMI) interval estimations in death investigations. To use insects in estimating PMI, we must be able to determine the insect age at the time of discovery and backtrack to time of oviposition. Unfortunately, existing development models of forensically important insects are only linear approximations and do not take into account the curvilinear properties experienced at extreme temperatures. A series of experiments were conducted with Lucilia sericata, a forensically important blow fly species, that met …

The Uncertain Climate Footprint Of Wetlands Under Human Pressure, Ana Maria Roxana Petrescu, Annalea Lohila, Juha-Pekka Tuovinen, Dennis D. Baldocchi, Ankur R. Desai, Nigel T. Roulet, Timo Vesala, Albertus Johannes Dolman, Walter C. Oechel, Barbara Marcolla, Thomas Friborg, Janne Rinne, Jaclyn Hatala Matthes, Lutz Merbold, Ana Meijide, Gerard Kiely, Matteo Sottocornola, Torsten Sachs, Donatella Zona, Andrej Varlagin, Derrick Y.F. Lai, Elmar Veenendaal, Frans-Jan W. Parmentier, Ute Skiba, Magnus Land, Arjan Hensen, Jacobus Van Huissteden, Lawrence B. Flanagan, Narasinha J. Shurpali, Thomas Grünwald, Elyn R. Humphreys, Marcin Jackowicz-Korczynski, Mika A. Aurela, Tuomas Laurila, Carsten Grüning, Chiara A.R. Corradi, Arina P. Schrier-Uijl, Torben R. Christensen, Mikkel P. Tamstorf, Mikhail Mastepanov, Pertti J. Martikainen, Shashi Verma, Christian Bernhofer, Alessandro Cescatti

School of Natural Resources: Faculty Publications

Significant climate risks are associated with a positive carbon–temperature feedback in northern latitude carbon-rich ecosystems,making an accurate analysis of human impacts on the net greenhouse gas balance of wetlands a priority. Here, we provide a coherent assessment of the climate footprint of a network of wetland sites based on simultaneous and quasi-continuous ecosystem observations of CO₂ and CH₄ fluxes. Experimental areas are located both in natural and in managed wetlands and cover a wide range of climatic regions, ecosystem types, and management practices. Based on direct observations we predict that sustained CH₄ emissions in natural ecosystems are …

Breeding Time In A Migratory Songbird Is Predicted By Drought Severity And Group Size, Charles R. Brown, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Global climate change is altering the breeding phenology of many organisms, and one reported consequence of warmer average temperatures is earlier breeding times in migratory songbirds of north temperate latitudes. Less studied are the potential interactions between earlier breeding and social behavior in colonial species. We investigated how breeding time, as measured by colony initiation dates across the entire summer, in Cliff Swallows (Petrochelidon pyrrhonota) of southwestern Nebraska, USA, changed over a 30-year period and could be predicted by climatic variables, year, and colony size. Mean colony initiation date became earlier over the study, with variation best predicted …

Transdisciplinary Research On Environmental Governance: A View From The Inside, Katherine Mattor, Michele Betsill, Ch'aska Huayhuaca, Heidi Huber-Stearns, Theresa Jedd, Faith Sternlieb, Patrick Bixler, Matthew Luizza, Antony S. Cheng

School of Natural Resources: Faculty Publications

No abstract provided.

Atrazine And Nitrate In Public Drinking Water Supplies And Non-Hodgkin Lymphoma In Nebraska, Usa, Martha G. Rhoades, Jane L. Meza, Cheryl L. Beseler, Patrick J. Shea, Andy Kahle, Julie M. Vose, Kent M. Eskridge, Roy F. Spalding

School of Natural Resources: Faculty Publications

A secondary analysis of 1999–2002 Nebraska case-control data was conducted to assess the risk of non-Hodgkin lymphoma (NHL) associated with exposure to nitrate- and atrazine-contaminated drinking water. Water chemistry data were collected and weighted by well contribution and proximity of residence to water supply, followed by logistic regression to determine odds ratios (OR) and 95% confidence intervals (CI). We found no association between NHL risk and exposure to drinking water containing atrazine or nitrate alone. Risk associated with the interaction of nitrate and atrazine in drinking water was elevated (OR, 2.5; CI, 1.0–6.2). Risk of indolent B-cell lymphoma was higher …

Nondetection Sampling Bias In Marked Presence-Only Data, Trevor Hefley, Andrew J. Tyre, David M. Baasch, Erin E. Blankenship

School of Natural Resources: Faculty Publications

1 Species distribution models (SDM) are tools used to determine environmental features that influence the geographic distribution of species’ abundance and have been used to analyze presence-only records. Analysis of presenceonly records may require correction for nondetection sampling bias to yield reliable conclusions. In addition, individuals of some species of animals may be highly aggregated and standard SDMs ignore environmental features that may influence aggregation behavior.

2 We contend that nondetection sampling bias can be treated as missing data. Statistical theory and corrective methods are well developed for missing data, but have been ignored in the literature on SDMs. We …

Synchrony Of Net Nitrogen Mineralization And Maize Nitrogen Uptake Following Applications Of Composted And Fresh Swine Manure In The Midwest U.S., Terrance D. Loecke, Cynthia A. Cambardella, Matt Liebman

School of Natural Resources: Faculty Publications

Understanding how the quality of organic soil amendments affects the synchrony of nitrogen (N) mineralization and plant N uptake is critical for optimal agronomic N management and environmental protection. Composting solid livestock manures prior to soil application has been promoted to increase N synchrony; however, few field tests of this concept have been documented. Two years of replicated field trials were conducted near Boone, Iowa to determine the effect of composted versus fresh solid swine manure (a mixture of crop residue and swine urine and feces produced in hoop structures) on Zea mays (maize) N uptake, in situ soil net …

Operational Meris-Based Nir-Red Algorithms For Estimating Chlorophyll-A Concentrations In Coastal Waters — The Azov Sea Case Study, Wesley J. Moses, Anatoly A. Gitelson, Sergey Berdnikov, Vladislav Saprygin, Vasily Povazhnyi

School of Natural Resources: Faculty Publications

We present here results that strongly support the use of MERIS-based NIR-red algorithms as standard tools for estimating chlorophyll-a (chl-a) concentration in turbid productive waters. The study was carried out as one of the steps in testing the potential of the universal applicability of previously developed NIR-red algorithms, which were earlier calibrated using a limited set of MERIS imagery and in situ data from the Azov Sea and the Taganrog Bay, Russia, and data that were synthetically generated using a radiative transfer model. We used an extensive set of MERIS imagery and in situ data collected over …

Tracking Large Carnivore Dispersal Using Isotopic Clues In Claws: An Application To Cougars Across The Great Plains, Viviane Hénaux, Larkin A. Powell, Keith A. Hobson, Clayton Kent Nielsen, Michelle A. Larue

School of Natural Resources: Faculty Publications

1. Cougar (Puma concolor) populations, like other large carnivores, have increased during recent decades and may be recolonizing their former ranges in Midwestern North America. The dispersal routes taken by these animals from established populations are unknown and insight into these movements would facilitate their conservation and management.

2. We inferred the origin and migration route of four dispersing cougars using stable hydrogen (δD) and carbon (δ¹³C) isotope values along one of their claws. We compared isotopic variations within claws to regional and large-scale isoscapes of δD and δ¹³C values in prey species. Using …

River Geomorphology And Fish Barriers Affect On Spatial And Temporal Patterns Of Fish Assemblages In The Niobrara River, Nebraska, Greg A. Wanner, Mark A. Pegg, Steven Schainost, Robert A. Klumb, Dane A. Shuman

School of Natural Resources: Faculty Publications

The Niobrara River in northern Nebraska traverses the heart of the Great Plains with portions of the river protected under the National Wild and Scenic River system managed by the National Park Service. The Niobrara River changes from a narrow, entrenched stream to a wide, highly braided river with four fish barriers and 36 distinct geomorphic segments in the lower 531 river kilometers (rkm). Our objectives were to examine the spatial and temporal patterns of fish assemblages in the Niobrara River related to environmental variables, fish barriers, and river geomorphology. Tote-barge electrofishing occurred monthly from June to September in 2009 …

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 …

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 …