Major field margin vegetation types in France and their relationships with climate, agricultural landscapes and management intensity

ABSTRACTArable field margins are an important semi-natural habitat providing multiple functions in agroecosystems. Despite three decades of research, analyses of species assemblage and functional traits are lacking. Leveraging a national monitoring network in metropolitan France, we aim to provide a comprehensive taxonomic and functional synthesis of field margin flora, outline main field margin types and explore their associations with management practices, climate, and agricultural landscapes. We analysed data from 532 field margins surveyed between 2013 and 2017, using both uni- and multivariate analyses. Field margins exhibited great diversity with 711 distinct taxa (12% of all flora in mainland France) at the national scale and an average of 16 species per 10 m2 locally. While field margins contained few species of conservation value, they offered a refuge for many declining species as well as rare arable weed species. We identified seven main field margin types, each linked to distinct conditions of climate, soil, landscape and agricultural practices. Mediterranean field margins notably differed from all others. In the main cluster, vineyard margins also stood out as distinct from annual crop margins. Additionally, field margins in landscapes with a high proportion of grassland differed from those within intensively cultivated field crop plains in conventional agriculture. Overall, our study highlights the high botanical diversity of field margins and their interest for plant conservation in agricultural landscapes. Promoting the installation and/or maintenance of field margins through agri-environmental schemes should thus favour biodiversity conservation and associated ecosystem provision.KEYWORDS: Field marginsvegetation typeagricultural practicesagroecosystemarable weedsfloraconservation valuetypology AcknowledgmentsThe 500 ENI network is developed by the French Ministry of Agriculture (DGAL) under the Ecophyto framework. We thank the Office Français de la Biodiversité (OFB) for the funding of scientific coordination of the network (GT STEP & GTP) as well as Benoît Ricci and Christine Meynard for leading the GT STEP and the GTP respectively. We thank all the contributors that have collected the data in the field, the farmers who provided information on their practices as well as all the coordinators of the network: Camila Andrade, Victor Dupuy, Nora Rouillier (MNHN), Jérôme Jullien, Olivier Rousselle and Nicolas Lenne (DGAL – Ministry in charge of Agriculture). We thank Pierre-Antoine Précigout and two anonymous reviewers for their constructive comments on the manuscript.Disclosure statementNo potential conflict of interest was reported by the author(s).Author contributionsGF conceived the study and analysed data; LH participated in data analysis by producing some of the explanatory variables used; GF wrote the first draft with significant contributions from IP, LH and AA. All authors contributed to the final version of the manuscript.Data availability statementThe raw data are the property of the Ministry of Agriculture and are open to French public research on request. The consolidated data used for this article were produced by the GT STEP and the GTP. They are available on request from the authors and under conditions, by signing a charter of use.Supplementary dataSupplemental data for this article can be accessed online at https://doi.org/10.1080/23818107.2023.2269243Additional informationFundingOffice Français de la Biodiversité (OFB) under the GT STEP (SIREPA N°4231) and GTP (OFB-21-1642) projects