Conserving biodiversity in agricultural landscapes: a win-win for farmer and wildlife?

Abstract

Although agriculture depends critically on biodiversity-based ecosystem services such as insect pollination, conservation of biodiversity in agricultural landscapes has seen little uptake by the agricultural sector. We argue that this is largely because we lack knowledge on the relative importance of pollination compared to conventional agricultural inputs. Using the real-world variation in pollination and agricultural management of 36 commercial leek seed production fields in France and Italy, we show that the benefits of having more wild pollinators is at least as large as the benefits of management enhancing plant quality. Although the bulk of the pollination services was delivered by a few abundant bumblebee species, a diverse pollinator community replaced, or complemented these dominant species, depending on the crop variety. We furthermore show that crop yields are equally large, or even larger with 50% less agricultural inputs, and are consistently larger with more pollinator visits. Both the dominant and the scarce crop pollinators were positively correlated with cover of semi-natural habitats and the regional pollinator species pool, illustrating the benefit of conserving natural elements in agricultural landscapes. However, the dominant crop pollinators were largely absent in the landscape just prior to leek flowering, possibly because they are specialized in exploiting mass-flowering (crop) plants. Identifying where these important pollinators acquire their resources in agricultural landscapes throughout their flight period is essential to convince the agricultural sector to conserve biodiversity in agricultural landscapes and how to take measures.