Physical Sciences and Mathematics Commons^™

Differential Soil Respiration Responses To Changing Hydrologic Regimes, Vincent J. Pacific, Brian L. Mcglynn, Diego Andrés Riveros-Iregui, Howard E. Epstein, Daniel J. Welsch

School of Natural Resources: Faculty Publications

Soil respiration is tightly coupled to the hydrologic cycle (i.e., snowmelt and precipitation timing and magnitude). We examined riparian and hillslope soil respiration across a wet (2005) and a dry (2006) growing season in a subalpine catchment. When comparing the riparian zones, cumulative CO₂ efflux was 33% higher, and peak efflux occurred 17 days earlier during the dry growing season. In contrast, cumulative efflux in the hillslopes was 8% lower, and peak efflux occurred 10 days earlier during the drier growing season. Our results demonstrate that soil respiration was more sensitive to drier growing season conditions in wet (riparian) …

Integrating Remote Sensing And Geographic Information Systems, James W. Merchant, Sunil Narumalani

School of Natural Resources: Faculty Publications

Remote sensing and geographic information systems (GIS) comprise the two major components of geographic information science (GISci), an overarching field of endeavor that also encompasses global positioning systems (GPS) technology, geodesy and traditional cartography (Goodchild 1992, Estes and Star 1993, Hepner et al. 2005). Although remote sensing and GIS developed quasi-independently, the synergism between them has become increasingly apparent (Aronoff 2005). Today, GIS software almost always includes tools for display and analysis of images, and image processing software commonly contains options for analyzing ‘ancillary’ geospatial data (Faust 1998). The significant progress made in ‘integration’ of remote sensing and GIS has …

Remote Sensing Of Cropland Agriculture, M. Duane Nellis, Kevin P. Price, Donald Rundquist

School of Natural Resources: Faculty Publications

Remote sensing has long been used in monitoring and analyzing agricultural activities. Well prior to the first coining of the term ‘remote sensing’ in 1958 by Eveyln Pruitt of the U.S. Office of Naval Research (Estes and Jensen 1998), scientists were using aerial photography to complete soil and crop surveys associated with agricultural areas in the United States and other parts of the world (Goodman 1959). Most of such work in the 1930s involved general crop inventories by the U.S. Department of Agriculture and soil survey mapping as part of the work of the then U.S. Soil Conservation Service. With …

Non-Destructive Estimation Of Anthocyanins And Chlorophylls In Anthocyanic Leaves, Anatoly A. Gitelson, Olga B. Chivkunova, Mark N. Merzlyak

School of Natural Resources: Faculty Publications

The anthocyanin and chlorophyll contents in leaves provide valuable information about the physiological status of plants. Thus, there is a need for accurate, efficient, and practical methodologies to estimate these biochemical parameters of vegetation. In this study, we tested the performance and accuracy of several nondestructive, reflectance-based techniques for estimating anthocyanin and chlorophyll contents in leaves of four unrelated species, European hazel ( Corylus avellana ), Siberian dogwood ( Cornus alba = Swida alba ), Norway maple ( Acer platanoides ), and Virginia creeper ( Parthenocissus quinquefolia ), with widely variable pigment content and composition. An anthocyanin reflectance index, which …

Non-Destructive Detection Of Water Stress And Estimation Of Relative Water Content In Maize, Art I. Zygielbaum, Anatoly A. Gitelson, Timothy J. Arkebauer, Donald C. Rundquist

School of Natural Resources: Faculty Publications

Non-destructive estimation of leaf water content provides vital information about vegetation productivity. We report here on controlled seven day experiments using greenhouse-grown maize. Fifty plants were randomly assigned to two equal groups: water stressed and well watered. Spectroscopic, relative water content (RWC), and chlorophyll concentration measurements were made daily. Because water molecules absorb radiation in near- and middle-infrared, most efforts to sense water deficit remotely utilize infrared wavelengths. In these experiments, we identified a strong, systematic, and repeatable relationship between photosynthetically active radiation (PAR, 400-700 nm) albedo and leaf RWC. We show that visible spectrum reflectance provides a means to …

Nondestructive Estimation Of Anthocyanin Content In Grapevine Leaves, Mark R. Steele, Anatoly A. Gitelson, Donald C. Rundquist, Mark N. Merzlyak

School of Natural Resources: Faculty Publications

The anthocyanin (Anth) content in leaves provides valuable information about the physiological status of plants. Thus, there is a need for accurate, efficient, practical methodologies to estimate this biochemical parameter. Reflectance measurement is a means of quickly and nondestructively assessing leaf Anth content in situ. The objective of this study was to test the overall performance and accuracy of nondestructive techniques for estimating Anth content in grapevine leaves. Relationships were established between Anth content and four vegetation indices: NIR (near-infrared)/green, red/green, anthocyanin reflectance index (ARI, based on reflectances in bands within the green and the red-edge regions), and a modified …

A Bio-Optical Algorithm For The Remote Estimation Of The Chlorophyll-A Concentration In Case 2 Waters, Anatoly A. Gitelson, Daniela Gurlin, Wesley Moses, Tadd Barrow

School of Natural Resources: Faculty Publications

The objective of this work was to test the performance of a recently developed three-band model and its special case, a two-band model, for the remote estimation of the chlorophyll-a (chl-a) concentration in turbid productive case 2 waters. We specifically focused on (a) determining the ability of the models to estimate chl-a < 20 mg m⁻³, typical for coastal and estuarine waters, and (b) assessing the potential of MODIS and MERIS to estimate chl-a concentrations in turbid productive waters, using red and near-infrared (NIR) bands. Reflectance spectra and water samples were collected in 89 stations over lakes in …

Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley J. Moses, Anatoly A. Gitelson, V. Povazhnyy

School of Natural Resources: Faculty Publications

We present and discuss here the results of our work using MODIS (moderate resolution imaging spectroradiometer) and MERIS (medium resolution imaging spectrometer) satellite data to estimate the concentration of chlorophyll-a (chl-a) in reservoirs of the Dnieper River and the Sea of Azov, which are typical case II waters, i.e., turbid and productive. Our objective was to test the potential of satellite remote sensing as a tool for near-real-time monitoring of chl-a distribution in these water bodies. We tested the performance of a recently developed three-band model, and its special case, a two-band model, which use the …

Variability Of Anaerobic Animal Waste Lagoon Delta15N Source Signatures, Sadayappan Mariappan, Mary Exner Spalding, Glen E. Martin, Roy F. Spalding

School of Natural Resources: Faculty Publications

High ammonium-N concentrations derived from animal wastes stored and partially treated in earthen anaerobic lagoons at confined feeding facilities can seep to groundwater. δ¹⁵N-NH₄⁺ values from +2.0 to +59.1‰ in 13 lagoons complicate identification of lagoon seepage as well as land-applied lagoon effluent in ground and surface waters. The spectrum of δ¹⁵N values requires site-specific isotope characterization of the potential source. Feed and fresh manure and urine δ¹⁵N values indicate that most N isotopic fractionation occurs after excretion. Lagoon management clearly affects enrichment. δ¹⁵N-total Kjeldahl N (TKN) and δ^{15 …}

Long-Term Agricultural Land-Use Trends In Nebraska, 1866–2007, Tim L. Hiller, Larkin A. Powell, Tim D. Mccoy, Jeffrey J. Lusk

School of Natural Resources: Faculty Publications

Although landscape changes from anthropogenic causes occur at much faster rates than those from natural processes (e.g., geological, vegetation succession), human perception of such changes is often subjective, inaccurate, or nonexistent. Given the large-scale land-use changes that have occurred throughout the Great Plains, the potential impacts of land-use changes on ecological systems, and the insight gained from knowledge of land-use trends (e.g., to compare to wildlife population trends), we synthesized information related to land-use trends in Nebraska during 1866–2007. We discussed and interpreted known and potential causes of short- and long-term land-use trends based on agricultural and weather data; farm …

Ecological Divergence Of Two Sympatric Lineages Of Buggy Creek Virus, An Arbovirus Associated With Birds, Charles R. Brown, Abinash Padhi, Amy T. Moore, Mary Bomberger Brown, Jerome E. Foster, Martin Pfeffer, Valerie A. O'Brien, Nicholas Komar

School of Natural Resources: Faculty Publications

Most arthropod-borne viruses (arboviruses) show distinct serological subtypes or evolutionary lineages, with the evolution of different strains often assumed to reflect differences in ecological selection pressures. Buggy Creek virus (BCRV) is an unusual RNA virus (Togaviridae, Alphavirus) that is associated primarily with a cimicid swallow bug (Oeciacus vicarius) as its vector and the Cliff Swallow (Petrochelidon pyrrhonota) and the introduced House Sparrow (Passer domesticus) as its amplifying hosts. There are two sympatric lineages of BCRV (lineages A and B) that differ from each other by .6% at the nucleotide level. Analysis of 385 …

2009 Interior Least Tern And Piping Plover Monitoring, Research, Management, And Outreach Report For The Lower Platte River, Nebraska, Mary Bomberger Brown, Joel G. Jorgensen

School of Natural Resources: Faculty Publications

This document reports on our monitoring, research, management, and outreach activities during the past 12 months (2009). We prepared it to inform our partners, cooperating agencies, funding sources, and other interested parties of our activities and to provide a preliminary summary of our results.

The Tern and Plover Conservation Partnership (TPCP), based at the University of Nebraska–School of Natural Resources, and the Nongame Bird Program (NBP), based at the Nebraska Game and Parks Commission (NGPC) work cooperatively on Interior Least Tern and Piping Plover monitoring, research, management, and education-outreach activities. While the proximate focus of our work is the Lower …

Incorporation Of Crop Phenology In Simple Biosphere Model (Sibcrop) To Improve Land-Atmosphere Carbon Exchanges From Croplands, Erandathie Lokupitiya, S. Denning, K. Paustian, I. Baker, K. Schaefer, Shashi B. Verma, T. Meyers, C. J. Bernacchi, Andrew E. Suyker, M. L. Fischer

School of Natural Resources: Faculty Publications

Croplands are man-made ecosystems that have high net primary productivity during the growing season of crops, thus impacting carbon and other exchanges with the atmosphere. These exchanges play a major role in nutrient cycling and climate change related issues. An accurate representation of crop phenology and physiology is important in land-atmosphere carbon models being used to predict these exchanges. To better estimate time-varying exchanges of carbon, water, and energy of croplands using the Simple Biosphere (SiB) model, we developed crop-specific phenology models and coupled them to SiB. The coupled SiBphenology model (SiBcrop) replaces remotely-sensed NDVI information, on which SiB originally …

Corrigendum To “Incorporation Of Crop Phenology In Simple Biosphere Model (Sibcrop) To Improve Land-Atmosphere Carbon Exchanges From Croplands” Published In Biogeosciences, 6, 969–986, 2009, Erandathie Lokupitiya, S. Denning, K. Paustian, I. Baker, K. Schaefer, Shashi B. Verma, T. Meyers, C. J. Bernacchi, Andrew E. Suyker, M. L. Fischer

School of Natural Resources: Faculty Publications

In the above mentioned manuscript a mistake in Fig. 11 occured. The corrected version of the figure is as follows.

A Century Of Climate Change For Fairbanks, Alaska, Gerd Wendler, Martha Shulski

School of Natural Resources: Faculty Publications

Climatological observations are available for Fairbanks, Interior Alaska, for up to 100 years. This is a unique data set for Alaska, insofar as it is of relatively high quality and without major breaks. Applying the best linear fit, we conclude that the mean annual temperature rose from -3.6°C to -2.2°C over the century, an increase of 1.4°C (compared to 0.8°C worldwide). This comparison clearly demonstrates the well-known amplification or temperature change for the polar regions. The observed temperature increase is neither uniform over the time period nor uniform throughout the course of a year. The winter, spring, and summer seasons …

Lithobates Catesbeianus (American Bullfrog) Predation On Cliff Swallows, Mary Bomberger Brown, Charles R. Brown

School of Natural Resources: Faculty Publications

During a 25-year study of Cliff Swallows (Petrochelidon pyrrhonota) in southwestern Nebraska, we observed Lithobates catesbeianus prey on, or attempt to prey on, Cliff Swallows. As we were mist-netting Cliff Swallows at a 10-nest colony on 7 July 1998, a L. catesbeianus attempted to eat a Cliff Swallow that was caught in the net.

Lichen Recovery Following Heavy Grazing By Reindeer Delayed By Climate Warming, David R. Klein, Martha Shulski

School of Natural Resources: Faculty Publications

Introduced reindeer, Rangifer tarandus, over exploited lichen-rich plant communities on St. Matthew Island in the Bering Sea. A die-off of the reindeer followed, exacerbated by extreme weather in 1964, resulting in extirpation of the reindeer. A similar pattern of removal of lichens as major components of plant communities has occurred following introductions of reindeer to other islands at high latitudes. By 1985, two decades following die-off of the reindeer, total lichen biomass was only 6% of that in similar plant communities on adjacent Hall Island, not reached by the reindeer. By 2005, 41 y after the reindeer die-off, lichen …

A Scanner-Based Approach To Soil Profile-Wall Mapping Of Root Distribution, J. M. Dauer, J. M. Withington, J. Oleksyn, J. Chorover, O. A. Chadwick, P. B. Reich, D. M. Eissenstat

School of Natural Resources: Faculty Publications

No abstract provided.

Landscape Structure Control On Soil Co2 Efflux Variability In Complex Terrain: Scaling From Point Observations To Watershed Scale Fluxes, Diego Andrés Riveros-Iregui, Brian L. Mcglynn

School of Natural Resources: Faculty Publications

We investigated the spatial and temporal variability of soil CO₂ efflux across 62 sites of a 393-ha complex watershed of the northern Rocky Mountains. Growing season (83 day) cumulative soil CO₂ efflux varied from ~300 to ~2000 g CO₂ m^—2, depending upon landscape position, with a median of 879.8 g CO₂ m^—2. Our findings revealed that highest soil CO₂ efflux rates were observed in areas with persistently high soil moisture (riparian meadows), whereas lower soil CO₂ efflux rates were observed on forested uplands (98% of watershed area). Furthermore, upslope accumulated …

Spring Home Ranges Of White Bass In Irrigation Reservoirs Of The Republican River Basin, Nebraska, D. R. Martin, Larkin A. Powell, K. L. Pope

School of Natural Resources: Faculty Publications

Fishery biologists have documented small home ranges, relative to available habitat, for many littoral freshwater fishes. Home ranges for pelagic species, such as white bass Morone chrysops, are generally not well described, yet are thought to be large. We studied white bass movement using acoustic telemetry in two irrigation reservoirs of the Republican River basin in south-western Nebraska. Acoustic transmitters were implanted in fall of the previous year and tracking occurred a minimum of once per week throughout spring (mid-March to May) 2007 and 2008. Linear home ranges were calculated from observed locations of individual fish. Twelve of the …

Seasonal Changes In Depth Of Water Uptake For Encroaching Trees Juniperus Virginiana And Pinus Ponderosa And Two Dominant C4 Grasses In A Semiarid Grassland, Kathleen D. Eggemeyer, Tala Awada, F. Edwin Harvey, David A. Wedin, Xinhua Zhou, C. William Zanner

School of Natural Resources: Faculty Publications

We used the natural abundance of stable isotopic ratios of hydrogen and oxygen in soil (0.05–3 m depth), plant xylem and precipitation to determine the seasonal changes in sources of soil water uptake by two native encroaching woody species (Pinus ponderosa P. & C. Lawson, Juniperus virginiana L.), and two C₄ grasses (Schizachyrium scoparium (Michx.) Nash, Panicum virgatum L.), in the semiarid Sandhills grasslands of Nebraska. Grass species extracted most of their water from the upper soil profile (0.05–0.5 m). Soil water uptake from below 0.5 m depth increased under drought, but appeared to be minimal in …

Simulation Of Boundary Layer Trajectory Dispersion Sensitivity To Soil Moisture Conditions: Mm5 And Noah-Based Investigation, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Near Surface Atmospheric Response To Simulated Changes In Land-Cover, Vegetation Fraction, And Soil Moisture Over Western Kentucky, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Impact Of Empire Expansion On Household Diet: The Inka In Northern Chile’S Atacama Desert, Sheila D. Vinton, Linda Perry, Karl J. Reinhard, Calogero M. Santoro, Isabel Teixeira-Santos

School of Natural Resources: Faculty Publications

The impact of expanding civilization on the health of American indigenous societies has long been studied. Most studies have focused on infections and malnutrition that occurred when less complex societies were incorporated into more complex civilizations. The details of dietary change, however, have rarely been explored. Using the analysis of starch residues recovered from coprolites, here we evaluate the dietary adaptations of indigenous farmers in northern Chile’s Atacama Desert during the time that the Inka Empire incorporated these communities into their economic system. This system has been described as ‘‘complementarity’’ because it involves interaction and trade in goods produced at …

Scaling Up Of Co2 Fluxes From Leaf To Canopy In Maize-Based Agroecosystems, Timothy J. Arkebauer, Elizabeth A. Walter-Shea, Mark A. Mesarch, Andrew E. Suyker, Shashi Verma

School of Natural Resources: Faculty Publications

Carbon dioxide fluxes are being measured in three maize-based agroecosystems in eastern Nebraska in an effort to better understand the potential for these systems to sequester carbon in the soil. Landscape-level fluxes of carbon, water and energy were measured using tower eddy covariance systems. In order to better understand the landscape-level results, measurements at smaller scales, using techniques promoted by John Norman, were made and scaled up to the landscape-level. Single leaf gas exchange properties (CO₂ assimilation rate and stomatal conductance) and optical properties, direct and diffuse radiation incident on the canopy, and photosynthetically active radiation (PAR) reflected and …

Probabilistic Movement Model With Emigration Simulates Movements Of Deer In Nebraska, 1990–2006, Charles J. Frost, Scott E. Hygnstrom, Andrew J. Tyre, Kent M. Eskridge, David M. Baasch, Justin R. Boner, Gregory M. Clements, Jason M. Gilsdorf, Travis C. Kinsell, Kurt C. Vercauteren

School of Natural Resources: Faculty Publications

Movements of deer can affect population dynamics, spatial redistribution, and transmission and spread of diseases. Our goal was to model the movement of deer in Nebraska in an attempt to predict the potential for spread of chronic wasting disease (CWD) into eastern Nebraska. We collared and radio-tracked >600 white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) in Nebraska during 1990–2006.We observed large displacements (>10 km) for both species and sexes of deer, including migrations up to 100 km and dispersals up to 50 km. Average distance traveled between successive daily locations was 166m for …

Panarchy: Discontinuities Reveal Similarities In The Dynamic System Structure Of Ecological And Social Systems, Ahjond S. Garmestani, Craig R. Allen, Lance Gunderson

School of Natural Resources: Faculty Publications

In this paper, we review the empirical evidence of discontinuous distributions in complex systems within the context of panarchy theory and discuss the significance of discontinuities for understanding emergent properties such as resilience. Over specific spatial-temporal scale ranges, complex systems can configure in a variety of regimes, each defined by a characteristic set of self-organized structures and processes. A system may remain within a regime or dramatically shift to another regime. Understanding the drivers of regime shifts has provided critical insight into system structure and resilience. Although analyses of regime shifts have tended to focus on the system level, new …

A System For Estimating Bowen Ratio And Evaporation From Waste Lagoons, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Photosynthetic Response Of Soybean To Twospotted Spider Mite (Acari: Tetranychydae) Injury, Adeney De Freitas Bueno, Regiane Cristina Oliveira De Freitas Bueno, Paul David Nabity, Leon George Higley, Odair Aparecido Fernandes

School of Natural Resources: Faculty Publications

The twospotted spider mite Tetranychus urticae Koch is a common pest on soybean plants. To clarify plantarthropod interaction on mite-soybean system, leaf fluorescence, photosynthetic responses to variable carbon dioxide levels, and chlorophyll content were evaluated. Significant photosynthetic rate reduction was observed due to stomatal limitation. Stomatal closure was the major plant physiological response. As a consequence, there was reduction in photosynthetic rates. Surprisingly, plants did not show chlorophyll content reduction associated with photosynthetic impairment. No differences in fluorescence data indicate that T. urticae injury did not impair the function of light harvesting and photoelectron transport. These results showed that T. …

Measuring And Modeling Co2 And H2O Fluxes In Complex Terrain, Diego Andrés Riveros-Iregui, Brian L. Mcglynn

School of Natural Resources: Faculty Publications

The feedbacks between the water and the carbon cycles are of critical importance to global carbon balances. Forests and forest soils in northern latitudes are important carbon pools because of their potential as sinks for atmospheric carbon. However there are significant unknowns related to the effects of hydrologic variability, mountainous terrain, and landscape heterogeneity in controlling soil carbon dioxide (CO₂) efflux. Mountainous terrain imposes large spatial heterogeneity in the biophysical controls of soil CO₂ production and efflux, including soil temperature, soil water content, vegetation, substrate, and soil physical properties. Further complications are introduced by the superimposed temporal …