Digital Commons Network^™

Effects Of Binary Combinations Of Herbicides On Freshwater Algae, Jill K. Taylor

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

No abstract provided.

Inside Unlv, Betty Blodgett, Tom Flagg, Diane Russell

Inside UNLV

No abstract provided.

Movement Of Rainbow And Brown Trout In Relation To Water Quality And Food Availability In Lake Ogallala, Nebraska, Corey M. Huxoll

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

No abstract provided.

Effects Of Woody Cover In The Landscaping On Riparian Avifauna And A Preliminary Nesting Assessment, Micah W. Perkins

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

No abstract provided.

Movements And Habitat Use By Hatchery-Reared Pallid Sturgeon In The Lower Platte River, Nebraska, Vaughn A. Snook

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

No abstract provided.

Seasonal Patterns Of Photosynthesis In Douglas Fir Seedlings During The Third And Fourth Year Of Exposure To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

The interactive effects of elevated atmospheric CO₂ and temperature on seasonal patterns of photosynthesis in Douglas fir (Psuedotsuga menziesii (Mirb.) Franco) seedlings were examined. Seedlings were grown in sunlit chambers controlled to track either ambient (~400 p.p.m.) CO₂ or ambient +200 p.p.m. CO₂, and either ambient temperature or ambient +4 °C. Light-saturated net photosynthetic rates were measured approximately monthly over a 21 month period. Elevated CO₂ increased net photosynthetic rates by an average of 21% across temperature treatments during both the 1996 hydrologic year, the third year of exposure, and the 1997 hydrologic year. Elevated …

Fluxnet: A New Tool To Study The Temporal And Spatial Variability Of Ecosystem-Scale Carbon Dioxide, Water Vapor, And Energy Flux Densities, Dennis Baldocchi, Eva Falge, Lianhong Gu, Richard Olson, David Hollinger, Steve Running, Peter Anthoni, Ch. Bernhofer, Kenneth Davis, Robert Evans, Jose Fuente, Allen Goldstein, Gabriel Katul, Beverly Law, Xuhui Lee, Yadvinder Malhi, Tilden Meyers, William Munge, Walt Oechel, K.T. Paw U, Kim Pilegaard, H.P. Schmid, Riccardo Valentini, Shashi Verma, Timo Vesala, Kell Wilson, Steve Wofsy

School of Natural Resources: Faculty Publications

FLUXNET is a global network of micrometeorological flux measurement sites that measure the exchanges of carbon dioxide, water vapor, and energy between the biosphere and atmosphere. At present over 140 sites are operating on a long-term and continuous basis. Vegetation under study includes temperate conifer and broadleaved (deciduous and evergreen) forests, tropical and boreal forests, crops, grasslands, chaparral, wetlands, and tundra. Sites exist on five continents and their latitudinal distribution ranges from 70°N to 30°S.

FLUXNET has several primary functions. First, it provides infrastructure for compiling, archiving, and distributing carbon, water, and energy flux measurement, and meteorological, plant, and soil …

Test Of An Extended Mathematical Approach To Calculate Maize Leaf Area Index And Leaf Angle Distribution, Elizabeth A. Walter-Shea, Mark A. Mesarch

School of Natural Resources: Faculty Publications

No abstract provided.

Evaluation Of An Algorithm For Predicting Albedo In Heliotropic Crops, Elizabeth A. Walter-Shea, A. Weiss

School of Natural Resources: Faculty Publications

No abstract provided.

Value Of Incorporating Satellite-Derived Land Cover Data In Mm5/Place For Simulating Surface Temperatures, Todd M. Crawford, David J. Stensrud, Franz Mora, James W. Merchant, Peter J. Wetzel

School of Natural Resources: Faculty Publications

The Parameterization for Land–Atmosphere–Cloud Exchange (PLACE) module is used within the Fifth- Generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) to determine the importance of individual land surface parameters in simulating surface temperatures. Sensitivity tests indicate that soil moisture and the coverage and thickness of green vegetation [as manifested by the values of fractional green vegetation coverage (fVEG) and leaf area index (LAI)] have a large effect on the magnitudes of surface sensible heat fluxes. The combined influence of LAI and fVEG is larger than the influence of soil moisture on the partitioning of the surface energy …

Some Perspectives On Recent In Situ Air Temperature Observations: Modeling The Microclimate Inside The Radiation Shields*, X. Lin, Kenneth Hubbard, Elizabeth A. Walter-Shea, James Brandle, G.E. Meyer

School of Natural Resources: Faculty Publications

Air temperature measurement has inherent biases associated with the particular radiation shield and sensor deployed. The replacement of the Cotton Region Shelter (CRS) with the Maximum–Minimum Temperature System (MMTS) and the introduction of Automated Surface Observing System (ASOS) air temperature observing systems during the NWS modernization introduced bias shifts in federal networks that required quantification. In rapidly developing nonfederal networks, the Gill shield temperature systems are widely used. All of these systems house an air temperature sensor in a radiation shield to prevent radiation loading on the sensors; a side effect is that the air temperature entering a shield is …

Impacts Of Predation On Northern Bobwhite And Scaled Quail, Dale Rollins, John P. Carroll

School of Natural Resources: Faculty Publications

Northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata) populations have declined throughout most of their distribution, and these declines have become more dramatic in recent years. In this review, we examine the role of predation in quail management. Predation is the major source of nest loss and of mortality for young and adult quail. Mean nest success across studies reviewed was 28%. Estimates of annual survival rates have varied from 5 to 26% for radiotelemetry studies and from 15 to 30% based on age-ratio studies. Breeding season survival estimates ranged from 13 to 51% in telemetry …

Bollgard Cotton: An Assessment Of Global Economic, Environmental, And Social Benefits, Julie M. Edge, John H. Benedict, John P. Carroll, H. Keith Reding

School of Natural Resources: Faculty Publications

Insect-protected crops like Bollgard (Monsanto Company, St. Louis) Bacillus thuringiensis (Bt) cotton are bringing cotton growers new alternatives to broad-spectrum insecticide use in integrated pest management. After five years (1996-2000) of commercial use, a number of benefits of Bt cotton technology to growers, the environment, and society at large have been reported; however, the benefits of the technology have not been examined to date from a holistic point of view. Accordingly, the objectives of this paper were to examine the potential economic, environmental, and social benefits of Bt cotton compared with broad-spectrum insecticide use, as reported in current literature, …

Effects Of Landsat 5 Thematic Mapper And Landsat 7 Enhanced Thematic Mapper Plus Radiometric And Geometric Calibrations And Corrections On Landscape Characterization, James E. Vogelmann, Dennis Helder, Ron Morfitt, Michael J. Choate, James W. Merchant, Henry Bulley

United States Geological Survey: Staff Publications

The Thematic Mapper (TM) instruments on board Landsats 4 and 5 provide high-quality imagery appropriate for many different applications, including land cover mapping, landscape ecology, and change detection. Precise calibration was considered to be critical to the success of the Landsat 7 mission and, thus, issues of calibration were given high priority during the development of the Enhanced Thematic Mapper Plus (ETM+). Data sets from the Landsat 5 TM are not routinely corrected for a number of radiometric and geometric artifacts, including memory effect, gain/bias, and interfocal plane misalignment. In the current investigation, the effects of correcting vs. not correcting …

Effects Of Fire Ants (Hymenoptera: Formicidae) On Hatching Turtles And Prevalence Of Fire Ants On Sea Turtle Nesting Beaches In Florida, Craig R. Allen, Elizabeth A. Forys, Kenneth G. Rice, Daniel P. Wojcik

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Red imported fire ants (Solenopsis invicta Buren) have increasingly been observed in loggerhead (Caretta caretta L.) and green (Chelonia mydas L.) sea turtle nests in Florida, and in the nests of freshwater turtles. They may be attracted to the disturbance, mucous and moisture associated with turtle nesting and establish foraging tunnels into turtle nests shortly after egg-laying, thus increasing the vulnerability of hatchlings to fire ant predation. We conducted experiments on a freshwater turtle (Pseudemys nelsoni Carr) to determine the potential impacts of S.invicta on turtle hatchlings. Over 70% of hatchlings were killed by S.invicta during …

The Non-Indigenous Ant, Solenopsis Invicta, Reduces Loggerhead Shrike And Native Insect Abundance, Craig R. Allen, R. Scott Lutz, Tim Lockley, Sherman A. Phillips Jr., Stephen Demarais

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The red imported fire ant (Solenopsis invicta Buren) is an aggressive, non-indigenous species that is a threat to native biota in the southeastern United States. We determined the effect of S. invicta on loggerhead shrike (Lanius ludovicianus L.) abundance and investigated a possible mechanism of impact, which is a reduction in insect prey availability. We used a fire ant bait (hydramethylnon) to reduce fire ant populations on one randomly chosen member of each of five pairs of 202-ha study areas in the Texas coastal Bend region, and also measured shrike relative abundance and a volumetric index of insect …

Potential Fire Ant (Hymenoptera: Formicidae) Impact On The Endangered Schaus Swallowtail (Lepidoptera: Papilionidae), Elizabeth A. Forys, Anna Quistorff, Craig R. Allen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The Schaus swallowtail, Papilio aristodemus ponceanus , historically occurred in tropical hardwood hammocks from South Miami to the upper Florida Keys and is currently listed as federally endangered. Much of the remaining hardwood hammock habitat is fragmented by roads and human development that may alter the microhabitat within the hammocks and increase the probability of invasion by non-native predators and competitors. One non-indigenous species that has recently invaded the Florida Keys, and that may impact the Schaus swallowtail is the red imported fire ant ( Solenopsis invicta Buren). We estimated abundance of red imported fire ants in Schaus swallowtail habitat …

Effects Of Fire Ants (Hymenoptera: Formicidae) On Hatching Turtles And Prevalence Of Fire Ants On Sea Turtle Nesting Beaches In Florida, Craig R. Allen, Elizabeth A. Forys, Kenneth G. Rice, Daniel P. Wojcik

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Red imported fire ants (Solenopsis invicta Buren) have increasingly been observed in loggerhead (Caretta caretta L.) and green (Chelonia mydas L.) sea turtle nests in Florida, and in the nests of freshwater turtles. They may be attracted to the disturbance, mucous and moisture associated with turtle nesting and establish foraging tunnels into turtle nests shortly after egg-laying, thus increasing the vulnerability of hatchlings to fire ant predation. We conducted experiments on a freshwater turtle (Pseudemys nelsoni Carr) to determine the potential impacts of S.invicta on turtle hatchlings. Over 70% of hatchlings were killed by S.invicta during …

The Likely Cause Of Extinction Of The Tree Snail Orthalicus Reses Reses (Say), E.A. Forys, A. Quistorff, Craig R. Allen, D.P. Wojcik

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The Stock Island tree snail, Orthalicus reses reses, went extinct in its native range in the Florida Keys in 1992. Fortunately, O. r. reses has been introduced elsewhere and further reintroductions are currently planned. Before these reintroductions are implemented, it is important to try and determine which factors were most likely to have caused the decline and extinction. While habitat destruction was probably the ultimate reason why there were so few tree snails, it is likely that an interaction of habitat fragmentation and the invasion of an exotic predator caused the final decline that lead to the extinction in …

Red Imported Fire Ants: Impact On Biodiversity, Daniel P. Wojcik, Craig R. Allen, Richard J. Brenner, Elizabeth A. Forys, Donald P. Jouvenaz, R. Scott Lutz

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The red imported fire ant, Solenopsis invicta Buren (hereafter referred to as imported fire ant), long considered a regional problem, is receiving renewed attention nationwide, with infestations found in Arizona, Maryland, Nevada, New Mexico, and Virginia (Mitchell 1996). Recently, infestations discovered in several regions of California caused great public concern (Brennan 1999, Schrader 1999). Initially, infestations appeared to be isolated in almond groves in Kern County; presumably these infestations originated from bee hives transported interstate for the purpose of pollinating crops. Separately, ornamental plants arriving in Las Vegas, NV, were infested with fire ants, and records showed that the point …

Nonlethal Methods Of Examining Fish Stomach Contents, Jan F. Kamler, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Several nonlethal methods have been developed to determine the stomach contents of fish, including gastroscopes, tubes, stomach suction, stomach flushing, emetics, forceps, and chronic fistulas. By reviewing the literature on this subject, we found that the effectiveness (ability to remove all stomach contents) of the different methods depends on size, age, species of fish, and the size of the food items in the stomach. Overall, various methods of stomach flushing were the most effective method of recovering stomach items from a variety of fishes. Mechanized pressure appeared to be the most efficient method of stomach flushing for most large fishes. …

A Caloric-Based Evaluation Of Diet Indices For Largemouth Bass, Kevin Lee Pope, Michael Lee Brown, Walter Gilbert Duffy, Paul Herbert Michaletz

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Selection of methods for quantitative description and assessment of food habits is a concern for trophic investigations. We used diet data for largemouth bass Micropterus salmoides, to compare a caloric-based approach with eight diet indices: percent frequency of occurrence, percent total number, percent total weight, mean relative number, mean relative volume, relative importance index, prey-importance index, and mean stomach fullness. Mean caloric contribution of stomach contents for each prey taxon was used as a standard to compare diet indices. Temporal differences in composition and caloric contents of largemouth bass stomach contents were apparent. Most diet indices provided similar assessments …

Assessment Of Outputs From Smith-Root Model-5.0 Gpp And Model-7.5 Gpp Electrofishers, Kevin L. Pope, Brian E. Van Zee, Michael C. Mayo, Mohammed Rahman

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We evaluated the outputs from eight Smith-Root electrofishers (two factory-rigged model-5.0 GPP boats, four biologist-rigged model-5.0 GPP boats, and two biologist-rigged model- 7.5 GPP boats), using an oscilloscope to determine the actual waveforms (voltage as a function of time), current, and power produced for various settings. Differences were found in average power outputs among the six model-5.0 GPP electrofishing boats. In terms of average power output, biologist-rigged electrofishing boats using generators and control boxes purchased from Smith-Root were as or more effective than those rigged by Smith-Root. However, factory-rigged boats generally contained additional safety features that should be considered when …

Anglers Tagging And Marking Fish: Provincial And State Fishery Agency Views, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

In recent years, the involvement of anglers in fish tagging programs has begun to capture the interest of managers. I conducted a mail survey of provincial and state fishery agencies to discern where anglers could legally tag, mark, or attach telemetry devices to fish. In addition, I documented current provincial and state agency views toward fish tagging or marking by anglers. Anglers were allowed to tag or mark fish in most provinces and states; however, more restrictions were placed on marking and telemetering fish than on tagging. Of the issues covered in this survey, respondents indicated that fish mortality and …

Ant–Seed Mutualisms: Can Red Imported Fire Ants Sour The Relationship?, Jennifer A. Zettler, Timothy P. Spira, Craig R. Allen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Invasion by the red imported fire ant, Solenopsis invicta, has had negative impacts on individual animal and plant species, but little is known about how S. invicta affects complex mutualistic relationships. In some eastern forests of North America, 30% of herbaceous species have ant-dispersed seeds. We conducted experiments to determine if fire ants are attracted to seeds of these plant species and assessed the amount of scarification or damage that results from handling by fire ants. Fire ants removed nearly 100% of seeds of the ant-dispersed plants Trillium undulatum, T. discolor, T. catesbaei, Viola rotundifolia, and Sanguinaria canadensis. …

Modeling Viable Mammal Populations In Gap Analyses, Craig R. Allen, L. G. Pearlstine

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Gap analysis is an approach to conserving biological diversity that maps species richness and identifies sites that ought to be protected but are not in conservation networks. Gap analyses based on species richness may have high error rates when species models are based solely on species-habitat association, because patches too small to support populations are still considered to be potential habitat. We incorporated information on the home range and dispersal distances of the mammals of Florida to estimate minimum critical areas (MCA) to support minimum viable populations for each mammal species. Incorporating MCA decreases the area occupied by the highest …

Potential Fire Ant (Hymenoptera: Formicidae) Impact On The Endangered Schaus Swallowtail (Lepidoptera: Papilionidae), Elizabeth A. Forys, Anna Quistorff, Craig R. Allen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The Schaus swallowtail, Papilio aristodemus ponceanus, historically occurred in tropical hardwood hammocks from South Miami to the upper Florida Keys and is currently listed as federally endangered. Much of the remaining hardwood hammock habitat is fragmented by roads and human development that may alter the microhabitat within the hammocks and increase the probability of invasion by non-native predators and competitors. One non-indigenous species that has recently invaded the Florida Keys, and that may impact the Schaus swallowtail is the red imported fire ant (Solenopsis invicta Buren). We estimated abundance of red imported fire ants in Schaus swallowtail habitat …

The Spatial Distribution Of Diversity Between Disparate Taxa: Spatial Correspondence Between Mammals And Ants Across South Florida, Usa, Craig R. Allen, L. G. Pearlstine, D.P. Wojcik, W.M. Kitchens

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Gap Analysis takes a proactive landscape-level approach to conserving native species by identifying nodes of high biological diversity. It uses vertebrate species richness as an index of overall biological diversity. However, it remains unknownwhether or not the spatial distribution of vertebrate diversity correspondswith the diversity of other taxa. We tested whether landscape-level diversity patterns corresponded between a vertebrate and an invertebrate taxon, mammals and ants, across the southern half of the Florida peninsula, USA. Composite digital maps with a 30-m spatial resolution were produced for each taxon. Spatial correspondence between the taxa was determined by normalizing and then subtracting the …

2,3,7,8-Tetrachlorodibenzo-P-Dioxin Induces Apoptotic Cell Death And Cytochrome P4501a Expression In Developing Fundulus Heteroclitus Embryos, Barbara Holland Toomey, Susan Bello, Mark E. Hahn, Susannah Cantrell, Peggy Wright, Donald E. Tillitt, Richard T. Di Giulio

United States Geological Survey: Staff Publications

Fundulus heteroclitus embryos were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during early development using nanoinjection or water bath exposure. TCDD caused developmental abnormalities that included hemorrhaging, loss of vascular integrity, edema, stunted development and death. The LC₅₀ and LD₅₀ of TCDD for Fundulus embryos were ~19.7 ± 9.5 pg TCDD/µl (water bath) and 0.25 ± 0.09 ng TCDD/g embryo (nanoinjection). To identify a possible cause for these developmental abnormalities we analyzed the effects of TCDD on apoptotic cell death and cytochrome P4501A (CYP1A) expression in the embryos. TCDD exposure increased apoptotic cell death in several tissues including brain, …

Impact Of Climate And Parent Material On Chemical Weathering In Loess-Derived Soils Of The Mississippi River Valley, Daniel R. Muhs, E. A. Bettis Iii, J. Been, J. P. Mcgeehin

United States Geological Survey: Staff Publications

Peoria Loess-derived soils on uplands east of the Mississippi River the midcontinent of North America (Ruhe, 1969; Hall valley were studied from Louisiana to Iowa, along a south-to-north and Anderson, 2000), Alaska (Muhs et al., 2001), and gradient of decreasing precipitation and temperature. Major element China (Maher et al., 1994). Critical to paleoclimatic interanalyses of deep loess in Mississippi and Illinois show that the composi- pretations, using paleosols, are reliable climofunctions tion of the parent material is similar in the northern and southern for modern soils, which give an understanding of soil parts of the valley. We hypothesized that in …