Search for dissertations about: "macroinvertebrates"

Showing result 16 - 20 of 21 swedish dissertations containing the word macroinvertebrates.

  2. 16. Species community structure and functional redundancy in Swedish headwater streams : local versus regional control

    Author : Emma Göthe; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Streams and rivers only contain a small proportion of the Earth's freshwater, but nevertheless harbour much biodiversity. Headwater streams are the most prevalent running water environments, but despite their wide distribution, they are often excluded from important freshwater legislation and national monitoring programmes. READ MORE

  4. 17. Agricultural expansion impacts on wetland ecosystem services from Kilombero Valley, Tanzania

    Author : Edmond Alavaisha; Regina Lindborg; Steve Lyon; Jennie Barron; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecosystem services; land use change; management practices; fertilization; irrigation; water quality; and smallholder; Physical Geography; naturgeografi;

    Abstract : Land use change has major impact on the world’s wetland ecosystems and biodiversity. The motivation behind this change has been to increase agricultural production, often resulting in negative effects on water quality and soil fertility. READ MORE

  5. 18. Rarity in boreal stream: patterns, causes and consequences

    Author : Per-Ola Hoffsten; Bo W. Svensson; Umeå universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 19. Phenotypic plasticity and the evolution of an inducible morphological defence in crucian carp

    Author : Lars Pettersson; Biodiversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Animal ecology; Benefits; Costs; Predation; Chemical cues; Fish; Djurekologi;

    Abstract : In this thesis, I have investigated factors (cues, benefits, and costs) affecting the evolution of an inducible morphological defence in crucian carp (Carassius carassius). Inducible defences are favoured over permanent defences when prey have reliable cues to detect predators, when defences are effective but costly, and when predation pressure is variable and unpredictable, but sometimes strong. READ MORE

  7. 20. Methylmercury in boreal freshwater food webs

    Author : Pianpian Wu; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Mercury (Hg) and bioaccumulation of its organic form methylmercury (MeHg) has long been regarded as a global issue for human and wildlife health. This is of particular concern for Sweden, where forest harvests and wetlands remain hotspots of MeHg export to boreal freshwaters. READ MORE