Sökning: "pollinators"
Visar resultat 6 - 10 av 45 avhandlingar innehållade ordet pollinators.
6. Selection and Floral Evolution in Platanthera bifolia and P. chlorantha (Orchidaceae)
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
7. Effects of Farming Practice on Pollinators and Pollination across Space and Time
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
8. Pollinators, Enemies, Drought, and the Evolution of Reproductive Traits in Primula farinosa
Sammanfattning : In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits and population differentiation in the insect-pollinated, self-incompatible, perennial herb Primula farinosa. More specifically, I (1) determined whether the effects of floral display and interactions with pollinators and seed predators, and plant reproductive success were frequency-dependent and affected by surrounding vegetation context, (2) examined the consequences of intermittent drought years on population dynamics using numerical simulations based on demographic data collected over seven years, (3) analyzed among-population differentiation in flowering phenology and reproductive allocation, and its relationship to soil-depth at the site of origin. LÄS MER
9. The impact of forest on pest damage, pollinators and pollination services in an Ethiopian agricultural landscape
Sammanfattning : The distribution of wild biodiversity in agroecosystems affect crop performance and yield in various ways. In this thesis I have studied the impact of wild biodiversity, in terms of trees and forest structures, on crop pests, pollinators and the pollination services provided in a heterogeneous landscape in southwestern Ethiopia. LÄS MER
10. Ecology of pollinators, pests and natural enemies in agricultural landscapes : ensuring a sustainable supply of clover seeds
Sammanfattning : The human population and its food consumption continues to grow and the environmental impact of meeting future food demands depends on how we expand the food supply. Already, agricultural intensification has led to biodiversity declines, which in turn can have direct and indirect effects on agricultural production. LÄS MER
