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 92 for “"tundra"”.
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Remote sensing characterisation of the forest-tundra ecotone
… zone between the boreal forest and Arctic tundra, the Forest-tundra ecotone (FTE), is an area of high ecological and climatological significance. Satellite remote sensing has the potential to enable accurate circumarctic mapping and characterisation of both latitudinal and altitudinal FTEs. …
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Higher fungi in soils of coastal Arctic tundra plant communities
… was determined in North American coastal Arctic tundra soils near Barrow, Alaska. Soils were examined at one centimeter intervals from the surface to the depth of thaw, 0-24 cm, over a three year period during the International Biological Programme Tundra Biome study. Examined were 1217 soil …
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In situ carbon dioxide flux from Arctic tundra during freeze- up
… cores was examined during freeze-up of arctic tundra. Three habitats which dominate tundra topography, polygon trough, ridge and basin, produced significantly different amounts of CO₂ when soil temperatures were above 0 C. A significant positive correlation between soil temperatures between 10 …
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Runoff from hummock-covered Arctic tundra hillslopes in the continuous permafrost zone
… within a 95 ha catchment (Siksik Creek) in the tundra region of the Canadian western Arctic were studied for three years (1992-1994). Measurements over the study included all hydrological inputs, monitoring of active layer and water table depths, chemical tracer-based measurements of subsurface …
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Religious Conversion and Nenets Bricolage: Making Modernity in the Polar Ural Tundra
… among the Nenets people living in the Polar Ural tundra. In the post-Soviet period new opportunities have been created for cross-cultural interaction, revealing a global religious market place and opening up Siberia to an ‘army’ of missionaries from different countries, making the Polar Urals a …
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Land-atmosphere exchange of carbon in a high-Arctic wet tundra ecosystem
… methane (CH4), was measured in a high-Arctic wet tundra ecosystem (Rylekærene) in Zackenberg, north-eastern Greenland. Rylekærene was a heterogeneous area concerning the source strength of CH4 and concerning which environmental variables that best determine the CH4 fluxes. For the central parts of …
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Investigating ecological drivers and impacts of vegetation change in sub Antarctic tundra
Understanding the impact of environmental change on vegetation dynamics requires considering the individualistic responses of plant species, which are influenced by their specific habitat requirements and biotic interactions. For instance, habitat generalist species often have broad environmental …
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Arctic shrub growth responses to environmental drivers and implications for tundra community decomposition
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-05-01
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The role of acid phosphatases in the phosphorus nutrition of arctic tundra plants
… with two major rooting strategies in arctic tundra plants was examined: that of Eriophorum vagina tum, a dominant plant in tussock tundra ecosystems, with its predominantly non-mycorrhizal root system; and that of ectomycorrhizal roots. Eriophorum has phosphatase activity which is evenly …
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Ground-based hyperspectral and spectro-directional reflectance characterization of Arctic tundra vegetation communities : field spectroscopy and field spectro-goniometry of Siberian and Alaskan tundra in preparation of the EnMAP satellite mission
The Arctic tundra, covering approx. 5.5 % of the Earth’s land surface, is one of the last ecosystems remaining closest to its untouched condition. Remote sensing is able to provide information at regular time intervals and large spatial scales on the structure and function of Arctic ecosystems. But …
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Nitrogen uptake patterns by snow addition in a sub-Arctic dry heath tundra ecosystem
The Arctic heath tundra ecosystem is undergoing rapid transformations driven by climate change,which particularly affectssnow accumulation and the length of the growing season. In this study, I examined the influence of snow depth on parameters such as water content, soil temperature, microbial …
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The modeled effects of fire on carbon balance and vegetation abundance in Alaskan tundra
… the world. Changes have been observed within the tundra that are attributed to this trend, including active layer thickening, shrubland expansion, and increases in fire frequency. Whether tundra remains a global net sink of carbon could depend upon the effects of fire on vegetation, specifically …
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Tundra fire driven surface subsidence increases spectral diversity on the Yukon-Kuskokwim Delta, Alaska
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-03-01 without embargo terms
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Exchange of radiatively active trace gases in tundra environments, with particular attention to methane
This thesis is concerned with trace gas flux in tundra environments, the main subject of study being methane. Methane emission from tundra soils has in recent years attracted increasing attention due to the possible associated feed-back effect on man-made climate change. The presented data are …
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Estimation of microbial biomass in natural and perturbated tundra by the ATP bioluminescence assay
Arctic north slope tundra soil was found to contain sufficient microbial biomass for decomposition indicating that the slow decomposition of the tundra may be due to inhibited metabolic activity. Samples were collected from the International Biological Program Tundra Biome site at Barrow, Alaska …
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Soil phosphatases: factors affecting enzyme activity in Arctic tussock tundra and Virginia mineral soils
The effect of pH, temperature, substrate concentration, and orthophosphate on abiontic phosphomonoesterase activity was examined in disturbed and undisturbed Arctic soils with variable moisture content and in Virginia forest, grassland and agricultural soils. Distribution of acid and alkaline …
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Spruce bark beetle disturbance in the forest-tundra ecotones of southwest Yukon: impacts and predisposing factors
… factors that may have predisposed the forest-tundra ecotones of southwest Yukon to spruce bark beetle (Dendroctonus rufipennis) infestation, and investigated the subsequent effects of insect disturbance on the growth and establishment of white spruce (Picea glauca). Specific objectives were to …
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Fine-Scale Mechanisms Influencing Germination Success, Seedling Growth and Survival in an Alpine Forest-Tundra Ecotone
… than 2% of all seeds were dispersed into alpine tundra. Additionally, germinant losses were also one third higher when seedlings were not protected from predators. (2) Germination success was highest in partially scarified quadrats relative to unscarified and completely scarified quadrats. This …
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Trapped? Evidence of changes in relative plant abundance after long-term grazing exclosure across the Tundra.
… to long-term grazing exclusion is across the tundra biome. This thesis aims to review the current grazing literature to identify if similar situations are happening elsewhere in the tundra. I reviewed articles that experimentally excluded large and medium herbivores for ten or more years. The …
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