Sökning: "interspecific competition"

Visar resultat 11 - 15 av 24 avhandlingar innehållade orden interspecific competition.

  1. 11. 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

  3. 12. The effects of stage-specific differences in energetics on community structure

    Författare :Tim Schellekens; Andre de Roos; Tom Anderson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ontogenetic diet shift; stage-structured biomass model; food-dependence; growth; development; Earth sciences; Geovetenskap; NATURAL SCIENCES; NATURVETENSKAP; Earth Sciences with Specialization Environmental Analysis; geovetenskap med inriktning mot miljöanalys;

    Sammanfattning : When intraspecific individuals differ in resource intake, scramble competition occurs among inferior individuals growing food-dependently. Scramble can be released through predation mortality. As a consequence of this release, production rates in inferior individuals increase and biomass overcompensation in the subsequent life-stages may occur. LÄS MER

  4. 13. Interactions between Eurasian lynx and wolverines in the reindeer husbandry area

    Författare :Jenny Mattisson; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In conservation and management, carnivore species are often treated as isolated units, even though interspecific interactions can have important implications for the behaviour, demography and distribution of the species involved. In this thesis I used individual based GPS-location data to study interactions between two solitary predators in the reindeer husbandry area in Northern Scandinavia: The Eurasian lynx (Lynx lynx), an obligate predator, and the wolverine (Gulo gulo), an opportunistic predator and scavenger. LÄS MER

  5. 14. Growth and nitrogen economy of cereal-legume sole- and intercrops, and their effects on weed suppression

    Författare :James Ajal; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : Crop production currently faces the dilemma of using methods that increase crop yield but with adverse environmental effects, or attaining lower yields with less environmental impacts. Applying ecological principles has shown potential in finding a middle-ground of maintaining crop yield with less inputs. LÄS MER

  7. 15. Sex and violence in lobsters - a smelly business

    Författare :Malin Skog; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dominance; urine signals; recognition; Aggressive behaviours; intermoult mating; sexual dimorphism; European lobster; chemical communication; Homarus gammarus; aesthetasc morphology;

    Sammanfattning : The aim of this thesis was to study the chemical communication involved in aggressive and reproductive behaviours in the European lobster (Homarus gammarus). Both male and female H. gammarus established and maintained dominance, but the sexes used different strategies for dominance maintenance. LÄS MER