Sökning: "niche limitation"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden niche limitation.

  1. 1. 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

  3. 2. Soil phosphorus – a multidimensional resource that plays an important role for grassland plant species richness

    Författare :Jakob Sandberg; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; niche dimension; nutrient limitation; niche differentiation; competition; soil nitrogen; soil phosphorus; plant diversity; species richness; Grassland; land use; landscape scale;

    Sammanfattning : The semi-natural grassland habitats contain an important part of the plant diversity in Europe. Changes in farming practices have lead to drastic decreases in plant species richness. The aim of the present thesis is to contribute to the knowledge about mechanisms governing the plant species richness in grasslands with emphasis on soil nutrients. LÄS MER

  4. 3. Spatial Modelling of Coastal Fish – Methods and Applications

    Författare :Göran Sundblad; Ulf Bergström; Alfred Sandström; Peter Eklöv; Christian Möllmann; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; habitat; niche; species distribution modelling; juvenile; fish; larvae; spawning; Marine ecology; Marin ekologi; NATURAL SCIENCES; NATURVETENSKAP; Freshwater ecology; Limnisk ekologi; Biology; Biologi; Biology with specialization in Limnology; Biologi med inriktning mot limnologi; Biologi med inriktning mot zooekologi; Biology with specialization in Animal Ecology; Limnologi; Limnology;

    Sammanfattning : Environmental factors influence species and habitats on multiple scales creating a mosaic of distribution patterns. Studying factors shaping these patterns are central to our understanding of population dynamics and ultimately ecosystem functioning. LÄS MER

  5. 4. Plant responses after drainage and restoration in rich fens

    Författare :Kalle Mälson; Håkan Rydin; Sebastian Sundberg; Harri Vasander; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Ecology; brown mosses; bryophytes; colonization; competition; dispersal limitation; liming; mire; peatland; rewetting; wetland restoration; Ekologi;

    Sammanfattning : Rich fens are an important, but threatened, habitat type in the boreal landscape. In this thesis I have examined responses of rich fen vascular plants and bryophytes after drainage and restoration.The effects of drainage on the rich fen flora were observed in a long time study and the responses were rapid and drastic. LÄS MER

  7. 5. Ontogenetic scaling and the development of within-cohort size structure

    Författare :Magnus Huss; Lennart Persson; Pär Byström; David Post; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cannibalism; competition; density-dependence; resource feedbacks; hatching; growth; ontogenetic niche shifts; Perca fluviatilis; size variation; larval fish; Freshwater ecology; Limnisk ekologi; zooekologi; Animal Ecology;

    Sammanfattning : It is increasingly recognized that individuals of the same species differ from each other and influence and respond to their environment in unique ways. This thesis deals with size variation among individuals that not only are of the same species but also of similar age. LÄS MER