Physical Sciences and Mathematics Commons^™

Modeling Vulnerability Of Groundwater To Pollution Under Future Scenarios Of Climate Change And Biofuels-Related Land Use Change: A Case Study In North Dakota, Usa, Ruopu Li, James W. Merchant

School of Natural Resources: Faculty Publications

Modeling groundwater vulnerability to pollution is critical for implementing programs to protect groundwater quality.Most groundwater vulnerability modeling has been based on current hydrogeology and land use condi- tions. However, groundwater vulnerability is strongly dependent on factors such as depth-to-water, recharge and land use conditions thatmay change in response to future changes in climate and/or socio-economic condi- tions. In this research, a modeling framework, which employs three sets of models linked within a geographic information system (GIS) environment, was used to evaluate groundwater pollution risks under future climate and land use changes in North Dakota. The results showed that areas with …

Where Has All The Road Kill Gone?, Charles R. Brown, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

An estimated 80 million birds are killed by colliding with vehicles on U.S. roads each year [1], and millions more die annually in Europe [2] and elsewhere. Losses to vehicles are a serious problem for which various changes in roadway design and maintenance have been proposed [3]. Yet, given the magnitude of the mortality reported for some species [4], we might expect natural selection to favor individuals that either learn to avoid cars or that have other traits making them less likely to collide with vehicles. If so, the frequency of road kill should decline over time. No information is …

Behavioural Salinity Preferences Of Juvenile Green Sturgeon Acipenser Medirostris Acclimated To Fresh Water And Full-Strength Salt Water, J. B. Poletto, D. E. Cocherell, A. P. Klimley, J. J. Cech Jr., N. A. Fangue

School of Natural Resources: Faculty Publications

To quantify the salinity preference of juvenile green sturgeon Acipenser medirostris, two groups of A. medirostris [140 days post hatch (dph); total length (L_T) 38.0–52.5 cm] were acclimated to either near fresh water (mean ± S.E. salinity = 3.2 ± 0.6) or full-strength salt water (34.1 ± 1.2) over 8 weeks. Following acclimation, the two groups were divided into experimental and control groups, where experimental A. medirostris from both freshwater and saltwater acclimations were individually introduced (200–220 dph) into a rectangular salinity-preference flume (maximum salinity gradient: 5–33). Control A. medirostris were presented with only their acclimation …

Long-Term Agro-Ecosystem Research (Ltar) Network To Establish The Platte River – High Plains Aquifer Ltar, Brian J. Wienhold, Tala Awada

School of Natural Resources: Faculty Publications

The University of Nebraska-Lincoln (UNL), the USDA-ARS Agro-ecosystem Management Research Unit (AMRU) in Lincoln, and Environmental Management Research Unit (EMRU) in Clay Center propose to establish a Long-term Agro-ecosystem Research (LTAR) Network site with a focus on the northern portion of the High Plains Aquifer. Over 95 percent of the water withdrawn from the aquifer is for agricultural use, and – unlike the portion of the aquifer underlying southern Kansas, Oklahoma, and Texas where significant drawdown has occurred – ground water levels have remained relatively stable since 1960. However, this stability might be in jeopardy with projected climate variability and …

The Importance Of Spring And Autumn Atmospheric Conditions For The Evaporation Regime Of Lake Superior, Christopher Spence, P.D. Blanken, John D. Lenters, N. Hedstrom

School of Natural Resources: Faculty Publications

Feedbacks between ice extent and evaporation have long been suspected to be important for Lake Superior evaporation because it is during autumn and winter when latent heat fluxes are highest. Recent direct measurements of evaporation made at the Stannard Rock Lighthouse have provided new information on the physical controls on Lake Superior evaporation, in particular that evaporation can react within hours to days to a change in synoptic conditions. However, the large heat capacity of the lake creates a strong seasonal cycle of energy storage and release. There is a complex interaction among heat storage, evaporation, and ice cover that …

The Influence Of Different Cover Types On American Robin Nest Success In Organic Agroecosystems, John E. Quinn, Amy I. Oden, James R. Brandle

School of Natural Resources: Faculty Publications

There are many opportunities for biodiversity conservation in organic farm systems. Successful and sustainable conservation efforts in organic systems, however, need to measure appropriate outcomes. In particular, data are needed on the breeding success of associated wildlife species. We measured nesting success of the American Robin (Turdus migratorius) in woodlands embedded within eight organic farms in eastern Nebraska. We modeled daily nest survival rate to identify land use and land cover patterns that optimize conservation of birds in organic farm systems. The percentage of a crop in the fields adjacent to linear woodlands best predicted daily survival rate. …

Aspects Of Northern Bobwhite Ecology On South Florida Rangeland., J. A. Martin, W. E. Palmer, Carroll J. P.

School of Natural Resources: Faculty Publications

Abstract During 2004 and 2005, we monitored breeding season survival, home range, habitat use, density, and reproduction of northern bobwhite (Colinus virginianus) in the peninsular region of Florida, USA. We radio-tagged 81 birds across a 20-km2 cattle ranch consisting predominately of rotationally grazed pastureland. Birds were radio-tracked three to five times per week until mortality or the transition to nonbreeding season. We found no difference in home range size among the sexes, ages, or their interaction. Mean home range size pooled for years, sexes, and age class was 56.28 ha (±7.87 SE). Home ranges of bobwhites were not distributed among …

Overwinter Mortality Of Sympatric Juvenile Bluegill And Yellow Perch In Mid-Temperate Prairie Lakes, Jeffrey C. Jolley, Mark A. Kaemingk, David W. Willis, Richard S. Holland

School of Natural Resources: Faculty Publications

Substantial mortality can occur in age-0 fish populations during their first year of life, especially in winter; this can potentially influence overall recruitment into the adult population. As such, we compared relative abundances between fall and spring catches of sympatric juvenile bluegill Lepomis macrochirus Rafinesque and yellow perch Perca flavescens (Mitchill) to evaluate the magnitude of overwinter mortality across locations (five lakes for two years) and through time (one lake for six years). In addition, we compared both quantile-quantile and increment plots, based on length-frequency histograms from fall- and spring-caught cohorts from 2004 to 2010, to determine if mortality was …

Pressures To Publish: Catalysts For The Loss Of Scientific Writing Integrity?, Cari-Ann Hayer, Mark A. Kaemingk, Jason J. Breeggemann, Daniel Dembkowski, David Deslauriers, Tobias Rapp

School of Natural Resources: Faculty Publications

Publishing research is the final step in the scientific process and is used as the primary means for disseminating research findings to the scientific community. Publishing can embody many personal motivations (e.g., gratification, seeing a finished product in print, desire to further science) for authors as well as professional benefits (e.g., promotion, tenure, future funding opportunities). As the scientific workforce and competition for jobs and funding increase, publishing productivity has become a driving factor for many authors, which may lead to writing practices that violate integrity. In this essay, we discuss writing actions that may be considered a violation of …

Field Guide For Nebraska Aquatic Invasive Species (Fg-26)

School of Natural Resources: Faculty Publications

No abstract provided.

Field Guide For Nebraska Invasive Plants (Fg-27)

School of Natural Resources: Faculty Publications

What are Invasive Species: Invasive species are non-native organisms introduced into new ecosystem whose introduction and ability to spread causes environmental or economic harm, or harm to human health. Once established, these species cause irreparable harm, including: introducing disease; competing with native specics; changing the physical characteristics of natural areas; and negatively impacting local and national economies.

Invasive Species Regulations: This guide identifies federal and state-listed noxious weeds. Federal noxious weeds are regulated by the U.S. Department of Agriculture; State noxious weeds are regulated by the Nebraska Department of Agriculture Animal and Plant Health Noxious Weed Program. Aquatic invasive …

Fostering Student Sense Making In Elementary Science Learning Environments: Elementary Teachers’ Use Of Science Curriculum Materials To Promote Explanation Construction, Laura Zangori, Cory Forbes, Mandy Biggers

School of Natural Resources: Faculty Publications

While research has shown that elementary (K-5) students are capable of engaging in the scientific practice of explanation construction, commonly-used elementary science curriculum materials may not always afford them opportunities to do so. As a result, elementary teachers must often adapt their science curriculum materials to better support students’ explanation construction and foster student sense making. However, little research has been conducted to explore if and, if so, how and why, elementary teachers modify science curriculum materials to engage students in explanation construction. We use an embedded mixed methods research design to explore elementary teachers’ (n = 45) curricular adaptations …

The Under-Ice Microbiome Of Seasonally Frozen Lakes, Stefan Bertilsson, Amy Burgin, Cayelan C. Carey, Samuel B. Fey, Hans-Peter Grossart, Lorena M. Grubisic, Ian D. Jones, Georgiy Kirillin, Jay T. Lennon, Ashley Shade, Robyn L. Smyth

School of Natural Resources: Faculty Publications

Compared to the well-studied open water of the ‘‘growing’’ season, under-ice conditions in lakes are characterized by low and rather constant temperature, slow water movements, limited light availability, and reduced exchange with the surrounding landscape. These conditions interact with ice-cover duration to shape microbial processes in temperate lakes and ultimately influence the phenology of community and ecosystem processes. We review the current knowledge on microorganisms in seasonally frozen lakes. Specifically, we highlight how under-ice conditions alter lake physics and the ways that this can affect the distribution and metabolism of auto- and heterotrophic microorganisms. We identify functional traits that we …

Students Understanding Of Cells And Heredity: Patterns Of Understanding In The Context Of A Curriculum Implementation In Fifth And Seventh Grades, Dante Cisterna, Michelle Williams, Joi Merritt

School of Natural Resources: Faculty Publications

No abstract provided.

Recent Updates Of The Calibration-Free Evapotranspiration Mapping (Cremap) Method, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Modeling The Production Of Multiple Ecosystem Services From Agricultural And Forest Landscapes In Rhode Island, Tingting Liu, Nathaniel H. Merrill, Arthur J. Gold, Dorothy Q. Kellogg, Emi Uchida

School of Natural Resources: Faculty Publications

No abstract provided.

High Spatial Resolution Mapping Of Elevated Atmospheric Carbon Dioxide Using Airborne Imaging Spectroscopy: Radiative Transfer Modeling And Power Plant Plume Detection, Philip E. Dennison, Andrew K. Thorpe, Eric R. Pardyjak, Dar A. Roberts, Yi Qi, Robert O. Green, Eliza S. Bradley, Christopher C. Funk

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 …

Validation Of Noah-Simulated Soil Temperature In The North American Land Data Assimilation System Phase 2, Youlong Xia, Michael Ek, Justin Sheffield, Ben Livneh, Maoyi Huang, Helin Wei, Song Feng, Lifeng Luo, Jesse Meng, Eric Wood

School of Natural Resources: Faculty Publications

Soil temperature can exhibit considerable memory from weather and climate signals and is among the most important initial conditions in numerical weather and climate models. Consequently, a more accurate long term land surface soil temperature dataset is needed to improve weather and climate simulation and prediction, and is also important for the simulation of agricultural crop yield and ecological processes. The North American Land Data Assimilation phase 2 (NLDAS-2) has generated 31 years (1979–2009) of simulated hourly soil temperature data with a spatial resolution of 1/8°. This dataset has not been comprehensively evaluated to date. Thus, the purpose of this …

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 …

Correction Of Location Errors For Presence-Only Species Distribution Models, Trevor Hefley, David M. Baasch, Andrew J. Tyre, Erin E. Blankenship

School of Natural Resources: Faculty Publications

1. Species distribution models (SDMs) for presence-only data depend on accurate and precise measurements of geographical and environmental covariates that influence presence and abundance of the species. Some data sets, however, may contain both systematic and random errors in the recorded location of the species. Environmental covariates at the recorded location may differ from those at the true location and result in biased parameter estimates and predictions from SDMs.

2. Regression calibration is a well-developed statistical method that can be used to correct the bias in estimated coefficients and predictions from SDMs when the recorded geographical location differs from the …

Statistical Indicators And State–Space Population Models Predict Extinction In A Population Of Bobwhite Quail, Trevor Hefley, Andrew J. Tyre, Erin E. Blankenship

School of Natural Resources: Faculty Publications

Early warning systems of extinction thresholds have been developed for and tested in microcosm experiments, but have not been applied to populations of wild animals. We used state–space population models and a statistical indicator to detect a transcritical bifurcation extinction threshold in a population of bobwhite quail (Colinus virginianus) located in an agricultural region experiencing habitat deterioration and loss. The extinction threshold was detectible using two independent data sets. We compared predictions from state–space population models to predictions from a statistical indicator and found that predictions were corroborated. Using state–space population models, we estimated that our study population …

Miscanthus Establishment And Overwintering In The Midwest Usa: A Regional Modeling Study Of Crop Residue Management On Critical Minimum Soil Temperatures, Christopher J. Kucharik, Andy Vanloocke, John D. Lenters, Melissa M. Motew

School of Natural Resources: Faculty Publications

Miscanthus is an intriguing cellulosic bioenergy feedstock because its aboveground productivity is high for low amounts of agrochemical inputs, but soil temperatures below ‒3.5°C could threaten successful cultivation in temperate regions. We used a combination of observed soil temperatures and the Agro-IBIS model to investigate how strategic residue management could reduce the risk of rhizome threatening soil temperatures. This objective was addressed using a historical (1978–2007) reconstruction of extreme minimum 10 cm soil temperatures experienced across the Midwest US and model sensitivity studies that quantified the impact of crop residue on soil temperatures. At observation sites and for simulations that …

Assessing Migration Of Ruby-Throated Hummingbirds (Archilochus Colubris) At Broad Spatial And Temporal Scales Evaluación De La Migración De Archilochus Colubris A Escalas Amplias De Tiempo Y Espacio, Jason Courter, Ron J. Johnson, William C. Bridges Jr., Kenneth Hubbard

School of Natural Resources: Faculty Publications

Phenological patterns in birds appear to be temperature-dependent in part, and global temperatures are undergoing change. Many studies of bird phenology are conducted at broad temporal but local spatial scales, making it difficult to assess how temperature affects bird migration across landscapes. Recently, networks of “citizen science” volunteers have emerged whose collective efforts may improve phenology studies as biases associated with such efforts are recognized and addressed. We compared mean Rubythroated Hummingbird (Archilochus colubris) first arrival dates from Journey North (2001-2010) with data from the North American Bird Phenology Program (1880-1969). Ruby-throated Hummingbirds arrived earlier in the more recent period …

The Agricultural Model Intercomparison And Improvement Project (Agmip): Protocols And Pilot Studies, Cynthia Rosenzweig, J. W. Jones, J. L. Hatfield, Alex Ruane, K. J. Thornburn, J. M. Antle, G. C. Nelson, C. Porter, S. Janssen, B. Basso, F. Ewert, D. Wallach, G. Baigorria, J. M. Winter

School of Natural Resources: Faculty Publications

The Agricultural Model Intercomparison and Improvement Project (AgMIP) is a major international effort linking the climate, crop, and economic modeling communities with cutting-edge information technology to produce improved crop and economic models and the next generation of climate impact projections for the agricultural sector. The goals of AgMIP are to improve substantially the characterization of world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Analyses of the agricultural impacts of climate variability and change require a transdisciplinary effort to consistently link state-of-the-art climate scenarios to crop and economic models. Crop model …

The Agricultural Model Intercomparison And Improvement Project (Agmip): Protocols And Pilot Studies, Cynthia Rosenzweig, J. W. Jones, J. L. Hatfield, A. C. Ruane, K. J. Boote, P. Thornburn, J. M. Antle, G. C. Nelson, C. Porter, S. Janssen, S. Asseng, B. Basso, F. Ewert, D. Wallach, G. Baigorria, J. M. Winter

School of Natural Resources: Faculty Publications

The Agricultural Model Intercomparison and Improvement Project (AgMIP) is a major international effort linking the climate, crop, and economic modeling communities with cutting-edge information technology to produce improved crop and economic models and the next generation of climate impact projections for the agricultural sector. The goals of AgMIP are to improve substantially the characterization of world food security due to climate change and to enhance adaptation capacity in both developing and developed countries. Analyses of the agricultural impacts of climate variability and change require a transdisciplinary effort to consistently link state-of-the-art climate scenarios to crop and economic models. Crop model …

Maximizing A New Quantity In Sequential Reserve Selection, Adam W. Schapaugh, Andrew J. Tyre

School of Natural Resources: Faculty Publications

The fundamental goal of conservation planning is biodiversity persistence, yet most reserve selection methods prioritize sites using occurrence data. Numerous empirical studies support the notion that defining and measuring objectives in terms of species richness (where the value of a site is equal to the number of species it contains, or contributes to an existing reserve network) can be inadequate for maintaining biodiversity in the long term. An existing site-assessment framework that implicitly maximized the persistence probability of multiple species was integrated with a dynamic optimization model. The problem of sequential reserve selection as a Markov decision process was combined …

Spatial And Temporal Unpredictability Of Colony Size In Cliff Swallows Across 30 Years, Charles R. Brown, Mary Bomberger Brown, Erin A. Roche

School of Natural Resources: Faculty Publications

Most colonially breeding animals occupy colonies that range in size from a few pairs to thousands of individuals, but the causes of colony size variation are largely unknown. Three general hypotheses are: (1) that variation in colony size is maintained by fluctuating selection via spatial and temporal changes in fitness associated with different colony sizes; (2) that colony formation reflects heterogeneity in habitat, with some sites having resources to support more individuals than others; and (3) that individuals assess the presence or annual reproductive success of current colony residents at each site and aggregate preferentially at high-quality sites. These hypotheses …

Potential Water Quality Impacts Originating From Land Burial Of Cattle Carcasses, Qi Yuan, Daniel D. Snow, Shannon L. Bartelt-Hunt

School of Natural Resources: Faculty Publications

Among the conventional disposal methods for livestock mortalities, on‐farm burial is a preferred method, but the potential water quality impacts of animal carcass burial is not well understood. Typically, on‐farm burial pits are constructed without liners to prevent percolation of leachate into soil and groundwater. To date, no information is available on temporal trends for contaminants in leachate produced from livestock mortality pits. In our study, we examined the concentrations of conventional contaminants (electrical conductivity, COD, TOC, TKN, TP, and solids) as well as some antimicrobials and steroid hormones for a period of 20 months. High concentrations of conventional contaminants …

The Relative Importance Of Exogenous And Substrate-Derived Nitrogen For Microbial Growth During Leaf Decomposition, B. M. Cheever, J. R. Webster, E. E. Bilger, S. A. Thomas

School of Natural Resources: Faculty Publications

Heterotrophic microbes colonizing detritus obtain nitrogen (N) for growth by assimilating N from their substrate or immobilizing exogenous inorganic N. Microbial use of these two pools has different implications for N cycling and organic matter decomposition in the face of the global increase in biologically available N. We used sugar maple leaves labeled with ¹⁵N to differentiate between microbial N that had been assimilated from the leaf substrate (enriched with ¹⁵N) or immobilized from the water (natural abundance ¹⁵N:¹⁴N) in five Appalachian streams ranging in ambient NO₃-N concentrations from about 5 to 900 …