Sökning: "small population size"

Visar resultat 1 - 5 av 161 avhandlingar innehållade orden small population size.

  1. 1. Effects of size-dependent predation and competition on population and community dynamics

    Detta är en avhandling från Umeå : Institutionen för ekologi, miljö och geovetenskap. Umeå universitet

    Författare :Karin Nilsson; Umeå universitet.; [2010]
    Nyckelord :size-structure; cannibalism; resource competition; predation; emergent facilitation; population regulation; population dynamics; overcompensation; density-dependence; cycles; zooekologi; Animal Ecology;

    Sammanfattning : Most animals grow substantially during their lifetime and change in competitive ability, predatory capacity and their susceptibility to predation as they grow. This thesis addresses the implications of this on regulation and dynamics within populations as well as between population interactions. LÄS MER

  2. 2. Small remnant habitats Important structures in fragmented landscapes

    Detta är en avhandling från Stockholm : Department of Physical Geography, Stockholm University

    Författare :Jessica Lindgren; Stockholms universitet.; [2017]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Alpha-diversity; Beta-diversity; Biological pest control; Canopy cover; Connectivity; Ecosystem function; Fleshy fruits; Forest edge; Forest management; Forest specialist species; Fragmentation; Functional diversity; Gamma-diversity; Grassland specialist species; Green infrastructure; Habitat amount hypothesis; Island biogeography; Midfield islets; Plant diversity; Plant-pollinator interaction; Pollination; Remnant habitat; Seed predation; Small habitats; Species richness; Structural heterogeneity; Physical Geography; naturgeografi;

    Sammanfattning : The world-wide intensification of agriculture has led to a decline in species richness due to land use change, isolation, and fragmentation of natural and semi-natural habitats in agricultural and forestry landscapes. As a consequence, there is a current landscape management focus on the importance of green infrastructure to mitigate biodiversity decline and preserve ecosystem functions e. LÄS MER

  3. 3. Population viability analysis for plants practical recommendations and applications

    Detta är en avhandling från Stockholm : Botaniska institutionen

    Författare :Satu Ramula; Stockholms universitet.; Södertörns högskola.; [2006]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES Biology; NATURVETENSKAP Biologi; demography; matrix population models; population viability analysis; population growth rate; stochastic models;

    Sammanfattning : Population viability analysis (PVA) is commonly used in conservation biology to predict population viability in terms of population growth rate and risk of extinction. However, large data requirements limit the use of PVA for many rare and threatened species. LÄS MER

  4. 4. Population divergence at small spatial scales – theoretical and empirical investigations in perch

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Sara Bergek; Uppsala universitet.; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Perca fluviatilis L.; Perch; Small scale genetic differentiation; Morphometrics; Isolation by distance; Dispersal; Gene flow; Microsatellites; Spatiotemporal stability; Barriers; NATURAL SCIENCES Biology; NATURVETENSKAP Biologi; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology; NATURVETENSKAP Biologi Terrestrisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

    Sammanfattning : Genetically structured populations arise when gene flow between groups of individuals is hindered by geographical, behavioural or temporal barriers. The identification of such groups is important for understanding evolution and has large implications for conservation concern. LÄS MER

  5. 5. Genomic analysis of the process leading up to the extinction of the woolly mammoth

    Detta är en avhandling från Stockholm : Department of Zoology, Stockholm University

    Författare :Patrícia Pečnerová; Stockholms universitet.; [2018]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; woolly mammoth; Mammuthus primigenius; extinction; Wrangel Island; ancient DNA; palaeogenetics; population genetics; genomics; genomic erosion; genetic drift; inbreeding; population size; Systematic Zoology; zoologisk systematik och evolutionsforskning;

    Sammanfattning : Species worldwide are subject to contractions in both abundance and geographical range, and their persistence in a changing environment may thus depend on the ability to survive in small and fragmented populations. Despite the urgent need to understand how extinction works, our knowledge of pre-extinction genetic processes is limited because techniques allowing population and conservation genomics to be studied in wild threatened populations have become available only recently. LÄS MER