Industrialized chemical agriculture has caused a decline of many important insects across the globe, while organic farming can promote biodiversity by using fewer harmful sprays and by providing critical food and habitat resources. A new study published in the Journal of Applied Ecology shows that there is no silver bullet strategy to promote insect diversity in farmland, and to do so at a regional scale, collaboration must occur between organic and non-organic farmers. Specifically, the study shows beneficial insect populations will increase if farms incorporate flowers or flowering crops regardless of organic management. However, organically managed farms and field edges supported the greatest diversity of wild plants. 

The researchers studied impacts of four farming treatments on the diversity, abundance, and community composition of wild plants and beneficial beetles, spiders, butterflies and wild bees. The four farming treatments were: 1) Conventionally managed flowering fields not used for food production, 2) Organically managed mono-crop of winter spelt, 3) Organically managed flowering mixed-crop, 4) and the control of conventionally managed winter wheat fields. The study took place on 17 field sites across three years, and found that field edges,  regardless of crop types and management, had the highest richness of beneficial carabid beetles and spiders. Species richness of wild bees and butterflies was highest in fields with flowers (both conventionally and organically managed) with no difference between inner fields and outer edges. Also, the amount of farmland in a 500-meter buffer area around the study site also affected community composition of all insects and spiders. The authors suggest that to improve the overall function of ecosystems, complementary species need to be supported, and agricultural policy that fosters collaboration between farms and farm management strategies will be the most effective. Specifically they call for governmental policies to cover the costs of coordinating collaboration schemes that prioritize supporting biodiversity.

Banner photo credit: Elena Shirnina; unsplash.com