Organic farming has been proposed a key agri-environment scheme to counteract the negative impact of agricultural intensification on biodiversity. The high expenditure invested in this conservation programme has led to a rapidly growing number of studies evaluating its effectiveness. However, most of these studies have focused on birds, plants and insects in temperate crops and grasslands which may have led to species- and area-biased conclusions.

To fill this gap, we investigated the effectiveness of organic farming on bats and arachnids in Mediterranean vineyards. Using a paired design, we assessed the relative importance of farming system alongside with landscape characteristics and vineyard structure for these taxa. We decided to focus our case study on bats and arachnids given that (i) they are both situated in high tropic level and play an important role as pest suppression in farmland; (ii) they are considered as bioindicators of ecological changes; and (iii) they have different functional traits (mobility, dispersal ability and home range size) which we hypothesized determine how they respond to organic farming.

Overall, our study shows that organic farming enhances the abundance and richness of arachnids in vineyards. However, we found that organic farming on its own did not promote bat activity nor bat species richness, regardless of the landscape context. We demonstrated that landscape features were the main drivers of bat activity as bats were significantly more active over vineyard plots located closer to hedgerows and freshwater sites. This implies that the designation of adequate conservation strategies in Mediterranean agroecosystems will require a multi-scale approach.

Jeremy Froidevaux, final year SWBio DTP student

Paper: ‘Does organic farming enhance biodiversity in Mediterranean vineyards? A case study with bats and arachnids’ by J. S.P.Froidevaux B. Louboutin and  G. Jones in Agriculture, Ecosystems & Environment