The importance of species phylogenetic relationships and species traits for the intensity of plant-soil feedback

Abstract

Plant-soil feedback (PSF) represents an important process affecting natural plant communities. While many previous studies demonstrated the variation in the intensity of PSF between species, the mechanisms driving these differences are still largely unexplored. The aim of the study was to explore the importance of species traits and species phylogenetic relationships on the intensity of plant-soil feedback. To do this we used a classical design to test plant soil feedback, i.e., a two-phase experiment consisting of conditioning and cultivation phase. In the conditioning phase, we used 30 different species from the Carduoidea subfamily of Asteraceae and conditioned soil by each of these species separately. In the cultivation phase, we observed growth of four of these species in all the soils. We predict that the intensity of PSF will be more intense between plants which are more closely related than between unrelated species. As an alternative, we explore the possibility that the intensity of PFS will be a function of plant traits related to nutrient acquisition by the plant. The intensity of feedback was significantly dependent on phylogeny in several cases indicating that more closely related species show more similar feedback effects. The feedback response was also affected by the chemical composition of the cultivated soil. In addition, the intensity of feedback was affected by height of the cultivating species and its ability to accumulate nitrogen and phosphorus in their leaves. While in most of these cases there is an indication that plants grow better in soils cultivated by smaller species accumulating less nutrients, in some cases the pattern in opposite. The direction and intensity of plant-soil feedback also strongly differed between life stages with seedling number commonly showing a response which was opposite to the response of the adults. Synthesis: The results supported our expectation that plant-soil feedback may be affected by species phylogenetic relationships. In addition, we have shown that also plant traits and the effect of the conditioning plant on soil chemistry may be useful factors allowing us to predict the intensity of plant-soil feedback in the system.