Search for dissertations about: "vegetational composition"

Found 4 swedish dissertations containing the words vegetational composition.

  2. 1. Nitrogen, parasites and plants : key interactions in boreal forest ecosystems

    Author : Joachim Strengbom; Lars Ericson; Gaius R Shaver; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Critical loads; Deschampsia flexuosa; amino acids; mycorrhizal fungi; natural enemies; N deposition; N limitation; vegetational composition; Valdensia heterodoxa; Vaccinium myrtillus;

    Abstract : In the work described in this thesis I studied how increases in nitrogen (N) inputs may affect plant community structure in boreal forest understorey vegetation. These phenomena were investigated in N fertilization experiments and along a national N deposition gradient. READ MORE

  4. 2. A green future with thawing permafrost mires? : a study of climate-vegetation interactions in European subarctic peatlands

    Author : Julia Bosiö; Institutionen för naturgeografi och ekosystemvetenskap; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fennoscandia; carbon; greenhouse gas; photosynthesis; PAR; snow; climate change; permafrost; peatland; subarctic;

    Abstract : Climate projections indicate that Arctic and sub-Arctic regions are facing a significant change in climate during the 21st century. With warmer temperatures precipitation is also expected to increase, and in particular winter precipitation. READ MORE

  5. 3. The Ups and Downs of the Holocene: Exploring Relationships between Global CO2 and Climate Variability in the North Atlantic Region

    Author : Catherine Jessen; Kvartärgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; marklära; geomorfologi; climatology; klimatologi; rapid climate change; Holocene climate; atmospheric CO2 concentrations; geochemical proxy indicators; Paleobotanik; palynology; Geology; palynologi; fylogeni; geomorphology; fysisk geografi; Geologi; physical geography; kartografi; pedology; cartography; phylogeny; Palaeobotany; stomatal frequency; lake sediments;

    Abstract : This thesis aimed to examine the relationship between climate and atmospheric CO2 concentrations through rapid climate changes during the Holocene. Climate was reconstructed using high-resolution, radiocarbon dated, lake sediment geochemical proxies (magnetic susceptibility, loss-on-ignition, total carbon/nitrogen/sulphur determinations and biogenic silica), vegetational reconstruction (pollen analysis) and stomatal frequency based CO2 reconstructions. READ MORE

  6. 4. Constructed Wetlands and Deconstructed Discourses : Greenhouse gas fluxes and discourses on purifying capacities

    Author : Elisabeth Johansson; Bo Svensson; Linköpings universitet; []
    Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; växthuseffekter; vattenrening; miljöaspekter; INTERDISCIPLINARY RESEARCH AREAS; TVÄRVETENSKAPLIGA FORSKNINGSOMRÅDEN;

    Abstract : This thesis is a study within the sciences ofconstructed wetlands. It has two sections. Section one is a natural scienrific study ofgas fluxes from construcred wetlands and section two is an analysis ofhow natural sciences describe constructed wetlands. READ MORE