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Visar resultat 1 - 5 av 14 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Plant species diversity in semi-natural grasslands. Effects of scale, landscape structure and habitat history

    Författare :Triin Reitalu; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; habitat fragmentation; landscape diversity; habitat connectivity; historical maps; continuity; land-use history;

    Sammanfattning : The thesis examines the impact of present and past landscape structure, habitat history and management on different aspects of present-day plant species diversity in fragmented semi-natural grasslands in Sweden and in Estonia. Species diversity was significantly associated with present and/or past grassland connectivity in the majority of the studies in the thesis. LÄS MER

  3. 2. Description of spatial and temporal distributions of epiphytic lichens

    Författare :Håkan Lättman; Per Milberg; Bengt Gunnar Jonsson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; centroid; continuity; lichen; movement; range shift; direction; dispersal; ecological continuity; establishment; global change; global warming; habitat availability; håkan lättman; Biology; Biologi;

    Sammanfattning : Lichens are, in most cases, sensitive to anthropogenic factors such as air pollution, global warming, forestry and fragmentation. Two studies are included in this thesis. The first is an evaluation of the importance of old oak for the rare epiphytic lichen Cliostomum corrugatum (Ach.) Fr. LÄS MER

  4. 3. Semi-natural grasslands: landscape, history and plant species diversity

    Författare :Lotten Jönsson; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; Land-use history; cadastral maps; habitat continuity; fragmentation; landscape context; habitat connectivity;

    Sammanfattning : This thesis explores the impact of past and present landscape and habitat structure on present levels of vascular plant species diversity within fragmented semi-natural grasslands. Within the Jordtorp-area, a mosaic agricultural landscape on the island of Öland (Sweden), historical land-use changes and the development of semi-natural grasslands was characterized, over a time-period of almost 300 years, using historical maps, aerial photographs and a high-resolution imagery. LÄS MER

  5. 4. Remote sensing of grassland communities : integrated effects of soil nutrients and habitat age

    Författare :Oskar Löfgren; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Remote sensing; Plant ecology; semi-natural grassland; Nitrogen; Phosphorus; Semi-natural grassland; Plant ecology; Remote sensing; Nitrogen; Phosphorus; Spectral reflectance; grassland specialists; Succession;

    Sammanfattning : Semi-natural grasslands are characterized by high fine-scale plant species richness. The richest grassland communities, with many habitat-specialist species, are found in ancient grassland sites that have a long continuity of grazing management and low levels of soil nutrients. Grazed grasslands were widespread in the historical landscape. LÄS MER

  7. 5. Strengthening conservation through green infrastructure : linking protected areas, habitats and species

    Författare :Ewa Orlikowska; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The green infrastructure (GI) concept was developed to mitigate habitat fragmentation. The European Union (EU) defines GI as “a strategically planned network of natural and semi-natural areas …designed and managed to deliver a wide range of ecosystem services and to improve connectivity of protected areas in order to promote multifunctional landscapes”. LÄS MER