Sökning: "dispersal"

Visar resultat 16 - 20 av 314 avhandlingar innehållade ordet dispersal.

  1. 16. Physical and biological dispersal barriers in invasive, bloom-forming microalgae

    Författare :Ingrid Sassenhagen; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dispersal barriers; microalgae; phenotypic differentiation; population genetics; priority effects;

    Sammanfattning : For a long time microorganisms were assumed to have unlimited dispersal due to their small size and high cell numbers. Most microbial species can be transported by water currents, in water droplets by wind and attached to other organisms. LÄS MER

  3. 17. Species extinctions in food webs : local and regional processes

    Författare :Anna Eklöf; Bo Ebenman; Peter Münger; Marcel Holyoak; Linköpings universitet; []
    Nyckelord :Extinction; food web; metacommunity; dispersal; species loss; migration; habitat fragmentation; connectance; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : Loss of biodiversity is one of the most severe threats to the ecosystems of the world. The major causes behind the high population and species extinction rates are anthropogenic activities such as overharvesting of natural populations, pollution, climate change and destruction and fragmentation of natural habitats. LÄS MER

  4. 18. Description of spatial and temporal distributions of epiphytic lichens

    Författare :Håkan Lättman; Per Milberg; Bengt Gunnar Jonsson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; centroid; continuity; lichen; movement; range shift; direction; dispersal; ecological continuity; establishment; global change; global warming; habitat availability; håkan lättman; Biology; Biologi;

    Sammanfattning : Lichens are, in most cases, sensitive to anthropogenic factors such as air pollution, global warming, forestry and fragmentation. Two studies are included in this thesis. The first is an evaluation of the importance of old oak for the rare epiphytic lichen Cliostomum corrugatum (Ach.) Fr. LÄS MER

  5. 19. The spatial and temporal dynamics of plant-animal interactions in the forest herb Actaea spicata

    Författare :Hugo von Zeipel; Johan Ehrlén; Ove Eriksson; Saskya van Nouhuys; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Eupithecia immundata; parasitoid; rodent; seed predation; dispersal; recruitment; multitrophic; metapopulation; trophic cascades; community complexity; Biology; Biologi; Plant Ecology; växtekologi;

    Sammanfattning : Landscape effects on species performance currently receives much attention. Habitat loss and fragmentation are considered major threats to species diversity. Deciduous forests in southern Sweden are previous wooded pastures that have become species-rich communities appearing as islands in agricultural landscapes, varying in species composition. LÄS MER

  7. 20. Insect Diversity in Changing Landscapes

    Författare :Markus Franzén; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; växtparasitologi; Entomologi; plant parasitology; Zoology; Zoologi; Entomology; Ekologi; Ecology; butterfly; bee; dispersal; extinction; Djurekologi; Animal ecology;

    Sammanfattning : During recent decades, concern about the loss of biodiversity has increased. To change this negative trend there is an urgent need for effective conservation measures and there are ample evidence that conservation of organisms without an understanding of their ecology and behaviour is impossible. LÄS MER