Physical Sciences and Mathematics Commons^™

Crab Louse Infestation In Pre-Columbian America, F. M. Rick, G. C. Rocha, K. Dittmar, C. E. A. Coimbra Jr., Karl J. Reinhard, F. Bouchet, L. F. Ferreira, A. Araújo

School of Natural Resources: Faculty Publications

Until now, Pthirus pubis infestation in ancient human populations had only been recorded in the Old World. We found crab lice on South American mummified bodies from the Atacama Desert region. Crab louse eggs were found attached to the pubic hairs of a 2,000-yr-old Chilean mummy. Well-preserved adults were found in sediment and clothing from a Peruvian mummy dated 1,000 yr ago. Paleoparasitological evidence expands the knowledge of the distribution of this ectoparasite in ancient populations. As with many other parasites, pubic lice recorded in Andean populations show the antiquity of this parasite in the New World. It is likely …

Phase And Amplitude Of Ecosystem Carbon Release And Uptake Potentials As Derived From Fluxnet Measurements, Eva Falge, John Tenhunen, Dennis D. Baldocchi, Marc Aubinet, Peter Bakwin, Paul Berbigier, Christian Bernhofer, Jean-Marc Bonnefond, George Burba, Robert Clement, Kenneth J. Davis, Jan A. Elbers, Matthias Falk, Allen H. Goldstein, Achim Grelle, Andre Granier, Thomas Grunwald, Jon Gundmondsson, David Hollinger, Ivan A. Janssens, Petri Keronen, Andrew S. Kowalski, Gabriel Katul, Beverly E. Law, Yadvinder Malhi, Tilden Meyers, Russell K. Monson, Eddy Moors, J. William Munger, Walt Oechel, Kyawtha Paw U, Kim Pilegaard, Ullar Rannik, Corinna Rebmann, Andrew E. Suyker, Halldor Thorgeirsson, Giampiero Tirone, Andrew Turnipseed, Kell Wilson, Steve Wofsy

School of Natural Resources: Faculty Publications

As length and timing of the growing season are major factors explaining differences in carbon exchange of ecosystems, we analyzed seasonal patterns of net ecosystem carbon exchange (F_NEE) using eddy covariance data of the FLUXNET data base (http://www-eosdis.ornl.gov/FLUXNET). The study included boreal and temperate, deciduous and coniferous forests, Mediterranean evergreen systems, rainforest, native and managed temperate grasslands, tundra, and C3 and C4 crops. Generalization of seasonal patterns are useful for identifying functional vegetation types for global dynamic vegetation models, as well as for global inversion studies, and can help improve phenological modules in SVAT or biogeochemical models. …

Seasonality Of Ecosystem Respiration And Gross Primary Production As Derived From Fluxnet Measurements, Eva Falge, Dennis D. Baldocchi, John Tenhunen, Marc Aubinet, Peter Bakwin, Paul Berbigier, Christian Bernhofer, George Burba, Robert Clement, Kenneth J. Davis, Jan A. Elbers, Allen H. Goldstein, Achim Grelle, Andre Granier, Jon Gundmundsson, David Hollinger, Andrew S. Kowalski, Gabriel Katul, Beverly E. Law, Yadvinder Malhi, Tilden Meyers, Russell K. Monson, J. William Munger, Walt Oechel, Kyaw Tha Paw U, Kim Pilegaard, Ullar Rannik, Corinna Rebmann, Andrew E. Suyker, Riccardo Valentini, Kell Wilson, Steve Wofsy

School of Natural Resources: Faculty Publications

Differences in the seasonal pattern of assimilatory and respiratory processes are responsible for divergences in seasonal net carbon exchange among ecosystems. Using FLUXNET data (http://www.eosdis.ornl.gov/FLUXNET) we have analyzed seasonal patterns of gross primary productivity (F_GPP), and ecosystem respiration (F_RE) of boreal and temperate, deciduous and coniferous forests, Mediterranean evergreen systems, a rainforest, temperate grasslands, and C₃ and C₄ crops. Based on generalized seasonal patterns classifications of ecosystems into vegetation functional types can be evaluated for use in global productivity and climate change models. The results of this study contribute to our understanding …

Environmental Controls Over Carbon Dioxide And Water Vapor Exchange Of Terrestrial Vegetation, B. E. Law, E. Falge, L. Gu, D. D. Baldocchi, P. Bakwin, P. Berbigier, K. Davis, A. J. Dolman, M. Falk, J. D. Fuentes, A. Goldstein, A. Granier, A. Grelle, D. Hollinger, I. A. Janssens, P. Jarvis, N. O. Jensen, G. Katul, K. Mahli, G. Matteucci, T. Meyers, R. Monson, W. Munger, W. Oechel, R. Olson, K. Pilegaard, K. T. Paw U, H. Thorgeirsson, R. Valentini, Shashi Verma, T. Vesala, K. Wilson, S. Wofsy

School of Natural Resources: Faculty Publications

The objective of this research was to compare seasonal and annual estimates of COM₂ and water vapor exchange across sites in forests, grasslands, crops, and tundra that are part of an international network called FLUXNET, and to investigating the responses of vegetation to environmental variables. FLUXNETs goals are to understand the mechanisms controlling the exchanges of CO₂,water vapor and energy across a spectrum of time and space scales, and to provide information for modeling of carbon and water cycling across regions and the globe. At a subset of sites, net carbon uptake (net ecosystem exchange, the net …

Prairie Dogs And The Prairie Ecosystem, Scott E. Hygnstrom, Dallas R. Virchow

School of Natural Resources: Faculty Publications

Prairie dogs play an important role in the prairie ecosystem by creating unique patches of habitat in the expansive prairies of the American West. Their daily activities change the physical characteristics of the community, which leads to increased plant and animal diversity. Prairie dogs are a source of food for several predators, and their burrows provide homes for a variety of species, including the burrowing owl and endangered black-footed ferret. They also provide recreational opportunities for nature observers, photographers, and the sporting public. The presence of large, healthy prairie dog towns, however, is not always compatible with agriculture and other …

Field Guide To The Geology Of The Harlan County Lake Area, Harlan County, Nebraska, With A History Of Events Leading To Construction Of Harlan County Dam, Robert F. Diffendal Jr., Duane R. Mohlman, R. George Corner, F. Edwin Harvey, K. J. Warren, Scott Summerside, Roger K. Pabian, Duane A. Eversoll

School of Natural Resources: Faculty Publications

The year 2002 will mark the fiftieth anniversary of completion of the Harlan County Dam and Multi-Purpose Reservoir. This seems a good time to write about the history of and reasons for building the dam, the effects of the dam and reservoir on the Republican River valley, and the geologic features seen along the shores of the lake and areas nearby. As many junior authors helped produced this educational circular, they are listed in the table of contents. All other sections were written by the senior author.

Includes July 2016 update: Addendum of photographs showing fault traces on drought-exposed lake …

Impact Of Irrigation On Midsummer Surface Fluxes And Temperature Under Dry Synoptic Conditions: A Regional Atmospheric Model Study Of The U.S. High Plains, Jimmy O. Adegoke, Roger A. Pielke Sr., J. Eastman, Rezaul Mahmood, Kenneth G. Hubbard

School of Natural Resources: Faculty Publications

The impact of irrigation on the surface energy budget in the U.S. high plains is investigated. Four 15-day simulations were conducted: one using a 1997 satellite-derived estimate of farmland acreage under irrigation in Nebraska (control run), two using the Olson Global Ecosystem (OGE) vegetation dataset (OGE wet run and OGE dry run), and the fourth with the Kuchler vegetation dataset (natural vegetation run) as lower boundary conditions in the Colorado State University Regional Atmospheric Modeling System (RAMS). In the control and OGE wet simulations, the topsoil in the irrigated locations, up to a depth of 0.2 m, was saturated at …

Structural And Geomorphological Evolution Of Huangshan (Yellow Mountain), Anhui Province, China, Pei-Hua Huang, Robert F. Diffendal Jr., Ming-Qing Yang

School of Natural Resources: Faculty Publications

Huangshan (Yellow Mountain) is an 1864-m granite massif situated at 30° 10′ N and 118° 11′ E, south of the lower reaches of the Yangtze River. The granite formed during the Early Cretaceous and was subsequently uplifted several times along faults. After the initial uplift, about 54 Ma, erosion proceeded to wear away the mountain for the next 30 Ma. By 24 Ma the Bright Summit Peneplain had formed. Renewed uplift in the Miocene along the same fault systems produced a mountain in the same place as the original one. This mountain was eroded to produce a second mature denudational …

Effect Of Time Of Temperature Observation And Estimation Of Daily Solar Radiation For The Northern Great Plains, Usa, Rezaul Mahmood, Kenneth Hubbard

School of Natural Resources: Faculty Publications

Daily incident solar radiation is an important input for numerous crop growth simulation models. However, lack of recorded solar radiation is a significant impediment for most crop–climate studies. The present study aimed to overcome the problem of sparse historical data of solar radiation over the northern Great Plains. The approach was to develop a physically based solar radiation model wherein estimates were possible with minimum input data. In addition, this study investigates impacts of time of observation bias on the model formulation. The proposed model (M-H) requires measured daily range of air temperature (maximum minus minimum) and estimated daily clear-sky …

Quality Control For Usda Nrcs Sm–St Network Soil Temperatures: A Method And A Dataset, Q. Steven Hu, Song Feng, Garry Schaefer

School of Natural Resources: Faculty Publications

In 1991, the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) established its Soil Moisture–Soil Temperature (SM–ST) Pilot Network consisting of 21 stations in 19 states in the contiguous United States. At each station, soil temperatures were measured at up to six different depths from 5.08 to 203.20 cm (or 2–80 in.) below the surface. Before 1997, the observations were made every 6 h, and they increased to hourly beginning in 1997. The goal of this network is to provide near–real time soil temperature and soil moisture observations in different regions across the United States for agricultural and …

Anthropogenic Land-Use Change In The North American Tall Grass-Short Grass Transition And Modification Of Near-Surface Hydrologic Cycle, Rezaul Mamood, Kenneth Hubbard

School of Natural Resources: Faculty Publications

During the 19th and 20th centuries, the landscape of the North American Great Plains was rapidly modified from natural grasslands to agricultural farmlands. These changes affected much of the continent with potential impacts in grasslands equal to deforestation elsewhere. Therefore, the resulting impacts on weather and climate should be studied. In this study, a soil water balance model is applied for 3 land uses at 3 locations. These locations are representative of the east to west declining precipitation gradient of the Great Plains. It was found, in McCook, Nebraska, for example, that annual total evapotranspiration for irrigated maize is 36% …

Pre-/Post-Knowledge Assessment Of An Earth Science Course For Elementary/Middle School Education Majors, David C. Gosselin, Joy L. Macklem-Hurst

School of Natural Resources: Faculty Publications

Many K-12 educators never experience active learning processes in their science courses that are part of their formal teacher preparation program because of the prevalence of the didactic teaching approach (lecture-read-answer) used in undergraduate science classrooms. From an educational perspective there are substantial benefits to experiencing the process of science through active learning strategies. A 16-week, one semester course entitled, “Earth Systems Science for Educators” has been designed at the University of Nebraska-Lincoln to use an active learning approach to improve student knowledge of basic Earth science concepts. To evaluate the extent to which their knowledge has improved, we developed …

Macrohabitat Composition Surrounding Successful And Depredated Northern Bobwhite Nests, Eric L. Staller, William E. Palmer, John P. Carroll

School of Natural Resources: Faculty Publications

Relationships among macrohabitat and depredation of northern bobwhite (Colinus virginianus) nests are poorly understood. Yet, macrohabitat composition may influence the nest predator community and, therefore, the vulnerability of northern bobwhite nests to depredation. We determined if macrohabitat composition surrounding bobwhite nests influenced nest placement, nest success, and which predators were responsible for depredating nests. We characterized macrohabitats at 2 scales, 8 and 16 ha, by surrounding both bobwhite nests, and an equal number of random locations, with a circular buffer. Random points were placed within the area used by bobwhites on our study area. We then determined the …

Energy Balance Closure At Fluxnet Sites, Kell Wilson, Allen Goldstein, Eva Falge, Marc Aubinet, Dennis D. Baldocchi, Paul Berbigier, Christian Bernhofer, Reinhart Ceulemans, Han Dolman, Chris Field, Achim Grelle, Andreas Ibrom, B. E. Law, Andy Kowalski, Tilden Meyers, John Moncrieff, Russ Monson, Walter Oechel, John Tenhunen, Shashi Verma, Riccardo Valentini

School of Natural Resources: Faculty Publications

A comprehensive evaluation of energy balance closure is performed across 22 sites and 50 site-years in FLUXNET, a network of eddy covariance sites measuring long-term carbon and energy fluxes in contrasting ecosystems and climates. Energy balance closure was evaluated by statistical regression of turbulent energy fluxes (sensible and latent heat (LE)) against available energy (net radiation, less the energy stored) and by solving for the energy balance ratio, the ratio of turbulent energy fluxes to available energy. These methods indicate a general lack of closure at most sites, with amean imbalance in the order of 20%. The imbalance was prevalent …

Vadose Zone Processes And Chemical Transport, H. M. Gaber, Steven Comfort, Patrick J. Shea, Thomas A. Machacek

School of Natural Resources: Faculty Publications

Permeable zerovalent iron (Fe⁰) barriers have become an estab- lished technology for remediating contaminated ground water. This same technology may be applicable for treating pesticides amenable to dehalogenation as they move downward in the vadose zone. By conducting miscible displacement experiments in the laboratory with metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide; a chloroacetanilide herbicide] under unsaturated flow, we provide proof-of-concept for such an approach. Transport experiments were conducted in repacked, unsaturated soil columns attached to vacuum chambers and run under constant matrix potential (-30 kPa) and Darcy flux (approximately 2 cm d^-1 ). Treatments included soil …

Land Surface Dynamics In Kazakhstan: Dynamic Baselines And Change Detection, Geoffrey M. Henebry, Kirsten M. De Beurs, Anatoly A. Gitelson

School of Natural Resources: Faculty Publications

Analysis of the spatio-temporal structure of NDVI in the Pathfinder AVHRR Land data set for Kazakhstan from 1981-1999 reveals significant changes in the distributions of the scale of fluctuation (SOF) before and after 1992 in some ecoregions at certain phases of the growing season. These differences are likely due to actual influences on the land surface and not changes in sensor characteristics. Further analysis is required to identify and quantify these influences.

Wood Thrush Movements And Habitat Use: Effects Of Forest Management For Red-Cockaded Woodpeckers, Jason Lang, Larkin A. Powell, David Krementz, Michael J. Conroy

School of Natural Resources: Faculty Publications

We monitored adult and juvenile breeding-season movements and habitat use of radio-tagged Wood Thrushes (Hylocichla mustelina) at the Piedmont National Wildlife Refuge, central Georgia, USA. We investigated the effects that management for Red-cockaded Woodpeckers (Picoides borealis), thinning and burning >30 year old loblolly pine (Pinus taeda) habitat, had on Wood Thrushes, a ground-foraging and midstory-nesting species. Adult Wood Thrush pairs regularly moved long distances between nesting attempts (range 1 to 17,388 m). The only experimental effect we found on adult movements was a decrease in weekly emigration rates (AP) from thinned and burned compartments …

Realtime Data Filtering Models For Air Temperature Measurements, Kenneth G. Hubbard, X. Lin

School of Natural Resources: Faculty Publications

Air temperature measurement biases caused by solar radiation and ambient wind speed are well-known. However, realtime air temperature filtering models are essential for generating homogeneous climate data by transforming one air temperature measurement system into another, and correcting in-situ air temperature biases especially for non-aspirated radiation shield systems. This study investigated the air temperature biases caused in the commonly used radiation shields in the United States, including the ASOS, MMTS, Gill, CRS, ASP-ES, and NON-ASPES shields along with corresponding temperature sensors. The realtime air temperature filtering models developed for each air temperature system are capable of removing the solar radiation …

Novel Algorithms For Remote Estimation Of Vegetation Fraction, Anatoly A. Gitelson, Yoram J. Kaufman, Robert Stark, Don Rundquist

School of Natural Resources: Faculty Publications

Spectral properties of a wheat canopy with vegetation fraction (VF) from 0% to 100% in visible and near-infrared (NIR) ranges of the spectrum were studied in order to devise a technique for remote estimation of VF. When VF was < 60%, from emergence till middle of the elongation stage, four distinct, and quite independent, spectral bands of reflectance existed in the visible range of the spectrum: 400 to 500 nm, 530 to 600 nm, near 670 nm, and around 700 nm. When VF was between 60% and 100%, reflectance in the NIR leveled off or even decreases with an increase of VF. The decreased reflectance in the NIR, occurring at or near the midseason, can be a limiting factor in the use of that spectral region for VF estimation. It was found that for VF > 60%, the information content of reflectance spectra in visible range can be expressed by only two independent pairs of spectral bands: (1) the blue from 400 to 500 nm and the red near 670 nm; (2) the green around 550 nm and the red edge region near 700 nm. We propose using only the visible range of the spectrum to quantitatively …

Call Parameters And Facial Features In Bats: A Surprising Failure Of Form Following Function, Amanda Goudy-Trainor, Patricia W. Freeman

School of Natural Resources: Faculty Publications

We attempted to correlate echolocation call parameters to a comprehensive array of ear and nose measurements from 12 families of bats. Surprisingly, we failed to find any significant relationships. We did find consistent differences between nasal and oral emitters such as: (a) nasal emitters have higher frequencies with maximum energy for their size than oral emitters, (b) nasal emitting bats tend to have longer, narrower skulls, and (c) nasal emitters have a shorter distance from the nostril to the eye (muzzle length).