Sökning: "Johan Ehrlén"

Visar resultat 1 - 5 av 30 avhandlingar innehållade orden Johan Ehrlén.

  1. 1. The role of microclimate for the performance and distribution of forest plants

    Författare :C. Johan Dahlberg; Kristoffer Hylander; Johan Ehrlén; Jason D. Fridley; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; performance; microclimate; spatial scales; continental; landscape; distribution patterns; distribution limits; phenology; vegetative development; reproductive development; vital rates; population growth rate; vascular plants; bryophytes; distribution modelling; Plant Ecology; växtekologi;

    Sammanfattning : Microclimatic gradients may have large influence on individual vital rates and population growth rates of species, and limit their distributions. Therefore, I focused on the influence of microclimate on individual performance and distribution of species. LÄS MER

  3. 2. Linking plant population dynamics to the local environment and forest succession

    Författare :Johan Petter Dahlgren; Johan Ehrlén; Ove Eriksson; Mark Rees; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Actaea spicata; Forest herbs; Forest succession; Integral projection model; Plant demography; Plant phenology; Population dynamics; Pre-dispersal seed predation; Seed mass; Soil potassium; Specific leaf area; Terrestrial ecology; Terrestisk ekologi; Plant Ecology; växtekologi;

    Sammanfattning : Linking environmental variation to population dynamics is necessary to understand and predict how the environment influences species abundances and distributions. I used demographic, environmental and trait data of forest herbs to study effects of spatial variation in environmental factors on populations as well as environmental change in terms of effects of forest succession on field layer plants. LÄS MER

  4. 3. Plant phenology in seasonal environments

    Författare :Elsa Fogelström; Johan Ehrlén; Johan P. Dahlgren; Arthur Weis; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Autumn phenology; Cardamine pratensis; evolutionary ecology; heritability; herbivore preference; fitness components; flowering time; growing season length; life-history; Lathyrus vernus; natural selection; population differentiation; phenology; spring phenology; Plant Ecology; växtekologi;

    Sammanfattning : Phenology, or the seasonal timing life-history events such as emergence, reproduction and senescence will determine the outcome of interactions between plants and both abiotic and biotic aspects of the environment. Such timing is therefore of utmost importance for plants in seasonal environments. LÄS MER

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

    Författare :Johan Ehrlén; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Vårärt; Ekologi; Botanik; Växtekologi;

    Sammanfattning : .... LÄS MER

  7. 5. The importance of search behavior and movements for spatial distributions of herbivorous insects

    Författare :Petter Andersson; Peter Hambäck; Johan Ehrlén; Tomas Roslin; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Olfactory search; Habitat heterogeneity; Species-traits; Immigration; Scaling relationships; Patch size; Plant-insect interactions; EAG; Odors; Pheromones; Plant Ecology; växtekologi;

    Sammanfattning : Insect populations commonly show large spatial variation in density, and much variation have been shown to be explained by the search behavior applied by the insect when locating habitat patches. This thesis explores the importance of odor-mediated attraction for immigration rates of herbivorous insects in relation to the size of the patches and the density of host plants within the patches. LÄS MER