Sökning: "habitat distribution"

Visar resultat 21 - 25 av 145 avhandlingar innehållade orden habitat distribution.

  1. 21. Evolution of Dispersal and Habitat Exploration in Butterflies

    Författare :Ulf Norberg; Hans Van Dyck; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ethology and behavioural ecology; Etologi och beteendeekologi; etologi; Ethology;

    Sammanfattning : The development of wings may be one of the most important reasons for the great diversity among insects. Being able to move makes it possible to colonise new areas and explore resources in the surroundings. However, developing dispersal-related traits, like wings or flight muscles, is costly and moving can also be dangerous. LÄS MER

  3. 22. Habitat selection and indirect interactions in fish communities : mechanisms to explain spatial distribution of perch, roach, and vendace

    Författare :Ulrika Beier; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : To increase the understanding of freshwater lake ecosystems, I have studied the habitat selection of perch (Perca fluviatilis L.), roach (Rutilus rutilus (L.)), and vendace (Coregonus albula (L.)). LÄS MER

  4. 23. Distribution and persistence of epiphyte metapopulations in dynamic landscapes

    Författare :Victor Johansson; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Habitat loss is a major cause of species extinction. Old trees have declined, and this continues because of poor management. Examples are development of secondary woodland in semi-open grasslands, and lack of natural tree regeneration. We therefore can expect that species associated with old tree are declining. LÄS MER

  5. 24. Metapopulation and metacommunity processes, dispersal strategies and life-history trade-offs in epiphytes

    Författare :Swantje Löbel; Håkan Rydin; Tord Snäll; Lars E. Ericson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asexual; biodiversity; bryophytes; dispersal limitation; establishment; evolution of reproductive traits; germination; growth; habitat fragmentation; landscape dynamics; local processes; patch-tracking; pH; reproduction; species richness; species interactions; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : The aim of this thesis was to increase knowledge about metapopulation and metacommunity processes in patchy, dynamic landscapes, using epiphytic bryophytes as a model system. Host trees and deciduous forest stands in the coniferous landscape are patchy, temporal and undergo changes in habitat quality during succession. LÄS MER

  7. 25. Conservation biology and genetic structure of fringe populations of the scarce heath butterfly in Sweden

    Författare :Anna Cassel; Volker Loeschcke; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Genetics; fragmentation; genetic structure; mobility; inbreeding; habitat requirements; Lepidoptera; Genetik; Clinical genetics; Klinisk genetik; Conservation Biology; naturvårdsbiologi;

    Sammanfattning : During the past century, about 82% of meadows and pastures have been lost in Sweden, with negative consequences for their flora and fauna. An example is the scarce heath butterfly, which is one of the red-listed species threatened by such habitat loss through afforestation. LÄS MER