Plant encroachment increase multifunctionality in bauxite residue by constructing diverse and stable microbial communities

Purpose

Long-term weathering promotes the development of the microbial communities and increased microbial diversity in bauxite residue. However, the effect of different vegetation cover on the diversity and stability of microbial community are still poorly understood.

Methods

In this study, residue samples from three typical vegetation cover including Artemisia (BA), Cynodon (BC), and Hedysarum (BH) were collected in a bauxite residue disposal areas (BRDA). Illumina high-throughput sequencing technology was applied to determine the microbial communities in bauxite residue.

Results

Residues in vegetated sites exhibited lower alkalinity and higher nutrients level, as well as higher microbial biomass and activities, suggesting that plant encroachment significantly increased multifunctionality in bauxite residue. In addition, plant encroachment also induced the development of microbial communities and increased microbial and enhanced network stability. Furthermore, our results showed that the microbial diversity and network stability were significantly positive correlated with multifunctionality in bauxite residue. Long-term plant encroachment promoted functional bacterial assemblages (mostly Rhizobiaceae, Blastocatellaceae, Acidobacteriaceae, Sphingonmonadaceae, Frankiaceae), which were also the core species in microbial network.

Conclusions

Plant encroachment could increase microbial diversity and network stability, thus promote the elevation of multifunctionality in bauxite residue. Rhizobiaceae, Blastocatellaceae, Acidobacteriaceae, Sphingonmonadaceae, Frankiaceae played important roles in the promotion of multifunctionality in bauxite residue. Our results highlight the necessity of conserving and augmenting the abundance of functional bacterial assemblages to ensure the stable provision of ecosystem functions in bauxite residue disposal areas.