Rare methanotrophs adapt to broader environmental gradients than abundant methanotrophs in the riparian zone of the Three Gorges Reservoir

Abstract

Soil communities are intricately linked to ecosystem functioning. Uncovering the responses of rare and abundant taxa to environmental change is vital for understanding methanotrophic community assembly and ecosystem function. It is unclear what the proportions of the different taxa are in riparian soil and how environmental change may impact these, and thereby affect the structure and assembly of different communities. Considering both abundant and rare taxa, we investigated environmental thresholds and phylogenetic signals related to the ecological preferences of methanotrophic communities under complex environmental gradients, and explore the factors that influence their assembly. It has ecological significance for predicting how communities will gather in response to changing environmental conditions. It was found that methanotrophs had different ecological network patterns across land‐use types, with the network complexity of abundant taxa being higher in grasslands and woodlands than that of rare taxa. Different ecological preference thresholds and phylogenetic signals were observed between abundant and rare subcommunities in the riparian zone, with rare taxa possessing potentially broader environmental adaptation capabilities. Rare taxa were phylogenetically clustered closer together than abundant taxa. The assembly of abundant taxa was dominated by stochastic processes, whereas the assembly of rare taxa was dominated by deterministic processes. Soil pH played an important role in regulating the balance between the assembly processes of abundant and rare subcommunities. The deterministic assembly of rare taxa and the stochastic assembly of abundant taxa increased with pH values. We revealed the complexity of a co‐occurring ecological network, identified the mediators of methanotrophic community assembly, and examined the adaptability of rare and abundant methanotrophic species to different environmental gradients. These findings indicate that it is possible to predict the generation and maintenance of methanotrophic community diversity by studying how methanotrophs will respond to environmental changes in the riparian zone during vegetation restoration projects.