Finally we want to draw attention to the methodology used in this work. As previously noted, we have obtained trait values from the literature and public databases. These values represent static measures of traits and do not take into account that selection pressures operate at the individual level, and may, in time, lead to differences in trait values between populations that are under different environmental conditions. In this work, variation in weed tsa inhibitor composition between different tillage systems may be thought to be due to species different responses to tillage intensity as a function of their trait values. Therefore we think, in this case, that the use of trait values from the literature may be valid. Another possible drawback of using trait values from published sources is that some floras are not well represented and missing trait values may produce a bias in the results. We lack some traits values for eleven species (Table S2), but this may not be an issue for our work. Species with missing trait values were all recorded in low abundance and for only a few years of the experiment, and we used functional diversity metrics which, except for FRic consider trait values weighted by species abundance.