COS 115-7
Phylogenetic divergence in forest trees determine plant-soil feedbacks
Plant-soil feedbacks are important drivers of ecosystem structure, productivity and diversity and are increasingly viewed as an important link in understanding the consequences of global change. Plants may condition soils through the addition of chemical compounds and organic matter as well as providing habitat for microorganisms. Soil conditioning may have performance consequences for the individual, conspecifics or heterospecifics via plant-soil feedbacks. Plant-soil feedbacks may have important landscape-level consequences, where they have been identified as a major force structuring tropical ecosystems as well as important drivers of productivity. Methods that generalize observed patterns in plant-soil feedbacks will be important for better understanding the consequences of global change. Plant phylogenetic relationships may provide an ideal tool for generalizing observations of feedback effects.
By utilising 15 species representing two eucalypt subgenera occurring on the island state of Tasmania, Australia, we aimed to determine whether plant-soil feedbacks are influenced by plant phylogeny. We conducted a fully factorial experiment testing the responses of eucalypt species belonging to both subgenera to potting soil inoculated with samples of soil conditioned by species of each subgenus. We hypothesized that the conditioned soil microbial communities within soil inoculum would influence seedling performance and that phylogeny would predict feedback effects.
Results/Conclusions
Our results show that plant-soil feedbacks may be phylogenetically conserved among genetic lineages. We identified a strong phylogenetic conditioning x phylogenetic response interaction, where the performance of one subgenus displayed a negative plant-soil feedback, while the other displayed no significant feedback effect. These data provide evidence that phylogenetic lineages differentially condition soils and that species respond to conditioned soils (home vs. away soil) depending on which phylogenetic lineage they belong. Taking a phylogenetic approach to plant-soil feedbacks may, therefore, allow an understanding of the interactions of whole phylogenetic lineages with their soil environment. These findings have implications for understanding ecosystem structure, productivity and diversity in a rapidly changing climate.