Sökning: "species assemblages"

Visar resultat 16 - 20 av 69 avhandlingar innehållade orden species assemblages.

  1. 16. What are the effects of natural versus human-caused acidity on stream species diversity and ecosystem functioning?

    Författare :Zlatko Petrin; Björn Malmqvist; Steve J. Ormerod; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; acid rain; aquatic insects; biodiversity; ecosystem function; Biology; Biologi;

    Sammanfattning : Human activities have caused acidification of freshwater systems on a large scale resulting in reduced species diversity and ecological functioning in many lakes and streams. However, many naturally acidic freshwater systems have also been found, for instance in northern Sweden. LÄS MER

  3. 17. The importance of wetlands for biodiversity in agricultural and urban landscapes

    Författare :Elisabeth Lundkvist; Linköpings universitet; []
    Nyckelord :Dytiscidae; diving beetles; wetland; pond; diversity; assemblage; CCA; ordination; variation partitioning; community structure; flight; migration;

    Sammanfattning : The aim in this thesis was to study the importance of different types of wetlands for the biodiversity in a landscape. The landscapes were both agricultural and urban, and wetlands were in different successional stages. Diving beetles (Dytiscidae) were used as study organisms. LÄS MER

  4. 18. The role of regeneration in plant niche differentiation and habitat specialization

    Författare :Dirk-Jan ten Brink; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; seed mass; seed size; drought; shade; seed germination; seed dormancy; seedling establishment; plant community ecology; assembly rules; habitat specialization; plant recruitment; Regeneration; niche differentiation; phylogenetic independent contrasts; plant traits; soil fertility; comparative ecology;

    Sammanfattning : To predict the effects of environmental change and nature management on the distribution of plant species, it is crucial to understand the mechanisms of plant niche differentiation and habitat specialization. The importance to habitat specialization of particular plant traits and requirement of the regenerative phase of the plants life has received scanty interest. LÄS MER

  5. 19. Jurassic and Early Cretaceous selachians - focus on southern Scandinavia

    Författare :Jan Rees; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geology; Paleontologi; Palaeontology; Lissodus; palaeoecology; England; Denmark; Sweden; sharks; selachians; Jurassic; Early Cretaceous; physical geography; Geologi; fysisk geografi;

    Sammanfattning : The Jurassic and Early Cretaceous selachian faunas of Scania (Skåne), southern Sweden and the island of Bornholm (Denmark) have been investigated. Three Early Jurassic shark tooth assemblages have been recorded and investigated, one from Hettangian strata and the other two from Pliensbachian sediments. LÄS MER

  7. 20. Community Assembly and Spatial Ecology of Saproxylic Coleoptera

    Författare :Jonas Victorsson; Mats Björklund; Stefan Ås; Anne Magurran; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Terrestrial ecology; Terrestisk ekologi; Animal Ecology; zooekologi;

    Sammanfattning : Community assembly is the process deciding inclusion/exclusion of species in a developing community. Spatial ecology integrates spatial habitat factors with local biotic interactions within a given patch. I used standardized tree bolts (0.35-1 m long) to sample saproxylic (wood living) beetles in natural and managed forest types. LÄS MER