Search for dissertations about: "population limitation"

Showing result 1 - 5 of 100 swedish dissertations containing the words population limitation.

  2. 1. Population differentiation in Lythrum salicaria along a latitudinal gradient

    Author : Katarina Olsson; Jon Ågren; Susan Kalisz; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology; additive genetic variance; clinal variation; evolutionary constraints; G matrix; genetic correlation; natural selection; pollen limitation; population differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Abstract : In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. READ MORE

  4. 2. Single-cell population genetics and dispersal limitation of a bloom-forming microalga

    Author : Raphael Gollnisch; Enhet akvatisk ekologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Gonyostomum semen; algal blooms; invasive species; population structure; RADseq; single-cell whole genome amplification; multiple displacement amplification; calcium; pH; iron;

    Abstract : Microalgal range expansions are increasing in frequency and magnitude worldwide mostly due to anthropogenic factors. However, they often remain unnoticed until mass development (algal blooms) occurs due to difficulties in detection when population densities are low. READ MORE

  5. 3. Effects of farmland heterogeneity at multiple spatial and temporal scales on house sparrow (Passer domesticus) population ecology

    Author : Maria von Post; Biodiversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Farmland heterogeneity; house sparrow; agricultural intensification; farm specialisation; landscape complementation; resource separation; population limitation;

    Abstract : Strong declines of European farmland birds in recent decades are assumed to be caused by decreased food availability resulting from agricultural intensification and concomitant loss of farmland heterogeneity. One of the species suffering particularly strong declines in NW European countries is the house sparrow. READ MORE

  6. 4. Herbivory, pollen limitation and population dynamics in Lathyrus vernus

    Author : Johan Ehrlén; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Vårärt; Ekologi; Botanik; Växtekologi;

    Abstract : .... READ MORE

  7. 5. Plant Population Dynamics and Biotic Interactions in two Forest Herbs

    Author : Christel Gustafsson; Martin Zobel; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Sanicula europaea; Dentaria bulbifera; Cost of reproduction; grazing; competition; dispersal limitation; patch suitability; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; ekologisk botanik; Ecological Botany;

    Abstract : In Sweden today, deciduous woodlands are often restricted to small isolated remnants of what it once was. Managing practices have changed concerning both cattle grazing and logging. Thus, dispersal, habitat requirements and their importance for forest species distributions become a relevant issue. READ MORE