Sökning: "tree hollow"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden tree hollow.

  1. 1. Population biology and conservation of beetles and pseudoscorpions associated with hollow oaks

    Författare :Thomas Ranius; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systematic zoology; wood mould; tree hollow; pseudoscorpion; population variability; Osmoderma eremita; metapopulation; mark-recapture; habitat fragmentation; genetic structure; dispersal; beetle; computer simulation; taxonomy; zoogeography; Zoologisk systematik; djurgeografi;

    Sammanfattning : Many species associated with old trees are threatened, as this habitat has decreased severely in Europe during the last 200 years. In old oaks, hollows with wood mould often form in the trunks and these harbour a specialized fauna mainly consisting of beetles, flies and pseudoscorpions. LÄS MER

  3. 2. Habitat requirements and preservation of the beetle assemblages associated with hollow oaks

    Författare :Nicklas Jansson; Per Milberg; Karl-Olof Bergman; Simon Grove; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : One of the most endangered assemblages of species in Europe is saproxylic beetles associated with old trees. To be able to conserve these species there is a need of developing methods to survey the fauna and to evaluate the conservation value of different oak habitats, develop instruments for landscape planning and detailed knowledge of species habitat requirements. LÄS MER

  4. 3. Metapopulation ecology of Osmoderma eremita - dispersal, habitat quality and habitat history

    Författare :Jonas Hedin; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; extinction debt; habitat history; habitat quality; pheromone; telemetry; capture-mark-recapture; metapopulation; dispersal; oak; Osmoderma eremita; beetle; Animal ecology; Djurekologi;

    Sammanfattning : This thesis starts with a review of different biodiversity assessment methods in forests and the rest deals with the metapopulation ecology of Osmoderma eremita, a threatened beetle living in hollow trees. I concentrate on the effect of dispersal, habitat quality and habitat history for the presence, population size and future survival of this species. LÄS MER

  5. 4. The Effect of Crosslinking on Morphology and Electrical Properties in LDPE Intended for Power Cables

    Författare :Susanne Nilsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LDPE; morphology; electrical treeing; peroxide; crosslinking; XLPE; water treeing;

    Sammanfattning : Crosslinked polyethylene (XLPE) is used as underground cable insulation due to its outstanding electrical properties and high temperature dimension stability. XLPE is often made by peroxide initiated crosslinking of low density polyethylene (LDPE). The introduction of unsaturations, i.e. LÄS MER

  7. 5. The significance of ethylene and ETHYLENE RESPONSE FACTORS in wood formation of hybrid aspen

    Författare :Bernard Wessels; Hannele Tuominen; Judith Felten; Totte Niittylä; Kurt Fagerstedt; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; ethylene; wood formation; hybrid aspen; Populus; ETHYLENE RESPONSE FACTOR; ERF85; ERF139; cambium; lignin; xylem expansion; secondary cell wall; tension wood; cambial derivative cell fate; vessel element; time-lapse photography; molekylär bioteknik inst f nat vet biokemi ; molecular biotechnology dept of biochem ; genetik; Genetics; Physiological Botany; fysiologisk botanik;

    Sammanfattning : The woody tissues serve to stabilise plants, store nutrients and translocate water and minerals. The formation of wood, or ’secondary xylem’, follows a well-defined developmental gradient which is initiated by cell division activity in the vascular cambium. LÄS MER