Field margin management for promoting plant diversity – A functional approach to investigating the effects of multiple measures on plant community dynamics.

Strategies to counteract the loss of arable plant diversity often target field margins. Yet there is still need for research on how arable plant diversity is impacted by the type, scale and diversity of margin management. To assess this experimentally, we combined five measures imposing different disturbance regimes (flower-strip mown twice a year, tilling in spring or autumn, adding sand as substrate, and frequent mowing as a control) at two spatial scales.We explored how plant community dynamics are affected by both single measures and their combination. We addressed four hypotheses: H1) single measures shift community weighted mean (CWM) values of functional traits and reduce the within-measure community weighted standard deviation (CWSD) of these traits; H2) heavy disturbance (early tilling and sand) causes taxonomic and functional diversity (alpha-diversity) to increase over time; H3) combining different measures increases dissimilarity (beta-diversity) and thus gamma-diversity across measures; and H4) increased spatial heterogeneity of measures promotes all levels of diversity.