Sökning: "Seed limitation"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden Seed limitation.

  1. 1. Plant community assembly in grazed grasslands

    Författare :Bryndís Marteinsdóttir; Eriksson Ove; Cousins Sara A. O.; Johan Ehrlén; Meelis Pärtel; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Assembly rules; dispersal limitation; environmental filtering; establishment limitation; ex-arable fields; functional traits; landscape history; semi-natural grasslands; seed bank; seed augmentation; seed rain; trait based filtering; Plant Ecology; växtekologi;

    Sammanfattning : Species assembly into local communities from the surrounding region can be caused either by species failure to reach the site (i.e. seed limitation) or to establish (i.e. LÄS MER

  3. 2. Recruitment ecology and fungal interactions in mycoheterotrophic Ericaceae

    Författare :Veronika A. Johansson; Ove Eriksson; Andrew Taylor; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 454 Pyrosequencing; Dispersal limitation; Dust seeds; Ectomycorrhiza; Ericaceae; Microsite limitation; Monotropa hypopitys; Mycoheterotroph; Pyroleae; Seed limitation; Stable isotopes; Subterranean seedling; Symbiotic germination; Tricholoma; Plant Ecology; växtekologi;

    Sammanfattning : There are generally two contrasting alternatives to what limits recruitment in plants, namely the availability of seeds (seed limitation) or the quality or quantity of suitable sites (microsite limitation). Dust seeds, the smallest existing seeds, lack or have minimal nutrient reserves. LÄS MER

  4. 3. Reproductive patterns of birches (Betula spp.) in northern Sweden

    Författare :Stig-Olov Holm; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Reproduction; Betula; seed-quality; seed-set; pollination; pollen-limitation; pollen-competition; tree-line; environmental gradient; seed weight; seedling survival; Semudobia;

    Sammanfattning : The aim of this thesis was to study patterns of reproduction of Betula pendula and B. pubescens coll. along an altitudinal, coastal-inland, gradient in northern Sweden. The altitudinal variation was related to the distribution of the birch taxa along the gradient. LÄS MER

  5. 4. Plant-animal interactions and seed output of two insectpollinated herbs

    Författare :Anna R. Waites; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; plant reproduction; pollen limitation; pollinator behaviour; heterostyly; seed predation; Lythrum salicaria; Pedicularis palustris; stigma receptivity; self-pollen; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : I combined comparative and experimental studies in the field and in the greenhouse to examine factors influencing reproductive success in two insect-pollinated herbs, the tristylous, selfincompatible perennial Lythrum salicaria and the self-compatible, biennial Pedicularis palustris. More specifically, I explored (i) the effects of plant population characteristics on the intensity and outcome of interactions with pollinators and seed predators, (ii) whether flower morphology affects duration of stigma receptivity, and (iii) whether damage-induced reduction in floral display reduces pollinator visitation and increases pollen limitation. LÄS MER

  7. 5. Plant colonization of oak plantations - the interactive effects of local environment and land-use history

    Författare :Karin Valtinat; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nitrogen mineralization; Phosphorus; Plant ecology; Växtekologi; Soil acidity; Seed sowing; Dispersal limitation; Species diversity; Indicator species analysis; Functional groups; Succession; Understory vegetation; Land-use history; Temperate forest;

    Sammanfattning : In Europe, only small fragments of deciduous woodlands remain intact and species dependent on this ecosystem have declined. In southern Sweden, a shifting trend during the 20th century, with more afforestations on former arable land, resulted in new oak stands. These new stand are either on former arable fields or on continuously forested land. LÄS MER