Ecosystem multifunctionality (EMF) is the capacity of an ecosystem to provide multiple functions simultaneously. Microorganisms are proxies of soil communities and harbor various functional features, thus supporting multiple ecosystem function. However, the complex relationships between microbial network and EMF, especially at a large spatial scale, remain largely unknown.

Aquatic Ecosystem Processes Group of Wuhan Botanical Garden selected 30 higher-order rivers for soil, sediment and water sampling along a latitudinal gradient across eastern China to calculate EMF using 18 variables related to nitrogen cycling, nutrient pool, plant productivity, and water quality. Meanwhile, the microbial diversity and co-occurrence network were also analyzed.

In riparian rhizosphere and bulk soils, but not in channel sediments, EMF had significant negative associations with latitude. In channel sediments, microbial taxonomic and functional richness in the low-latitude group were prominently higher than those in the high-latitude group. The complexity of microbial co-occurrence networks increased with increasing latitude.

The contributions investigation of abiotic and biotic factor to EMF revealed that environmental conditions, especially, geographic and climatic factors, were the main drivers of EMF. Microbial diversity and network complexity contributed little to explaining EMF, and only betweenness centralization significantly related to EMF.

This study fills a critical knowledge gap regarding the latitudinal patterns and drivers of EMF in river ecosystems and gives new insights into how microbial diversity and network complexity affect EMF from a metagenomic perspective.

This research was funded by the National Natural Science Foundation of China. The relevant results have been published in mSystems entitled “Linking ecosystem multifunctionality to microbial community features in rivers along a latitudinal gradient”. 

Latitudinal effects on EMF through multiple thresholds approach (Image by WBG)

Partial least squares path model showing the cascading effects of environmental and microbial factors on EMF average (A, B) and EMF weighted (C, D) (Image by WBG)