Conclusions
In this study, we found that both aboveground plant biomass and SOC
increased with increasing plant species richness. Plant species richness
had greater effects on SOC than on aboveground biomass. Aridity and
overgrazing decreased aboveground plant biomass and SOC through
decreasing plant species richness, whereas haying had less detrimental
effects on ecosystem functions and enhanced plant diversity. Together,
the results demonstrated that climate change and grazing mainly threaten
soil carbon storage in a synergistic way via their detrimental
effects on plant diversity. However, the study also shows that certain
management types like haying can maintain plant diversity and soil
carbon storage. Moreover, the beneficial effects of plant diversity are
particularly important in arid environments. Therefore, grassland
management should be adapted to ongoing global climate change.