Abstract: Background and aims Above- and belowground biodiversity determines the capacity of ecosystems to provide multiple functions simultaneously (i.e., multifunctionality), while their relative importance along environmental gradients remains unclear. Our objective of this study was to investigate how plant and microbial diversity along an altitudinal gradient afected soil multifunctionality in grasslands.
Methods The efects of plant and microbial (including bacteria, fungi and archaea) diversity on soil multifunctionality were estimated along a 2300 m altitudinal gradient across six grassland types in the Tianshan Mountain, China. The soil multifunctionality was calculated based on 12 parameters related to carbon, nitrogen, phosphorous cycling, and soil nutrient status.
Results The relative importance of plant and microbial diversity to soil multifunctionality shifted at an altitude of 1900 m while threshold for each soil function varied along altitudinal gradient. At low altitudes (<1900 m), plant species richness showed a robust positive efect and had a more substantial impact on soil multifunctionality than microbial diversity. Altitude had a signifcant efect on plant species richness via indirect means by altering soil moisture. At high altitudes (>1900 m), soil multifunctionality was infuenced by a combination of plant and microbial diversity. Similarly, fungal richness was positively associated with soil multifunctionality, while archaeal richness had the opposite efect.
Conclusion The efect of plant and soil microbial diversity on soil multifunctionality was mediated by altitude in grasslands, which can guide the restoration eforts aimed to maximize soil multifunctionality in grassland ecosystems.
Keywords:Plant species richness · Soil microbial diversity · Soil multifunctionality · Altitude
