Effekter av landskapets sammansättning på humlearters förekomst
The species in the genus bumblebees (Bombus) are important pollinators. In the world there are 250 bumblebee species and there are 34 species in Norway. The purpose of this study is 1) to assess changes in the species composition of bumblebees in twenty different places in Norway that have been inventoried first one time between 1939-1960 and the second time in 2012, and 2) to relate species richness and distributions to current landscape composition with the aid of orthophotos. In this study, I have used regression analyzes on the different bumblebee species that were present or absent at the inventory, using the premises of the following variables: low or high altitude, latitude, longitude and seven different types of land use (farmland, building/plots, open land/pasture, forest, wetland and open or snow-covered ground above the tree line) to see if there was any relationship between each species and the different variables.
I have not analyzed what the landscape looked like at the first inventories and therefore we cannot say whether it has changed and if that is why species number has decreased. This would be interesting to study further and to see if there is any relationship between landscape changes and bumblebee?s species decline. All species are dependent of flora and, if there is no suitable flora at the current location, there will be no bumblebees.