Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 113 for “"Natural ecosystems"”.
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Simultaneous determination of nitrous oxide and ammonia for measurement of in-situ fluxes from natural ecosystems by gas chromatography with headspace autosampler and electron capture detection
<p>Anthropogenic disturbance of the soil nitrogen cycle by changes in nitrogen and carbon availability influences the production of N2O and NH 3 emissions to the atmosphere affecting the environment and human health. This dissertation presents a new method for automated gas chromatographic analysis …
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Remote Sensing & GIS for Land Cover/ Land Use Change Detection and Analysis in the Semi-Natural Ecosystems and Agriculture Landscapes of the Central Ethiopian Rift Valley
… countries. The terrestrial and aquatic ecosystems in Abijjata Shala Lakes National Park (ASLNP) and the Important Bird Areas (IBAs) around the park are considered to be one of the most important home ranges for birds. However, little is known about the effect of land use/land cover …
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Carex establishment on reclaimed oil sands landscapes : a case study at Suncor Energy Inc.
… to be low in plant diversity compared with naturally occurring plant communities. Approximately 66 Carex species inhabit the oil sand region. This thesis is unique and represents the first large scale study of Carex establishment on reclaimed oil sands landscapes. Research compared diversity …
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Grass invasion in urban lowland fynbos fragments on the Cape Flats : does nutrient addition play a role?
Invasion by exotic grasses is a major threat to natural ecosystems in many parts of the world. On the Cape Flats in Cape Town, grasses were observed to be invading lowland fynbos fragments which are a high priority for conservation. The observation in other parts of the world that nutrient …
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Fate of genetically modified plant tissue in soil: what happens to the DNA
… risen over genetically engineered DNA entering natural ecosystems. This work focused on modeling the fate of transgenic DNA released from plant tissue into the soil"--Abstract, page iii.
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Simulation, sensitivity analysis, and optimization of bioprocesses using dynamic flux balance analysis
Microbial communities are a critical component of natural ecosystems and industrial bioprocesses. In natural ecosystems, these communities can present abrupt and surprising responses to perturbations, which can have important consequences. For example, climate change can influence drastically the …
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Ghost Forests of the Mid-Atlantic : how sea-level rise is killing our coastlines
… of the disruptive changes in store for both natural ecosystems and human habitation. Dying coastal forests herald other coastal landscape changes: after the forests start to die, so do the marshes that live in zones between ocean and forest. As sea-level rise and human development combine to …
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Evolutionary responses to global change: an experimental test of the effect of altered precipitation on hybridization rates in sunflower (Helianthus)
Climate change is rapidly altering natural ecosystems. Plastic and adaptive responses to climate change (i.e., range shifts and phenology) have been widely noted across taxa. However, the effects of climate change on evolutionary processes such as interspecific gene flow (hybridization) are less …
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Identification of Quorum Sensing Genes in Hypersaline Microbial Mats
… ultimately define the overall functionality of ecosystems. Bacterial communities in all ecosystems likely utilize signaling pathways to adapt to localized changes in environmental conditions. One such pathway is called quorum sensing (QS), a cell-density dependent phenomenon involving the …
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Diversity, variability and persistence elements for a non-equilibrium theory of eco-evolutionary dynamics
Natural ecosystems persist in variable environments by virtue of a suite of traits that span from the individual to the community, and from the ecological to the evolutionary scenarios. How these internal characteristics operate to allow living beings to cope with the uncertainty present in their …
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One Size Doesn't Fit All: Developing Bioavailability-based Models for Zinc Toxicity to Microalgae
… industrialisation are intensifying pressures on natural ecosystems. This includes metal contamination in freshwater environments. Australia is a major miner and refiner of zinc ore. These operations could lead to increased risk of zinc contamination to freshwater systems due to spills, discharge …
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From microbiome diversity to endophyte ecology in the wild grass Agrostis capillaris
… for studying plant-microbiome interactions in natural ecosystems. This thesis is of interest to ecologists seeking to understand the dynamics of the plant microbiome in the wild, as well as to the phytopathologists working with the Zymoseptoria genus.
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Uso de técnicas espectroscópicas no estudo de solos em diferentes feições geomorfológicas na microbacia de vaca brava, AREIA - pb.
… caused significant changes in the dynamics of natural ecosystems. As a result of the adoption of intensive mechanization and inadequate management, soil presents changes in its physical, chemical and biological, losing nutrients, organic matter and thereby reducing crop yields. Therefore, …
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Susceptibility Of Headwater Catchment Hydrology To Persistent Droughts And Forest Structure Modification - A Plot To Catchment Scale Analysis
… United States are critical environments to natural ecosystems and are a vital component of water resources to many communities and industries and may be strongly affected by changing climate and altered disturbance regimes. To better quantify how these systems may be affected by climate …
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Systems approaches to infer microbial community interactions and their impacts on ecosystem function
… challenges in human health and the health of natural ecosystems. Here, I show how systems approaches can be leveraged to overcome the inherent limitations of inferring microbial community interactions directly from correlation structure, which has been the standard approach in the microbiome …
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The productive landscape : wetland rehabilitation at the lower reaches of the Liesbeek River
… site works, that embodies the process of natural water filtration, using water from the Liesbeek River. Natural ecosystems are restored through the cultivation of endangered wetland plants in controlled growing beds for wetland rehabilitation on the site. Filtered water from the …
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Propagation from meteorological drought to agricultural drought under climate change
… that is the pathway to impacts on crops and natural ecosystems, and water resources (e.g., aquifer recharge).
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Blood host preferences and competitive inter-species dynamics within an African malaria vector species complex inferred from signs of animal activity around aquatic larval habitats distributed across a gradient of fully domesticated to fully pristine ecosystems in southern Tanzania
… or blood utilization behaviours in pristine natural ecosystems, where these known preferred hosts are scarce or completely absent. This study investigated larval habitat occupancy and species composition of the An. gambiae complex, together with the availability of various potential mammalian …
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Wolves and Livestock: A review of tools to deter livestock predation and a case study of a proactive wolf conflict mitigation program developed in the Blackfoot Valley, Montana
… native predator that have top down effects upon natural prey species. This in turn affects the web of plants and animals that make up natural ecosystems. This fact, as well as the strong emotional connection that some stakeholders have to wolves creates a tense value laden debate when wolves come …
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Wolves and Livestock: A review of tools to deter livestock predation and a case study of a proactive wolf conflict mitigation program developed in the Blackfoot Valley, Montana
… native predator that have top down effects upon natural prey species. This in turn affects the web of plants and animals that make up natural ecosystems. This fact, as well as the strong emotional connection that some stakeholders have to wolves creates a tense value laden debate when wolves come …
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