Evolutionary history shapes grassland productivity through opposing effects on complementarity and selection

Area of Science:

• Ecology
• Evolutionary Biology
• Ecosystem Science

Background:

• Phylogenetic diversity (PD), representing evolutionary history, is crucial for ecosystem function but often confounded with species richness and functional trait diversity (FD) in experiments.
• Few studies experimentally isolate PD's impact on ecosystem processes.

Purpose of the Study:

• To experimentally demonstrate the independent effects of PD on grassland primary productivity.
• To disentangle the roles of PD, FD, and species richness in mediating ecosystem function.

Main Methods:

• Experimental manipulation of PD, FD, and species richness in grassland communities.
• Partitioning diversity effects to quantify contributions of complementarity and selection.
• Analyzing clade-level effects on functional traits and productivity.

Main Results:

• Higher PD significantly increased primary productivity by enhancing complementarity, independent of FD and species richness.
• PD influenced productivity via clade-level trait effects, notably in the Asteraceae family.
• FD reduced selection effects but did not impact complementarity.

Conclusions:

• PD is a critical, independent driver of ecosystem function, influencing productivity through complementarity and selection.
• Understanding PD's role advances ecological theory and informs biodiversity conservation and restoration strategies.