Aridity-driven shift in biodiversity–soil multifunctionality relationships

TLDR

Relationships between biodiversity and ecosystem multifunctionality are context‑dependent, and while plant and soil microbial diversity both regulate multifunctionality, their relative importance across environmental gradients is poorly understood. The study relates plant and microbial diversity to soil multifunctionality across 130 dryland sites spanning a 4,000 km aridity gradient in northern China. The authors assessed plant and microbial diversity and soil multifunctionality across these sites to examine how their relationships vary with aridity. In less arid regions plant species richness positively associates with soil multifunctionality, whereas in more arid regions fungal diversity shows a positive association; this shift occurs at an aridity level of ~0.8, a boundary predicted to move 28 % geographically by the end of the century, underscoring that biodiversity loss of plants and microorganisms may have especially strong consequences under low and high aridity, respectively, and highlighting the need for climate‑specific conservation strategies.

Abstract

Relationships between biodiversity and multiple ecosystem functions (that is, ecosystem multifunctionality) are context-dependent. Both plant and soil microbial diversity have been reported to regulate ecosystem multifunctionality, but how their relative importance varies along environmental gradients remains poorly understood. Here, we relate plant and microbial diversity to soil multifunctionality across 130 dryland sites along a 4,000 km aridity gradient in northern China. Our results show a strong positive association between plant species richness and soil multifunctionality in less arid regions, whereas microbial diversity, in particular of fungi, is positively associated with multifunctionality in more arid regions. This shift in the relationships between plant or microbial diversity and soil multifunctionality occur at an aridity level of ∼0.8, the boundary between semiarid and arid climates, which is predicted to advance geographically ∼28% by the end of the current century. Our study highlights that biodiversity loss of plants and soil microorganisms may have especially strong consequences under low and high aridity conditions, respectively, which calls for climate-specific biodiversity conservation strategies to mitigate the effects of aridification.