Plants and soil biota co-regulate stability of ecosystem multifunctionality under multiple environmental changes.

The increase in phosphorus (P) and nitrogen (N) inputs, as well as soil acidification resulting from multiple environmental changes, has profound effects on the attributes of plant and soil biota communities, and on ecosystem functions. However, how these community attributes impact ecosystem multifunctionality (EMF) and its stability under multiple environmental changes remains unclear. By integrating datasets over four consecutive years from an experiment with enrichments of soil acidification and N and P in a semiarid grassland on the Mongolian Plateau, we explored the effects of environmental changes on community attributes (species richness, asynchrony, and compositional temporal stability) of plants and soil biota (bacteria, fungi, and nematodes) and their associations with EMF stability. The attributes of plants and soil biota showed opposite responses to nutrient enrichment under soil acidification and non-acidification conditions. Soil acidification had a more significant effect on the community attributes of plants and soil biota, as well as on the components of EMF stability, than nutrient enrichment. Soil acidification decreased both the mean and stability of EMF, while N enrichment increased the mean of EMF. P did not have a significant effect on the components of EMF stability, but N and P showed positive interactive effects on the mean and stability of EMF. We also found that plant and soil biota richness had a positive effect on EMF, while plant asynchrony and soil biota compositional stability determined EMF stability. The community attributes of plants and soil biota co-regulate the components of EMF stability under multiple environmental changes. These findings highlight the urgent need to protect the biodiversity of plants and soil biota to maintain EMF and its stability, especially for ecosystems undergoing multiple environmental changes.