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Showing result 1 - 5 of 33 swedish dissertations matching the above criteria.

2. 1. Circumpolar impacts of herbivores on Arctic tundra vegetation

   Author : Elin Lindén; Johan Olofsson; Maja K. Sundqvist; Mariska te Beest; Elisabeth S. Bakker; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; herbivores; grazing; Arctic; circumpolar; tundra; vegetation; plant defence; secondary metabolites; shrub birch; exclosures; vegetation; species diversity; biology; biologi;

   Abstract : Arctic tundra vegetation provides many ecological services that have implications for the global climate. However, the tundra biome is currently changing in response to increasing temperatures. Herbivores may mitigate some of these responses to warming through their impact on Arctic vegetation. READ MORE

4. 2. Geophysical Applications of Vegetation Modeling

   Author : Jed O Kaplan; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Environmental chemistry; Växtbiokemi; Plant biochemistry; CH4; CO2; stable isotopes; carbon cycle; wetland; ice core; methane; Holocene; mammoths; tundra; ice age; LGM; biogeography; biome; biogeochemistry; Vegetation model; Miljökemi; Physical geography; geomorphology; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

   Abstract : This thesis describes the development and selected applications of a global vegetation model, BIOME4. The model is applied to problems in high-latitude vegetation distribution and climate, trace gas production, and isotope biogeochemistry. READ MORE

5. 3. Long-lasting ecological legacies of reindeer on tundra vegetation

   Author : Dagmar D. Egelkraut; Johan Olofsson; Bruce Forbes; Hans Tømmervik; René van der Wal; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Alternative stable state; Herbivory; Historical contingency; Nutrient cycling; Plant-herbivore interactions; Plant-soil feedbacks; Rangifer tarandus; Reindeer herding; Traditional land use; Tundra vegetation;

   Abstract : Reindeer can have strong effects on the plant species composition and functioning of tundra ecosystems, and often promote a transition towards a graminoid-dominated vegetation type. As a result, they influence many ecological processes, such as nutrient dynamics, soil biotic composition and functioning, and carbon storage. READ MORE

6. 4. Impact of climate warming on Arctic plant diversity: phylogenetic diversity unravels opposing shrub responses in a warming tundra

   Author : Ruud Scharn; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Arctic; Oroarctic; Tundra; long-term warming; soil moisture; vegetation change; shrubification; biodiversity; phylogenetic diversity; plant community structure;

   Abstract : The Arctic biome is at significant risk, with recent observations suggesting that climate change is warming the Arctic nearly four times faster than the global average. Last decade, evidence from experimental warming studies and observations of ambient warming over time shows how increasing air temperature in the Arctic has led to changes to arctic vegetation, and encroachment of trees and shrubs into the tundra. READ MORE

7. 5. Interactions between gray-sided voles (Clethrionomys rufocanus) and vegetation in the Fennoscandian tundra

   Author : Jonas Dahlgren; Lauri Oksanen; Johan Olofsson; John Terborgh; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; gray-sided voles; tundra vegetation; trophic cascades; plant-herbivore interactions; bilberry; plant communities; herbivory; plant resistance; Terrestrial ecology; Terrestisk ekologi;

   Abstract : I have, in this thesis, studied the interactions between gray-sided voles (Clethrionomys rufocanus) and tundra vegetation, on islands in, and mainland sites close to the lake Iešjávri, in northern Norway. As isolated islands are virtually free of predation, I have been able to compare plant-herbivore interactions in the presence and absence of predators. READ MORE