Sökning: "altitudinal gradient"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden altitudinal gradient.

  1. 1. Population Differentiation in Solidago virgaurea along Altitudinal Gradients

    Författare :Anna Bergsten; Jon Ågren; Staffan Karlsson; Kari Lehtilä; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; population differentiation; altitudinal gradient; plant nutrient status; resorption efficiency; resorption proficiency; flowering phenology; countergradient variation; reproductive effort; flower production; cost of reproduction; Biology; Biologi; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : Altitudinal gradients offer attractive opportunities for studies of population differentiation in response to environmental heterogeneity. In this thesis, I examined population differentiation along altitudinal gradients by combining common-garden experiments with field studies and experiments in alpine, subalpine and boreal populations of the perennial herb Solidago virgaurea. LÄS MER

  3. 2. Herbivory and plant community structure in a subarctic altitudinal gradient

    Författare :Jon Moen; Nancy Huntly; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; arctic and alpine vegetation; competition; exclosures; lemmings; plant defences; plant-plant interactions; Ranunculus glacialis; snow-bed; structuring factors; tall herb meadow; vertebrate grazing; voles;

    Sammanfattning : The object of this thesis was to study plant community structure, especially in relation to vertebrate herbivory, in an altitudinal gradient in the Fennoscandian mountain chain.A sowing experiment in a high alpine Ranunculus glacialis population showed that seeds germinated better in cleared microsites than under established individuals. LÄS MER

  4. 3. Reproductive allocation and costs of reproduction in subarctic herbs : A resource-based perspective

    Författare :Åsa M. Hemborg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Altitudinal gradient; Plant size; Predispersal seed predation; Reproductive effort; Resourcedynamics; Seasonal variation; Sexual dimorphism; Somatic costs; Unisexual plants; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The influence of internal and external factors on two major plant life history components, i.e., reproductive allocation and costs of reproduction, was examined for nine perennial herbs in subarctic Swedish Lapland. In one study, comparisons were made between Sweden and the French Alps. LÄS MER

  5. 4. Reproductive patterns of birches (Betula spp.) in northern Sweden

    Författare :Stig-Olov Holm; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Reproduction; Betula; seed-quality; seed-set; pollination; pollen-limitation; pollen-competition; tree-line; environmental gradient; seed weight; seedling survival; Semudobia;

    Sammanfattning : The aim of this thesis was to study patterns of reproduction of Betula pendula and B. pubescens coll. along an altitudinal, coastal-inland, gradient in northern Sweden. The altitudinal variation was related to the distribution of the birch taxa along the gradient. LÄS MER

  7. 5. Climate Change sensitivity of Photosynthesis and Respiration in Tropical Trees

    Författare :Myriam Mujawamariya; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon dioxide; Climate change; Drought; Elevation gradient; Photosynthesis; Respiration; Tropical montane forest; Tropical trees; Warming;

    Sammanfattning : Tropical climate is getting warmer, with more pronounced dry periods in large areas. The productivity and climate feedbacks of future tropical forests depend on the ability of trees to acclimate their physiological processes, such as photosynthesis and leaf respiration, to these new conditions. LÄS MER