Ecosystem multifunctionality (EMF) is the ability of an ecosystem to provide multiple functions simultaneously. Microorganisms are proxies for soil communities and possess diverse functional traits that support multiple ecosystem functions. However, the complex relationships between the microbial network and EMF, especially at a large spatial scale, remain largely unknown.

Researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences selected 30 higher-order rivers for soil, sediment, and water sampling along a latitudinal gradient in 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 was significantly higher in the low-latitude group than those in the high-latitude group. The complexity of microbial co-occurrence networks increased with increasing latitude.

Investigation of the contributions abiotic and biotic factors 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 was significantly related to EMF.

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

Results were 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)