Using functional traits to evaluate the weediness potential of spontaneous vegetation in an agroecological transition

Abstract

This study examines the weedinesspotential of spontaneous vegetation in an agroecosystemundergoing an agroecological transition inBuenos Aires Province, Argentina. We sampled parcelsunder three types of agronomic management—conventional, agroecological with annual crops andagroecological with perennial crops—along withnon-managed terraces. We assessed floristic andfunctional diversity based on seven traits associatedwith weediness: clonality, growth form, life cycle,dispersal syndrome, plant fecundity, maximum potentialvegetation height, and seed size. In floristic terms,a principal component analysis clearly separated theparcels into three distinct groups: terrace, conventionallymanaged, and agroecological. The weedinesspotential of spontaneous vegetation showed distinctdifferences across the types of land management.Conventional parcels were characterized mainly byhigh-weediness species (non-clonal annuals, herbaceous,with high fecundity and having small seeds)whereas terrace parcels were characterized by lowweedinessspecies (shrubby perennials with hemerochoricdispersal, low fecundity and large seeds).Agroecological parcels exhibited mixed weedinesstraits, and those with annual crops were largely composedof herbaceous non-clonal annuals with intermediatetraits and hemerochoric dispersal. Agroecologicalparcels with perennial crops featured mainlygraminoids, annuals and stoloniferous species withintermediate traits. Consequently, terrace parcels areunlikely to contribute significantly to common weedyvegetation. Understanding functional traits related tothe weediness of spontaneous vegetation is essentialfor agriculture, as it can help promote beneficial speciesand control harmful ones, supporting the transitionto agroecological practices and improving ecosystemprocesses while reducing pesticide use.