Physical Sciences and Mathematics Commons^™

Seasonal Relationships Between Foliar Moisture Content, Heat Content And Biochemistry Of Lodgepole Pine And Big Sagebrush Foliage, Yi Qi, W. Matt Jolly, Philip E. Dennison, Rachael C. Kropp

School of Natural Resources: Faculty Publications

No abstract provided.

Rescaling Of The Complementary Relationship For Land Surface Evaporation, R. Crago, J. Szilagyi, R. Qualls, J. Huntington

School of Natural Resources: Faculty Publications

No abstract provided.

Metapopulation Viability Of An Endangered Shorebird Depends On Dispersal And Human-Created Habitats: Piping Plovers (Charadrius Melodus) And Prairie Rivers, Sara L. Zeigler, Daniel H. Catlin, Mary Bomberger Brown, Lauren R. Dinan, James D. Fraser, Kelsi L. Hunt, Joel G. Jorgensen

School of Natural Resources: Faculty Publications

Background: Many species are distributed as metapopulations in dynamic landscapes, where habitats change through space and time. Individuals locate habitat through dispersal, and the relationship between a species and landscape characteristics can have profound effects on population persistence. Despite the importance of connectivity in dynamic environments, few empirical studies have examined temporal variability in dispersal or its effect on metapopulation dynamics. In response to this knowledge gap, we studied the dispersal, demography, and viability of a metapopulation of an endangered, disturbance-dependent shorebird. We examined three subpopulations of piping plovers (Charadrius melodus) on the lower Platte and Missouri rivers …

Local Perspectives On Environmental Insecurity And Its Influence On Illegal Biodiversity Exploitation, Meredith L. Gore, Michelle L. Lute, Jonah H. Ratsimbazafy, Andry Rajaonson

School of Natural Resources: Faculty Publications

Environmental insecurity is a source and outcome of biodiversity declines and social conflict. One challenge to scaling insecurity reduction policies is that empirical evidence about local attitudes is overwhelmingly missing. We set three objectives: determine how local people rank risk associated with different sources of environmental insecurity; assess perceptions of environmental insecurity, biodiversity exploitation, myths of nature and risk management preferences; and explore relationships between perceptions and biodiversity exploitation. We conducted interviews (N = 88) with residents of Madagascar’s Torotorofotsy Protected Area, 2014. Risk perceptions had a moderate effect on perceptions of environmental insecurity. We found no effects of environmental …

Sustainable Grassland Management: An Exploratory Study Of Progressive Ranchers In Nebraska, Stephanie M. Kennedy, Mark E. Burbach, Maggi S. Sliwinski

School of Natural Resources: Faculty Publications

Well-managed grasslands provide numerous ecosystem services. Ranchers who employ sustainable grazing practices limit grassland conversion and conserve critical habitats. This phenomenological study explored the grassland management decisions of progressive ranchers in Nebraska. Each individual interviewed for this study is proactive about the state of their grasslands, whether they are motivated by financial or conservation factors. Throughout the evolution of their businesses, these ranchers have taken steps to improve their management techniques and continue to employ new strategies while planning for the long-term productivity of their grasslands. For policy makers and educators seeking to improve grassland management decisions, demonstrating new methods …

Flight Initiation Distances Of Nesting Piping Plovers (Charadrius Melodus) In Response To Human Disturbance, Joel G. Jorgensen, Lauren R. Dinan, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Birds frequently interact with people when they occur in coupled human-ecological or anthropogenic environments, which makes the protection of legally protected species a challenge. Flight initiation distances (FIDs) are often used to inform development of appropriate buffer distances required for human exclusion zones used to protect birds nesting in anthropogenic landscapes. Piping Plovers (Charadrius melodus) are protected by the Endangered Species Act in the United States and often nest in areas used by humans. Studies evaluating Piping Plover FIDs are limited and implementation of exclusion zones has been inconsistent across the species’ range. We measured Piping Plover response …

A Framework For Understanding The Characteristics Of Complexity In Biology, Joseph Dauer, Jenny Dauer

School of Natural Resources: Faculty Publications

Understanding the functioning of natural systems is not easy, although there is general agreement that understanding complex systems is an important goal for science education. Defining what makes a natural system complex will assist in identifying gaps in research on student reasoning about systems. The goal of this commentary is to propose a framework that explicitly defines the ways in which biological systems are complex and to discuss the potential relevance of these complexity dimensions to conducting research on student reasoning about complexity in biology classrooms. We use an engineering framework for dimensions of complexity and discuss how this framework …

Consequences Of Hatch Phenology On Stages Of Fish Recruitment, David M. Bogner, Mark A. Kaemingk, Melissa R. Wuellner

School of Natural Resources: Faculty Publications

Little is known about how hatch phenology (e.g., the start, peak, and duration of hatching) could influence subsequent recruitment of freshwater fishes into a population. We used two commonly sympatric fish species that exhibit different hatching phenologies to examine recruitment across multiple life stages. Nine yellow perch (Perca flavescens) and bluegill (Lepomis macrochirus) annual cohorts were sampled from 2004 through 2013 across larval, age-0, age-1, and age-2 life stages in a Nebraska (U.S.A.) Sandhill lake. Yellow perch hatched earlier in the season and displayed a more truncated hatch duration compared to bluegill. The timing of hatch …

Estimating Carbon Storage In Windbreak Trees On U.S. Agricultural Lands, W. B. Possu, James R. Brandle, G. M. Domke, M. Schoeneberger, Erin E. Blankenship

School of Natural Resources: Faculty Publications

Assessing carbon (C) capture and storage potential by the agroforestry practice of windbreaks has been limited. This is due, in part, to a lack of suitable data and associated models for estimating tree biomass and C for species growing under more opengrown conditions such as windbreaks in the Central Plains region of the United States (U.S.). We evaluated 15 allometric models using destructively sampled Pinus ponderosa (Lawson & C. Lawson) data from field windbreaks in Nebraska and Montana. Several goodness-of-fit metrics were used to select the optimal model. The Jenkins’ et al. model was then used to estimate biomass for …

Foraging Decisions Underlying Restricted Space Use: Effects Of Fire And Forage Maturation On Large Herbivore Nutrient Uptake, Edward J. Raynor, Anthony Joern, Jesse B. Nippert, John M. Briggs

School of Natural Resources: Faculty Publications

Recent models suggest that herbivores optimize nutrient intake by selecting patches of low to intermediate vegetation biomass. We assessed the application of this hypothesis to plains bison (Bison bison) in an experimental grassland managed with fire by estimating daily rates of nutrient intake in relation to grass biomass and by measuring patch selection in experimental watersheds in which grass biomass was manipulated by prescribed burning. Digestible crude protein content of grass declined linearly with increasing biomass, and the mean digestible protein content relative to grass biomass was greater in burned watersheds than watersheds not burned that spring (intercept; F_{1,251 …}

A Remotely Sensed Pigment Index Reveals Photosynthetic Phenology In Evergreen Conifers, John A. Gamon, K. Fred Huemmrich, Christopher Y.S. Wong, Ingo Ensminger, Steven Garrity, David Y. Hollinger, Asko Noormets, Josep Peñuelas

School of Natural Resources: Faculty Publications

In evergreen conifers, where the foliage amount changes little with season, accurate detection of the underlying “photosynthetic phenology” from satellite remote sensing has been difficult, presenting challenges for global models of ecosystem carbon uptake. Here, we report a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity, leading to a “chlorophyll/carotenoid index” (CCI) that tracks evergreen photosynthesis at multiple spatial scales. When calculated from NASA’s Moderate Resolution Imaging Spectroradiometer satellite sensor, the CCI closely follows the seasonal patterns of daily gross primary productivity of evergreen conifer stands measured by eddy covariance. This discovery …

Mesoscale Climatology And Variation Of Surface Winds Over The Chukchi–Beaufort Coastal Areas, Jing Zhang, Fuhong Liu, Wei Tao, Jeremy Krieger, Martha Shulski, Xiangdong Zhang

School of Natural Resources: Faculty Publications

The detailed mesoscale climatology of surface winds in the Chukchi–Beaufort Seas and adjacent Arctic Slope region is analyzed using the recently developed Chukchi–Beaufort High-Resolution Atmospheric Reanalysis (CBHAR). Within the study area, surface winds are mainly driven by the prevailing synoptic weather patterns of the Beaufort high and Aleutian low and are further modulated by local geographic features through thermodynamic and dynamic processes. Sea breezes, up- or downslope winds, and the mountain barrier jets are all clearly captured by CBHAR. Sea breezes emerge in June–September and last most of the day, with a maximum spatial extent 100km inland and 50 km …

Winter Diet And Hunting Success Of Canada Lynx In Colorado, Jacob S. Ivan, Tanya M. Shenk

School of Natural Resources: Faculty Publications

Information regarding the diet of Canada lynx (Lynx canadensis) at the southernmost extent of its range is critical for managing the species under current and predicted climate conditions. Therefore, from 1999–2009, we investigated winter diet and hunting strategies of Canada lynx in Colorado, USA by tracking individuals in the snow to identify sites where lynx encountered and killed prey. Similar to other parts of lynx range, snowshoe hares (Lepus americanus) were the primary winter food in Colorado, especially when considering total biomass consumed. Red squirrels (Tamiasciurus hudsonicus) comprised the bulk of the remaining food …

The Sensitivity Of Carbon Exchanges In Great Plains Grasslands To Precipitation Variability, M. D. Petrie, N. A. Brunsell, R. Vargas, S. L. Collins, L. B. Flanagan, N. P. Hanan, M. E. Litvak, Andrew E. Suyker

School of Natural Resources: Faculty Publications

In the Great Plains, grassland carbon dynamics differ across broad gradients of precipitation and temperature, yet finer-scale variation in these variables may also affect grassland processes. Despite the importance of grasslands, there is little information on how fine-scale relationships compare between them regionally. We compared grassland C exchanges, energy partitioning and precipitation variability in eight sites in the eastern and western Great Plains using eddy covariance and meteorological data. During our study, both eastern and western grasslands varied between an average net carbon sink and a net source. Eastern grasslands had a moderate vapor pressure deficit (VPD = 0.95 kPa) …

Status Of Knowledge Of The Shovelnose Sturgeon (Scaphirhynchus Platorynchus, Rafinesque, 1820), Q. E. Phelps, S. J. Tripp, M. J. Hamel, J. Koch, E. J. Heist, J. E. Garvey, K. M. Kappenman, M. A. H. Webb

School of Natural Resources: Faculty Publications

The range of Shovelnose Sturgeon (SVS) Scaphirhynchus platorynchus in the great rivers of central North America has contracted, but most remaining populations are considered stable, likely due to a combination of successful harvest regulations and longitudinal continuity of many river reaches, despite damming in upper reaches. The evolutionary relationships of SVS relative to sister taxa is still a matter of debate. Genetic diversity varies across the range, with substantial haplotype overlap among SVS and its congeners. Shovelnose Sturgeon mature early at 5–7 years, and spawn every 2– 3 years. Some individuals may spawn in fall. Whether this species migrates is …

Spatiotemporal Patterns Of Water Table Fluctuations And Evapotranspiration Induced By Riparian Vegetation In A Semiarid Area, Weifeng Yue, Tiejun Wang, Trenton E. Franz, Xunhong Chen

School of Natural Resources: Faculty Publications

Groundwater evapotranspiration (ET_g) links various ecohydrological processes and is an important component in regional water budgets. In this study, an extensive monitoring network was established in a semiarid riparian area to investigate various controls on the spatiotemporal pattern of water table fluctuations (WTFs) and ET_g induced by riparian vegetation. Along a vegetation gradient (~1200 m), diurnal WTFs were observed during a growing season in areas covered by woody species (Populus sect. Aigeiros and Juniperus virginiana) and wet slough vegetation (Panicum virgatum and Bromus inermis) with deeper root systems; whereas, no diurnal WTFs were …

Temporal Variability In Aboveground Plant Biomass Decreases As Spatial Variability Increases, Devan Allen Mcgranahan, Torre J. Hovick, R. Dwayne Elmore, David M. Engle, Samuel D. Fuhlendorf, Stephen L. Winter, James R. Miller, Diane M. Debinski

School of Natural Resources: Faculty Publications

Ecological theory predicts that diversity decreases variability in ecosystem function. We predict that, at the landscape scale, spatial variability created by a mosaic of contrasting patches that differ in time since disturbance will decrease temporal variability in aboveground plant biomass. Using data from a multi-year study of seven grazed tallgrass prairie landscapes, each experimentally managed for one to eight patches, we show that increased spatial variability driven by spatially patchy fire and herbivory reduces temporal variability in aboveground plant biomass. This pattern is associated with statistical evidence for the portfolio effect and a positive relationship between temporal variability and functional …

Temporal Variability In Aboveground Plant Biomass Decreases As Spatial Variability Increases, Devan Allen Mcgranahan, Torre J. Hovick, R. Dwayne Elmore, David M. Engle, Samuel D. Fuhlendorf, Stephen L. Winter, James R. Miller, Diane M. Debinski

School of Natural Resources: Faculty Publications

Ecological theory predicts that diversity decreases variability in ecosystem function. We predict that, at the landscape scale, spatial variability created by a mosaic of contrasting patches that differ in time since disturbance will decrease temporal variability in aboveground plant biomass. Using data from a multi-year study of seven grazed tallgrass prairie landscapes, each experimentally managed for one to eight patches, we show that increased spatial variability driven by spatially patchy fire and herbivory reduces temporal variability in aboveground plant biomass. This pattern is associated with statistical evidence for the portfolio effect and a positive relationship between temporal variability and functional …

Developing Coherent Conceptual Storylines: Two Elementary Challenges, Deborah Hanuscin, Kelsey Lipsitz, Dante Cisterna-Alburquerque, Kathryn A. Arnone, Delinda Van Garderen, Zandra De Araujo, Eun Ju Lee

School of Natural Resources: Faculty Publications

No abstract provided.

2016 Interior Least Tern And Piping Plover Monitoring, Research, Management, And Outreach Report For The Lower Platte River, Nebraska, Mary Bomberger Brown, 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 (2015 – 2016). 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 data, data analyses, results, summaries, and interpretations found in this document are not final and should be considered as such when being cited or referred to in documents, reports, proposals, or presentations. Please contact us before using any of this material and for additional information that may be available.

In an effort to …

Atmospheric Sensitivity To Roughness Length In A Regional Atmospheric Model Over The Ohio-Tennessee River Valley, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Geographic Variation, Null Hypotheses, And Subspecies Limits In The California Gnatcatcher: A Response To Mccormack And Maley, Robert M. Zink, Jeffrey G. Groth, Hernan Vázquez-Miranda

School of Natural Resources: Faculty Publications

We interpreted the results of nuclear DNA sequencing to be inconsistent with the recognition of California Gnatcatcher (Polioptila californica) subspecies. McCormack and Maley (2015) suggested that our data did support 2 taxa, one of which was P. c. californica, listed as Threatened under the Endangered Species Act (ESA). We summarize here how 2 sets of researchers with access to the same data reached different conclusions by including different analyses. We included the southern subspecies’ boundary from the taxonomy of Atwood (1991), the taxonomic basis for the ESA listing, which resulted in an Analysis of Molecular Variance that …

Fluctuating Fire Regimes And Their Historical Effects On Genetic Variation In An Endangered Shrubland Specialist, Hernan Vázquez-Miranda, Kelly R. Barr, C. Craig Farquhar, Robert M. Zink

School of Natural Resources: Faculty Publications

The Pleistocene was characterized by worldwide shifts in community compositions. Some of these shifts were a result of changes in fire regimes, which influenced the distribution of species belonging to fire-dependent communities. We studied an endangered juniper–oak shrubland specialist, the black-capped vireo (Vireo atricapilla). This species was locally extirpated in parts of Texas and Oklahoma by the end of the 1980s as a result of habitat change and loss, predation, brood parasitism, and anthropogenic fire suppression. We sequenced multiple nuclear loci and used coalescence methods to obtain a deeper understanding of historical population trends than that typically available …

Modeling Gross Primary Production Of Maize And Soybean Croplands Using Light Quality, Temperature, Water Stress, And Phenology, Anthony L. Nguy-Robertson, Andrew E. Suyker, Xiangming Xiao

School of Natural Resources: Faculty Publications

Vegetation productivity metrics, such as gross primary production (GPP) may be determined from the efficiency with which light is converted into photosynthates, or light use efficiency (ϵ). Therefore, accurate measurements and modeling of ϵ is important for estimating GPP in each ecosystem. Previous studies have quantified the impacts of biophysical parameters on light use efficiency based GPP models. Here we enhance previous models utilizing four scalars for light quality (i.e., cloudiness), temperature, water stress, and phenology for data collected from both maize and soybean crops at three Nebraska AmeriFlux sites between 2001 and 2012 (maize: 26 field-years; soybean: …

Parent-Offspring Resemblance In Colony-Specific Adult Survival Of Cliff Swallows, Charles R. Brown, Erin A. Roche, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Survival is a key component of fitness. Species that occupy discrete breeding colonies with different characteristics are often exposed to varying costs and benefits associated with group size or environmental conditions, and survival is an integrative net measure of these effects. We investigated the extent to which survival probability of adult (≥ 1-year old) cliff swallows (Petrochelidon pyrrhonota) occupying different colonies resembled that of their parental cohort and thus whether the natal colony had long-term effects on individuals. Individuals were cross-fostered between colonies soon after hatching and their presence as breeders monitored at colonies in the western Nebraska …

Variation In Avian Vocalizations During The Non-Breeding Season In Response To Traffic Noise, Amy I. Oden, Mary Bomberger Brown, Mark E. Burbach, James R. Brandle, John E. Quinn

School of Natural Resources: Faculty Publications

Low-frequency traffic noise that leads to acoustic masking of vocalizations may cause birds to alter the frequencies or other components of their vocalizations in order to be heard by conspecifics and others. Altering parts of a vocalization may result in poorer vocal performance or the message contained in the vocalization being received incorrectly. During the winters of 2011–2012 and 2012–2013, we recorded and measured the “chick-a-dee” call of Black-capped Chickadees (Poecile atricapillus) and the “po-ta-to-chip” call of American Goldfinches (Spinus tristis) to determine whether components of the calls produced in areas of high traffic noise and …

Uncertainty In Simulating Gross Primary Production Of Cropland Ecosystem From Satellite-Based Models, Wenping Yuan, Wenwen Cai, Anthony L. Nguy-Robertson, Huajun Fang, Andrew E. Suyker, Yang Chen, Wenjie Dong, Shuguang Liu, Haicheng Zhang

School of Natural Resources: Faculty Publications

Accurate estimates of gross primary production (GPP) for croplands are needed to assess carbon cycle and crop yield. Satellite-based models have been developed to monitor spatial and temporal GPP patterns. However, there are still large uncertainties in estimating cropland GPP. This study compares three light use efficiency (LUE) models (MODIS-GPP, EC-LUE, and VPM) with eddy-covariance measurements at three adjacent AmeriFlux crop sites located near Mead, Nebraska, USA. These sites have different croprotation systems (continuous maize vs. maize and soybean rotated annually) and water management practices (irrigation vs. rainfed). The results reveal several major uncertainties in estimating GPP which need to …

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 …

Joint Control Of Terrestrial Gross Primary Productivity By Plant Phenology And Physiology, Jianyang Xia, Shuli Niu, Philippe Ciais, Ivan A. Janssens, Jiquan Chen, Christof Ammann, Altaf Arain, Peter D. Blanken, Alessandro Cescatti, Damien Bonal, Nina Buchmann, Peter S. Curtis, Shiping Chen, Jinwei Dong, Lawrence B. Flanagan, Christian Frankenberg, Teodoro Georgiadis, Christopher M. Gough, Dafeng Hui, Gerard Kiely, Jianwei Li, Magnus Lund, Vincenzo Magliulo, Barbara Marcolla, Lutz Merbold, Leonardo Montagnani, Eddy J. Moors, Jorgen E. Olesen, Shilong Piao, Antonio Raschi, Oliver Roupsard, Andrew E. Suyker, Marek Urbaniak, Francesco P. Vaccari, Andrej Varlagin, Timo Vesala, Matthew Wilkinson, Ensheng Weng, Georg Wohlfahrt, Liming Yan, Yiqi Luo

School of Natural Resources: Faculty Publications

Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate–carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of biotic and abiotic factors operating mainly through changes in vegetation phenology and physiological processes. However, it is still unclear how plant phenology and physiology can be integrated to explain the spatiotemporal variability of terrestrial GPP. Based on analyses of eddy–covariance and satellite-derived data, we decomposed annual terrestrial GPP into the length of the CO2 uptake period …

Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker

School of Natural Resources: Faculty Publications

Vegetation productivity metrics such as gross primary production (GPP) at the canopy scale are greatly affected by the efficiency of using absorbed radiation for photosynthesis, or light use efficiency (LUE). Thus, close investigation of the relationships between canopy GPP and photosynthetically active radiation absorbed by vegetation is the basis for quantification of LUE. We used multiyear observations over irrigated and rainfed contrasting C3 (soybean) and C4 (maize) crops having different physiology, leaf structure, and canopy architecture to establish the relationships between canopy GPP and radiation absorbed by vegetation and quantify LUE. Although multiple LUE definitions are reported in the literature, …