Sökning: "niche overlap"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden niche overlap.

  1. 1. Species interactions in streams - effects of predation, competition and ecosystem properties

    Författare :Erika Nilsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; behaviour; species abundance; stable isotopes; habitat complexity; niche width; niche overlap; competition; streams; predation;

    Sammanfattning : Stream ecosystems are dynamic and they have an inherent environmental variability. Organisms that live in streams are adapted to the continuously changing environment and the presence or absence of species are determined by their environmental requirements, while abundance is most often affected by interactions, such as competition and predation, with other species that are found in the same habitat. LÄS MER

  3. 2. Genetic variation, clonal diversity and breeding system in sedges (Carex)

    Författare :Olle Jonsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systematic botany; Carex ericetorum; Carex caryophyllea; Carex bigelowii; Carex arenaria; phenology; niche; genet identification; clone size; isozyme; gene flow; introgression; allozyme; gene diversity; population genetics; taxonomy; morphology; phytogeography; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Sammanfattning : In this thesis I investigate genetic variation in clonal plants within the wind-pollinated plant family Cyperaceae and, in particular, in species of Carex. Clonal diversity and the spatial distribution of clones (genets) within populations was investigated in Carex bigelowii (in Iceland and Scandinavia) and C. LÄS MER

  4. 3. Variation in Pseudorchis albida s.l. (Orchidaceae) and Carex capitata s.l. (Cyperaceae) : Morphology, genetic diversity, ecology and systematics

    Författare :Lars-Gunnar Reinhammar; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Pseudorchis; Carex; morphologic variation; allozymes; immigration history; regeneration niche; biodiversity; ordinations; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; systematisk botanik; Systematic Botany;

    Sammanfattning : In the Scandinavian flora, several species-pairs where one member is an alpine species andthe other is a closely related lowland species, have been described. The aim of this studywas to investigate two such examples, viz. Pseudorchis albida s.s. LÄS MER

  5. 4. The dynamics of social movements : essays on competition and diffusion

    Författare :Charlotta Stern; Peter Marsden; Stockholms universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Sociology; sociologi;

    Sammanfattning : In this thesis various aspects of social movement competition and diffusion is studied. The first part of the thesis focus on movement competition and especially on how competition relates to the ability of movements to attract members. LÄS MER

  7. 5. Trophic resource use and partitioning in multispecies ungulate communities

    Författare :Robert Spitzer; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Over the past decades, ungulates across the northern hemisphere have been expanding in range and numbers. This has raised concerns about their impacts, particularly on shared resources with humans, e.g., timber trees. LÄS MER