Physical Sciences and Mathematics Commons^™

Analysis Of Integrated Farming Systems In Eastern Nebraska, Lori A. Hoagland

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

Agroecosystems in the U.S. are beset with social, ecological and environmental problems as large industrial farming methods are edging out small family-sized farms and replacing ecological services provided by biodiversity with synthetic inputs and practices. While many of the benefits of smaller diversified or integrated farming systems are well known, farm producers need a concrete model that shows how integration is possible and with what crops. The objective of this study was to investigate some of these supplemental farm activities, and identify and evaluate whether they were compatible given the time and resource constraints of a typical eastern Nebraska farm. …

A Regional Gis-Based Analysis Of Elk Habitat Suitability In Northwestern Nebraska, Justin W. Fischer

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

The need to accurately assess the use and suitability of elk (Cervus elaphus spp.) habitat at regional scales will continue to increase as human development encroaches into what was once optimum elk habitat. The objectives of this research were to calculate the relative proportions of habitat use by elk in the Pine Ridge region of Northwestern Nebraska from a set of radio-collared elk locations and generate a habitat suitability model. Habitat variables (Iandcover type, aspect, slope, distance to a road, road density, and distance from the ponderosa pine edge) were measured for each elk location (n = 5,787 dating …

A Regional Gis-Based Analysis Of Elk Habitat Suitability In Northeast Nebraska, J W. Fisher

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

No abstract provided.

Effectiveness Of Frightening Devices For Reducing Deer Damage In Cornfields, Jason M. Gilsdorf

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

No abstract provided.

Influence Of Light And Nutrients On Atrazine Toxicity To Freshwater Algae, Crystal J. Hansen

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

No abstract provided.

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 …

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% …

Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland

Geology Faculty Publications

New mapping, structural analysis, and 40Ar/39Ar dating reveal an unusually well‐constrained history of Late Eocene extension in the Copper Mountains of the northern Basin and Range province. In this area, the northeast‐trending Copper Creek normal fault juxtaposes a distinctive sequence of metacarbonate and granitoid rocks against a footwall of Upper Precambrian to Lower Cambrian quartzite and phyllite. Correlation of the hanging wall with footwall rocks to the northwest provides an approximate piercing point that requires 8–12 km displacement in an ESE direction. This displaced fault slice is itself bounded above by another normal fault (the Meadow Fork Fault), which brings …

Inside Unlv, Diane Russell, Betty Blodgett, Richard Jensen, Cate Weeks

Inside UNLV

No abstract provided.

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 …

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 …

Inside Unlv, Diane Russell, Richard Jensen, Andy Grossman, Kevin Force

Inside UNLV

No abstract provided.

Evidence For The Timing And Duration Of The Last Interglacial Period From High-Precision Uranium-Series Ages Of Corals On Tectonically Stable Coastlines, Daniel R. Muhs

United States Geological Survey: Staff Publications

The last interglacial period has a timing and duration that can be estimated from U-series dating of emergent, coral-bearing deposits on tectonically stable coastlines. High-precision dating from Bermuda, the Bahamas, Hawaii, and Australia suggests that the last interglacial period had a sea level at least as high as present from ∼128,000 to 116,000 yr B.P. Sea level reached a near-present level more quickly after the close of the penultimate glacial period than at the close of the last glacial period and the duration of high sea level is longer than that implied by the deep-sea record.

Assessing State-Wide Biodiversity In The Florida Gap Analysis Project, L. G. Pearlstine, S. E. Smith, L. A. Brandt, C. R. Allen, W. M. Kitchens, J. Stenberg

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The Florida Gap (FI-Gap) project provides an assessment of the degree to which native animal species and natural communities are or are not represented in existing conservation lands. Those species and communities not adequately represented in areas being managed for native species constitute 'gaps' in the existing network of conservation lands. The United States Geological Survey Gap Analysis Program is a national effort and so, eventually, all 50 states will have completed it. The objective of FI-Gap was to provide broad geographic information on the status of terrestrial vertebrates, butterflies, skippers and ants and their respective habitats to address the …

Initial Mortality Of Black Bass In B.A.S.S. Fishing Tournaments, Gene R. Wilde, Calub E. Shavlik, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We studied the initial mortality of black bass Micropterus spp. that were captured, weighed in, and released in fishing tournaments conducted by the Bass Anglers Sportsman Society between 1972 and 1998. Mean annual initial mortality (i.e., mortality before weigh-in and release) ranged from 1% to 30%. Initial mortality was greatest during the 1970s (15.2%) and decreased during the 1980s (5.7%) and 1990s (1.9%). Because initial mortality was uniformly low ( ≤5%) after 1982, we used results for 1983–1998 to assess relationships involving initial mortality. Initial mortality was correlated with bag size, mean fish weight per angler, and number of fish …

Adaptive Inference For Distinguishing Credible From Incredible Patterns In Nature, C. S. Holling, Craig R. Allen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Strong inference is a powerful and rapid tool that can be used to identify and explain patterns in molecular biology, cell biology, and physiology. It is effective where causes are single and separable and where discrimination between pairwise alternative hypotheses can be determined experimentally by a simple yes or no answer. But causes in ecological systems are multiple and overlapping and are not entirely separable. Frequently, competing hypotheses cannot be distinguished by a single unambiguous test, but only by a suite of tests of different kinds, that produce a body of evidence to support one line of argument and not …

Biodiversity Of Fungi In Red Imported Fire Ant (Hymenoptera: Formicidae) Mounds, Jennifer A. Zettler, Thomas M. Mcinnis Jr., Craig R. Allen, Timothy P. Spira

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The red imported fire ant, Solenopsis invicta Buren, became established in North America more than 70 yr ago, and it currently occupies most of the southeastern United States. Fire ants change the physical and chemical components of soil, which likely infuence soil fungi in ant mounds. To determine the effects of fire ants on soil fungi, we sampled soil from fire ant mounds and the surrounding nonmound soil. In addition, we sampled soil from the nests of the native ant Aphaenogaster texana carolinensis Wheeler. We found that both fire ant mounds and native ant nests had greater fungal abundance but …

Implications Of Body Mass Patterns: Linking Ecological Structure And Process To Wildlife Conservation And Management, Jan P. Sendzimir, Craig R. Allen, Lance H. Gunderson, Craig A, Stow

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The unprecedented scale of problems affecting wildlife ecology today overwhelms many managers. Challenges are no longer local in origin, but rather a tangle of local, regional and even global externalities often interacting in unpredictable ways. Previously isolated ecosystems have become increasingly connected at global, hemispheric and regional levels, eroding their integrity. Endocrine-disrupting compounds applied in Mexico have changed avian sexual development in the Great Lakes (Colborn et al. 1996). Chamois (Rupicapra rupicapra) reproduction in the Carpathian mountains falters when the color of newborns is no longer cryptic because climate change prematurely melts snow cover (K. Perzanowski, Polish Academy …

Functional Group Change Within And Across Scales Following Invasions And Extinctions In The Everglades Ecosystem, Elizabeth A. Forys, Craig R. Allen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Cross-scale resilience theory predicts that the combination of functional diversity within scales and functional redundancy across scales is an important attribute of ecosystems because it helps these systems resist minor ecological disruptions and regenerate after major disturbances such as hurricanes and fire. Using the vertebrate fauna of south Florida, we quantified how the loss of native species and invasion by nonnatives may alter functional group richness within and across scales. We found that despite large changes in species composition due to potential extinctions and successful invasions by nonnative species, functional group richness will not change significantly within scales, there will …

Variability Between Scales: Predictors Of Nomadism In Birds Of An Australian Mediterraneanclimate Ecosystem, Craig R. Allen, Denis A. Saunders

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Nomadism in animals is a response to resource distributions that are highly variable in time and space. Using the avian fauna of the Mediterranean-climate region of southcentral Australia, we tested a number of variables to determine if they predicted nomadism. These variables were species body mass, the distance in body mass terms to the edge of a body mass aggregation, and diet (for example, seeds, invertebrates, nectar, or plants). We utilized two different classifications of the avifauna that diverged in their definition of nomadic to build two different predictive models. Using both classifications, distance to the edge of a body …

Cross-Scale Morphology, Craig R. Allen, C.S. Holling

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The scaling of physical, biological, ecological and social phenomena has become a major focus of efforts to develop simple representations of complex systems. Much of the attention has been on discovering universal scaling laws that emerge from simple physical and geometric processes. But there are regular patterns of departures both from those scaling laws and from continuous distributions of attributes of systems; these departures often demonstrate the development of self-organized interactions between living systems and physical processes over narrower ranges of scale. Cross-scale morphology refers to morphological attributes of animals that are influenced by interaction with ecological structures and patterns …

Influence Of The Proximity And Amount Of Human Development And Roads On The Occurrence Of The Red Imported Fire Ant In The Lower Florida Keys, Elizabeth A. Forys, Craig R. Allen, Daniel P. Wojcik

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We examined the influence of both the proximity and extent of human developments and paved roads on the presence of the predatory, non-indigenous, red imported fire ant (Solenopsis invicta). This species was inadvertently introduced into the United States at the port of Mobile, Alabama, around 1930 and rapidly spread to many southeastern states, including Florida. More recently, S. invicta colonized the Florida Keys, an area with a high proportion of rare and endemic vertebrate and invertebrate species. We placed bait transects in transitional salt-marsh, pineland, and hardwood hammocks on 13 of the lower Florida Keys and compared habitat …

Derivation Of A Tasselled Cap Transformation Based On Landsat 7 At-Satellite Reflectance, C. Huang, Wylie L. Yang, Collin Homer, G. Zylstra

United States Geological Survey: Staff Publications

A new tasselled cap transformation based on Landsat 7 at-satellite reflectance was developed. This transformation is most appropriate for regional applications where atmospheric correction is not feasible. The brightness, greenness and wetness of the derived transformation collectively explained over 97% of the spectral variance of the individual scenes used in this study.

Organochlorine Chemical Residues In Fish From The Mississippi River Basin, 1995, C.J. Schmitt

United States Geological Survey: Staff Publications

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Fish were collected in late 1995 from 34 National Contaminant Biomonitoring Program (NCBP) stations and 13 National Water Quality Assessment Program (NAWQA) stations in the Mississippi River basin (MRB) and in late 1996 from a reference site in West Virginia. Four composite samples, each comprising (nominally) 10 adult common carp (Cyprinus carpio) or black bass (Micropterus spp.) of the same sex, were collected from each site and analyzed for organochlorine chemical residues by gas chromatography with electron capture detection. At the NCBP stations, which are located on relatively large rivers, concentrations of organochlorine chemical residues were generally lower than …

Strontium Isotopic Signatures Of The Streams And Lakes Of Taylor Valley, Southern Victoria Land, Antarctica: Chemical Weathering In A Polar Climate, W. B. Lyons, Carmen A. Nezat, Larry V. Benson, Thomas D. Bullen, Elizabeth Y. Graham, Jesicca Kidd, Kathleen A. Welch, James M. Thomas

United States Geological Survey: Staff Publications

We have collected and analyzed a series of water samples from three closed-basin lakes (Lakes Bonney, Fryxell, and Hoare) in Taylor Valley, Antarctica, and the streams that flow into them. In all three lakes, the hypolimnetic waters have different ⁸⁷Sr/⁸⁶Sr ratios than the surface waters, with the deep water of Lakes Fryxell and Hoare being less radiogenic than the surface waters. The opposite occurs in Lake Bonney. The Lake Fryxell isotopic ratios are lower than modern-day ocean water and most of the whole-rock ratios of the surrounding geologic materials. A conceivable source of Sr to the system …

Cross-Scale Structure And Scale Breaks In Ecosystems And Other Complex Systems, Craig R. Allen, C. S. Holling

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The five articles in this special feature extend the discovery of regular patterns of deviation from scaling laws and from continuous distributions of attributes in ecosystems and other complex systems. These patterns suggest that these systems organize over discrete ranges of scale and that organization abruptly shifts with changes in scale. If this is so, scaling laws (for example, see West 1997, 1999; Zipf 1949) serve only as the baseline from which to measure those departures, and those departures indicate “scale breaks” (transitions) between scales of structure in complex systems. Patterns in the deviations from a scaling-law baseline may provide …