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39,403 full-text articles. Page 947 of 949.

Diurnal Fluctuations In Shallow Groundwater Levels And In Streamflow Rates And Their Interpretation: A Review, Zoltan Gribovszki, Jozsef Szilagyi, Peter Kalicz 2010 University of West Hungary

Diurnal Fluctuations In Shallow Groundwater Levels And In Streamflow Rates And Their Interpretation: A Review, Zoltan Gribovszki, Jozsef Szilagyi, Peter Kalicz

Papers in Natural Resources

No abstract provided.


Complementary-Relationship-Based Evapotranspiration Mapping (Cremap) Technique For Hungary, Jozsef Szilagyi, Akos Kovacs 2010 University of Nebraska-Lincoln

Complementary-Relationship-Based Evapotranspiration Mapping (Cremap) Technique For Hungary, Jozsef Szilagyi, Akos Kovacs

Papers in Natural Resources

No abstract provided.


Introduction To The Basic Drivers Of Climate, Alison P. Stevens 2010 University of Nebraska-Lincoln

Introduction To The Basic Drivers Of Climate, Alison P. Stevens

Papers in Natural Resources

Climates on Earth vary from the warm, wet tropics to the cold, dry Arctic and Antarctic. What drives this variation?

Every day, we note the weather: temperature, rain, cloud cover, wind and humidity. Climate is the long-term prevailing weather in an area and is largely determined by temperature and precipitation. The climate in a desert is hot and dry. The climate in the tropics is warm and wet. The climate of a particular area is the largest determinant to the life found there. Climate is a key focus in ecology. Variations in climate include daily and seasonal cycles. Climatic variation ...


Finding The Smoothest Path To Success: Model Complexity And The Consideration Of Nonlinear Patterns In Nest-Survival Data Encontrando El Camino Mas Facil Hacia El Exito: Complejidad De Los Modelos Y Consideraci6n De Patrones No Lineales En Datos De Supervivencia De Nidos, Max Post van der Burg, Larkin A. Powell, Andrew J. Tyre 2010 University of Nebraska-Lincoln

Finding The Smoothest Path To Success: Model Complexity And The Consideration Of Nonlinear Patterns In Nest-Survival Data Encontrando El Camino Mas Facil Hacia El Exito: Complejidad De Los Modelos Y Consideraci6n De Patrones No Lineales En Datos De Supervivencia De Nidos, Max Post Van Der Burg, Larkin A. Powell, Andrew J. Tyre

Papers in Natural Resources

Quantifying patterns of nest survival is a first step toward understanding why birds decide when and where to breed. Most studies of nest survival have relied on generalized linear models (GLM) to explore these patterns. However, GLMs require assumptions about the models' structure that might preclude finding nonlinear patterns in survival data. Generalized additive models (GAM) provide a flexible alternative to GLMs for estimating linear and nonlinear patterns in data. Here we present a comparison of GLMs and GAMs for explaining variation in nest-survival data. We used two different model-selection criteria, the Bayes (BIC) and Akaike (AIC) information criteria, to ...


Upwelling Couples Chemical And Biological Dynamics Across The Littoral And Pelagic Zones Of Lake Tanganyika, East Africa, Jessica R. Corman, P. B. McIntyre, B. Kuboja, W. Mbemba, D. Fink, C. W. Wheeler, C. Gans, E. Michel, A. S. Flecker 2010 University of Nebraska - Lincoln

Upwelling Couples Chemical And Biological Dynamics Across The Littoral And Pelagic Zones Of Lake Tanganyika, East Africa, Jessica R. Corman, P. B. Mcintyre, B. Kuboja, W. Mbemba, D. Fink, C. W. Wheeler, C. Gans, E. Michel, A. S. Flecker

Papers in Natural Resources

We studied the effects of upwelling on nutrient and phytoplankton dynamics in the pelagic and littoral zones of Lake Tanganyika near Kigoma, Tanzania. During the dry season of 2004, a rise in the thermocline and sudden drop in surface water temperatures indicated a substantial upwelling event. Increases in concentrations of nitrate, soluble reactive phosphorus, and silica in the surface waters occurred simultaneously after the temperature drop. Within days, chlorophyll a concentrations increased and remained elevated, while inorganic nutrient concentrations returned to preupwelling levels and organic nutrient concentrations peaked. We observed parallel temporal patterns of water temperature, nutrient concentrations, and phytoplankton ...


An Evaluation Of Duck And Ring-Necked Pheasant Nest Survival And Nest Density In Relation To Patch Size And Landscape Variables In Eastern South Dakota, Keith J. Fisk 2010 South Dakota State University

An Evaluation Of Duck And Ring-Necked Pheasant Nest Survival And Nest Density In Relation To Patch Size And Landscape Variables In Eastern South Dakota, Keith J. Fisk

Electronic Theses and Dissertations

Grassland ecosystems in South Dakota have experienced significant transformations over the last 100 years. Landscapes are currently dominated by large agricultural fields interspersed with small, isolated grassland patches. These isolated grassland patches are hypothesized to experience decreased nest survival rates for ring-necked pheasants (Phasianus colchicus) and dabbling duck species due to small size and high degrees of fragmentation. Several natural resource agencies currently conserve grasslands throughout eastern South Dakota, but wildlife managers seek more information on how the size and spatial arrangement of grasslands affect targeted conservation strategies. Therefore, the objectives of this study were to: (1) evaluate the relationship ...


The Index Of Biological Integrity And The Bootstrap: Can Random Sampling Error Affect Stream Impairment Decisions?, Christine L. Dolph, Aleksey Y. Sheshukov, Christopher J. Chizinski, Bruce Vondracek, Bruce N. Wilson 2010 University of Minnesota

The Index Of Biological Integrity And The Bootstrap: Can Random Sampling Error Affect Stream Impairment Decisions?, Christine L. Dolph, Aleksey Y. Sheshukov, Christopher J. Chizinski, Bruce Vondracek, Bruce N. Wilson

Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications

Multimetric indices, such as the Index of Biological Integrity (IBI), are increasingly used bymanagement agencies to determine whether surface water quality is impaired. However, important questions about the variability of these indices have not been thoroughly addressed in the scientific literature. In this study, we used a bootstrap approach to quantify variability associated with fish IBIs developed for streams in two Minnesota river basins. We further placed this variability into a management context by comparing it to impairment thresholds currently used in water quality determinations for Minnesota streams. We found that 95% confidence intervals ranged as high as 40 points ...


The Impact Of Rare Taxa On A Fish Index Of Biotic Integrity, Haibo Wan, Christopher J. Chizinski, Christine L. Dolph, Bruce Vondracek, Bruce N. Wilson 2010 University of Minnesota

The Impact Of Rare Taxa On A Fish Index Of Biotic Integrity, Haibo Wan, Christopher J. Chizinski, Christine L. Dolph, Bruce Vondracek, Bruce N. Wilson

Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications

The index of biotic integrity (IBI) is a commonly used bioassessment tool that integrates abundance and richness measures to assess water quality. In developing IBIs that are both responsive to human disturbance and resistant to natural variability and sampling error, water managersmust decide how to weigh information about rare and abundant taxa, which in turn requires an understanding of the sensitivity of indices to rare taxa. Herein, we investigated the influence of rare fish taxa (within the lower 5% of rank abundance curves) on IBI metric and total scores for stream sites in two of Minnesota’smajor river basins, the ...


A Modelling Approach To Evaluate Potential Management Actions Designed To Increase Growth Of White Perch In A High-Density Population, Christopher J. Chizinski, Kevin L. Pope, G.R. Wilde 2010 Texas Tech University

A Modelling Approach To Evaluate Potential Management Actions Designed To Increase Growth Of White Perch In A High-Density Population, Christopher J. Chizinski, Kevin L. Pope, G.R. Wilde

Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications

A deterministic, age-structured population model was developed to simulate potential management scenarios designed to increase growth of individuals (quantified by maximum length) in a hypothetical population of white perch, Morone americana (Gmelin). Four scenarios were developed that included non-selective mortality of adult white perch, increased mortality of age groups most influential on population growth, increased age-0 mortality and inhibiting recruitment after spawning. The greatest increase in maximum length occurred with nonselective adult mortality when population biomass was reduced by 97%; lesser increases in maximum length were achieved with the other management scenarios. Populations returned to their original state after control ...


Risk Assessment: Simultaneously Prioritizing The Control Of Invasive Plant Species And The Conservation Of Rare Plant Species, Thaddeus K. Miller, Craig R. Allen, Wayne G. Landis, James W. Merchant 2010 Univeristy of Nebraska-Lincoln

Risk Assessment: Simultaneously Prioritizing The Control Of Invasive Plant Species And The Conservation Of Rare Plant Species, Thaddeus K. Miller, Craig R. Allen, Wayne G. Landis, James W. Merchant

Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications

Although the consequences of the homogenization of Earth’s flora and fauna are not well understood, experts agree that biological invasions pose hazards to rare species. As a result, there is a need for a systematic approach to assess risks from invasive species. The Relative Risk Model can be adapted to assess combinations of rare species, invasive species, and regions. It also can be applied to different taxonomic groups and at different spatial scales. This flexibility makes it a promising tool for invasive species risk assessment. We used the Relative Risk Model to quantify risks posed to endangered plant species ...


Methods For Assessing Fish Populations, Kevin L. Pope, Steve E. Lochmann, Michael K. Young 2010 University of Nebraska-Lincoln

Methods For Assessing Fish Populations, Kevin L. Pope, Steve E. Lochmann, Michael K. Young

Nebraska Cooperative Fish & Wildlife Research Unit -- Staff Publications

Fisheries managers are likely to assess fish populations at some point during the fisheries management process. Managers that follow the fisheries management process (see Chapter 5) might find their knowledge base insufficient during the steps of problem identification or management action and must assess a population before appropriate actions can be taken. Managers will implement some type of assessment during the evaluation step as a means of measuring progress relative to objectives. Choosing how to assess a population is an important decision because managers strive to maximize their knowledge of a population while minimizing the time and money expended to ...


Conservation Status Of Australian Snubfin Dolphin, Orcaella Heinsohni, And Indo-Pacific Humpback Dolphin, Sousa Chinensis, In The Capricorn Coast, Central Queensland, Australia, Daniele Cagnazzi 2010 Southern Cross University

Conservation Status Of Australian Snubfin Dolphin, Orcaella Heinsohni, And Indo-Pacific Humpback Dolphin, Sousa Chinensis, In The Capricorn Coast, Central Queensland, Australia, Daniele Cagnazzi

Theses

This study examined populations of Australian snubfin dolphins (Orcaella heinsohni) and Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting the coastal waters of the Capricorn Section of the Great Barrier Reef Marine Park, Queensland, Australia. A total of 189 humpback dolphins and 54 snubfin dolphins were identified during 1,760 hours and 20,248 kms of transect surveys completed between 2006 and 2008 in the Capricorn Coast region. Humpback dolphins were found in three different sites: Port Curtis, Keppel Bay and the Northern Region of the study area. In contrast, snubfin dolphins were found only in the Keppel Bay study area. Both ...


Applying Paleolimnological Techniques To Sub-Tropical East Australian Estuaries, Brendan Logan 2010 Southern Cross University

Applying Paleolimnological Techniques To Sub-Tropical East Australian Estuaries, Brendan Logan

Theses

This thesis examines the application of paleolimnological techniques, pioneered and developed predominately in northern hemisphere freshwater environments, to sub-tropical east Australian estuaries. The aim of this research was to determine how successfully these techniques - in particular those related to coring, dating, diatom analysis and stable isotope analysis – can be either applied or adapted to the estuarine environment to reconstruct nutrient levels in the absence of monitoring data. This will allow pre-impact environmental conditions of estuaries to be determined, which in turn will aid future management decisions.

Fifty-two estuaries from a spatially large geographic area were initially sampled, to create a ...


Ecological And Evolutionary Connectivity Of Reef Corals In Subtropical Eastern Australia : Implications For The Persistence Of High-Latitude Coral Populations, Annika ME Noreen 2010 Southern Cross University

Ecological And Evolutionary Connectivity Of Reef Corals In Subtropical Eastern Australia : Implications For The Persistence Of High-Latitude Coral Populations, Annika Me Noreen

Theses

Coral reefs worldwide are threatened by a variety of pressures, and climate change models predict increasing levels of chronic stress as well as acute disturbances for most reefs. In addition to these global threats, populations on remote reefs are also predicted to be vulnerable due to their isolation from potential source reefs, usually low population size and associated increased extinction risk. Critical for the future of these reefs is dispersal and gene flow between populations (connectivity). This study investigated connectivity, population subdivision, and genetic diversity for three scleractinian reef coral species in discontinuous high-latitude nearshore coral communities and offshore reefs ...


Correlation Of River Terrace Sequences: Widden Brook, Australia, Michael D. Cheetham 2010 Southern Cross University

Correlation Of River Terrace Sequences: Widden Brook, Australia, Michael D. Cheetham

Theses

Terrace sequences can represent regional or continental scale factors such as climatic fluctuations, neotectonic activity and base-level change. However, they can also reflect random incision events brought about by local scale, geomorphic threshold exceedance and subsequent complex response. Through the description and interpretation of the physical landscape and by use of a detailed construction of the chronology, this study explores the formative processes of three discontinuous but adjacent, Late Quaternary step-terrace sequences.

Terrace remnants on Widden Brook, a sandy alluvial stream in southeastern Australia, were examined and correlated longitudinally to establish their evolutionary history. Three distinct, discontinuous terrace sequences, the ...


The Challenges Of Wastewater Irrigation In Developing Countries, M. Qadir, D. Wichelns, L. Raschid-Sally, Peter G. McCornick, P. Drechsel, A. Bahri, P. S. Minhas 2010 International Center for Agricultural Research in the Dry Areas

The Challenges Of Wastewater Irrigation In Developing Countries, M. Qadir, D. Wichelns, L. Raschid-Sally, Peter G. Mccornick, P. Drechsel, A. Bahri, P. S. Minhas

Water for Food Faculty Publications

The volume of wastewater generated by domestic, industrial, and commercial sources has increased with population, urbanization, improved living conditions, and economic development. The productive use of wastewater has also increased, as millions of small-scale farmers in urban and peri-urban areas of developing countries depend on wastewater or wastewater-polluted water sources to irrigate high-value edible crops for urban markets, often as they have no alternative sources of irrigation water. Undesirable constituents in wastewater can harm human health and the environment. Hence, wastewater irrigation is an issue of concern to public agencies responsible for maintaining public health and environmental quality. For diverse ...


Challenges And Prospects Of Sustainable Groundwater Management In The Indus Basin, Pakistan, Asad Sarwar Qureshi, Peter G. McCornick, A. Sarwar, Bharat R. Sharma 2010 International Water Management Institute

Challenges And Prospects Of Sustainable Groundwater Management In The Indus Basin, Pakistan, Asad Sarwar Qureshi, Peter G. Mccornick, A. Sarwar, Bharat R. Sharma

Water for Food Faculty Publications

In Pakistan, on-demand availability of groundwater has transformed the concept of low and uncertain crop yields into more assured crop production. Increased crop yields have resulted in food security and improved rural livelihoods. However, this growth has also led to problems of overdraft, falling water tables, and degradation of groundwater quality, and yields generally remain well below potential levels. Over the last three decades, Pakistan has tried several direct and indirect management strategies for groundwater management. However the success has been limited. This paper argues that techno-institutional approaches such as introducing water rights, direct or indirect pricing, and permit systems ...


Correlation Between Normalized Difference Vegetation Index And Malaria In A Subtropical Rain Forest Undergoing Rapid Anthropogenic Alteration, Nicole M. Wayant, Diego Maldonado, Antonieta Rojas de Arias, Blanca Cousino, Douglas G. Goodin 2010 University of Nebraska - Lincoln

Correlation Between Normalized Difference Vegetation Index And Malaria In A Subtropical Rain Forest Undergoing Rapid Anthropogenic Alteration, Nicole M. Wayant, Diego Maldonado, Antonieta Rojas De Arias, Blanca Cousino, Douglas G. Goodin

Center for Advanced Land Management Information Technologies--Publications

Time-series of coarse-resolution greenness values derived through remote sensing have been used as a surrogate environmental variable to help monitor and predict occurrences of a number of vector-borne and zoonotic diseases, including malaria. Often, relationships between a remotely-sensed index of greenness, e.g. the normalized difference vegetation index (NDVI), and disease occurrence are established using temporal correlation analysis. However, the strength of these correlations can vary depending on type and change of land cover during the period of record as well as inter-annual variations in the climate drivers (precipitation, temperature) that control the NDVI values. In this paper, the correlation ...


Recursive Streamflow Forecasting: A State-Space Approach, Jozsef Szilagyi, Andras Szollosi-Nagy 2010 University of Nebraska-Lincoln

Recursive Streamflow Forecasting: A State-Space Approach, Jozsef Szilagyi, Andras Szollosi-Nagy

Papers in Natural Resources

No abstract provided.


Locus Of Control, Sources Of Motivation, And Mental Boundaries As Antecedents Of Leader-Member Exchange Quality, John E. Barbuto Jr., Dayna Finch Weltmer, Lisa A. Pennisi 2010 University of Nebraska-Lincoln

Locus Of Control, Sources Of Motivation, And Mental Boundaries As Antecedents Of Leader-Member Exchange Quality, John E. Barbuto Jr., Dayna Finch Weltmer, Lisa A. Pennisi

Papers in Natural Resources

No abstract provided.


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