Effects of conventional and organic management on plant and insect communities in a traditional elephant garlic crop

Agricultural management has a great infuence on biodiversity and its services in agroecosystems. In Europe, a relevant proportion of biodiversity is dependent on low-input agriculture. To assess the efects of agricultural management on biodiversity, in this study we surveyed the communities of arable plants, diurnal fying insects, and pollinators in three conventional and in two organic felds of a traditional Elephant garlic (Allium ampeloprasum L.) crop of the Valdichiana area, in Tuscany (central Italy). The sampling was carried out twice during the season: in spring, during crop growing, and in summer, after crop harvesting. We assessed the efects of the diferent agricultural management on the richness and composition (species occurrence and abundance) of the three communities using univariate and multivariate analyses. Concerning our specifc case study, only plant species richness was signifcantly higher in organic felds (15.7±2.7 species per plot), compared to conventional ones (5.4±2.3 species per plot). Regarding community composition, only pollinators showed a marginally signifcant diference between conventional and organic felds. Conversely, the efect of specifc felds signifcantly explained diferences in composition of all the investigated groups (plants, total insects, and pollinators). The results suggest that, in our case study, the emerged diferences in diversity of the investigated communities were mainly attributable to environmental and management factors related to single felds, more than to organic or conventional farming. Such evidence could be partly due to the very local scale of the study, to the heterogeneity of the surveyed felds, and to the reduced number of surveyed felds. Further investigation is therefore needed.