Analysis of weed dispersal to predict chances of re-colonisation

The protection of rare arable weeds and the restoration of biodiversity in agroecosystems have become an important issue in most European countries. Traditional analyses of weed dispersal focussing on the prediction and control of infestations have to be adapted to the new aim of restoration ecology by quantifying chances of re-colonisation within fields and across field borders. This study analyses within-field spread of weeds under usual arable cultivation whereas between-field colonisation usually not aided by machinery was simulated in undisturbed controls. The experiments were conducted on an arable farm in the central German lowlands 6 years after conversion to organic management. The test species, Lithospermum arvense and Silene noctiflora, have declined in recent decades but belong to the characteristic weed community. Dispersal was analysed by recording seedling emergence around patches of introduced mother plants where the species were absent.