Sökning: "pollination"
Visar resultat 11 - 15 av 67 avhandlingar innehållade ordet pollination.
11. A network perspective on ecosystems, societies and natural resource management
Sammanfattning : This thesis employs a network perspective in studying ecosystems and natural resource management. It explores the structural characteristics of social and/or ecological networks and their implications on societies’ and ecosystems’ ability to adapt to change and to cope with disturbances while still maintaining essential functions and structures (i. LÄS MER
12. Small remnant habitats : Important structures in fragmented landscapes
Sammanfattning : The world-wide intensification of agriculture has led to a decline in species richness due to land use change, isolation, and fragmentation of natural and semi-natural habitats in agricultural and forestry landscapes. As a consequence, there is a current landscape management focus on the importance of green infrastructure to mitigate biodiversity decline and preserve ecosystem functions e. LÄS MER
13. Pollinator-mediated selection and the evolution of floral traits in orchids
Sammanfattning : In this thesis, I combined manipulations of traits and pollination environment with analysis of phenotypic selection to examine causes of variation in strength and mode of selection on floral traits, and I conducted a reciprocal sowing experiment to test for local adaptation in germination success. I tested the following predictions (1) the opportunity for selection, and the strength of pollinator-mediated and net selection increase with increasing pollen limitation, (2) the effects of traits affecting pollinator attraction and traits affecting pollination efficiency are non-additive and this leads to pollinator-mediated correlational selection, (3) the effects of spur length on pollen removal, pollen receipt, and female fitness differ between populations with short-tongued and populations with long-tongued pollinators, and (4) local adaptation at the stage of germination contributes to the maintenance of ecotypes growing in grasslands and woodlands, respectively. LÄS MER
14. Small biotopes: Landscape and management effects on pollinators
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
15. Reproductive patterns of birches (Betula spp.) in northern Sweden
Sammanfattning : The aim of this thesis was to study patterns of reproduction of Betula pendula and B. pubescens coll. along an altitudinal, coastal-inland, gradient in northern Sweden. The altitudinal variation was related to the distribution of the birch taxa along the gradient. LÄS MER
