β-diversity in temperate grasslands is driven by stronger environmental
filtering of plant species with large genomes
Abstract
Elucidating mechanisms underlying community assembly and biodiversity
patterns is central to ecology and evolution. Genome size (GS, i.e.
nuclear DNA content) determines species’ capacity to tolerate
environmental stress and therefore potentially drives community
assembly. However, its role in driving β-diversity (i.e., spatial
variability in species composition) remains unclear. We measured GS for
161 plant species and investigated their occurrences within plant
communities across 52 sites spanning a 3200-km transect in the temperate
grasslands of China. Using species distribution modelling, we found that
environmental factors showed larger effects on β-diversity of large-GS
than that of small-GS species and that communities with abundant
resources had a greater representation of large-GS species. The latter
finding was confirmed following analysis of data from a 10-yr resource
(water, nitrogen, and phosphorus) manipulation experiment in which
resource addition resulted in increased community weighted GS based on
plant biomass estimates, suggesting that large-GS species are more
sensitive to environmental resource limitation and explaining the
greater environmental selection on β-diversity of large-GS species.
These findings highlight the roles of GS in driving community assembly
and predicting species responses to global change.