Sökning: "limnisk och marin ekologi"

Visar resultat 1 - 5 av 96 avhandlingar innehållade orden limnisk och marin ekologi.

  1. 1. Function and dynamics of woody debris in boreal forest streams

    Författare :Niklas Dahlström; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; Boreal forest; CPOM; CWD; forest management; geomorphology; LWD; riparian forest; retention; residence time; streams; Sweden; woody debris; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Terrestrisk; limnisk och marin ekologi;

    Sammanfattning : The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. LÄS MER

  2. 2. Plants go with the flow : predicting spatial distribution of plant species in the boreal forest

    Författare :Ursula Zinko; Christer Nilsson; Håkan Rydin; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; boreal forest; vascular plant; species richness; wetness index; soil pH; bryophyte; lichen; substrate; stand age; plot size; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The main objectives of this thesis are to study if a topographic wetness index (TWI) could be used as a tool for predicting the spatial distribution of vascular plant species richness in the boreal forest as well as to study congruence in species richness between vascular plants, liverworts, mosses and lichens. A wetness index ln(a/tanβ) based on topography was used to assign a specific TWI-value to every 20 x 20m grid in two 25 km2 boreal forest landscapes (differing in average soil pH) in northern Sweden. LÄS MER

  3. 3. Predators in low arctic tundra and their impact on community structure and dynamics

    Författare :Maano Aunapuu; Tarja Oksanen; Ola Atlegrim; Oswald J. Schmitz; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; arthropods; coexistence; community dynamics; competition; food webs; hypothesis of exploitation ecosystems; intraguild predation; small mustelids; trophic cascades; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

    Sammanfattning : The abundance of predators and their impact on ecosystem dynamics is a vividly discussed topic in current ecology. In my studies, incorporating field observations, field experiments and theoretical modeling, I explored the importance of predators and predation in a low arctic tundra ecosystem in northern Norway. LÄS MER

  4. 4. Biodiversity in fragmented boreal forests : assessing the past, the present and the future

    Författare :Håkan Berglund; Bengt Gunnar Jonsson; Jari Kouki; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; bryophytes; CWD; edge effects; fragmentation; fungi; habitat destruction; historical records; indicator; lichens; regression; species-area relationship; value pyramids; woody debris; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The aims of this thesis are to (1) analyze the predictability (indicators) of plant and fungal species diversity in old-growth forests, and (2) assess the history and biodiversity of woodland key habitats (WKHs) and their potential to maintain species diversity in fragmented boreal forest landscapes. Predictability was explored in Granlandet nature reserve, an unexploited landscape composed of discrete old-growth Picea forest patches of varying size isolated by wetland, reflecting conditions of insular biota at stochastic equilibrium. LÄS MER

  5. 5. Macroalgae in the Baltic Sea : responses to low salinity and nutrient enrichment in Ceramium and Fucus

    Författare :Lena Bergström; Lars Ericson; Lena Kautsky; Erik Bonsdorff; Christine A Maggs; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ecology; adaptation; asexual reproduction; Baltic Sea; Gulf of Bothnia; salinity; macroalgae; nutrients; sexual reproduction; stress; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : The brackish Baltic Sea is a marginal environment for both marine and freshwater species. The rate of ecological differentiation is presumably high due to strong selection pressure from a gradient of decreasing salinity that has been present in its current state for only about 3 000 years. LÄS MER