Visar resultat 1 - 5 av 37 avhandlingar innehållade ordet pollinators.
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
Sammanfattning : Agricultural intensification has caused severe declines among biodiversity in European farmland over the last half century. The transformation of the agricultural landscape has led to reduced availability of key resources such as food, nesting habitat and shelter. LÄS MER
Sammanfattning : The intensification of agriculture during the second half of the twentieth century, has caused sever declines of farmland biodiversity, where loss of semi-natural habitats is one of the major drivers. To halt further loss of habitat and biodiversity, agri-environmental schemes (AES) are used to compensate farmers to use methods less harmful to the environment. LÄS MER
Sammanfattning : Natural selection mediated by pollinators has influenced the evolution of floral diversity of the flowering plants (angiosperms). The scope of this thesis was to study: 1) phenotypic selection, 2) mating systems, and 3) floral shifts involved in plant speciation. Model plant species were Platanthera bifolia and P. chlorantha (Orchidaceae). LÄS MER
Sammanfattning : Several studies have found that organic farms support higher biodiversity, but results vary between studies such that some also show no or even negative effects. There can be many reasons why studies comparing organic and conventional farming show conflicting results. LÄS MER