Summary

Evolutionary history shapes the interspecific relatedness and intraspecific variation, which
has a profound influence on plant functional traits and productivity. However, it is far from
clear how the phylogenetic relatedness among species and intraspecific variation could
contribute to the observed variance in plant biomass responses to climate warming.

We compiled a dataset with 284 species from warming experiments to explore the relative
importance of phylogenetic, intraspecific, experimental and ecological factors to warming
effects on plant biomass, using phylogenetic eigenvector regression and variance decomposition.

Our results showed that phylogenetic relatedness could account for about half the total
variance in biomass responses to warming, which were correlated with leaf economic traits at
the family level but not at species level. The intraspecific variation contributed to approximately
one-third of the variance, whereas the experimental design and ecological characteristics
only explained 7–17%.

These results suggest that intrinsic factors (evolutionary history) play more important roles
than extrinsic factors (experimental treatment and environment) in determining the
responses of plant biomass to warming at the global scale. This highlights the urgent need
for land surface models to include evolutionary aspects in predicting ecosystem functions
under climate change.