Plant community composition steers grassland vegetation via soil legacy effects

Soil legacy effects are commonly highlighted as drivers of plant community dynamics and species co-existence. However, experimental evidence for soil legacy effects of conditioning plant communities on responding plant communities under natural conditions is lacking. We conditioned 192 grassland plots using six different plant communities with different ratios of grasses and forbs and for different durations. Soil microbial legacies were evident for soil fungi, but not for soil bacteria, while soil abiotic parameters did not significantly change in response to conditioning. The soil legacies affected the composition of the succeeding vegetation. Plant communities with different ratios of grasses and forbs left soil legacies that negatively affected succeeding plants of the same functional type. We conclude that fungal-mediated soil legacy effects play a significant role in vegetation assembly of natural plant communities.

Methods
Vegetation recordings were assessed by visual estimation of each plant species present.

Nine soil samples were taken and pooled per subplot and these were homogenized as a representitive subplot sample. A subsample was taken for bacterial (16S) and fungal (ITS2) sequencing. 

For further extensive methodology, see Heinen et al. (2020) Ecology Letters.