Humlor i urbana miljöer: Vilka förutsättningar krävs för att de ska gynnas?

Sammanfattning: Land-use changes have led to a decline in suitable habitats for bumblebees, which may affect pollination of crops and wild flowers. Urban green areas such as parks and private gardens have the potential to favor bumblebees and it is thus important to understand how such areas should be designed. The aim with this study is to investigate what is needed to favor bumblebees in the urban environment, in terms of flower resources, nesting habitats and how far they can fly to gather resources. This study shows that the most important flower families for bumblebees are Fabaceae, Boraginaceae and Lamiaceae. Most bumblebees are generalists when choosing a place for nesting, but the most common nesting place is under ground in old rodent nests or above ground in association with vegetation. The distance travelled to gather nectar and pollen varies a lot between the different bumblebee species and even between different individuals of the same species. In general bumblebees with large nests travel further away from the nest to gather resources and they can fly up to several kilometers away. In conclusion bumblebee species are essential pollinators that are important to protect and therefore further investigation is needed to determine if the available resources in the cities of Sweden are good enough to ensure a stable population of pollinators with a large diversity.