Role of organic and conventional field boundaries on boreal bumblebees and butterflies

This study examined how field boundary habitat quality and farming system (organic or conventional) affect species richness and abundance of diurnal lepidopterans and bumblebees in boreal agricultural landscapes. The results showed positive effects of field boundary area on lepidopteran diversity, as well as positive effects of nectar flower abundance on lepidopterans and bumblebee abundance. Organic farming did not show any significant effects on lepidopteran diversity. The results suggested that a successful conservation strategy for lepidopterans occurring in boreal agroecosystems depend on proper management of field boundaries, irrespective of farming regime. As bumblebee diversity tended to be higher at organic plots it is concluded that these important pollinators might be able to react on even small changes in habitat quality of cultivated lands. The results concord with a general hypothesis that effects of organic farming might be overpowered by effects of landscape structure in heterogeneous landscapes.