Natural recovery of bare patches to healthy alpine meadow reduces soil microbial diversity in a degraded high-altitude grassland, West China

Abstract

Aim

Patchy degradation of alpine meadow is a common phenomenon in the natural ecosystem of the QTP, and the advent of bare patches (BPs) in degraded meadow impairs its ecosystem functions. Soil microbial diversity is an important biomarker essential to maintain the health of the meadow ecosystem. At present, there is a lack of understanding about how soil microbial communities change during the natural recovery of patchily degraded BPs in alpine meadows on the QTP.

Method

We analyzed soil archaea/bacteria and fungi at different recovery stages from BP, and their relationship with carbon fluxes during peak growth. The patches at different recovery stages were monitored to determine the changing patterns of soil microbial diversity and to establish the relationship between microbial communities and ecosystem carbon functions during the recovery process of BP.

Results

We found that the recovery of BP to healthy alpine meadow caused significant structural changes in the soil archaeal/bacterial and fungal communities, as evidenced by a significant decrease in their alpha-diversity. The recovery of bare patches leads to changes in soil nitrate nitrogen, pH, available phosphorus, microbial biomass carbon, and soil water content. All of them either directly or indirectly affected microbial community composition and alpha-diversity. Soil microbial alpha-diversity was negatively correlated with carbon sequestration and the respiratory rate of carbon flux components.

Conclusion

It is concluded that the diversity of soil microorganisms was significantly reduced as bare patches of the degraded meadow naturally recovered to become healthy meadow.