Search for dissertations about: "dispersal"
Showing result 16 - 20 of 310 swedish dissertations containing the word dispersal.
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16. Physical and biological dispersal barriers in invasive, bloom-forming microalgae
Abstract : 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. READ MORE
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17. Species extinctions in food webs : local and regional processes
Abstract : 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. READ MORE
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18. Description of spatial and temporal distributions of epiphytic lichens
Abstract : 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. READ MORE
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19. The spatial and temporal dynamics of plant-animal interactions in the forest herb Actaea spicata
Abstract : 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. READ MORE
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20. Insect Diversity in Changing Landscapes
Abstract : 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. READ MORE