Sökning: "habitat quality"

Visar resultat 21 - 25 av 83 avhandlingar innehållade orden habitat quality.

  1. 21. Microbial adaptations and controlling mechanisms of surface-associated microhabitat heterogeneity in aquatic systems

    Författare :Jan Torsten Jeske; Stefan Bertilsson; Annelie Wendeberg; Andreas Schramm; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microbial habitat heterogeneity; Biology with specialization in Limnology; Biologi med inriktning mot limnologi;

    Sammanfattning : Habitat heterogeneity is a driving factor for speciation and ecosystem functioning and is well studied in macro-ecology. Yet our understanding of microbial adaptations, and governing processes is incomplete. LÄS MER

  3. 22. Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery

    Författare :Tove Lund Jörgensen; Michael Tedengren; Nick Graham; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; anthropogenic disturbance; coral reef habitat; fish community; coastal ecosystems; conservation management; spatial ecology; seascape perspective; holistic approach; marin ekotoxikologi; Marine Ecotoxicology;

    Sammanfattning : Coral reefs have one of the highest levels of biodiversity of all ecosystems in the world and are important for both human livelihood and food security throughout many tropical countries. However, due to increased anthropogenic pressure on marine ecosystems, especially during the last couple of decades, coral reefs have become critically over-fished, and many reefs are now in a degraded state and are facing additional future threats due to further over-exploitation, chemical pollution, sedimentation, and effects of climate change. LÄS MER

  4. 23. Dynamics of omnivorous crayfish in freshwater ecosystems

    Författare :Karin Olsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; crayfish; freshwater ecosystems; niche width; growth rate; stable isotope analysis; recruitment; RNA:DNA analysis; Ecology; food availability and quality; trophic position; population dynamics;

    Sammanfattning : In this thesis I examine the dynamics of crayfish in streams and lakes. I have studied the influence of abiotic and biotic factors on abundance, growth, trophic position, niche breadth, and recruitment of crayfish, by conducting field studies, an outdoor channel experiment and timeseries analysis. LÄS MER

  5. 24. Aspects of heterogeneity : effects of clear-cutting and post-harvest extraction of bioenergy on plants in boreal forests

    Författare :Marcus Åström; Christer Nilsson; Katherine Frego; Umeå universitet; []
    Nyckelord :aspect; clear-cutting; disturbance; habitat quality; liverworts; logging residues; mosses; resilience; slash; slope; topography;

    Sammanfattning : Abstract. The objectives of this thesis are to evaluate (1) the influence of slope aspect on boreal plant responses to clear-cutting and (2) the effects of post-harvest extraction of bioenergy (logging residues or slash) on plant composition, richness and performance in clear-cuts. LÄS MER

  7. 25. The big picture from small landscapes : investigations of spatial patterns and processes using a model metacommunity

    Författare :Jens Åström; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Habitat fragmentation is a major current threat to natural environments. Still, fundamental questions of what influences ecological communities in spatially structured habitats are unanswered. In this thesis, microarthropods in moss patches were used in a model system, where both biotic and abiotic factors could be manipulated. LÄS MER