Sökning: "Grasslands"

Visar resultat 31 - 35 av 72 avhandlingar innehållade ordet Grasslands.

1. 31. Hyperspectral and multispectral remote sensing for mapping grassland vegetation

   Författare :Thomas Möckel; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plant diversity Partial least squares Ellenberg indicators Vegetation index Heterogeneity;

   Sammanfattning : As a consequence of agricultural intensification, large areas of species-rich grasslands have been lost and farmland biodiversity has declined. Previous studies have shown that the continuity of grazing management can have a significant influence on the environmental conditions and the levels of plant species diversity in grassland habitats. LÄS MER

3. 32. 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

4. 33. Seed mobility and connectivity in changing rural landscapes

   Författare :Alistair G. Auffret; Sara Cousins; Robin Pakeman; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Biodiversity; Conservation; Functional connectivity; Historical ecology; Human-mediated dispersal; Invasive species; Landscape Ecology; Long-distance dispersal; Restoration; Seed bank; Seed dispersal; Seed rain; Structural connectivity; Physical Geography; naturgeografi;

   Sammanfattning : The success or failure of many organisms to respond to the challenges of habitat destruction and a warming climate lies in the ability of plant species to disperse between isolated habitats or to migrate to new ranges. European semi-natural grasslands represent one of the world's most species-rich habitats at small scales, but agricultural intensification during the 20th century has meant that many plant species are left only on small fragments of former habitat. LÄS MER

5. 34. Soil phosphorus – a multidimensional resource that plays an important role for grassland plant species richness

   Författare :Jakob Sandberg; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; niche dimension; nutrient limitation; niche differentiation; competition; soil nitrogen; soil phosphorus; plant diversity; species richness; Grassland; land use; landscape scale;

   Sammanfattning : The semi-natural grassland habitats contain an important part of the plant diversity in Europe. Changes in farming practices have lead to drastic decreases in plant species richness. The aim of the present thesis is to contribute to the knowledge about mechanisms governing the plant species richness in grasslands with emphasis on soil nutrients. LÄS MER

7. 35. Pollinators and Insect Pollination in Changing Agricultural Landscapes

   Författare :Lina Herbertsson; Miljövetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pollinators; pollination; agri-environment schemes; beekeeping; oilseed rape; sown flower strips; agri-environment measures;

   Sammanfattning : Agricultural intensification and associated loss of semi-natural grasslands, has resulted in reduced landscape heterogeneity. A concomitant loss of forage and nest sites for pollinating insects has driven declines across several pollinator taxa. LÄS MER