Natural Resources and Conservation Commons^™

Hydraulics Near Unscreened Diversion Pipes In Open Channels: Large Flume Experiments, Ali Ercan, M. Levent Kavvas, Kara Carr, Zachary Hockett, Houssein Bandeh, Timothy D. Mussen, Dennis E. Cocherell, Jamilynn B. Poletto, Joseph J. Cech Jr., Nann A. Fangue

School of Natural Resources: Faculty Publications

Most of the water diversions on the Sacramento and San Joaquin Rivers (California, United States) and their tributaries are currently unscreened. These unscreened diversions are commonly used for irrigation and are potentially harmful to migrating and resident fishes. A large flume (test section: 18.29 m long, 3.05 m wide and 3.20 m high) was used to investigate the hydraulic fields near an unscreened water diversion under ecologically and hydraulically relevant diversion rates and channel flow characteristics. We investigated all combinations of three diversion rates (0.28, 0.42, and 0.57 m³/s) and three sweeping velocities (0.15, 0.38, and 0.61 m/s), …

Droughtscape, Spring 2017, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

Drought center helps islands reduce drought vulnerability

2017 sees above-average precipitation, warmer temps

California pulls out of drought

After tech transfer, training Tunisia launches first drought map

Drought center releases 2016 annual report

Book chapter focuses on drought and health

U2U wraps up, brings useful tools to farmers

Survey finds drought info leads to better decisions

Public Perception Of Leadership In The Municipal Solid Waste Sector, Allison Creeger

Department of Environmental Studies: Undergraduate Student Theses

No abstract provided.

Saving Money While Participating In Urban Agriculture, Jill Wieneke

Department of Environmental Studies: Undergraduate Student Theses

With more and more people pouring into urban areas, many have become unattached to where their food comes from and are disengaged with local food systems. Urban agriculture (UA) can bring people closer to healthy foods and be a potential savings. This will bring more resilience to a community and amend food insecurities Through this case study at the Hawley Hamlet Neighborhood Garden, urban gardeners can understand the capabilities of UA and the effects of food affordability into urban settings. This case study is an example of vegetable outputs and cost savings that can be obtained at a community garden …

Influences Of Catch-And-Release Angling On Fish Avoidance Behavior, Alexis D. Fedele

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

Newly opened recreational fisheries provide the opportunity to explore direct social impacts on controlled (i.e., managed), naïve (i.e., previously unexploited by anglers) population of fish. Herein, we examine the direct influence of angling on wild fish populations, and aim to identify the behavioral outcomes in fish resulting from angling through laboratory experiments. Using two naïve fish populations from newly opened reservoirs in Nebraska, we assessed the short-term (30 d) response of fish populations to recreational angling. At one reservoir, we noted declining catch rates in catch-and-release regulated fish but not in harvested-regulated fish. We hypothesized that catch-and-released fish were given …

Varying Perspectives On Landscape Diversity, Benet Kinghorn

Department of Environmental Studies: Undergraduate Student Theses

No abstract provided.

Population Structure Analysis Of Western Painted Turtles, Charrissa Zuerlein

Department of Environmental Studies: Undergraduate Student Theses

Changes in the population structure, specifically the age, size and sex composition, of Western painted turtles can be studied to gain insight into the changes that will occur in closely related endangered species. As species with temperature-dependent sex determination (TSD), the sex ratios of new clutches are affected by climate, and this could cause problems for the species as climate changes occur. This study focuses on fluctuations in the population structure of a single population located near Cedar Point Biological Station in Ogallala, Nebraska. Each summer from 2005-2016 turtles were caught using floating basking traps and hoop nets. Results show …

Influence Of Internal Variability On Population Exposure To Hydroclimatic Changes, Justin S. Mankin, Daniel Viviroli, Mesfin Mekonnen, Arjen Y. Hoekstra, Radley M. Horton, Jason E. Smerdon, Noah S. Diffenbaugh

Daugherty Water for Food Global Institute: Faculty Publications

Future freshwater supply, human water demand, and people’s exposure to water stress are subject to multiple sources of uncertainty, including unknown future pathways of fossil fuel and water consumption, and ‘irreducible’ uncertainty arising from internal climate system variability. Such internal variability can conceal forced hydroclimatic changes on multi-decadal timescales and near-continental spatial-scales. Using three projections of population growth, a large ensemble from a single Earth system model, and assuming stationary per capita water consumption, we quantify the likelihoods of future population exposure to increased hydroclimatic deficits, which we define as the average duration and magnitude by which evapotranspiration exceeds precipitation …

Feasibility Analysis Of Using Inverse Modeling For Estimating Field-Scale Evapotranspiration In Maize And Soybean Fields From Soil Water Content Monitoring Networks, Foad Foolad, Trenton E. Franz, Teijun Wang, Justin Gibson, Ayse Kilie, Richard Allen, Andrew E. Suyker

School of Natural Resources: Faculty Publications

In this study, the feasibility of using inverse vadose zone modeling for estimating field-scale actual evapotranspiration (ETa/ was explored at a long-term agricultural monitoring site in eastern Nebraska. Data from both point-scale soil water content (SWC) sensors and the areaaverage technique of cosmic-ray neutron probes were evaluated against independent ETa estimates from a co-located eddy covariance tower. While this methodology has been successfully used for estimates of groundwater recharge, it was essential to assess the performance of other components of the water balance such as ETa. In light of recent evaluations of land surface models (LSMs), independent estimates of hydrologic …

Effects Of Initial Aquifer Conditions On Economic Benefits From Groundwater Conservation, T. Foster, N. Brozovic, A. P. Butler

Daugherty Water for Food Global Institute: Faculty Publications

Worldwide, there is growing recognition of the need to reduce agricultural groundwater use in response to rapid rates of aquifer depletion. To date, however, few studies have evaluated how benefits of conservation vary along an aquifer’s depletion pathway. To address this question, we develop an integrated modeling framework that couples an agro-economic model of farmers’ field-level irrigation decisionmaking with a borehole-scale groundwater flow model. Unique to this framework is the explicit consideration of the dynamic reductions in well yields that occur as an aquifer is depleted, and how these changes in intraseasonal groundwater supply affect farmers’ ability to manage production …

The Irreversible Momentum Of Clean Energy, Barack Obama

United States Department of Energy: Publications

The release of carbon dioxide (CO₂) and other greenhouse gases (GHGs) due to human activity is increasing global average surface air temperatures, disrupting weather patterns, and acidifying the ocean. Left unchecked, the continued growth of GHG emissions could cause global average temperatures to increase by another 4°C or more by 2100 and by 1.5 to 2 times as much in many midcontinent and far northern locations. Although our understanding of the impacts of climate change is increasingly and disturbingly clear, there is still debate about the proper course for U.S. policy—a debate that is very much on display …

Long-Term Analysis Of The Asynchronicity Between Temperature And Precipitation Maxima In The United States Great Plains, Paul Flanagan, Jeffrey B. Basara, Xiangming Xiao

School of Natural Resources: Faculty Publications

Agriculture is a critical industry to the economy of the Great Plains (GP) region of North America and sensitive to change in weather and climate. Thus, improved knowledge of meteorological and climatological conditions during the growing season and associated variability across spatial and temporal scales is important. A distinct climate feature in the GP is the asynchronicity (AS) between the timing of temperature and precipitation maxima. This study investigated a long-term observational data set to quantify the AS and to address the impacts of climate variability and change. Global Historical Climate Network Daily (GHCN-Daily) data were utilized for this study; …

Enhancing Dynamical Seasonal Predictions Through Objective Regionalization, Saleh Satti, Benjamin F. Zaitchik, Hamaba S. Babr, Tsegaye Tadesse

School of Natural Resources: Faculty Publications

Improving seasonal forecasts in East Africa has great implications for food security and water resources planning in the region. Dynamically based seasonal forecast systems have much to contribute to this effort, as they have demonstrated ability to represent and, to some extent, predict large-scale atmospheric dynamics that drive interannual rainfall variability in East Africa. However, these global models often exhibit spatial biases in their placement of rainfall and rainfall anomalies within the region, which limits their direct applicability to forecast-based decision-making. This paper introduces a method that uses objective climate regionalization to improve the utility of dynamically based forecast-system predictions …

Complex Variation In Habitat Selection Strategies Among Individuals Driven By Extrinsic Factors, Edward J. Raynor, Hawthorne L. Beyer, John M. Briggs, Anthony Joern

School of Natural Resources: Faculty Publications

Understanding behavioral strategies employed by animals to maximize fitness in the face of environmental heterogeneity, variability, and uncertainty is a central aim of animal ecology. Flexibility in behavior may be key to how animals respond to climate and environmental change. Using a mechanistic modeling framework for simultaneously quantifying the effects of habitat preference and intrinsic movement on space use at the landscape scale, we investigate how movement and habitat selection vary among individuals and years in response to forage quality–quantity tradeoffs, environmental conditions, and variable annual climate. We evaluated the association of dynamic, biotic forage resources and static, abiotic landscape …

Carbon Flux Phenology From The Sky: Evaluation For Maize And Soybean, Alexandria G. Mccombs, Cuizhen Wang, Ankur Desai, Andrew E. Suyker, Sebastien C. Bird

School of Natural Resources: Faculty Publications

Carbon flux phenology is widely used to understand carbon flux dynamics and surface exchange processes. Vegetation phenology has been widely evaluated by remote sensors; however, very few studies have evaluated the use of vegetation phenology for identifying carbon flux phenology. Currently available techniques to derive net ecosystem exchange (NEE) from a satellite image use a single generic modeling subgroup for agricultural crops. But, carbon flux phenological processes vary highly with crop types and land management practices; this paper reexamines this assumption. Presented here are an evaluation of ground-truth remotely sensed vegetation indices with in situ NEE measurements and an identification …

The Roles Of Ecology, Behavior And Effective Population Size In The Evolution Of A Community., C.M. Hung, S. Drovetski, R. M. Zink

School of Natural Resources: Faculty Publications

No abstract provided.

Acoustic Characteristics Of Lekking Male Greater Prairie-Chicken (Tympanuchus Cupido Pinnatus) Vocalizations (Supplement), Cara E. Whalen, Mary Bomberger Brown, Joann Mcgee, Larkin A. Powell, Edward J. Walsh

School of Natural Resources: Faculty Publications

Boom

Cackle

Whine

Whoop

Reproductive Ecology Of Interior Least Tern And Piping Plover In Relation To Platte River Hydrology And Sandbar Dynamics, Jason M. Farnsworth, David M. Baasch, Chadwin B. Smith, Kevin L. Werbylo

School of Natural Resources: Faculty Publications

Investigations of breeding ecology of interior least tern (Sternula antillarum athalassos) and piping plover (Charadrius melodus) in the Platte River basin in Nebraska, USA, have embraced the idea that these species are physiologically adapted to begin nesting concurrent with the cessation of spring floods. Low use and productivity on contemporary Platte River sandbars have been attributed to anthropomorphically driven changes in basin hydrology and channel morphology or to unusually late annual runoff events. We examined distributions of least tern and piping plover nest initiation dates in relation to the hydrology of the historical central Platte River …

Temporal Migration Shifts In The Aransas-Wood Buffalo Population Of Whooping Cranes (Grus Americana) Across North America, Joel G. Jorgensen, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Birds are altering the phenology of critical life history events, including migration, in response to the effects of global climate change. Whooping Cranes (Grus americana) are one of the most critically endangered birds in the world. Their remnant population, referred to as the Aransas-Wood Buffalo Population, numbers between 300-400 individuals and migrates between the U.S. Gulf of Mexico coast and north-central Canada twice each year. Previous analyses suggested Whooping Crane migration was temporally constant in spring and fall. New analyses of observations spanning 1942-2016 show Whooping Crane migration is now occurring earlier in spring by approximately 22 days …

Drivers Of Nitrogen Transfer In Stream Food Webs Across Continents, B. C. Norman, M. R. Whiles, S. M. Collins, A. S. Flecker, S. K. Hamilton, S. L. Johnson, E. J. Rosi-Marshall, L. R. Ashkenas, W. B. Bowden, C. L. Crenshaw, T. Crowl, W. K. Dodds, R. O. Hall, R. El-Sabaawi, N. A. Griffiths, E. Marti, W. H. Mcdowell, S. D. Peterson, H. M. Rantala, T. Riis, K. S. Simon, J. L. Tank, S. A. Thomas, D. Von Schiller, J. R. Webster

School of Natural Resources: Faculty Publications

Studies of trophic-level material and energy transfers are central to ecology. The use of isotopic tracers has now made it possible to measure trophic transfer efficiencies of important nutrients and to better understand how these materials move through food webs. We analyzed data from thirteen ¹⁵N-ammonium tracer addition experiments to quantify N transfer from basal resources to animals in headwater streams with varying physical, chemical, and biological features. N transfer efficiencies from primary uptake compartments (PUCs; heterotrophic microorganisms and primary producers) to primary consumers was lower (mean: 11.5%, range:100%). Total N transferred (as a rate) was greater in streams …

Partitioning Assimilatory Nitrogen Uptake In Streams: An Analysis Of Stable Isotope Tracer Additions Across Continents, J. L. Tank, E. Martí, T. Riis, D. Von Schiller, A. J. Reisinger, W. K. Dodds, M. R. Whiles, L. R. Ashkenas, W. B. Bowden, S. M. Collins, C. L. Crenshaw, T. A. Crowl, N. A. Griffiths, N. B. Grimm, S. K. Hamilton, S. L. Johnson, W. H. Mcdowell, B. M. Norman, E. J. Rosi, K. S. Simon, S. A. Thomas, J. R. Webster

School of Natural Resources: Faculty Publications

Headwater streams remove, transform, and store inorganic nitrogen (N) delivered from surrounding watersheds, but excessive N inputs from human activity can saturate removal capacity. Most research has focused on quantifying N removal from the water column over short periods and in individual reaches, and these ecosystem-scale measurements suggest that assimilatory N uptake accounts for most N removal. However, cross-system comparisons addressing the relative role of particular biota responsible for incorporating inorganic N into biomass are lacking. Here we assess the importance of different primary uptake compartments on reach-scale ammonium (NH₄⁺-N) uptake and storage across a wide range …

Tolerance: The Forgotten Child Of Plant Resistance, Robert K. D. Peterson, Andrea C. Varella, Leon G. Higley

School of Natural Resources: Faculty Publications

Plant resistance against insect herbivory has greatly focused on antibiosis, whereby the plant has a deleterious effect on the herbivore, and antixenosis, whereby the plant is able to direct the herbivore away from it. Although these two types of resistance may reduce injury and yield loss, they can produce selection pressures on insect herbivores that lead to pest resistance. Tolerance, on the other hand, is a more sustainable pest management strategy because it involves only a plant response and therefore does not cause evolution of resistance in target pest populations. Despite its attractive attributes, tolerance has been poorly studied and …

Review Of Great Plains Geology By Robert F. Diffendal, Jon Trevelyan

School of Natural Resources: Faculty Publications

Professor Robert Diffendal Jr's little guidebook to the Great Plains of the USA makes for a fascinating read for an Englishman like me, who has never been there (but wants to). As he says in the article opposite, they rarely correspond to the impression most people have of them. For example, they are not just flat plains with cowboys herding longhorn cattle as you might imagine from the movies (in fact, they probably rarely were). Rather, it is clear from the guide that they can provide a visitor with an interesting mixture of geology, palaeontology, ecotourism and archaeology. In addition, …

Parallel Seasonal Patterns Of Photosynthesis, Fluorescence, And Reflectance Indices In Boreal Trees, Kyle R. Springer, Ran Wang, John A. Gamon

School of Natural Resources: Faculty Publications

Tree species in the boreal forest cycle between periods of active growth and dormancy alter their photosynthetic processes in response to changing environmental conditions. For deciduous species, these changes are readily visible, while evergreen species have subtler foliar changes during seasonal transitions. In this study, we used remotely sensed optical indices to observe seasonal changes in photosynthetic activity, or photosynthetic phenology, of six boreal tree species. We evaluated the normalized difference vegetation index (NDVI), the photochemical reflectance index (PRI), the chlorophyll/carotenoid index (CCI), and steady-state chlorophyll fluorescence (F_S) as a measure of solar-induced fluorescence (SIF), and compared these …

Parallel Seasonal Patterns Of Photosynthesis, Fluorescence, And Reflectance Indices In Boreal Trees, Kyle R. Springer, Ran Wang, John A. Gamon

School of Natural Resources: Faculty Publications

Tree species in the boreal forest cycle between periods of active growth and dormancy alter their photosynthetic processes in response to changing environmental conditions. For deciduous species, these changes are readily visible, while evergreen species have subtler foliar changes during seasonal transitions. In this study, we used remotely sensed optical indices to observe seasonal changes in photosynthetic activity, or photosynthetic phenology, of six boreal tree species. We evaluated the normalized difference vegetation index (NDVI), the photochemical reflectance index (PRI), the chlorophyll/carotenoid index (CCI), and steady-state chlorophyll fluorescence (F_S) as a measure of solar-induced fluorescence (SIF), and compared these …

Potential Of Windbreak Trees To Reduce Carbon Emissions By Agricultural Operations In The Us, William Ballesteros Possu, James R. Brandle, Michele Schoeneberger

School of Natural Resources: Faculty Publications

Along with sequestering C in forest, trees on farms are able to contribute to greenhouse mitigation through emission avoidance mechanisms. To evaluate the magnitude of these contributions, emission avoidance contributions for field and farmstead windbreak designs in regions across the United States were estimated, along with greenhouse gas (GHG) emission budgets for corn, soybean, winter wheat, and potato operations. We looked at farming scenarios with large (600 ha), mid (300 ha), and small-size (60 ha) farms containing farmsteads built before and after 2000, and growing different cropping systems. Windbreak scenarios were assumed to be up to 5% of the crop …

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 …

How Do Undergraduate Stem Mentors Reflect Upon Their Mentoring Experiences In An Outreach Program Engaging K-8 Youth?, Kari Nelson, Jaime Sabel, Cory Forbes, Neal Grandgenett, William Tapprich, Christine E. Cutucache

School of Natural Resources: Faculty Publications

Background: Many university students are becoming involved in mentoring programs, yet few studies describe the impact of mentoring on the mentor. Additionally, many studies report that students graduating from college are not prepared to enter the workforce in terms of key career skills and/or content knowledge. Herein, we examine the impact of our program, NE STEM 4U (Nebraska Science, Technology, Engineering and Math for You), in which undergraduate (UG) mentors engage K-8 youth in after-school STEM experiments. The UGs reflected upon their experiences using post-mentoring evaluations, 12- and 24-week interviews, and exit surveys. Many of the questions asked of the …

Population Growth And Mortality Sources Of The Black Bear Population In Northern Georgia, Andrew R. Little, Adam Hammond, James A. Martin, Kristina L. Johannsen, Karl V. Miller

School of Natural Resources: Faculty Publications

An understanding of black bear (Ursus americanus) population trends and cause-specific mortality is needed to direct management decisions in northern Georgia given an increasing human population. Therefore, we evaluated black bear population trends and mortality sources across 26 counties and 18 Wildlife Management Areas in northern Georgia from 1979–2014. We collected harvest data from 6,433 individuals during the study period. Using age-at-harvest data, population reconstruction illustrated an increasing trend in the bear population for both males (λ = 1.113) and females (λ = 1.108). Bait station indices reflected a similar increase in the bear population based on increased …

Exploring Elementary Students’ Scientific Knowledge Of Agriculture Using Evidence-Centered Design, Molly Brandt, Cory Forbes, Jenny Keshwani

School of Natural Resources: Faculty Publications

The public is more disconnected from agriculture than ever. Americans are now two to four generations removed from the farm with a majority of Americans having no direct experience in agriculture. As a result, the public lacks the knowledge and appreciation of the food, fuel, and fiber it demands. The National Agricultural Learning Objectives (NALOs) were recently developed to describe students’ agricultural knowledge but have, as yet, not been used to guide research into students’ agricultural literacy. The purpose of this project is to further understand students’ agricultural literacy through NALO-based assessment of students’ knowledge. This study focused on the …