title: Organic fields sustain weed metacommunity dynamics in farmland landscapes.
abstract: Agro-ecosystems constitute essential habitat for many organisms. Agricultural intensification, however, has caused a strong decline of farmland biodiversity. Organic farming (OF) is often presented as a more biodiversity-friendly practice, but the generality of the beneficial effects of OF is debated as the effects appear often species- and context-dependent, and current research has highlighted the need to quantify the relative effects of local- and landscape-scale management on farmland biodiversity. Yet very few studies have investigated the landscape-level effects of OF; that is to say, how the biodiversity of a field is affected by the presence or density of organically farmed fields in the surrounding landscape. We addressed this issue using the metacommunity framework, with weed species richness in winter wheat within an intensively farmed landscape in France as model system. Controlling for the effects of local and landscape structure, we showed that OF leads to higher local weed diversity and that the presence of OF in the landscape is associated with higher local weed biodiversity also for conventionally farmed fields, and may reach a similar biodiversity level to organic fields in field margins. Based on these results, we derive indications for improving the sustainable management of farming systems.
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and Université de La Rochelle, Beauvoir-sur-Niort 79360, France laura.henckel@cebc.cnrs.fr.
authors.forename: Laura
authors.initials: L
authors.lastname: Henckel
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and Université de La Rochelle, Beauvoir-sur-Niort 79360, France Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, UK.
authors.forename: Luca
authors.initials: L
authors.lastname: Börger
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and Université de La Rochelle, Beauvoir-sur-Niort 79360, France INRA, UMR1347 Agroécologie, 17 Rue de Sully, Dijon cedex 21065, France IUT ENSAIA, UMR, 2 avenue de la Forêt de Haye, Vandoeuvre les Nancy 54 500, France.
authors.forename: Helmut
authors.initials: H
authors.lastname: Meiss
authors.affiliation: INRA, UMR1347 Agroécologie, 17 Rue de Sully, Dijon cedex 21065, France.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Gaba
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS and Université de La Rochelle, Beauvoir-sur-Niort 79360, France LTER 'Zone Atelier Plaine & Val de Sèvre', Centre d'Etudes Biologiques de Chizé, CNRS, Villiers-en-Bois 79360, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Bretagnolle
mesh_terms: D044822:Biodiversity; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005602:France; D058871:Organic Agriculture; D057685:Plant Weeds / Q000502:physiology*; D012621:Seasons; D014908:Triticum
keywords: agricultural intensification; agroecology; landscape heterogeneity; organic farming; spatial scale; weeds