Sökning: "subarctic Sweden"

Visar resultat 1 - 5 av 37 avhandlingar innehållade orden subarctic Sweden.

  1. 1. Winter browsing by moose and hares in subarctic birch forest : Scale dependency and responses to food addition

    Författare :Sara Öhmark; Thomas Palo; Glenn R. Iason; Bengt-Gunnar Jonsson; Lisa Shipley; Mittuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Herbivory; subarctic; hare; moose; spatial scale;

    Sammanfattning : Despite their difference in body size and morphology, the moose (Alces alces) andthe mountain hare (Lepus timidus) sustain themselves during winter on similar plantspecies and plant parts in in subarctic environments, namely apical twigs ofmountain birch (Betula pubescens ssp. czerepanovii). LÄS MER

  3. 2. Land-atmosphere interaction of a subarctic palsa mire

    Författare :Marcin Jackowicz-Korczynski; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; eddy covariance; chamber; methnaol; isoprene; nonmethane hydrocarbons; methane; carbon dioxide; carbon; mire; permafrost; subarctic; palsa; greenhouse gas;

    Sammanfattning : The main objective of this thesis was to quantitatively estimate the gaseous exchange of carbon dioxide (CO2) and methane (CH4) between a subarctic wetland ecosystem and the atmosphere. Additionally some initial estimates of the carbon input to the atmosphere of nonmethane hydrocarbons (NMHCs) were also obtained by combining different techniques in a joint setting. LÄS MER

  4. 3. Biogeochemistry in Subarctic birch forests : Perspectives on insect herbivory

    Författare :Jeppe Ågård Kristensen; MERGE: ModElling the Regional and Global Earth system; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biogeochemistry; Aboveground-belowground interactions; Herbivory; Insects; Subarctic; Birch; soil microbes;

    Sammanfattning : Herbivory can influence ecosystem processes, partly through long-term changes of the plant community compositions, but also more rapidly through the herbivores’ digestive alteration of the organic matter that is cycled through the soil and back to the primary producers. In the Subarctic mountain birch (Betula pubescens ssp. LÄS MER

  5. 4. Future stratospheric ozone depletion will affect a subarctic dwarf shrub ecosystem

    Författare :Ulf Johanson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Vaccinium; UVB; subarctic; shoot growth; ozone depletion; leaf thickness; irradiation system; heath ecosystem; Empetrum; dwarf shrubs; Calamagrostis; decomposition; Physiological biophysics; Växtfysiologi;

    Sammanfattning : The stratospheric ozone depletion and the concomitant increase in ultraviolet-B (UV-B, 280-320 nm) radiation is of global concern due to the effects of UV-B on living organisms. To investigate the effects of increased levels of UV-B, a field irradiation system was established at a subarctic dwarf shrub heath in Northern Sweden (68 °N). LÄS MER

  7. 5. Temporal and spatial variability of carbon cycling in a subarctic landscape

    Författare :Torbjörn Johansson; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geologi; physical geography; Geology; Växtekologi; Plant ecology; Permafrost; Herbivory; Subarctic; Aerial photography; Vegetation change; Carbon balance; fysisk geografi;

    Sammanfattning : This thesis deals with the carbon balance in a subarctic landscape at different temporal and spatial scales. Its focus is mainly on the peatland and mountain birch forest (Betula pubescens ssp. czerepanovii) ecosystems within the Abisko area in northernmost Sweden. This is an area with a temperature close to the 0 OC mean annual isotherm. LÄS MER