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1
Loman, Karen L. "The impact of an experiential science program on fourth-grade students' knowledge of and feelings about ecological science /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9904878.
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Zapata, Martha J. Zapata. "Spatial and temporal variability in aquatic-terrestrial trophic linkages in a subtropical estuary." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1515139504483898.
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Pokhrel, Lok R., Phillip R. Scheuerman, and Brajesh Dubey. "Evaluation of Experimental Design Options in Environmental Nano-Science Research." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/2874.
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Evaluation of Experimental Design Options in Environmental Nano-Science Research As an experimental research design plays a pivotal role in executing a research problem, it is imperative of a researcher to develop a suitable and sound research design. Utilizing robust statistical methods can further enhance the study power and thus allow drawing a logical conclusion. The same holds true for basic environmental science research, including research related to the effects of engineered nanomaterials in the environment.
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Meurk, Carla Siobhan. "Causally Appropriate Graphical Modelling for Time Series with Applications to Economics, Ecology and Environmental Science." Thesis, University of Canterbury. Mathematics and Statistics, 2005. http://hdl.handle.net/10092/1152.
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I apply the GMTS approach to graphical modelling of time series to data sets from economics, ecology and environmental science. This approach improves on traditional approaches to modelling insofar as it selects the most parsimonius model. I improve on this approach by removing some redundancies in the GMTS approach. However, a bias in terms of which links are selected means that it is unlikely that this model will select the best causal model.
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Pinkerton, Jeramy John. "Predicting the Potential Distribution of Two Threatened Stream Fish Species in Northeast Ohio." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461189304.
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Dinneen, Nathan. "Ranges of consideration: crossing the fields of ecology, philosophy and science studies." Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3292/.
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Environmental issues are often complex with many different constituents operating according to a broad range of communication techniques. In order to foster negotiations, different perspectives need to be articulated in lucid ways sensitive to various viewpoints and circumstances. In my thesis I investigate how certain approaches to environmental discourse effect dialogue and negotiation. My first two chapters focus on environmental problems surrounding rangeland ecology along the U.S./Mexico border; whereas the last two chapters explore more theoretical conflicts concerning the philosophy of nature. Throughout the thesis I show the significance of nonhumans (prairie dogs, cattle, biological assessment sheets, environmental laws, etc.) in the human community. Only by considering the roles of nonhumans do we broaden and enrich the conversation between ourselves concerning environmental issues.
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Snyder, Emma M. "Baseline Assessment of Dynamic Properties and Soil Resilience at Lawrence Woods State Nature Preserve." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387362944.
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Bryan, Jenelle Sue. "Environmental science curriculum for eleventh through twelfth grade classes." CSUSB ScholarWorks, 1998. https://scholarworks.lib.csusb.edu/etd-project/1508.
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Glenn, Steven W. "Alpine Biological Soil Crusts in theWashington North Cascades| a Distribution Study at Select Sites Across a Precipitation Gradient." Thesis, Prescott College, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3712344.
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<p> One of the least researched phenomena within the alpine regions of mountain biomes is the combination of primitive plants, algae, fungi, and lichens that are generally referred to as biological soil crusts. Sites containing well-developed biological soil crusts were examined in a variety of alpine, non-forested, vegetated landscapes in the North Cascade Mountains of Washington, USA. For each site, data were recorded for percent ground cover of biological soil crusts, slope aspect, and slope gradient of the terrain where the crust communities were located. For all of the sites, biological soil crusts were common, with a percent ground cover median of 29% and a range of 11% to 73%. The arrangement of the biological soil crusts on all sites was quite similar: all were clumped, as opposed to single, and random, as opposed to uniform. All of the soil crusts were found on soil exposed to direct sunlight. Few, if any, crusts were found in the shade of heavy forbs, or forest, or under accumulations of organic litter. When biological soil crusts were found associated with higher-order vegetation, it was with sparse graminoids, ericaceous woody shrubs, and stunted or krummholz Pinaceae trees. The biological soil crusts from this study exist on all locally undisturbed soil slope-gradients from 0% to almost 100%, and occurred on all aspects except for those in the Southwest quadrant. This study contains an extended literature review for desert and high latitude circumpolar crusts, as well as alpine biological soil crusts. Studies of biological soil crusts in subalpine and alpine environments are not common; it is hoped that this study will stimulate more research interest in these often overlooked pioneer biotic communities.</p>
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Kivalov, Sergey Nikolayevich. "Whole-Canopy Net Ecosystem Exchange and Water Use Efficiency in an Intermittent-Light Environment - Dynamic Approach." Thesis, State University of New York at Albany, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10842781.
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<p> An observed 20-30% increase in forest net ecosystem exchange (<i> NEE</i>) on partly cloudy days is often attributed to there being more uniform canopy illumination by diffuse radiation when clouds are present. However, the sky on such days is typically populated by fair-weather cumulus clouds, bringing dynamically changing shadow-to-light conditions on the order of minutes to the forest, with radiation alternating from 1000 W m<sup> -2</sup> in the clear sky to less than 400 W m<sup>-2</sup> in under-cloud shadows. These dynamically changing conditions cannot be investigated by the conventional time-averaged eddy-covariance flux method, which requires nearly steady-state turbulent conditions over much longer 20-30-min periods in order for the fluxes to converge to stationary values. We examine the “true” dynamics of the whole-canopy response to the light change by using a practical ensemble-flux method applied to eddy-covariance flux measurements from two distinct forest ecosystems: Harvard Forest (HF, 42.53°N, 72.17°W), temperate mid-latitude forest near Petersham, Massachusetts, USA, and Tapajós National Forest (LBA, 2.86°S, 54.96°W), an Amazonian evergreen tropical forest near Santarem, Pará, Brazil. Using the rapid change in radiative flux that occurs during the transition from cloud-induced shadow to light as a reference starting point, we combine sets of conditional illumination-change shadow-to-light and light-to-shadow transition events characteristic of cumulus-cloud conditions and parametrize distributions of light and shadow durations and rates of light change of the radiative-flux time series for different cloud conditions reported by standard weather stations. We investigate the sensitivity of the dynamics of forest response to the illumination transitions initiated by these conditional events, and identify an unexpected transient <i> NEE</i> maxima when <i>NEE</i> increases above the clear-sky steady-state equilibrium values (<i>NEE</i><sub>eq</sub>) within the first 10 min of the light period after the shadow-to-light transition, that we hypothesize to be a physiological forest response to the abrupt light change due to presence of the intercellular CO<sub>2</sub> pool in the leaf tissues. Overall <i>NEE</i> builds up during the sunlit periods, but in shadow heat and water stresses are reduced, thus increasing the water use efficiency (<i>WUE</i>). To conduct this analysis, we obtain similarity criteria for realizations defined by conditional events to combine them into the ensembles. With 300 similar realizations grab-sampled at 1-s intervals, we can reliably estimate (≤ 5% standard error) dynamic ensemble fluxes resolved on a 5-s time scale. By the successful application of the first-order system of the delay differential equations with the exponential approach-to-equilibrium solutions, we are able to justify the utility of the “Big-Leaf”-model approach to describe whole-canopy fluxes and provide the dynamic parametrizations of the “Big-Leaf” Active Thermal Layer as well as of the Transient Internal Layer above both forests when the light switches on after the cloud pass. By combining results of sensitivity analysis with modelled solutions applied to the real day-long fluctuating-light time series, we show that the variable light during fair-weather clouds (Shadow period duration < 100 s, Light period duration ≥ 300 s) is responsible for an increase in <i>NEE</i> above the <i>NEE</i><sub> eq</sub> of 15-25% for HF and 10-15% for LBA. This indicates that there is a fluctuating-light <i>NEE</i>-enhancement mechanism that can be considered to be a viable alternative to the existing hypothesis of a diffuse-radiation <i> NEE</i>-enhancement mechanism on partly-cloudy days. We show that on such days <i>Diffuse Fraction</i> can be linearly-related to <i> Cloudiness</i> estimated using the shadow-to-light change in a conditional-event radiative-flux ratio, connecting these two <i>NEE</i>-enhancement mechanisms. Combination of increased NEE with the relatively high plateau in <i>WUE</i> allows forests to operate efficiently in partly-cloudy conditions with maxima located in the <i>Cloudiness</i> range [0.1-0.3] and <i>Diffuse-Fraction</i> range [0.35-0.6], suggesting forest adaptations to the preferred lighting conditions and fair-weather cloudiness. </p><p>
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Keen, Eric Michael. "Whales of the rainforest| Habitat use strategies of sympatric rorqual whales within a fjord system." Thesis, University of California, San Diego, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10256131.
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<p> The energy needs of rorqual whales (f. Balaenopteridae) govern their relationship to marine habitats during the foraging season. However, their cryptic foraging strategies and extreme feeding behaviors complicate our effort to identify and protect habitats “critical” for rorquals. What is the relationship between rorquals and their habitat, and how must that shape conservation strategies? I addressed this question in the case of sympatric humpback (<i>Megaptera novaeangliae</i>) and fin whales (<i> Balaenoptera physalus</i>) in the marine territory of the Gitga’at First Nation in the Kitimat Fjord System of British Columbia. For three summers (2013-2015) I studied whales, their prey, and their environment aboard the <i> RV Bangarang</i> using oceanographic station sampling, systematic transect surveys, and opportunistic focal follows of whales (Chapter 1). Ocean sampling demonstrated the strong coupling of water features with offshore patterns in storm forcing and regional meteorology (Chapter 2). By combining these surveys with a long-term Gitga’at dataset, area humpback whales were found to practice a structured and persistent pattern in seasonal habitat use, which demonstrates how complex and habitat-specific a rorqual’s habitat use can be (Chapter 3). Both humpback and fin whales were found to respond to changes in krill supply in aggregative and behavioral thresholds that are set by a combination of intrinsic energetic needs and the context of local prey supply (Chapter 4). Associations with non-prey habitat features were markedly different in the two species (Chapter 5). Humpback distribution was more closely coupled to that of their prey and other habitat features, while fin whale distribution was driven broadly by site fidelity. Novel spatial analytics were used to identify the most probable environmental cues used by foraging whales (Chapter 6). Both species were found to be particularly sensitive to the depth of prey layers, which is governed largely by oceanographic features (Chapter 7). This coupling of habitat features and feeding performance influences the competitive dynamics of rorqual whales. The findings in this case study advance general theories on marine predator ecology and conservation, and have direct implications for the management of Gitga’at territory and the identification of fin whale critical habitat in Pacific Canada.</p>
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McAskill, Shannan C. "Interactive effects of environmental stressors and the invasive apple snail, Pomacea maculata, on tapegrass, Vallisneria americana." Thesis, Florida Gulf Coast University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1589202.
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<p> The island apple snail, <i>Pomacea maculata,</i> family Ampullariidae, is a large freshwater gastropod native to South America. <i>P. maculata </i> is known as a heavy consumer of aquatic plants. <i>P. maculata </i> was introduced to Florida in the 1990s and has rapidly spread throughout natural and man-made wetlands and waterways in the southeastern United States. Negative ecosystem impacts associated with <i>P. maculata</i> invasion include destruction of macrophyte communities via overgrazing, competitive exclusion of the native Florida apple snail <i>Pomacea paludosa,</i> and the potential transmission of toxins and parasites to predators. </p><p> Populations of <i>P. maculata</i> have been documented in freshwater tributaries of estuaries such as Mobile Bay, Alabama and the Caloosahatchee Estuary, Florida, and the snails may be moving into the estuaries themselves. The objectives of this study were: 1) to evaluate <i>P. maculata</i>'s potential to harm macrophytes like tapegrass, <i>Vallisneria americana, </i> in low-salinity estuarine environments, 2) to determine how the grazer's destructiveness might by moderated by environmental context (salinity, temperature, and the presence of other macrophyte species), and 3) to identify management and restoration strategies for <i>V. americana</i> to minimize the harm done by <i>P. maculata</i>. We accomplished these objectives with feeding trials and mesocosm experiments conducted under varying conditions of salinity, temperature, and macrophyte community composition. </p><p> We found that increasing salinity lowered <i>P. maculata</i> grazing pressure on <i>V. americana</i> but increasing temperature increased grazing pressure. Herbivory on <i>V. americana</i> was not reduced and was sometimes intensified when other aquatic plant species were present. The results of two mesocosm experiments suggested that salinity and snail presence have a nonadditive, antagonistic, effect on <i>V. americana.</i> I.e., in the absence of snails the plant performed best at 0 psu, whereas when snails were present the plant did best at 5-10 psu due to reduced snail grazing. Due to the significant sub-lethal impacts of salinity on <i>P. maculata</i>'s grazing and health it is unlikely that the snail's invasion will proceed beyond the lowest salinity portions of estuaries. These estuarine regions can therefore serve as a valuable refuge for <i>V. americana</i> populations, providing that effective water management keeps salinity below the approximately 10 psu threshold where significant direct harm occurs to the plants.</p>
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Chang, Tony. "A Spatiotemporal Analysis of Climate Change in the Greater Yellowstone Ecosystem and Its Effects on Pinus Albicaulis." Thesis, Montana State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10282954.
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<p> Climate change is arguably the biggest challenge facing humanity. Successful mitigation and adaption planning vitally requires more science in regard to its impacts on ecological systems. To address knowledge gaps regarding climate change impacts within the regional level, I performed a series of analyses on an "early responder" species in the Greater Yellowstone Ecosystem and examine how its distribution may be impacted by biotic and abiotic factors. My research aids in decision making processes for regional land managers that must address climate change in their policy decisions and increases ecological understanding at a landscape level. </p><p> This manuscript includes a detailed analysis of past, present, and projected climate in the Greater Yellowstone Ecosystem. I addressed the expected impacts of present and future climate shifts on the distribution of the sub-alpine tree species, whitebark pine (<i>Pinus albicaulis</i>) and its main disturbance agent, mountain pine beetle (<i>Dendroctonus ponderosae</i>). This research found a major reduction of suitable climate habitat for <i> P.albicaulis</i> within the Greater Yellowstone Ecosystem under multiple Global Circulation Models and Representative Concentration Pathway futures. Finally, this research determined that the recent <i>D.ponderosae</i> outbreak driven by climate effects in 2000–2010, that resulted in an unprecedented mortality event on <i>P.albicaulis</i> was more than double the risk area size of any previous outbreak since 1951. Although more studies are necessary to reduce uncertainty and make assertive recommendations for management actions, this research suggests that future sub-alpine stand structure and composition may be radically different than anything in recent history due to range shifts of suitable climate habitat and disturbance agents, and advocates for land managers to apply a multifaceted approach of competitor thinning and controlled burning to ensure the resilience and persistence of <i> P.albicaulis</i>.</p><p>
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McCabe, Jennifer D. "Explaining migratory behaviors using optimal migration theory." Thesis, The University of Maine, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10096288.
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<p> Bird migration is the regular seasonal movements between breeding and nonbreeding grounds. In general, birds that breed in the Northern Hemisphere tend to migrate northward in the spring to take advantage of increasing insect populations and lower predation pressures and fly south when food availability and weather conditions decline. Embarking on a journey that can stretch a thousand miles round trip is a dangerous and arduous undertaking. While en route migrants must stop and feed to replenish their depleted energy reserves, often in unfamiliar locations with unknown predation pressures. They also must react to weather conditions during flight and while on the ground. Additionally, areas of high quality habitats where birds can refuel efficiently and safely may be few and far between. Therefore, it's not surprising that mortality rates can be higher during migration than at any other period of the year. Behavioral decisions such as where and where to stop, how long to stay, and when to leave all involve costs and benefits with an ultimate goal to balance the costs and benefits on order to achieve a successful and efficient migration. Optimal migration theory, aims to explain how migrants balance behavioral and physiological parameters of migration that minimize total time spent on migration, total energy expended, or mortality risk. The eventual result of these optimization pressures is thought to be a gradient of behavioral strategies that optimize different combinations of the three currencies: time, energy, and risk. I investigated how migratory behaviors of North American songbirds in the autumn balance the three currencies. More specifically I 1) explored how stopover site selection varies across migratory strategies at the landscape (Chapter 2) and habitat-patch (Chapter 3) scale; 2) investigated the importance of wind for the evolution and maintenance of migratory routes (Chapter 4); and 3) explored how selection of wind conditions for migratory departure affects overall behavioral strategies (Chapter 5). With this research, I hope to further our predictive abilities of migratory behaviors under various environmental and geographic situations using an optimal migration framework.</p>
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Basu, Amitabha Spotila James R. "Development of a 'genetic signature of environmental lead exposure' in wild Peromyscus using combinatorial data from cDNA microarrays and blood metabolites /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2796.
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Tuttle, Graham. "Impacts and Management of the Invasive Russian Olive ( Elaeagnus Angustifolia L.) in a Hereogenous Riparian Ecosystem." Thesis, Colorado State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10604654.
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<p> Russian olive is an exotic actinorhizal tree intentionally introduced to the U.S. in the early 1900’s. It has become a dominant component of riparian ecosystems throughout the western U.S. Unlike most other riparian trees in the semi-arid west, Russian olive germinates and grows both in the open and in the understory of mature cottonwood stands. As an actinorhizal species, it forms an endosymbiosis with soil actinobacteria in the genus <i>Frankia</i> that allows for atmospheric N<sub>2</sub>-fixation. This leads to higher soil N concentrations and mineralization rates underneath the tree’s canopy than outside. Russian olive’s high abundance and impact on soil N suggest it may alter plant communities, but these impacts have not been previously demonstrated. I investigated the impacts of Russian olive on shading, soil N availability, and plant communities and documented how those impacts varied across a semi-arid riparian ecosystem along the South Fork of the Republican River in eastern Colorado. Of the suite of environmental variables I measured, presence or absence of cottonwood canopy had the largest effect on Russian olive impacts. Russian olive increased shading, soil N availability, and proportion exotic plant and forb cover more in the open than underneath a cottonwood overstory.</p><p> Actinorhizal endosymbioses provides an important N source in terrestrial ecosystems, but N<sub>2</sub>-fixation rates decrease due to high exogenous N and low photosynthetically active radiation (PAR). The amount that these environmental variables reduce N<sub>2</sub>-fixation in host-<i>Frankia </i> symbiosis types dictates the strength and duration of those symbioses’ impacts on ecosystems. To understand how the two main types of endosymbioses (<i>Alnus-</i> and <i>Elaeagnus-Frankia</i>) differ in their response to environmental variability, I conducted a greenhouse experiment comparing growth and nodulation between two genera of actinorhizal species, <i> Elaeagnus</i> and <i>Alnus,</i> across exogenous N and PAR levels. Overall, <i>Elaeagnus</i> species had higher nodulation rates and tissue % N than <i>Alnus</i> species. Nodulation rate and growth response to nodulation were both lower at low PAR than high PAR for both genera. The reduction in the growth response to nodulation at high exogenous N was lower in <i>Elaeagnus-Frankia</i> symbiosis than <i> Alnus-Frankia</i> symbiosis. These results suggest that <i>Elaeagnus </i> species are more likely to cause a greater and longer-lasting increase in soil N than <i>Alnus</i> species.</p><p> A main objective of exotic species management is to increase native plant cover. However, few studies monitor plant community response to exotic species management, and the few that have suggest secondary invasion is likely, particularly when effects of the target invasive persists and management efforts cause disturbance. To measure the role of these two factors in plant community response to Russian olive removal, I monitored soil N availability and plant communities along the South Fork of the Republican River two years before and three years after the tree’s removal. Russian olive’s impact on soil N availability persisted, with levels staying high around removed Russian olive stems three years after removal. The plant community around removed Russian olive also had no increase in native plant cover but a dramatic increase in kochia (<i> Bassia scoparia</i>) cover following removal. My research demonstrates that Russian olive increases exotic plant cover in areas it invades and simply removing the tree does not promote native species recovery.</p><p>
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Sloey, Taylor McCleery. "Environmental Constraints on the Establishment and Expansion of Freshwater Tidal Macrophytes| Applications to Restoration Ecology." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10002393.
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<p> The practice of restoration has been called the acid test for ecological theories, as theoretical outcomes may or may not occur in real life scenarios. Regardless, the need for increased communication between theory and practice is necessary to mutually benefit both disciplines. My dissertation research used several major ecological theories to formulate questions regarding environmental constraints on the establishment and expansion of several species of freshwater tidal macrophytes (Schoenoplectus acutus, Schoenoplectus californicus, and to a lesser extent, Typha latifolia). I investigated the response of these species at different life-history stages to various environmental stressors (i.e., degree of soil compaction, flooding duration, and nutrient availability) in both field and controlled greenhouse settings. These studies revealed that adult individuals are more tolerant to environmental stressors than their rhizome or seedling counterparts. Schoenoplectus californicus exhibited superior performance than S. acutus or T. latifolia in when subjected to extreme flooding and stressful abiotic conditions. My research regarding silicon and nitrogen nutrient availability emphasizes the role that Si plays in sustaining Schoenoplectus spp., especially in the presence of high nitrogen concentrations. Finally, my research showed that the species of concern are powerful ecosystem engineers and are capable of ameliorating their abiotic conditions over time. The information presented in my dissertation research provides specific, useful information for freshwater tidal marsh restoration managers and emphasizes the utility of incorporating theory to improve our understanding and stewardship of ecosystems. </p>
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Briland, Ruth. "Evaluating the causes and consequences of ecosystem change in Lake Erie: From plankton to fish." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532076326598788.
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Langendorf, R. E. "Mechanical Inference in Dynamic Ecosystems." Thesis, University of Colorado at Boulder, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10792156.
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<p> Empirical studies of graphs have contributed enormously to our understanding of complex systems, growing into a more scientific exploration of communities spanning the physical, biological, and social called network science. As the quantity and types of networks have grown so has their heterogeneity in quality and specificity resulting in a wealth of datasets that are not matched by existing theoretical methods. This is especially true in ecology where the majority of interactions are indirect and unobservable even in well-studied systems. As a result ecologists continue to grapple with three fundamental questions: Most basically, (i) `How do ecosystems function?' I answered this question by comparing networks to each other such that poorly-studied systems can be understood through their similarity to well-understood ones and theoretical models. To do this I created the alignment algorithm netcom which recasts ecosystem processes as statistical dynamics of diffusion kernels originating from a network's constituent nodes. Using netcom I constructed a supervised classifier which can distinguish processes in both synthetic and empirical network data. While this kind of inference works on currently available network data, I have shown how causality can serve as a more effective and unifying currency of ecological interaction. Measures of causality are even able to identify complex interactions across organizational scales of communities, answering the longstanding question (ii) `Can community structure causally determine dynamics of constituent species?' Moreover, causal inference can be readily combined with existing modeling frameworks to quantify dynamic interactions at the same scale as the underlying data. In this way we can answer the question (iii) `Which species in an ecosystem cause which other species?' These tools are part of a paradigm shift in ecology that offers the potential to make more reliable management decisions for dynamic ecosystems in real time using only observational data.</p><p>
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Wang, Yiwei. "Using novel technologies to confront challenges in predator conservation, community ecology, and citizen science." Thesis, University of California, Santa Cruz, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3617122.
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<p> Habitat fragmentation and loss is the primary driver of mammalian carnivore extinctions across the world. In the Santa Cruz Mountains of California, native carnivores navigate daily through a landscape highly impacted by human development and activities. The puma (<i>Puma concolor </i>) is the apex predator of this habitat, but it is susceptible to both direct and indirect influences of expanding human populations. Smaller predators are not only affected by anthropogenic disturbances, but also by intraguild competition with the more dominant pumas. </p><p> My dissertation utilizes new technologies to study the ecology and behavior of carnivores in a human dominated environment. In my first chapter, I catalogued puma behaviors in the wild using measurements recorded by accelerometers attached to the animals. I found that I could clearly distinguish movement from non-movement behavior, and that predation events had distinctive accelerometer signatures. The second chapter describes how I used movement data recorded by GPS (Global Positioning System) collars to evaluate puma behavioral responses to increasing development. Pumas primarily traveled nocturnally, and moved more often and further in areas of higher housing development. The increase in activity in human dominated landscapes could have major repercussions on the energetic expenditure of pumas living in fragmented areas. My third chapter addresses the impacts of human development and activities on the entire carnivore community. Combining passive and experimental observations using motion-detecting camera traps, I studied the spatiotemporal behavior of predators across a gradient of human influences. Mesopredator activity was restricted temporally in areas of high human use, and certain predators (e.g., pumas and foxes) were more sensitive to increasing development. </p><p> Lastly, education and outreach is an important component of carnivore conservation. In my fourth chapter, I describe results from a Facebook game I developed with collaborators. Players earned points by identifying wildlife species from camera trap photographs. I found that agreement among players was the most important determinant of accuracy, and that untrained Internet users could identify many wildlife species. The Internet is an emerging tool for outreach, and I hope my work encourages other ecologists to think creatively about incorporating citizen scientists into their research through social media.</p>
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Collier, Christopher D. "What are the Impacts of Anthropogenic Nitrogen Deposition on Biological Soil Crust Communities of the Colorado Plateau and the Oak Openings Regions?" University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449441330.
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Hogan, James Aaron. "Revisiting the Relative Roles of Land-Use and the Environment in Subtropical Wet Forest| 21-years of Dynamics from the Luquillo Forest Dynamics Plot, Puerto Rico." Thesis, University of Puerto Rico, Rio Piedras (Puerto Rico), 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1595301.
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<p> The Luquillo Forest Dynamics Plot (LFDP) has played a critical role in the initial discovery and subsequent investigation of many processes that govern tropical island wet forest dynamics. Previous work has identified past land use as the main factor in creating forest community compositional and structural differences across the plot. The responses of different species to past land-use intensity and to hurricane disturbances have created an evolving forest mosaic ideal for studying tropical forest successional dynamics. I revisited the interaction of land-use legacies and natural disturbance in the LFDP with new data and new approaches, with the motivation to reveal new information about the relative roles of anthropogenic disturbance and environmental-niche partitioning on tropical plant communities over time. </p><p> In the context of tropical forests and their successional dynamics, I asked how succession resulting from a history of human land use and more recent hurricanes interacts with background environmental variation to effect community structure and diversity. Community dynamics, in terms of forest structure and composition, were summarized over a twenty-one year period, noticing a decreasing trend in species richness over time and structural maturation of the forest, shown by a decline in small stems (trees < 10 cm diameter) as it recovered from the compound effect of two major hurricane disturbances – Hugo, 1989 and Georges, 1998. We evaluate the magnitude of past human land use effects over time and define indicator species for areas of differing land-use pressure within the 16-Ha permanent LFDP. Using redundancy analysis, plant community-environmental relationships with respect to soils and topography are quantified. Spatial variables, computed using a principle coordinates of neighborhood matrix, explained the majority of the variability in plant community composition between areas of high and low past land-use within the LFDP, meaning environmental differences (e.g. niche differentiation among tree species) were found to be secondary to land-use legacies in determining forest community composition. </p><p> Over two decades, the effect of past land-use peaked about 15-years following the first of two hurricanes, and remained relative stable over time. Despite damaging the forest, hurricanes preserved community differences in species composition and reinforced structural asymmetries due primarily to two species; <i> Dacryodes excels</i> Vahl., a dominant primary forest tree species, and <i> Casearia arborea</i> (Rich.) Urb., an abundant secondary forest species. Abiotic environmental factors (e.g. soil resources and topographic variation) were weak at explaining differences in forest community composition. Plant community-environmental relationships were stronger in more anthropogenically-disturbed areas, suggesting long-term effects of land use on tropical forest communities on current community dynamics.</p>
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Mills, Mystyn W. "Bringing light to below ground patterns| Arbuscular mycorrhizae fungi diversity along an elevation gradient in Southern California." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1597781.
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<p>Necessary for the diversity and survival of most terrestrial plants, arbuscular mycorrhizae (AMF) are fungi that form mutualistic symbiotic relationships with approximately 90 percent of terrestrial plant families. While the biodiversity and abundance of plants and animals have received much attention, these patterns for the belowground organisms on which they rely, such as AMF, remain poorly understood. While studies have found indications that AMF are fundamental to ecosystem structure and function, relatively few of these studies have been conducted in situ. In their ability to accommodate the complexity found in natural ecosystems, in situ studies may be vital in providing information relevant to the restoration and conservation of ecosystems. This thesis sought to explore in situ how AMF diversity and root colonization changed across ecosystems along an elevation gradient in Southern California. The findings indicate that certain soil parameters may be especially influential and that intra-species competition may play a role in AMF root colonization.
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Sommers, Pacifica. "Interacting effects of predation and competition in the field and in theory." Thesis, The University of Arizona, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10007216.
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<p>The principle of competitive exclusion holds that the strongest competitor for a single resource can exclude other species. Yet in many systems, more similar species appear to stably coexist than the small number of limiting resources. Understanding how and when similar species can stably coexist has taken on new urgency in managing biological invasions and their ecological impacts. Recent theoretical advances emphasize the importance of predators in determining coexistence. The effects of predators, however, can be mediated by behavioral changes induced in their prey as well as by their lethality. In this dissertation, I ask how considering multiple trophic levels changes our understanding of how a grass invasion (Pennisetum ciliare) affects species diversity and dynamics in southeastern Arizona. In considering interactions with plant consumers, and with the predators of those consumers, this research reveals more general ecological processes that determine species diversity across biological communities. I first present evidence from a grass removal experiment in the field that shows increased emergence and short-term survival of native perennial plants without grass. This is consistent with Pennisetum ciliare causing the observed concurrent decline in native plant abundance following invasion. I then present results from greenhouse and field studies consistent with that suppression of native plants being driven primarily through resource competition rather than increased rodent granivory. Granivorous rodents do not solely function as consumers, however, because they cache their harvested seeds in shallow scatter-hoards, from which seeds can germinate. Rodents thus act also as seed dispersers in a context-dependent mutualism. They primary granivores in areas invaded by Pennisetum ciliare are pocket mice (genus Chaetodipus), which have a well-studied tendency to concentrate their activity under plant cover to avoid predation by owls. Because the dense canopy of the grass may provide safer refuge, I hypothesized the pocket mice may be directly dispersing native seeds closer to the base of the invasive grass. Such a behavior could increase the competitive effect of the grass on native plant species, further driving the impacts of the invasion. By offering experimental seeds dusted in fluorescent powder and tracking where the seeds were cached, I show that rodents do preferentially cache experimental seeds under the grass. This dispersal interaction may be more general to plant interactions with seed-caching rodents across semi-arid regions that are experiencing plant invasions. Finally, I ask how the predator avoidance behavior exhibited by these rodents affects their ability to coexist with one another. Not only could their diversity affect that of the plant community, but the effects of plant invasions can cascade through other trophic levels. Theoretical understanding of how similar predator avoidance strategy alters coexistence had not yet been developed, however. Instead of a field study, therefore, I modified a general consumer-resource model with three trophic levels to ask whether avoidance behavior by the middle trophic level alters the ability of those species to coexist. I found that more effective avoidance behavior, or greater safety for less cost, increased the importance of resource partitioning in determining overall niche overlap. Lowering niche overlap between two species promotes their coexistence in the sense that their average fitness can be more different and still permit coexistence. These results provide novel understanding of behavioral modifications to population dynamics in multi-trophic coexistence theory applicable to this invasion and more broadly.
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Smart, Wayne Anthoony. "Assessing the Roles of Seabird Harvest and Non-native Rats on Grenadine Seabird Nesting Performance." Thesis, Arkansas State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13813639.
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<p> Seabird populations are declining worldwide. Two major causes of decline are non-native predators and seabird (indirect or direct) overexploitation; these have been suspected but not assessed in the Caribbean region, including in the southern Grenadine islands. Using cameras, questionnaire surveys, and nest monitoring, I explored the potential of invasive predator presence and seabird harvest in affecting nesting productivity of five species in five uninhabited islands during 2014–2017. Overall, nesting productivity increased (n = 567 nests) despite the confirmed presence of non-native rats. However, my survey of Grenada residents (n = 32 responses) and physical evidence found on the islands (e.g., gun shells) suggest that seabird harvest still occur and may be responsible for previous declines. Additionally, most contributors to harvest did not seem aware of any seabird-protective laws. Therefore, I recommend establishing a community-based monitoring program that educates and empowers residents to prevent seabird harvest and continue nest monitoring. </p><p>
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Li, Yueh-Fen. "An Integrated Study on Microbial Community in Anaerobic Digestion Systems." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385850266.
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Morales, Laura V. "Polylepis Regeneration and the Potential for Forest Expansion in the Peruvian Andes| The Influence of Cattle and Environmental Conditions." Thesis, University of California, Davis, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10264075.
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<p> <i>Polylepis</i> forests are a unique high-elevation forests dominated by trees of the <i>Polylepis</i> (Rosaceae) genus found only in South America. These forests are distinctive not only for growing at some of the highest elevations in the world, but because they are distributed as isolated forest islands inside a landscape otherwise dominated by grasses. This distribution is due in part to human disturbance on the landscape and there is interest in restoring cover of <i>Polylepis</i>. Understanding of regeneration dynamics and seedling ecology of <i>Polylepis</i> can help in the management of forests and the restoration of this forest cover, but there are important gaps in knowledge regarding theses aspects in most species. For the expansion of forest cover into current grassland areas, it is important to understand the ability of seedlings to colonize, survive and grow in these areas and identify important biotic and abiotic barriers to this. In this dissertation, I contribute to our understanding of these ecological aspects for two species of <i>Polylepis</i> (<i>P. sericea </i> and <i>P. weberbaueri</i>) using a series observational studies and manipulative experiments in forests found between 4000–4500 masl in Huascaran National Park (Ancash, Peru). </p><p> In Chapter 1, I surveyed patterns of seedling dispersion across forest-grassland boundaries along the elevational gradient and identified significant associations of seedling densities to environmental covariates at local and landscape scales. I found that seedling densities of both species decrease drastically at the edge of the forest canopy, and few seedlings are found in the grassland even within meters of the forest, suggesting significant barriers to seedling establishment in the grassland. Additionally, seedling densities of each species showed patterns with elevation and solar irradiation that mirrored those of adult distributions on the landscape and were different from each other, suggesting that each species has unique environmental tolerances that manifest in the seedling stage and are important to consider in their management and restoration. </p><p> In Chapter 2, I used a series of livestock exclusion experiments to examine the influence of domestic livestock on natural regeneration inside and outside the forest and test the hypothesis that livestock are a significant barrier to seedling establishment at forest-grassland edges. After one year of livestock exclusion, I found only partial support for this hypothesis. In <i>P. sericea</i> forest stands, seedling densities increased, and recruitment and seedling growth was higher in fenced grassland areas. However, in <i> P. weberbaueri</i> stands there was little change in juvenile densities and no differences in seedling performance, except that recruitment was lower in fenced forests areas compared to unfenced forest. This showed that the influences of livestock on <i>Polylepis</i> seedling may be different depending on the habitat and species of <i>Polylepis</i>. Additionally, we found that seedling survival was surprisingly high, and similar between forest and grassland habitat. </p><p> In Chapter 3, I used sowing and “wildling” transplant experiments within the previous exclosure experiments to tease apart early ontogenetic filters to seedling establishment in the grassland compared to the forest. I found that the seedling emergence stage is a strong bottleneck for seedling establishment in the grassland. Furthermore, I found that <i>P. weberbueri </i> seedling density inside the forest appears to be seed limited, and can be increased by sowing. Transplanted seedlings survival was lower than found previously for natural seedlings, but was also similar between both habitats. However, it appears that livestock depresses <i>P. sericea </i> transplant survival inside the forest. Only <i>P. weberbueri </i> seedlings showed differences in growth between habitats, declining in height in the grassland, but there was only evidence that livestock suppressed growth. I concluded that seedling transplant will be the most efficient way to increase seedlings in the grassland for restoration. </p><p> Together, the results of this dissertation suggest that both unassisted and assisted expansion of natural <i>Polylepis</i> forests faces significant barriers, in particular low seedling emergence in grassland is a strong bottleneck to establishment in this habitat. It remains unclear whether livestock are generally a barrier to forest expansion, as their effects appear to be specific to each species of <i>Polylepis</i>. Here, <i> P. sericea</i> appears to be more sensitive in both forest and grassland to livestock activity than <i>P. weberbaueri</i>, but future work should address longer-term effects of livestock exclusion to confirm the population trajectories observed after one year. Finally, wilding transplants of these species can be used in restoration to overcome the barrier emergence poses to <i>Polylepis</i> establishment in grassland, although with further research, seeding schemes may prove a viable strategy</p><p>
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Brister, Evelyn. "Presettlement Forest Composition in the Connecticut Tract of Western New York." Thesis, Rochester Institute of Technology, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10020365.
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<p> This study of the vegetation of the 100,000-acre Connecticut Tract in western New York examines the presettlement characteristics of the forest, including the tree species composition, tree density, and wetland extent. Presettlement vegetation studies add to what is known about the forests of this region before European settlement in the early 1800s brought widespread changes to these forests. The ecological data in original private land surveys from 1811 were transcribed and then analyzed using ArcGIS and IDRISI GIS software. The surveys contained both witness tree data and line descriptions, which were analyzed for species composition and community type and were compared with Forest Inventory and Analysis (FIA) data about the contemporary forest in the study area. The community type results together with surveyor notes were used to extrapolate wetland coverage, which was compared with the 2006 National Wetlands Inventory Database.</p><p> This study fills in missing historical data between the two largest land purchases in western New York and examines forest composition at a finer-grained scale than surveys of those land purchases. Comparing past and present vegetation clarifies past causes of temporal and spatial variability and provides a reference point for land managers who need to understand the effects of land-use history for ongoing restoration efforts.</p>
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Brandt, Erika. "Relating Plant Spatial Pattern, Plant Biodiversity, and Ecosystem Function to Management Practices in Experimental Restored Wetlands." Oberlin College Honors Theses / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1368092195.
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Buchholz, Seth D. "Rapid Cyanotoxin Detection Technology in Routine Monitoring and Citizen Science Groups." Bowling Green State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1616074976068045.
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Maurer, Kyle D. "Effects of Climate, Forest Structure, Soil Water, & Scale on Biosphere-Atmosphere Gas Exchange in a Great Lakes Mixed-Deciduous Forest." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366036482.
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Jackwood, Ryan. "Predicting Fate and Transport of Fecal Bacteria through Soils Using an Advection-Dispersion Model." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1384519085.
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Marshall, Nathaniel T. "Advancing Genetic Analyses and Implementing eDNA Metabarcoding for InvasiveSpecies Detection and Macroinvertebrate Community Composition." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1556893201129347.
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Rosam, Jodie Ray. "Assessment of light quality, variability, and seedling presence in Hawaiian lowland wet forests." Thesis, University of Hawai'i at Hilo, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1596447.
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<p>Hawaiian lowland wet forest (HLWF) plant species are light-limited, yet no information exists on how the understory light varies in relation to species invasion, or if patterns of seedling regeneration and light are linked. I measured the red-to-far-red ratio (R:FR) of light to assess light quality and quantified diurnal variability in three forest types: native-dominated, partially-invaded, and fully invaded by strawberry guava (Psidium cattleianum). I asked: (1) how does understory light quality vary relative to invasion? (2) Are there differences in light quality moving vertically among forest types? (3) Are patterns of seedling regeneration and understory light related? Native-dominated forests had the greatest light quality (highest R:FR), and Psidium cattleianum-dominated forests had the lowest. While I predicted that native seedlings would prefer high-quality light sites, all seedlings preferred medium quality environments. In invaded HLWF, native seedling regeneration is hindered, and restoration efforts should focus on non-native understory removal.
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LaCivita, Lisa Frances. "Amphibian Monitoring for Ecosystem Services, Citizen Engagement and Public Policy." Thesis, George Mason University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13421066.
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<p> This dissertation has both science and policy components. The research examines the presence or absence of two amphibian species in one Virginia County. Two amphibian species <i>Pseudacris crucifer</i> (Spring Peeper) and <i>Hyla versicolor</i> (Gray Tree Frog) are proposed to serve as a biotic indicator, or proxy, for water quality/watershed condition and ecosystem services. My dissertation hypothesized that amphibian presence of the target species would correlate with watershed integrity values, which was verified by statistical analysis. Greater amounts of amphibian presence correlated with higher watershed integrity scores. Detailed studies of amphibian occurrence, with continued monitoring, can document trends and behaviors of the target species. Facing concern for thresholds and factors that allow or limit amphibian presence, amphibian monitoring contributes to our understanding of anthropogenic impacts on biotic communities. </p><p> Both of the targeted amphibian species were distributed county-wide; occurrences were recorded in each of the major sub-watersheds. Areas surrounding the monitored road segments were calculated (using GIS technology) for the amount of areas assigned to one of four watershed integrity values. Amphibian occurrences correlated with watershed integrity scores using Spearman Rank Correlation. </p><p> What it means to possess watershed integrity sufficient to host amphibian populations brings science into the realm of public policy. Values, economics, demographics, education, politics and culture come into play. Watershed integrity, water quality and ecosystem condition, function and services directly impact human health and wellbeing, and can have profound influences on economic and cultural circumstances. </p><p> County-wide amphibian monitoring can establish an important baseline for ecological conditions, with the potential for citizen engagement. It is one more portal through which citizens may connect with the natural world. Connections to nature, along with environmental literacy and forward-looking public policies will be required to protect the ecosystem services upon which our communities depend. Monitoring for two or three amphibian species from public roads can become a citizen science effort that raises awareness of water resource issues. Aware and engaged citizens are needed to inspire governments and elected representatives to plan for 21<sup>st</sup> century conditions and sustainability. If engaging citizens, of all ages, in the workings of their own watershed will deepen their understanding of this vital, complex and dynamic system, then we may realize higher levels of water stewardship and sustainability.</p><p>
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Wang, Kai. "INTERACTIONS OF CYANOBACTERIA AND CO-OCCURRING MICROORGANISMS DURING CYANOBACTERIAL HARMFUL ALGAL BLOOMS." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1619622253977384.
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Pearl, Benjamin G. "Factors affecting Western Snowy Plover winter foraging habitat selection in San Francisco Bay ponds." Thesis, San Jose State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10011661.
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<p>Within the San Francisco Bay Area, Western Snowy Plovers (<i>Alexandrinus nivosus nivosus</i>) nest and winter in former salt ponds. They face a number of threats including human-altered habitats and high levels of predation by mesopredators and raptors. The South Bay Salt Pond Restoration Project (the Project) is a large wetland restoration project that will change and potentially eliminate Snowy Plover habitat in the region. As the Project returns salt ponds to tidal wetland, there will be less of the dry, flat, and sparsely vegetated habitat that plovers need for breeding and wintering habitat. A greater understanding of the specific microhabitat requirements for high quality plover foraging sites is needed. In particular, it is important for managers to understand what constitutes high quality wintering habitat for Snowy Plover numbers. This study assessed the characteristics at sites where Snowy Plovers winter in former salt ponds, especially habitat traits related to promoting plover foraging. Analysis of plover foraging habitat showed that plovers were associated with increasing plant height, water cover, and distance from perches and levees. This information is designed to inform restoration and management decisions in efforts to meet Snowy Plover recovery goals in the South San Francisco Bay. </p>
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Rahn, Matthew Edward. "Evaluating science and policy : conservation planning and the Endangered Species Act /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Bissonnette, Jennifer Newton. "An analysis of wetland patterns and functions at the watershed and sub-watershed scales, with *policy applications." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539616569.
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This dissertation addresses the need to define potential impacts of recent and proposed changes in federal wetland regulation in a quantifiable manner. Consideration was made not only of total wetland acreage and wetland types that could sustain losses, but also to categorize the effect such losses would have in terms of wetland functions, at the watershed scale. This work took a Geographic Information Systems (GIS) approach, and included employing a best-professional judgment model for scoring habitat, water quality and flood attenuation functions to determine potential cumulative impacts; a water quality study which related wetland and watershed variables to nutrient and sediment loads; and an amphibian metapopulation model to determine the effects of loss of landscape connectivity resulting from wetland management decisions. The study area encompassed several watersheds in Southern Virginia, USA. Results from best professional judgment model show that despite a decrease over the years in acreage receiving reduced regulatory protection, the functional caliber of wetlands afforded the least protection is actually higher with each new implementation of regulatory criteria. These results, and the results of similar models, updated as more information and data sets become available, should be a valuable tool for both regulators and managers at local, as well as regional and The water quality model reduced 41 wetland and watershed variables to 5 principal components, which were then used in regression equations to relate the variables to nutrient and sediment loads. Although differing variables played roles in different water quality components, the overriding factor affecting improved water quality related to the proportion of vegetated area found within a 100 meters of stream courses, with negative water quality related to the proportion of developed to vegetated areas within the 100 meter buffer. Results from the amphibian habitat model highlight the importance of the pattern of wetlands across the landscape. Removal of wetlands smaller than 0.5 acres had a greater influence on occupancy rates in all wetlands, presumably due to their position providing between wetland connectivity. Policy and management decisions should be altered to consider each of these conclusions if functional conservation is to be achieved.
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Perez, Rojas Nadejda. "Biogeochemistry of iron and phosphorus in soils impacted by penguin colonies in Antarctica." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27646.
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Penguin colonies from permanently cold environments have a strong impact on their surrounding ecosystem because their excrements provide ample nutrients to the soils and sediments. The high phosphate content of the penguin guano directly affects primary productivity. However, phosphate solubility is dependent on the presence of iron and other metals, which can form stable PO4-rich minerals. Phosphate can also be sorbed onto minerals, including iron oxides. The present study investigated the biogeochemistry of phosphorus in a 42 cm-deep soil profile on Gardiner Island in Antarctica in order to assess the effect of penguin excrements on P partitioning in the solid and aqueous phases. The results indicate that the porewaters were slightly acidic (pH 5-6) and contained extremely high levels of dissolved organic carbon (DOC; 120 mM), PO4 (120 mM), SO4 (27 mM), NO3 (18 mM), Cl (320 mM), F (2 mM), Sr (0.10 mM), Ca (18 mM) and Mg (150 mM) at the top of the soil profile. Dissolved iron concentrations were generally low (< 0.04 mM) and increased at a depth of 15-20 cm and at the bottom of the profile. Chemical extraction revealed the presence of two zones of reactive phosphorus (P-ascorbate extractable fraction) in the soil profile, i.e., at the surface and between 16 and 20 cm. Enriched reactive and crystalline iron fractions were also present at a depth of 16-20 cm, but fluctuated throughout the profile. The Fe(II)/Fe(III) molar ratio of the soil was greater than 1 at the surface of the profile and declined with depth. X-ray diffraction analysis showed that the soil likely contained berlinite, strengite and vivianite, along with silicates and quartz. Saturation index calculations also indicated that Ca and Mg-rich phosphate minerals were likely present in the soil. Based on the above results, the presence of penguin colonies on Gardiner Island strongly impacted the geochemical and mineralogical composition of the soil, as observed in other studies on bird guano impacted (ornithogenic) soils. In addition, the presence of both Fe(II) and Fe(III) points to the fact that the soil undergos redox changes, likely as a result of seasonal water table fluctuations. Microcosm experiments with selected samples from the soil profile and an iron-reducing bacterium indeed showed that iron and phosphorus were released into solution as a result of microbial iron reduction. However, abiotic systems also showed a release of phosphorus indicating that non Fe-rich phosphate minerals are soluble under the conditions prevailing in the growth medium.
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Russell, Gabrielle Nicole. "The Impact of Woody Debris on Bank Stability and Macroinvertebrates in IntermittentHeadwater Streams within the Western Allegheny Plateau." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1524857157950265.
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Gentilcore, Dominic M. "Response of Pinyon-juniper woodlands to fire, chaining, and hand thinning." Thesis, University of Nevada, Reno, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1591350.
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<p> Pinyon-juniper (<i>Pinus monophylla – Juniperus osteosperma</i>) woodlands have expanded and infilled over the last 150 years to cover more than 40 million ha in the Great Basin. Many land managers seek to remove Pinyon-juniper trees using a variety of treatments. This thesis looks at six different Pinyon-juniper removal projects in Central and Eastern Nevada. We established a total of 73 vegetation and soil monitoring plots (38 treated, 35 adjacent untreated) across six Pinyon-juniper removal projects in Central and Eastern Nevada to look at the effects of fire, hand thinning, and chaining. The four burns examined together in Chapter 1 had similar elevation, precipitation, and pre-treatment vegetation communities in the untreated areas, but the treated areas had significantly different responses to treatment. With nonmetric multidimensional scaling (NMS), we found a useful 3-axis ordination of the plots (stress=7.1, R<sup>2</sup>=.966). Within ordination space, the treated plots were well grouped by parent material. These results informed a Poisson generalized linear model that found parent material factorized explained 86.5% of the deviance in cheatgrass (<i>Bromus tectorum</i>) cover at the treated plots. The projects on soils derived from welded tuff had very little cheatgrass while soils derived from limestone or mixed limestone/volcanics were dominated by cheatgrass. Parent material should be considered an important factor when planning Pinyon-juniper removal treatments. Chapter 2 examined the effects of a hand thinning. The hand thinning significantly reduced tree cover [F(1,10) = 7.43, p = 0.027] to less than 2%. Perennial grasses on the site are slightly higher in the treated area. There was a significant increase in perennial grass cover from 2013 to 2014 [F(1,10) = 14.5, p = 0.003]. The hand thinning did not have significant effects on shrubs, annual grasses, annual forbs, perennial forbs, ground cover, stability, species richness, diversity, infiltration, or gap structure. Because hand thinning does not remove the shrubs or other perennials, site resistance can be maintained. With sufficient understory vegetation to maintain resistance post treatment (as in phase I or early phase II Pinyon-juniper woodlands), nonnative annual grasses are less likely to dominate after treatment. Chapter 3 examined the effects of a chaining. The effects of the 40-year old chaining are still significant even though Pinyon-juniper trees are reinvading and make up >5% of the cover in the treated area. The treated areas still have a much more productive understory than adjacent untreated areas. Perennial grass cover, frequency, and density was 2-5 times greater in the chained area. The treated area had fewer large gaps (>100 cm). However, interspace infiltration times were slower in the treatment (t(4)=-2.14, p=0.09). Surface and subsurface soil aggregate stability remained significantly lower in the treatment for vegetation-protected and unprotected samples (t(4)=3.53, p=0.024; t(4)=3.10, p=0.036). Chainings have long-term benefits for vegetation, but also long term impacts on soils and hydrologic ecosystem processes. When planning Pinyon-juniper removal treatments, land managers should consider the plant community, temperature and precipitation regime, and soils at the potential treatment location to better achieve desired outcomes.</p>
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Greenlee, Erin Symonds. "The Effects of a Warming Climate on the Migratory Strategies of a Putatively Non-Migratory Bird, the Gray Jay (Perisoreus canadensis)." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338485900.
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Guiher, Sara Nicole. "A Regional Management Strategy for Invasive Plants in the Oak Openings." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1503607896706064.
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Garcia, Jessica. "The Effects of Microcystin from Harmful Algal Blooms on the Immune Functioning of Aquatic Turtles and Tadpoles." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo154720353177829.
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Hough-Snee, Nathaniel. "Relationships between Riparian Vegetation, Hydrology, Climate and Disturbance across the Western United States." Thesis, Utah State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10154374.
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<p> Flow regime, the magnitude, duration and timing of streamflow, controls the development of floodplain landforms on which riparian vegetation communities assemble. Streamflow scours and deposits sediment, structures floodplain soil moisture dynamics, and transports propagules. Flow regime interacts with environmental gradients like climate, land-use, and biomass-removing disturbance to shape riparian plant distributions across landscapes. These gradients select for groups of riparian plant species with traits that allow them to establish, grow, and reproduce on floodplains – <i>riparian vegetation guilds.</i> Here I ask, <i>what governs the distributions of groups of similar riparian plant species across landscapes?</i> To answer this question, I identify relationships between riparian vegetation guilds and communities and environmental gradients across the American West. In Chapter One, I discuss guild-based classification in the context of community ecology and streams. In Chapter Two, I identified five woody riparian vegetation guilds across the interior Columbia and upper Missouri River Basins, USA, based on species’ traits and morphological attributes. I modeled guild occurrence across environmental gradients, including climate, disturbance, channel form attributes that reflect hydrology, and relationships between guilds. I found guilds’ distributions were related to hydrology, disturbance, and competitive or complementary interactions (niche partitioning) between co-occurring guilds. In Chapter Three, I examine floodplain riparian vegetation across the American West, identifying how hydrology, climate, and floodplain alteration shape riparian vegetation communities and their guilds. I identified eight distinct plant communities ranging from high elevation mixed conifer forests to gallery cottonwood forests to <i>Tamarisk</i>-dominated novel shrublands. I aggregated woody species into four guilds based on their traits and morphological attributes: an evergreen tree guild, a mesoriparian shrub guild, a mesoriparian tree guild, and a drought and hydrologic disturbance tolerant shrub guild. Communities and guilds’ distributions were governed by climate directly, and indirectly as mediated through streamflow. In Chapter Four, I discuss the utility of guild-based assessments of riparian vegetation, current limitations to these approaches, and potential future applications of the riparian vegetation guild concept to floodplain conservation and management. The classification of vegetation into functional trait-based guilds provides a flexible, framework from which to understand riparian biogeography, complementing other models frameworks for riparian vegetation.</p>
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Millet, Stephen. "Divergence and disagreement in contemporary anarchist communism : social ecology and anarchist primitivism." Thesis, University of Central Lancashire, 2002. http://clok.uclan.ac.uk/1749/.
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The strand of Nineteenth-Century Anarchism known as Anarchist-Communism conceived of the abolition of both state and market, and their replacement by a system of free distribution of goods organized through federated communes. While briefly this was the most developed and sophisticated strand of anarchism, it suffered an eclipse in the face of both the failure of the Russian Revolution, and the rise of the essentially a-theoretical industrial syndicalism that blossomed in many countries during the early decades of the twentieth century. With the expansion of the state and capitalism after WWII new forms of contestation appeared, most notably, in terms of Anarchist Communist theory, in the United States. In the 1960s and 1970s two currents emerged which represented the first significant development in anarchist communist theory for fifty years. These were the Social Ecology of Murray Bookchin, and a current which grew up around the Detroit underground paper Fifth Estate, later known as "Anarchist Primitivism". It is these two strands that are the subject of this research. Not surprisingly these two perspectives, appearing around a decade apart, and both in the same country, dealt with many of the same issues. What is more surprising is that in virtually every area, the conclusions they arrive at are completely different. In this research I locate these two strands historically as developments of Anarchist Communist theory, and examine their theories in four key areas: The Primitive, History, Reason and Rationality, and Technology. Examination of these areas serves to define the projects themselves, as well as highlighting how they disagree. To explain why they disagree, this work uses a methodological approach suggested Quentin Skinner. Skinner argued that in order to fully understand a text in the history of ideas, it is necessary to understand the author's intention in writing it. The study therefore examines not only the texts, but also the backgrounds of the writers concerned, their aims in producing it, and their approaches to debate with other theorists and perspectives. Through a combination of textual analysis and recovering the intentions of the writers, the high levels of disagreement can be accounted for.
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Smith, Joseph Stephen. "The Impact of Green Infrastructure on Stormwater Quality: A Sewershed-Scale Analysis of the Effects of Blueprint Columbus on Nutrients, Sediments, and Metals." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587651880895345.
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Thompson, Danielle Kaye. "Amphibian and Reptile Species Survey and Habitat Assessment: Incorporating Environmental Education and Outreach." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1208912407.
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