Sökning: "environmental stochasticity"

Visar resultat 11 - 15 av 15 avhandlingar innehållade orden environmental stochasticity.

  1. 11. Life histories and population dynamics

    Författare :Annie Jonsson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : During the last decades there has been a growing interest and attention to random variation in population densities and their causes. It has been shown that even in constant environments (deterministic population growth) the dynamics of populations can display random like behaviour depending on parameter values. LÄS MER

  3. 12. Assembly Mechanisms in Aquatic Bacterial Communities : The Role of Disturbances, Dispersal and History

    Författare :Mercè Berga Quintana; Silke Langenheder; Eva Lindström; Örjan Östman; Mathew Leibold; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; diversity; community composition; metacommunity;

    Sammanfattning : Environmental conditions, biotic interactions, dispersal and history have been suggested to be important processes influencing the spatial distribution of organisms and thus to affect community assembly. Understanding how these processes influence community assembly is important, particularly because community diversity and composition are suggested to be relevant for ecosystem functioning. LÄS MER

  4. 13. Conservation Genetics of the Eurasian Otter in Sweden

    Författare :Johanna Arrendal; Mats Björklund; Carles Vilà; Ralph Tiedemann; Uppsala universitet; []
    Nyckelord :Ecology; in situ conservation; individual identification; microsatellites; mtDNA; noninvasive genetic sampling; population dynamics; population size; PVA; restocking; Ekologi; Lutra lutra;

    Sammanfattning : In this thesis, molecular genetic methods were used to study a threatened species, the Eurasian otter. Estimates of population size and population dynamics parameters were obtained, the genetic effects of a restocking program was evaluated, and a population viability analysis was conducted to assess which demographic parameters are most important for the future viability of an otter population. LÄS MER

  5. 14. The ecological significance of cleistogamy

    Författare :Henrik Berg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; bet-hedging; chasmogamous; enviromnental variation; fitness; outcrossing; progeny; selling; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : Various aspects of cleistogamy, a reproductive system combining selfing in closed (cleistogamous) flowers and potential outcrossing in open (chasmogamous) flowers, were investigated in four perennial species. The main purpose was to shed some light on the adaptive value of having a dual reproductive strategy, and to test some hypotheses on the maintenance of xenogamy. LÄS MER

  7. 15. Colonisation and extinction of vascular plants on islands off the Swedish east coast

    Författare :Anders Löfgren; Lars Ericson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; plants; ecological succession; colonizing ability; population dynamics; grasslands; islands; Sweden; plant ecology; Plant Ecology; växtekologi;

    Sammanfattning : Persistence of species is a function of colonisation and extinction among patches at a regional scale. A decrease in area and an increased isolation of suitable patches may result in a decreased colonisation rate and an increased extinction rate among species. LÄS MER