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Visar resultat 1 - 5 av 142 avhandlingar som matchar ovanstående sökkriterier.
1. Disentangling Lecania
Sammanfattning : This thesis focuses on phylogenetic, taxonomic, ecological, and conservation aspects of the crustose lichen genus Lecania (Ramalinaceae, lichenized Ascomycota). Lecania has previously been defined on basis of relatively few morphological characters, and the genus had never been treated in molecular phylogenies. LÄS MER
2. Interaction strength and keystone species in model food webs
Sammanfattning : Ecological communities are often exposed to different kind of disturbances of varied magnitude. The response to disturbances can be affected by, among other factors, the strength of interactions between species within the community. LÄS MER
3. Effects of climate change on boreal wetland and riparian vegetation
Sammanfattning : Models of climate change predict that temperature will increase during the 21th century and the largest warming will take place at high northern latitudes. In addition to warming, predictions for northern Europe include increased annual precipitation and a higher proportion of the precipitation during winter falling as rain instead of snow. LÄS MER
4. VUV Emission and Energy Transfer Phenomena in Rare Gas Mixture Discharges
Sammanfattning : VUV emission spectra of Xe-X (X = He, Ne, Ar and Kr) and of Kr-Y (Y = He, Ne and Ar) mixtures with low concentrations of the heavier gases (0.1 - 1 %) and moderate total pressures (50 - 200 hPa) are recorded near each of the two resonance lines of Xe and Kr in DC glow capillary discharges. LÄS MER
5. Functional Extinctions of Species in Ecological Networks
Sammanfattning : Current rates of extinctions are estimated to be around 1000 times higher than background rates that would occur without anthropogenic impacts. These extinction rates refer to the traditional view of extinctions, i.e. numerical extinctions. LÄS MER
