Extensive vegetation management and semi-natural habitats increase plant alpha and gamma diversity in European vineyards

Permanent crops like vineyards have the potential to contribute to halting the biodiversity loss due to their spatiotemporal stability and lower disturbance frequency in vineyard inter-rows. However, anthropogenic pressures can be quite high in such agroecosystems and little is known about the relative impacts of local management intensity and landscape context on plant communities in viticultural landscapes. In this study, we examined how plant communities were affected by management intensity and landscape context in two European wine-growing regions. We established four plots within one inter-row and three transects in two neighbouring inter-rows and one undervine row in each of 70 paired vineyards (organic versus conventional farming) along a gradient of proportion of semi-natural habitats in the landscape. We analysed how alpha, beta and gamma diversity and plant species community composition at the vineyard scale responded to farming system, disturbance frequency, and semi-natural habitats. We found a positive impact of organic farming on alpha and gamma diversity and a significant influence of farming and transect type on species community composition. Besides farming system, disturbance frequency (tillage and mulching) reduced alpha diversity but increased beta diversity in the transects of both wine-growing regions. This difference could be attributed to the establishment of different plant communities of vineyards managed with higher or lower mulching and/or tillage intensity. At the landscape scale, higher proximity to and higher proportion of semi-natural habitats increased plant alpha and gamma diversity. Both landscape variables also explained significant variance of the plant community composition. Conservation of farmland biodiversity in vineyards should focus on supporting low-intensity diversified management operations and increasing shares of semi-natural habitats in the landscape.