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The Contribution Of Local And Transport Processes To Phytoplankton Biomass Variability Over Different Timescales In The Upper James River, Virginia, Qubin Qin, Jian Shen 2018 Virginia Institute of Marine Science

The Contribution Of Local And Transport Processes To Phytoplankton Biomass Variability Over Different Timescales In The Upper James River, Virginia, Qubin Qin, Jian Shen

Articles

Although both local processes (photosynthesis, respiration, grazing, and settling), and transport processes (advective transport and diffusive transport) significantly affect local phytoplankton dynamics, it is difficult to separate their contributions and to investigate the relative importance of each process to the local variability of phytoplankton biomass over different timescales. A method of using the transport rate is introduced to quantify the contribution of transport processes. By combining the time-varying transport rate and high-frequency observed chlorophyll a data, we can explicitly examine the impact of local and transport processes on phytoplankton biomass over a range of timescales from hourly to annually. For ...


Coastal Wetland Dynamics Under Sea-Level Rise And Wetland Restoration In The Northern Gulf Of Mexico Using Bayesian Multilevel Models And A Web Tool, Tyler Hardy 2018 The University of Southern Mississippi

Coastal Wetland Dynamics Under Sea-Level Rise And Wetland Restoration In The Northern Gulf Of Mexico Using Bayesian Multilevel Models And A Web Tool, Tyler Hardy

Master's Theses

There is currently a lack of modeling framework to predict how relative sea-level rise (SLR), combined with restoration activities, affects landscapes of coastal wetlands with uncertainties accounted for at the entire northern Gulf of Mexico (NGOM). I developed such a modeling framework – Bayesian multi-level models to study the spatial pattern of wetland loss in the NGOM, driven by relative RSLR, vegetation productivity, tidal range, coastal slope, and wave height – all interacting with river-borne sediment availability, indicated by hydrological regimes. These interactions have not been comprehensively investigated before. I further modified this model to assess the efficacy of restoration projects from ...


An Inventory Of Cicadellidae, Aphrophoridae, And Delphacidae (Hemiptera) In The Alvar Grasslands Of The Maxton Plains, Michigan, Max W. Spencer, James P. Dunn, Evan M. Szymczak 2018 Grand Valley State University

An Inventory Of Cicadellidae, Aphrophoridae, And Delphacidae (Hemiptera) In The Alvar Grasslands Of The Maxton Plains, Michigan, Max W. Spencer, James P. Dunn, Evan M. Szymczak

The Great Lakes Entomologist

Alvars are rare grassland communities found in the North American Great Lakes Region consisting of thin mineral soil over limestone bedrock and act as refugia for many unique and threatened endemic species. Few studies have catalogued Hemiptera species present in the alvars of the Maxton Plains on Drummond Island, MI. We aimed to add to these species lists, compare species diversity between alvar sites with varying levels of exposed bedrock, and test if an unpaved limestone road running through our sample sites influenced Hemipteran populations. We collected several prairie endemic species of Cicadellidae (Hemiptera), including a new record for the ...


Physiological Responses Of The State – Listed Texas Pigtoe To Environmental Stress, Sara M. Rumbelow 2018 University of Texas at Tyler

Physiological Responses Of The State – Listed Texas Pigtoe To Environmental Stress, Sara M. Rumbelow

Biology Theses

Systematic habitat destruction over the last 100 years combined with major anthropogenic stressors such as aquatic contaminants, exotic species, and economic endeavors are driving the decline in freshwater unionid species diversity. Two hundred fifty-seven individual adult Texas pigtoe (Fusconaia askewi) mussels (mean length, mm ± 1 SD; 58.7 ± 13.8) were collected from the upper Sabine river near Hawkins, Texas and taken to the University of Texas at Tyler to evaluate three factors likely impacting mussels in East Texas: siltation (a surrogate for bank erosion), elevated temperature and nitrogen. The impact of siltation was evaluated by burying mussels at two ...


Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow 2018 University of New Orleans

Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow

University of New Orleans Theses and Dissertations

Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United States throughout a year to determine contemporary genetic diversity and assess potential seasonal effects. Genetic diversity was found to be ...


Analysis Of Temperature And Salinity Effects On Growth And Mortality Of Oysters (Crassostrea Virginica) In Louisiana, Troy Sehlinger 2018 University of New Orleans

Analysis Of Temperature And Salinity Effects On Growth And Mortality Of Oysters (Crassostrea Virginica) In Louisiana, Troy Sehlinger

University of New Orleans Theses and Dissertations

Salinity (S) and temperature (T) control every facet of the eastern oyster (Crassostrea virginica) life cycle, principally reproduction, development, growth, and mortality. Previous studies conducted in in the Breton Sound (BR) and Barataria (BA) estuaries have reported differences in growth and mortality rates between the basins. In the present study, environmental conditions were synchronized to compare growth and mortality rates between basins at similar combinations of T and S. Results indicate that when T and S are the same (synchronized), seasonal oyster growth and mortality rates differ between BR and BA. Seasonal analyses revealed that as salinities increased in both ...


Using Anthropogenic Risks To Inform Salmonid Conservation At The Landscape Scale, Andrew W. Witt 2018 Utah State University

Using Anthropogenic Risks To Inform Salmonid Conservation At The Landscape Scale, Andrew W. Witt

All Graduate Theses and Dissertations

The expansion and industrialization of humanity has caused many unforeseen consequences to the natural world. Due to the importance of freshwater for people, rivers have been particularly altered to meet human needs, often at the expense of the natural world. Supplying water for farms, industries, and cities has reshaped the natural state of rivers by altering river paths, chemistry, and species compositions. These changes have harmed many species that prospered before widespread human alterations, including the native trout and salmon of western North America. As human populations continue to grow, new threats will surface for rivers, and the trout and ...


Understanding Plant Secondary Metabolites; Above And Below Ground, Andrea K. Clemensen 2018 Utah State University

Understanding Plant Secondary Metabolites; Above And Below Ground, Andrea K. Clemensen

All Graduate Theses and Dissertations

Plants naturally produce primary and secondary metabolites. Primary metabolites are directly involved with plant growth and metabolic function. Plant secondary metabolites (PSM) were once thought of as metabolic waste products, and more recently viewed as toxins to herbivores. However, ongoing research shows that PSM are beneficial to herbivores at low doses, and PSM aid plants by attracting pollinators, recovering from injury, protecting from ultraviolet radiation, increasing drought tolerance, and aid in defense against pathogens, diseases, and herbivores. Plant secondary metabolites also influence soil nutrient cycling, and can increase the sustainability of agroecosystems. Endophyte-infected tall fescue (Festuca arundinacea Schreb.) , which contains ...


Relationships Among Invasive Coqui Frogs, The Small Indian Mongoose And Rat Species In Hawaii, Shane A. Hill 2018 Utah State University

Relationships Among Invasive Coqui Frogs, The Small Indian Mongoose And Rat Species In Hawaii, Shane A. Hill

All Graduate Theses and Dissertations

Non-native species are increasing globally, and with this increase, it is likely that there will be new, unique relationships found among non-natives as well as additional impacts on native species. Rats and mongooses have been introduced to islands throughout the world where they impact native species, including birds, reptiles, and amphibians. The coqui frog was introduced to Hawaii in the 1980’s, where there were already abundant rat and mongoose populations. Previous research suggests that the high densities of coqui frogs may provide enough of a new food source for mongooses and rats that their populations would grow larger than ...


Integrated Management Of Billbugs (Coleoptera: Dryophthoridae) In Intermountain West Turfgrass, Madeleine M. Dupuy 2018 Utah State University

Integrated Management Of Billbugs (Coleoptera: Dryophthoridae) In Intermountain West Turfgrass, Madeleine M. Dupuy

All Graduate Theses and Dissertations

Billbugs are a serious pest of turfgrass in the Intermountain West. Billbug larvae severely discolor and eventually kill turfgrass by feeding in stems, on roots, and on crowns of the plant. Billbugs are typically managed with preventive, calendar-based applications of insecticides. Most of our knowledge on the biology and management of billbugs comes from research in the eastern U.S, and little is known about billbug biology and best management practices in the Intermountain West. First, I examined the seasonal activity of billbug life stages in Intermountain West turfgrass and developed a predictive degree-day model to better time management strategies ...


Patterns Of Threatened Vertebrates Based On Trophic Level, Diet, And Biogeography, Shaley A. Valentine 2018 Utah State University

Patterns Of Threatened Vertebrates Based On Trophic Level, Diet, And Biogeography, Shaley A. Valentine

All Graduate Theses and Dissertations

Humans have indirectly and directly contributed to the extinction of over 500 species within the past 500 years, a rate far higher than we have seen in the past. The high extinction rate and the fact that 18% of vertebrates may become extinct within the next century have pushed Earth into a biodiversity crisis. Understanding what makes species more at risk of extinction is needed to protect Earth’s biodiversity.

Generally, it is expected that predators have greater extinction risk than omnivores and herbivores because predators are larger in body size, depend on other animal species for food, need large ...


The Effects Of Enhanced Flows On Community Structure And Ecosystem Functioning In A Montane Utah River System, Joshua A. Epperly 2018 Utah State University

The Effects Of Enhanced Flows On Community Structure And Ecosystem Functioning In A Montane Utah River System, Joshua A. Epperly

All Graduate Theses and Dissertations

Due to growing human demands for freshwater within the last century, manmade flow alterations are now a common characteristic of rivers worldwide. Alterations to the volume and timing of flows in rivers are known to negatively impact aquatic biodiversity, biological productivity and ecosystem functions such as nutrient cycling. While previous research has focused on the effects of flow reductions and spates, there is a lack of knowledge on how high flows across longer timespans (i.e. ‘enhanced flows’) impact the structure of river communities and the integrity of ecosystem functions.

The Utah Reclamation, Mitigation and Conservation Commission has expressed interest ...


Biological Condition And Stressors Of Blm Wadeable Streams In Northeastern California And Northwestern Nevada, Nicole Cappuccio 2018 Utah State University

Biological Condition And Stressors Of Blm Wadeable Streams In Northeastern California And Northwestern Nevada, Nicole Cappuccio

All Graduate Theses and Dissertations

Taxpayer dollars can be used more efficiently by land management agencies to monitor streams if agency-wide monitoring protocols are adopted. To address this issue, the Bureau of Land Management (BLM) developed the National Aquatic Monitoring Framework (NAMF) to implement standardized assessments of stream condition and trend in the Western United States. As one of the first applications of the NAMFI sought to develop and apply an analytical framework to determine the biological condition of streams, extent of in stream stressors and their impact on biological condition, and anthropogenic sources of stressors in Northeast California and Northwest Nevada over three years ...


Impacts Of Phragmites Australis Management On Wetland Plant Community Recovery, Seedbank Composition, And The Physical Environment In The Chesapeake Bay, Eric L. G. Hazelton 2018 Utah State University

Impacts Of Phragmites Australis Management On Wetland Plant Community Recovery, Seedbank Composition, And The Physical Environment In The Chesapeake Bay, Eric L. G. Hazelton

All Graduate Theses and Dissertations

Biological invasions have adverse economic, cultural, and ecological effects worldwide. Among the most impactful in North America is the invasion of Phragmites australis (Phragmites), a large-scale clonal grass that rapidly colonizes wetlands. Phragmites crowds out native plants and alters habitat for native fauna. In doing so, Phragmites also alters human access to water resources and has adverse economic effects, including decreasing property value, inhibiting recreational use, and limiting populations of game species.

The efforts described in this dissertation are a component of a large, multidisciplinary effort to better understand the anthropogenic stressors to Chesapeake Bay, Maryland, at the land/water ...


Invasive Phragmites Australis Management In Great Salt Lake Wetlands: Context Dependency And Scale Effects On Vegetation And Seed Banks, Christine B. Rohal 2018 Utah State University

Invasive Phragmites Australis Management In Great Salt Lake Wetlands: Context Dependency And Scale Effects On Vegetation And Seed Banks, Christine B. Rohal

All Graduate Theses and Dissertations

Invasive plants can outcompete native plants, replacing diverse plant communities with monocultures, which can negatively impact the whole ecosystem. One invasive plant, Phragmites australis, has invaded wetlands across North America. In Utah’s Great Salt Lake, it has greatly reduced the area of native plants that are important habitat for migratory birds. Here we describe experiments that assess multiple treatments for Phragmites removal and evaluate the return of native plants after Phragmites management. The treatments were applied to Phragmites patches at two scales (small 1/4-acre plots and large 3-acre plots) and across multiple sites to evaluate how patch size ...


Effects Of Livestock Grazing Management Practices On Greater Sage-Grouse Nest And Female Survival, Seth J. Dettenmaier 2018 Utah State University

Effects Of Livestock Grazing Management Practices On Greater Sage-Grouse Nest And Female Survival, Seth J. Dettenmaier

All Graduate Theses and Dissertations

The decline in greater sage-grouse (Centrocercus urophasianus; sage-grouse) populations across western North America has been primarily attributed to loss and fragmentation of their sagebrush (Artemisia spp.) habitats. This habitat loss is largely the result of increased human activities, with grazing by domestic livestock as the most predominant land use across the sagebrush ecosystem in North America. The goal of my research was to increase our understanding of the effects of livestock on sage-grouse populations. I reviewed the peer-reviewed literature for all published studies that reported potential effects of grazing on grouse species worldwide. I found that there was an overall ...


Development And Fitness Consequences Of Onshore Behavior Among Polar Bears In The Southern Beaufort Sea Subpopulation, Kate M. Lillie 2018 Utah State University

Development And Fitness Consequences Of Onshore Behavior Among Polar Bears In The Southern Beaufort Sea Subpopulation, Kate M. Lillie

All Graduate Theses and Dissertations

Polar bears (Ursus maritimus) are experiencing rapid and substantial changes to their environment due to global climate change. Polar bears of the southern Beaufort Sea (SB) have historically spent most of the year on the sea ice. However, recent reports from Alaska indicate that the proportion of the SB subpopulation observed onshore during late summer and early fall has increased considerably. Previous research suggests that the number of polar bears onshore is linked to sea ice conditions and the availability of subsistence-harvested whale carcasses, which are referred to as bone piles. My objectives were to determine the development and fitness ...


Delineating Metrics Of Diversity For A Snake Community In A Rare Ecosystem, Zachary John Marcou 2018 Stephen F. Austin State University

Delineating Metrics Of Diversity For A Snake Community In A Rare Ecosystem, Zachary John Marcou

Electronic Theses and Dissertations

Snakes are among the least understood vertebrate groups despite their considerable diversity. A diverse community of snakes in an ecosystem can indicate a complex habitat structure that is capable of supporting a robust assemblage of other biota. I used remote photography arrays (RPA) to quantify metrics of diversity for the snake community occurring in a ~7,000–ha tract of contiguous Longleaf Pine (Pinus palustris) Savanna within the Angelina National Forest (ANF; Angelina and Jasper Cos., TX), over the course of two consecutive snake activity seasons. I quantified the snake species richness, Shannon diversity, and Shannon equitability for the snake ...


The Usefulness Of Gps Telemetry To Study Wolf Circadian And Social Activity, Samuel B. Merrill, L. David Mech 2018 New England Environmental Finance Center

The Usefulness Of Gps Telemetry To Study Wolf Circadian And Social Activity, Samuel B. Merrill, L. David Mech

USGS Northern Prairie Wildlife Research Center

This study describes circadian and social movement patterns of 9 wolves and illustrates capabilities and limitations of Global Positioning System (GPS) telemetry for analysis of animal activity patterns. Wolves were studied at the Camp Ripley National Guard Training Site in Little Falls, Minnesota, and were captured via helicopter net-gunning. All study wolves showed nocturnal movement patterns regardless of time of year. One wolf's movement pattern switched to diurnal when he conducted an extraterritorial foray from his natal territory. All data sets with GPS intervals <1 hour (n=4) showed crepuscular movement peaks. We identified patterns of den visitation and attendance, estimated minimum distances traveled and minimum rates of movement, and observed that GPS location intervals may affect perceived rates of wolf travel. Global Positioning System telemetry was useful in determining when pack members were traveling together or apart and how long a breeding female wolf spent near her pups (e.g., 0-month-old pups were left unattended by their mother for as long as 17 days).


Population Modeling For The Reintroduction Of Mexican Gray Wolves As Predators To Decrease The Feral Hog Population In The Southern United States., John H. Kauphusman III 2018 Minnesota State University, Mankato

Population Modeling For The Reintroduction Of Mexican Gray Wolves As Predators To Decrease The Feral Hog Population In The Southern United States., John H. Kauphusman Iii

Journal of Undergraduate Research at Minnesota State University, Mankato

Invasive species are a problem in the United States. As their populations continue to increase in size they disrupt ecological systems. One of the most notorious invasive species is the feral hog. In Texas, the hog populations cause ecological and agricultural damage that costs the state $52 million annually. The reason for the large continuously growing population is that the feral hogs, unlike its relatives in Europe, have no natural predators and hunters cannot suppress the population growth. In Europe, the gray wolf is a predator to the European wild boar. However, wolves in the U.S. have been extirpated ...


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