Alpine meadow degradation regulates soil microbial diversity via decreasing plant production on the Qinghai-Tibetan Plateau

In recent decades, alpine meadows have experienced severe degradation owing to external disturbances. Although soil microorganisms are critical for ecosystem services, little is known about their responses to soil degradation and the potential patterns in alpine meadows. To solve this question, we collected and analyzed soil samples from three degraded alpine meadows situated on the Qinghai-Tibet Plateau. We aimed to examine the effects of degradation on soil microbial diversity and identify the ecological predictors for the diversity of bacteria and fungi. Our results showed that alpine meadow degradation significantly changed soil bacterial and fungal diversity and community composition. Specifically, the relationship between bacterial and fungal diversity and degradation intensity was a hump-shaped, with the highest diversity observed at a moderate degradation level. Additionally, alpine meadow degradation-induced changes in microbial diversity were strongly correlated with decreased plant production, with fungal diversity showing a closer link with below-ground biomass (BGB) than with bacterial diversity. Our findings offer empirical evidence that intermediate disturbance (i.e., moderate degradation) may be beneficial for supporting soil biodiversity. This has important implications for informing policy and management strategies meant to conserve soil biodiversity and ecosystem services when facing anthropogenic change.