Phylogenetic structure of soil bacterial communities predicts ecosystem functioning.

Area of Science:

• Ecology
• Microbiology
• Evolutionary Biology

Background:

• Quantifying diversity using phylogeny-informed metrics is crucial for understanding ecosystem functioning (EF).
• The influence of diversity on EF is debated, with potential interactions between phylogenetic diversity and taxonomic identity.
• Traditional complementarity effects may be less important in soil bacterial communities than fitness differences.

Purpose of the Study:

• To test if phylogenetic community structure metrics predict microbially mediated EF in two contrasting ecosystems.
• To evaluate two metrics: Net Relatedness Index (NRI) and Phylogenetic Community Phylogenetic Structure (PCPS).
• To determine if taxonomic identity influences the relationship between phylogenetic diversity and EF.

Main Methods:

• Assessed phylogenetic diversity and community structure using NRI and PCPS metrics.
• Compared microbially mediated EF across soil bacterial communities in two ecosystems with differing environmental heterogeneity.
• Analyzed the interactive effects of phylogenetic diversity, taxonomic identity, and environmental gradients on EF.

Main Results:

• The relationship between phylogenetic diversity and EF was contingent on the taxonomic identity of dominant lineages.
• Phylogenetic diversity negatively correlated with EF in a high-fertility gradient ecosystem where Proteobacteria dominated.
• Phylogenetic diversity was unrelated to EF in a less heterogeneous ecosystem with coexisting abundant lineages.

Conclusions:

• Taxonomic identity is a critical factor modulating the impact of phylogenetic diversity on ecosystem functioning.
• Metrics incorporating taxonomic identity (like PCPS) enhance the prediction of EF in soil bacterial communities.
• Understanding lineage-specific traits and interactions is key to predicting ecosystem functioning in heterogeneous environments.