Svensson, Birgitta
- Institutionen för ekologi och växtproduktionslära, Sveriges lantbruksuniversitet
Sammanfattning
The aim of the thesis was to investigate in what way different agricultural landscapes and management routines affect the abundance and performance of bumblebees. The studies were conducted in the surroundings of Uppsala, in mid Sweden. The area consists of both intensive, large-scale farming and small agricultural fields surrounded by pastures, forests and lots of boundaries. Both the local habitat type and the amount of forest in the surrounding agricultural landscape affected bumblebee queens searching for nesting sites. Boundaries, together with other uncultivated areas, showed the highest densities of nest-seeking queens. Different bumblebee species chose nesting sites in different habitats. Few of the available plant species were used as foraging source for the bumblebees. The highest frequency of foraging bumblebees was found in clearings, road boundaries and pastures. There was a negative correlation between the number of nest-seeking bumblebees in spring in a habitat and the number of foraging bumblebees there the following summer. The most frequently visited plant species for bumblebees in general were preferred by all observed bumblebee species. Differences "castes" were found to prefer different plants. Two declining bumblebee species in the agricultural landscape, Bombus sylvarum and B. subterraneus, both forage on plant species preferably growing in boundary habitats. For prevalence of these species, such habitats have to be conserved in the modern agricultural landscape. A greater abundance of foraging bumblebee queens in spring was estimated in areas with a high volume of Salix caprea per ha (>1000 m³ crown volume). In areas with low volumes of S. caprea per ha (
Nyckelord
bumblebees; Bombus; nesting sites; foraging; willows; Salix caprea; habitat selection; agricultural landscape; semi-natural pastures; heterogeneity; Sweden
Publicerad i
Acta Universitatis Agriculturae Sueciae. Agraria
2002, nummer: 318
Utgivare: Swedish University of Agricultural Sciences
SLU författare
UKÄ forskningsämne
Ekologi
Publikationens identifierare
- ISBN: 91-576-5847-1
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/107621