Disentangling the heritable and plastic components of the competitive and facilitative effects of an alpine foundation species

Differences in effects between phenotypes of foundation species on subordinate species have been reported, but no study has separated their heritable and plastic components. In a subalpine community of the French Pyrenees, we observed two phenotypes of Festuca gautieri: tight cushions in dry convex outcrops with few subordinate species, and loose cushions in wet concave slopes with many subordinate species, suggesting differences in effects of the two phenotypes on subordinates. Using two reciprocal transplantation gardens, we studied the responses of the two phenotypes to changes in environmental conditions, thus assessing the contribution of heritability and plasticity to the phenotypic variation. Using a target cross-transplantation experiment, we assessed the plasticity and heritability bases of their contrasting effects. We also quantified the recolonisation of resident plants within the reciprocally transplanted cushions. We found that morphological differences between cushions ha...