Plant community composition but not plant traits determine the outcome of soil legacy effects on plants and insects

1.Plants leave species-specific legacies in the soil they grow in that can represent changes in abiotic or biotic soil properties. It has been shown that such legacies can affect future plants that grow in the same soil (plant-soil feedback, PSF). Such processes have been studied in detail, but mostly on individual plants. Here we study PSF effects at the community level and use a trait-based approach both in the conditioning phase and in the feedback phase to study how twelve individual soil legacies influence six plant communities that differ in root size.

2.We tested if (I) grassland perennial species with large root systems would leave a stronger legacy than those with small root systems, (II) grass species would leave a more positive soil legacy than forbs and (III) communities with large root systems would be more responsive than small-rooted communities. We also tested (IV) whether a leaf chewing herbivore and a phloem feeder were affected by soil legacy effects in a community...