Sökning: "species abundance"

Visar resultat 6 - 10 av 348 avhandlingar innehållade orden species abundance.

  1. 6. The threat from non indigenous species - ecosystem vulnerability, global distribution and co-occurrence with other major threats

    Författare :Helena Berglund; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; threats; distribution range; isolation; endemism; invasions; invaders; vulnerability; non indigenous species; rarity; threatened species;

    Sammanfattning : We live in a globalised world where people and goods travel large distances. Various species are brought along on these journeys, intentionally or as hitchhikers. Some of these species establish populations in regions to which they could not have spread without human assistance, and where they are considered to be non indigenous species (NIS). LÄS MER

  3. 7. On the abundance and distribution of organisms in fragmented riverscapes : Insights From Studies On Different Species And Spatiotemporal Scales

    Författare :Carl Tamario; Anders Forsman; Petter Tibblin; Erik Petersson; Johan Höjesjö; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Evolutionary Biology; Evolutionsbiologi;

    Sammanfattning : Dams in rivers modify the habitats and hinder dispersal and migration. Since moving around is an essential part of most organisms’ life histories, this represents a new regime for life in freshwater. LÄS MER

  4. 8. Diurnal variation of stratospheric short-lived species

    Författare :Maryam Khosravi; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; chlorine monoxide; short-lived species; Arctic ClO; diurnal variation; tropical middle stratosphere; Arctic stratosphere;

    Sammanfattning : Diurnal variation of stratospheric short-lived speciesMaryam KhosraviChalmers University of TechnologyDepartment of Earth and Space SciencesAbstractThe depletion of ozone in the stratosphere has a direct impact on the amount of ultravioletradiation reaching the Earth’s surface. The ozone abundance and distributionis controlled by the photo-chemical reactions and catalytic cycles involving halogens(chlorine and bromine), odd hydrogen and odd nitrogen species as well as by atmospherictransport. LÄS MER

  5. 9. Species interactions govern evolutionary and ecological effects of population harvesting

    Författare :Anna Gårdmark; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; population harvesting; species interactions; ecological community; Ekologi; Ecology; competition; predation; fisheries; spatial dynamics; maturation; population dynamics; life-history evolution; adaptation;

    Sammanfattning : Harvesting changes population abundance and can affect adaptation of several life-history traits. Harvesting can also have indirect effects ? effects on non-target species and secondary effects on target species ? because interactions between species in a community determine the relevant ecological and evolutionary feedback environment. LÄS MER

  7. 10. Responses of boreal forest understory plant communities to climate and forestry

    Författare :Ditte Marie Christiansen; Kristoffer Hylander; Johan Ehrlén; Signe Normand; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boreal forests; bryophytes; climate; climate change; community temperature index; demography; forest management; microclimate; plants; species interactions; species distributions; time-lags; transplant experiment; understory communities; Ecology and Evolution; ekologi och evolution;

    Sammanfattning : A warming climate is altering species distributions and community compositions. To understand and predict changes in species distributions to climate change, we often use species occurrences together with large-scale regional climate data. This can be problematic for several reasons. LÄS MER