Results of linear models testing variation in different measures of plant response to competition.

The measures were total biomass of (a) focal species (L. hispidus, P. lanceolata) and (b) associate species (F. rubra) when grown in mixture with each other; (c) total biomass growth response of focal species to competition (RIIc) and (d) the difference in growth response to inoculation of focal species and F. rubra when grown in mixture with each other (dRIIi mixture). Growth response parameters were calculated based on total plant biomass (root + shoot biomass), see Tables C-G in S2 File for results for root and shoot biomass separately. The explanatory factors tested were focal species (L. hispidus, P. lanceolata), inoculum origin (grassland, forest) and the interaction of both factors. For RIIc, values >0 indicate an increase and values <0 a decrease of plant biomass in response to competition. For, dRIIi mixture values >0 indicate a larger and values <0 a smaller growth benefit from inoculation to focal species compared with F. rubra, when plants were grown in mixture with each other. Where factor levels differ at p<0.1, group means (± SE) are displayed, with different letters indicating significant differences (p<0.05) according to post-hoc tests (Tukey HSD).