Mean (± 1SE) above-ground biomass of a community of four species (<i>Elymus glaucus</i>, <i>Nasella pulchra</i>, <i>Medicago lupulina</i> and <i>Sonchus oleraceus</i>) grown in the: a) absence (NoBr) versus presence of <i>B</i>.<i>nigra</i> plants from the invasive (Inv) or native (Nat)-range crossed with absence versus presence of <i>Achillea millefolium</i>, b) absence versus presence of root herbivory on invasive- or native-range <i>B</i>.<i>nigra</i> plants crossed with absence versus presence of <i>A</i>.<i>millefolium</i>.

<p>Mean (± 1SE) above-ground biomass of a community of four species (<i>Elymus glaucus</i>, <i>Nasella pulchra</i>, <i>Medicago lupulina</i> and <i>Sonchus oleraceus</i>) grown in the: a) absence (NoBr) versus presence of <i>B</i>.<i>nigra</i> plants from the invasive (Inv) or native (Nat)-range crossed with absence versus presence of <i>Achillea millefolium</i>, b) absence versus presence of root herbivory on invasive- or native-range <i>B</i>.<i>nigra</i> plants crossed with absence versus presence of <i>A</i>.<i>millefolium</i>.