Sökning: "plant density"

Visar resultat 16 - 20 av 148 avhandlingar innehållade orden plant density.

  1. 16. 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

  3. 17. Population biology of the clonal plant Ranunculus lingua

    Författare :Mats E. Johansson; Christer Nilsson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; clonal fragmentation; emergent macrophytes; fungal pathogens; hydrochoiy; invertebrate grazing; marginal population; Peronospora gigantea Prasocuris phellandrt regional abundance; rhizome production; size-number trade-off; vegetative reproduction; water-level fluctuation;

    Sammanfattning : The scope of this thesis was to identify, describe and quantify important life-history traits for the pseudoannual aquatic plant Ranunculus lingua in different ecological settings, by comparing populations from geographically marginal vs. central habitats. LÄS MER

  4. 18. Plant-soil-herbivore interactions in a high Arctic wetland - Feedbacks to the carbon cycle

    Författare :Julie Maria Falk; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic wetlands; carbon balance; herbivory; increased grazing pressure; methane fluxes; muskox exclusion; substrate avalibility; vegetation composition and density;

    Sammanfattning : Arctic ecosystems hold massive amounts of the global carbon in their soils and are of great importance for the global terrestrial exchange of greenhouse gases to the atmosphere. The arctic region has in general been acting as a C sink for the past 10000 years, however with climate change the C balance in some areas is shifting towards becoming a C source. LÄS MER

  5. 19. Plant Inducible Responses to Damage: Evolution and Ecological Implications

    Författare :Johannes Järemo; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; herbivory; inducible defences; compensation; Ecology; Ekologi;

    Sammanfattning : Abstract Inducible plant responses to damage, i.e. inducible defence responses and compensatory growth responses, are theoretically examined in an evolutionary and ecological context. Inducible defences are generally considered to be beneficial under conditions of low risk of herbivory and when initial damage is moderate. LÄS MER

  7. 20. Circumpolar impacts of herbivores on Arctic tundra vegetation

    Författare :Elin Lindén; Johan Olofsson; Maja K. Sundqvist; Mariska te Beest; Elisabeth S. Bakker; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; herbivores; grazing; Arctic; circumpolar; tundra; vegetation; plant defence; secondary metabolites; shrub birch; exclosures; vegetation; species diversity; biology; biologi;

    Sammanfattning : Arctic tundra vegetation provides many ecological services that have implications for the global climate. However, the tundra biome is currently changing in response to increasing temperatures. Herbivores may mitigate some of these responses to warming through their impact on Arctic vegetation. LÄS MER