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Visar resultat 1 - 5 av 16 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Interactions between natural enemies and the dioecious herb Silene dioica

    Författare :Viktoria Pettersson; Barbara E. Giles; Lars Ericson; Pia Mutikainen; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Silene dioica; Delia criniventris; Caryocolum viscariella; Microbotryum violaceum; plant-herbivore interactions; plant -pathogen interactions; sex bias; sex rato; successional gradients; fitness effects; Skeppsvik Archipelago; Terrestrial ecology; Terrestisk ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : About 6% of all angiosperms are dioecious. This separation of sexual function to male and female individuals, and the fundamentally different patterns of reproductive resource allocation that follows that separation, are thought to have important ecological and evolutionary consequences for plant enemy interactions. LÄS MER

  2. 2. Plant-Herbivore Interactions and Evolutionary Potential of Natural Arabidopsis lyrata Populations

    Författare :Adriana Puentes; Jon Ågren; Jenny Hagenblad; Roosa Leimu Brown; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; plant defenses; leaf herbivory; floral herbivory; ontogeny; G-matrix; trade-offs; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik; Biology with specialization in Evolutionary Genetics; Biologi med inriktning mot evolutionär genetik;

    Sammanfattning : In this thesis, I combined field, greenhouse and common-garden experiments to examine the ecological and evolutionary consequences of plant-herbivore interactions and the genetic architecture of fitness-related traits in the insect-pollinated, self-incompatible, perennial herb Arabidopsis lyrata. More specifically, I examined (1) whether damage to leaves and inflorescences affects plant fitness non-additively, (2) whether trichome production is associated with a cost in terms of reduced tolerance to leaf and inflorescence damage, (3) whether young plant resistance to a specialist insect herbivore varies among populations, and (4) whether the evolution of flowering time, floral display and rosette size is constrained by lack of genetic variation or by genetic correlations among traits. LÄS MER

  3. 3. The Effect of Snow on Plants and Their Interactions with Herbivores

    Författare :Mikaela Torp; Johan Olofsson; Christa Mulder; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Snow; arctic ecosystem; plant-herbivore interactions; phenology; nitrogen; phenolics; experimental manipulation; natural gradient; inter-annual variability; Biology; Biologi;

    Sammanfattning : The ongoing climate changes are predicted to accelerate fast in arctic regions with increases in both temperatures and precipitation. Although the duration of snow cover is generally expected to decrease in the future, snow depth may paradoxically increase in those areas where a large amount of the elevated precipitation will fall as snow. LÄS MER

  4. 4. Interactions between gray-sided voles (Clethrionomys rufocanus) and vegetation in the Fennoscandian tundra

    Författare :Jonas Dahlgren; Lauri Oksanen; Johan Olofsson; John Terborgh; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gray-sided voles; tundra vegetation; trophic cascades; plant-herbivore interactions; bilberry; plant communities; herbivory; plant resistance; Terrestrial ecology; Terrestisk ekologi;

    Sammanfattning : I have, in this thesis, studied the interactions between gray-sided voles (Clethrionomys rufocanus) and tundra vegetation, on islands in, and mainland sites close to the lake Iešjávri, in northern Norway. As isolated islands are virtually free of predation, I have been able to compare plant-herbivore interactions in the presence and absence of predators. LÄS MER

  5. 5. Plant-associated soil communities : Patterns, drivers and aboveground consequences

    Författare :Pil Uthaug Rasmussen; Ayco J. M. Tack; Martijn Bezemer; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aboveground-belowground interactions; arbuscular mycorrhiza; climate; dispersal; environmental drivers; fungi; genetic variation; nematodes; plant-herbivore interactions; soil communities; spatial patterns; ekologi och evolution; Ecology and Evolution;

    Sammanfattning : Soil contains a wealth of diversity – bacteria, fungi, nematodes, arthropods and earthworms are just some of the many organisms found belowground. These organisms play an important role in shaping the soil environment and they strongly influence plant fitness, diversity and community composition. LÄS MER