Bérenger Bourgeois1,2,3, François Munoz4, Guillaume Fried5, Lucie Mahaut2, Laura Armengot6, Pierre Denelle7, Jonathan Storkey8, Sabrina Gaba2,9,10, Cyrille Violle7. 1. Centre de Synthèse et d'Analyse sur la Biodiversité - Fondation pour la Recherche sur la Biodiversité, 13100, Aix-en-Provence, France. 2. Agroécologie, AgroSup Dijon, INRA, Univ. Bourgogne Franche-Comté, 21000, Dijon, France. 3. LTSER Zone Atelier "Plaine & Val de Sèvre", Centre d'Etudes Biologiques de Chizé, CNRS, 79360, Villiers-en-Bois, France. 4. Université Grenoble-Alpes, Laboratoire d'Ecologie Alpine, 38058, Grenoble, France. 5. Anses, Laboratoire de la Santé des Végétaux, Unité Entomologie et Plantes Invasives, 34988, Montferrier-sur-Lez, France. 6. FiBL, Research Institute of Organic Agriculture, 5070, Frick, Switzerland. 7. Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS - Université de Montpellier - Université Paul Valéry - EPHE, 34293, Montpellier, France. 8. Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK. 9. USC 1339, Centre d'Etudes Biologiques de Chizé, INRA, 79360, Villiers-en-Bois, France. 10. Centre d'Etudes Biologiques de Chizé, UMR 7372, CNRS & Université de La Rochelle, 79360, Villiers-en-Bois, France.
Abstract
PREMISE OF THE STUDY: Despite long-term research efforts, a comprehensive perspective on the ecological and functional properties determining plant weediness is still lacking. We investigated here key functional attributes of arable weeds compared to non-weed plants, at large spatial scale. METHODS: We used an intensive survey of plant communities in cultivated and non-cultivated habitats to define a pool of plants occurring in arable fields (weeds) and one of plants occurring only in open non-arable habitats (non-weeds) in France. We compared the two pools based on nine functional traits and three functional spaces (LHS, reproductive and resource requirement hypervolumes). Within the weed pool, we quantified the trait variation of weeds along a continuum of specialization to arable fields. KEY RESULTS: Weeds were mostly therophytes and had higher specific leaf area, earlier and longer flowering, and higher affinity for nutrient-rich, sunny and dry environments compared to non-weeds, although functional spaces of weeds and non-weeds largely overlapped. When fidelity to arable fields increased, the spectrum of weed ecological strategies decreased as did the overlap with non-weeds, especially for the resource requirement hypervolume. CONCLUSIONS: Arable weeds constitute a delimited pool defined by a trait syndrome providing tolerance to the ecological filters of arable fields (notably, regular soil disturbances and fertilization). The identification of such a syndrome is of great interest to predict the weedy potential of newly established alien plants. An important reservoir of plants may also become weeds after changes in agricultural practices, considering the large overlap between weeds and non-weeds.
PREMISE OF THE STUDY: Despite long-term research efforts, a comprehensive perspective on the ecological and functional properties determining plant weediness is still lacking. We investigated here key functional attributes of arable weeds compared to non-weed plants, at large spatial scale. METHODS: We used an intensive survey of plant communities in cultivated and non-cultivated habitats to define a pool of plants occurring in arable fields (weeds) and one of plants occurring only in open non-arable habitats (non-weeds) in France. We compared the two pools based on nine functional traits and three functional spaces (LHS, reproductive and resource requirement hypervolumes). Within the weed pool, we quantified the trait variation of weeds along a continuum of specialization to arable fields. KEY RESULTS: Weeds were mostly therophytes and had higher specific leaf area, earlier and longer flowering, and higher affinity for nutrient-rich, sunny and dry environments compared to non-weeds, although functional spaces of weeds and non-weeds largely overlapped. When fidelity to arable fields increased, the spectrum of weed ecological strategies decreased as did the overlap with non-weeds, especially for the resource requirement hypervolume. CONCLUSIONS: Arable weeds constitute a delimited pool defined by a trait syndrome providing tolerance to the ecological filters of arable fields (notably, regular soil disturbances and fertilization). The identification of such a syndrome is of great interest to predict the weedy potential of newly established alien plants. An important reservoir of plants may also become weeds after changes in agricultural practices, considering the large overlap between weeds and non-weeds.