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Articles 31 - 45 of 45
Full-Text Articles in Life Sciences
Intraspecific Genetic Variation, Population Structure, And Performance Of The Invasive Aquatic Macrophyte Eurasian Watermilfoil (Myriophyllum Spicatum) In Waterbodies With And Without Histories Of Chemical Herbicide Treatment Across Michigan, Taylor Zallek
Dissertations, Master's Theses and Master's Reports
Populations of invasive species are often subjected to novel selective forces in the form of anthropogenic control agents in their introduced ranges. These control agents, applied unevenly among populations within a species’ new range, can send invasive populations on drastically different evolutionary and ecological trajectories. In these studies, we aimed to see if different histories of chemical herbicide treatment are differentially influencing the genetic diversity, structure, and performance of populations of invasive watermilfoil (Myriophyllum spicatum and M. spicatum x M. sibiricum hybrids) from waterbodies in the state of Michigan. We sampled ten waterbodies with different histories of herbicide treatment …
Microbial Community Response To Light And Heavy Crude Oil In Freshwater Systems, Timothy M. Butler
Microbial Community Response To Light And Heavy Crude Oil In Freshwater Systems, Timothy M. Butler
Dissertations, Master's Theses and Master's Reports
With increased demand for oil, there is an increased risk for oil spills in many environments. A number of pipelines transport oil near or across freshwater systems including the Great Lakes. Microbes are capable of breaking down oil and have thus been proposed as tools for oil spill response through bioremediation. There is a need to understand the microbial response to diverse oil types in freshwater environments due to the lack of research into this topic. This study’s main objectives are to understand how the freshwater microbial communities respond to oil, and how the bacterial communities may respond to different …
Ecological Implications Of Foraging And Life-History In Three Cold-Adapted Species, Andrew Von Duyke
Ecological Implications Of Foraging And Life-History In Three Cold-Adapted Species, Andrew Von Duyke
Dissertations, Master's Theses and Master's Reports
This research investigates the ecology of: ringed seals (Pusa hispida), moose (Alces alces), and bowhead whales (Balaena mysticetus). Each of these species draws upon specialized strategies to meet the physical demands of life in their extreme environments. However, they are currently experiencing unprecedented changes in their habitats. This work adds to what is known about the behavior, physiology, and population dynamics of cold-adapted species—providing insights of value for an improved understanding of foraging and life-history theory, and informing conservation and ecosystem monitoring efforts. Chapter 1 provides a brief introduction to the scope of work …
The Dynamic Nature Of Forage Preference And Microhistological Atlas, John J. Henderson
The Dynamic Nature Of Forage Preference And Microhistological Atlas, John J. Henderson
Dissertations, Master's Theses and Master's Reports
Moose, Alces alces, are among the most iconic species in the northern circumpolar temperate forests. Multiple factors influence moose density. Winter is a time of severe dietary stress for moose because deciduous trees are leafless and available forage is limited to conifers with high plant secondary metabolites or low-energy deciduous twigs. Forage preference depends on the intrinsic forage properties, abundance of forage and environmental stressors. These stressors include predation risk and severity of climate that affect forage efficiency. We examined forage preference of moose on Isle Royale National Park during winter over a ten-year period. Diet was divided into …
Assessment Of Arctic Grayling Re-Introduction Potential In The Big Manistee River, Michigan., Cameron Goble
Assessment Of Arctic Grayling Re-Introduction Potential In The Big Manistee River, Michigan., Cameron Goble
Dissertations, Master's Theses and Master's Reports
Arctic Grayling Thymallus arcticus were once the dominant fluvial salmonid species in Michigan’s Lower Peninsula. By the late 19th century most populations in the State had experienced drastic declines and by 1936 the species was declared extinct in Michigan. Beginning in 2011 the Little River Band of Ottawa Indians and Michigan Technological University partnered on research to determine the feasibility of re-establishing the species in the Big Manistee River watershed which was home to one of the last Arctic Grayling populations in the Lower Peninsula. The objectives of this research were to: A) assess abiotic habitat suitability for Arctic …
Associations Between Invasive Eurasian Watermilfoil And Littoral Fish And Invertebrate Communities In The Keweenaw Waterway Of Lake Superior, Carmen Leguizamon
Associations Between Invasive Eurasian Watermilfoil And Littoral Fish And Invertebrate Communities In The Keweenaw Waterway Of Lake Superior, Carmen Leguizamon
Dissertations, Master's Theses and Master's Reports
The invasion of Eurasian watermilfoil (Myriophyllum spicatum) can influence littoral zone communities within lakes. Its formation of dense mats at the water surface can suppress native macrophyte growth and impact fish diets and community structure, as well as invertebrate assemblages. However, in the colder waters of the upper Great Lakes region, Eurasian watermilfoil is patchily distributed and integrates more with the native macrophyte community. In order to identify the associations of invasive Eurasian watermilfoil and the littoral communities of the Keweenaw Waterway of Michigan’s Upper Peninsula, we sampled invertebrates, fish, and macrophytes at sites that represented a gradient of Eurasian …
Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian
Dissertations, Master's Theses and Master's Reports
Anthropocentric water resources management affects aquatic habitats by changing streamflow regime. Understanding the impacts of water withdrawal from different sources and consumption by various economic sectors at different spatial and temporal scales is key to characterizing ecologically harmful streamflow disturbances. To this end, we developed a generic, integrative framework to characterize catchment scale water stress at annual and monthly time scales. The framework accounts for spatially cumulative consumptive and non-consumptive use impacts and associated changes in flow due to depletion and return flow along the stream network. Application of the framework to the U.S. Great Lakes Region indicates that a …
The Spatial Ecology Of Gray Wolves In The Upper Peninsula Of Michigan, 1994–2013, Shawn O'Neil
The Spatial Ecology Of Gray Wolves In The Upper Peninsula Of Michigan, 1994–2013, Shawn O'Neil
Dissertations, Master's Theses and Master's Reports
All natural processes are dynamic in space and time. Establishing the links between spatiotemporal patterns and ecological processes is critical for improving our understanding of natural systems. Empirical data representing wildlife populations is accumulating and increasingly involves spatiotemporal components. Wildlife monitoring programs for threatened, endangered, or other species of interest often involve radio-tracking of a sample of individual animals combined with census data. Such data are valuable both for conservation and management of populations and for testing ecological theories about species distribution and what influences patterns over time. We used 20 years of radio telemetry and snow tracking data to …
Impacts To Biodiversity And Ecosystem Services From Bioenergy Development: A Pan American Experience, Colin Phifer
Impacts To Biodiversity And Ecosystem Services From Bioenergy Development: A Pan American Experience, Colin Phifer
Dissertations, Master's Theses and Master's Reports
As part of a broader project that evaluated the social and ecological sustainability of bioenergy, I studied the effects of bioenergy associated land-use change and management on native bees and birds in two bioenergy-producing countries, the United States and Argentina. In Argentina, I worked in Entre Ríos province where eucalyptus (Eucalyptus spp.) plantations are being planted. These fast-growing trees are replacing pasture and annual crops, the current dominant land use. I surveyed for native bees and birds in pastures/annual crops and large-scale eucalyptus plantations, as well as mixed-use farms and native espinal savannas. Both birds and bees declined in …
Neutral And Adaptive Genetic Variation In North American Hardwood Tree Species, Sudhir Khodwekar
Neutral And Adaptive Genetic Variation In North American Hardwood Tree Species, Sudhir Khodwekar
Dissertations, Master's Theses and Master's Reports
'Northern Hardwoods,’ are a characteristic composition of multiple tree species and a part of the rich and diverse northeastern forests. Hardwoods e.g. oaks (Quercus: Fagaceae and Sugar maple), serve as foundation species and offer ecological and economical gains to wildlife and humans. Most of the forest trees go through many biotic and abiotic stresses, for example climate change in their long life span. To overcome these threats and to adapt to changing conditions, tree species need to maintain variation especially in adaptive genes. Therefore, it is necessary to analyze genetic diversity within forest tree populations and take appropriate …
Assessing The Impacts Of Climate Change On The Surface Temperature Of Inland Lakes In Michigan, Kaitlin Reinl
Assessing The Impacts Of Climate Change On The Surface Temperature Of Inland Lakes In Michigan, Kaitlin Reinl
Dissertations, Master's Theses and Master's Reports
The aim of this study was to validate and apply a lake model for predicting the susceptibility of small inland lakes in Michigan to changes in thermal regime and increased cyanobacteria growth as a result of future climate conditions. The Freshwater Lake Model was selected, tested for sensitivity to various inputs, and validated through comparison to observed conditions. The sensitivity analysis showed that the lake model was most sensitive to solar radiation, air temperature, and air humidity. Comparison of predicted climate data with observed conditions revealed highly variable climate model error. The lake model validation was conducted using 10 lakes …
Carbon Flux Dynamics In High Altitude Peatlands In The Ecuadorian Andes, Maria Elisa Sanchez Garces
Carbon Flux Dynamics In High Altitude Peatlands In The Ecuadorian Andes, Maria Elisa Sanchez Garces
Dissertations, Master's Theses and Master's Reports
Although knowledge of peatland CH4 and CO2 exchange in temperate mountain ecosystems is available, information about carbon (C) exchange in peatlands of the Andean mountains is limited and these ecosystems may behave differently given the particular characteristics of the Andean tropics. These ecosystems are highly productive and under pressure by grazing. Our first objective was to measure baseline carbon dioxide (CO2) and methane (CH4) flux in an undisturbed peatland in Cayambe-Coca National Park. Our second objective was to quantify CO2 and CH4 fluxes in an intensively cattle grazed peatland near Antisana Ecological …
Vegetation Dynamics And Nitrogen Cycling Responses To Simulated Emerald Ash Borer Infestation In Fraxinus Nigra-Dominated Wetlands Of Upper Michigan, Usa, Joshua Davis
Dissertations, Master's Theses and Master's Reports
Throughout many North American forests, the invasive emerald ash borer (EAB, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)) is a significant threat to biodiversity and ecosystem processes. The fate of Fraxinus nigra Marshall (black ash) is of particular concern, as it is frequently a dominant canopy species across much of its range. A multiyear manipulative study was conducted to investigate the potential impacts of EAB on vegetation dynamics and nitrogen (N) cycling in nine F. nigra-dominated wetlands of Upper Michigan, USA. The effects of early- and late-stage infestations were simulated by girdling (‘Girdle’) or felling (‘Ash-Cut’) all ash stems greater than …
Investigating The Role Of Polyploidy In The Response Of Chamerion Angustifolium To Increased Soil Nitrogen Availability And Insect Herbivory, Alex Bales
Dissertations, Master's Theses and Master's Reports
Human activities have more than doubled the input rate of nitrogen to terrestrial ecosystems. Increased soil nitrogen availability is associated with increased plant productivity, changes in plant resource allocation strategies, and changes in interactions between plants and their associated insect herbivores. For example, nitrogen-rich conditions can alter the physiological and chemical properties of plants in ways that increase their ability to deter herbivore attack (resistance) and maintain fitness following herbivore attack (tolerance). The ecological tolerance of plants to such abiotic and biotic environments is thought to be influenced by autopolyploidy, a commonly occurring phenomenon in plants in which individuals have …
Observations Of Hippopotamus H. Amphibius In The Little Scarcies River Of Sierra Leone And Arguments For Their Conservation Based On Roles They Play In Riverine Grasslands And Nutrient Loading, Lindsey R. Perry
Dissertations, Master's Theses and Master's Reports
A small population of Hippopotamus amphibius remains in Sierra Leone and conservation efforts may be needed to support the Hippos and their indirect benefits to fisheries and grassland production. The hippo is a known ecosystem engineer, and a potentially important contributor of nutrients to the river systems they inhabit supporting the food web and local fisheries. In this study I observed hippos in the Little Scarcies River and uplands of the Outamba-Kilimi National Park to estimate their numbers and ultimately their potential input of nutrients into the river. Hippos forage at night in grasslands neighboring rivers, removing up to 3.62 …