Data from: Aridity amplifies soil microbial influences and dampens plant diversity effects on lakeshore wetland multifunctionality

Lakeshore wetlands support multiple functions and services, including
primary productivity, carbon storage, and nutrient cycling. However,
empirical evidence on how ecosystem multifunctionality (EMF) in these
intrazonal systems is regulated by climatic aridity, and how plant and
microbial diversity jointly regulate EMF, remains scarce. In this study,
we surveyed 15 natural lakeshore wetlands across the Mongolian Plateau,
spanning a ~2,400 km gradient in climatic aridity, comprising 7 arid
(aridity index > 0.8) and 8 semiarid (aridity index < 0.8)
sites. Across these wetlands, we measured 12 ecosystem functions
representing carbon, nitrogen, and phosphorus cycling, soil fertility, and
productivity. We then assessed the relative importance of biotic (plant,
bacterial, and fungal diversity at local α- and regional β-scales) and
abiotic (soil moisture, pH, and seasonal climate) drivers of EMF. We found
that most individual functions were negatively associated with increasing
aridity, leading to a decline in EMF along the aridity gradient. In arid
regions, both bacterial and fungal diversity increased with aridity at
local (α) and regional (β) scales, thereby amplifying their positive
contributions to EMF. In contrast, in semiarid regions, both plant and
soil microbial diversity declined with aridity, while EMF was more jointly
influenced by soil moisture, pH, and seasonal climatic variation. Our
study shows that EMF in lakeshore wetlands reflects the interplay between
local biodiversity and regional aridity. Biodiversity contributes to EMF
in different ways across arid and semiarid regions, demonstrating that the
strength and direction of biodiversity effects depend on climatic context.
Together, these findings reveal that intrazonal wetlands, often overlooked
in biodiversity–function research, maintain multifunctionality through
region-specific mechanisms and offer practical guidance for restoring
ecosystem functions in degraded wetlands.