Pollination, wild bee communities and seed development in apple orchards of Sogn and Hardanger in Western Norway

Human progression has led to and is still creating massive land use changes. This is the main driver of biodiversity loss, and we are currently living in the sixth mass extinction. Increased human populations need increased food production, which rely heavily on ecosystem services. Pollination is estimated to be crucial for 70% of food crops used directly for human consumption, and especially fruit and berry crops such as apples are dependent on animal pollination often provided by insects. Several studies have shown that wild bees often are more effective pollinators than managed honeybees. In this study, I explore pollination in ten apple orchards in Sogn and Hardanger in Western Norway. These areas have not been extensively sampled since the 1950s, I found that the species common at that time still are common today. The abundance and diversity of wild bees varied greatly between sites. For wild bees to thrive in an area, they also need floral resources outside of the intense apple flowering period. I mapped the surrounding vegetation in a 200m radius of each orchard focusing on potential floral resources. Bumblebees seem to be positively affected by woodlands in the area, but I did not find definite effects from floral resources such as meadows. Managed honeybees can affect wild bees, I did not find any clear signs of competition but there were more bumblebees at sites further away from beehives. Apple seed set was also studied, of which the main difference in seed set were found between cultivars. Gravenstein apples contained a much smaller proportion of developed seeds than Aroma and Summerred apples.

Masteroppgave i biologi

BIO399

MAMN-BIO

MAMN-HAVSJ