Sökning: "Freshwater ecology"

Visar resultat 16 - 20 av 200 avhandlingar innehållade orden Freshwater ecology.

  1. 16. Spatial heterogeneity and biotic interactions : scaling from experiments to natural systems

    Författare :Ulf Bergström; Göran Englund; Erik Bonsdorff; Sebastian Diehl; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

    Sammanfattning : Much of current ecological theory stems from experimental studies. These studies have often been conducted in closed systems, at spatial scales that are much smaller than the systems of interest. LÄS MER

  3. 17. 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

  4. 18. Population dynamics of tundra-living grey-sided voles

    Författare :Per Ekerholm; Lauri Oksanen; Rolf Anker Ims; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Population dynamics; Tundra; Grey-sided vole; Cycles; Vole specialist predators; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

    Sammanfattning : This thesis deals with the dynamics of tundra living voles with emphasis on the most common one, the grey-sided vole (Clethrionomys rufocanus). The tundra area chosen for the study was Finnmarksvidda, a vast flatland in northernmost Norway. LÄS MER

  5. 19. Reproduction and moult in pied and collared flycatchers (Ficedula hypoleuca and F. albicollis) : A life-history approach

    Författare :Christer Hemborg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Breeding time; Costs of reproduction; Long-distance migrant; Moult-breeding overlap; Sexual conflict; Survival probability; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

    Sammanfattning : This thesis examines the trade-offs between investments in reproduction and self-maintenance (moult) in pied and collared flycatchers (Ficedula hypoleuca and F. albicollis). These two long-distance migratory passerine bird species were studied on the breeding grounds in Fennoscandia and in England. LÄS MER

  7. 20. Rarity in boreal stream: patterns, causes and consequences

    Författare :Per-Ola Hoffsten; Bo W. Svensson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Central Sweden; site occupancy; dispersal limitation; natural disturbances; recolonization; flight-morphology; metapopulation; habitat stability; spring specialists; Crunoecia irrorata; niche limitation; Isogenus nubecula; nestedness; longitudinal distribution; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

    Sammanfattning : Patterns of site occupancy among boreal stream insects were studied in central Sweden with focus on sparsely distributed species and the role of dispersal and niche limitations.In the study of dispersal limitation, I found that effects of an extraordinarily harsh winter in small to medium-sized streams were strongest in sites located in small streams and far from lake outlets. LÄS MER