Sökning: "ekologisk"

Visar resultat 1 - 5 av 154 avhandlingar innehållade ordet ekologisk.

  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. Evolution of Spur Length in a Moth-pollinated Orchid

    Författare :Elin Boberg; Jon Ågren; W. Scott Armbruster; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Platanthera bifolia; floral evolution; natural selection; pollination; spur length; population differentiation; divergent selection; disruptive selection; reproductive isolation; Biology; Biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : There is considerable evidence that pollinator shifts can explain many differences in flower morphology between closely related plant species, but the extent to which pollinator shifts can explain the maintenance of among-population variation in floral traits within species is poorly known. In this thesis, I combined comparative and experimental approaches to examine the evolution of floral traits in the moth-pollinated orchid Platanthera bifolia. LÄS MER

  4. 3. Benthic diatoms in the Gulf of Bothnia : Community analysis and diversity

    Författare :Svenja Busse; Michael Sullivan; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Baltic Sea; Biodiversity; Biomass; Community ecology; Diatoms; Multivariate analysis; Navicula; Phytobenthos; Salinity gradient; Scale; Size; Water movement; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : Benthic diatoms are valuable tools for biological monitoring and paleo-ecological reconstruction of past environmental conditions. This thesis aims at describing size-related properties of benthic diatoms and suggests that data assessment for community analysis can be improved by considering the importance of scale. LÄS MER

  5. 4. Long-term changes in macroalgal vegetation on the Swedish coast : An evaluation of eutrophication effects with special emphasis on increased organic sedimentation

    Författare :Britas Klemens Eriksson; Francisco Xavier Niell Castanera; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Baltic Sea; Eutrophication; Fragmentation; Fucus vesiculosus; Functional group; Gullmar Fjord; Macroalgae; Long-term changes; Reproduction; Sedimentation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : In this thesis I examine and evaluate the effects of a documented large-scale eutrophication on macroalgal vegetation on the Swedish coast. During the past century the load of nutrients has increased manifold in the Baltic Sea area, increasing primary production and organic sedimentation significantly. LÄS MER

  7. 5. Factors Affecting the Distribution of Rocky-Shore Macroalgae on the Swedish Coast : Morphological, Physiological, Reproductive and Genetic Aspects

    Författare :Gustav Johansson; John Raven; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The aim of this thesis was to examine factors affecting the distribution of macroalgal species both vertically (depth zonation) and geographically along the Baltic Sea salinity gradient. Interactions between the physical environment and basic biological traits of the algae are emphasised. LÄS MER