Rhizosphere and litter feedbacks to range-expanding plant species and related natives

1.   Plant-soil feedback (PSF) results from the net legacy effect that plants leave in the composition of soil communities and abiotic soil properties. PSF is induced by the rhizosphere and by litter inputs into the soil, however, we have little understanding of their individual contributions. Here, we examine feedback effects from the rhizosphere of living plants, decomposing litter, and their combination. 2.   We used four pairs of climate warming-induced range-expanding plant species and congeneric natives, and examined PSF effects on plant biomass production, as well as on decomposition in their new range. 3.   We tested the hypothesis that the plant rhizosphere provides less negative feedback to range-expanders than to the congeneric natives, and that feedback mediated by litter decomposition does not provide such a difference because decomposers might be less specialized than pathogens. To determine PSF, we used soil from the congener species within each pair as an “away”...