In the critical habitat of the giant panda, livestock grazing is reshaping the invisible yet vital world of soil microbes in an unexpected way. A new study reveals that while grazing alters soil properties, it paradoxically leads to an increase in soil bacterial diversity. Meanwhile, grazing disrupts the competitive hierarchy of the fungal kingdom, triggering a community shift from the singular dominance of Basidiomycota to a co-dominance structure with Ascomycota.

The researchers conducted a two-year fencing experiment in a primary coniferous forest, a key habitat for the endangered giant panda. By comparing fenced plots (no livestock) with adjacent unfenced plots (ambient grazing), they analyzed changes in soil properties and the diversity of soil bacteria and fungi. They then used structural equation modeling to untangle the complex web of interactions.

The team found that livestock grazing directly altered the soil environment by increasing soil pH and decreasing soil organic matter. These changes strongly suppressed the dominant fungal phylum, Basidiomycota, which is sensitive to shifts in soil chemistry and physical disturbance from trampling. The decline of this dominant competitor released subordinate microbial groups, such as Ascomycota fungi and Actinobacteria, from intense competitive pressure.

The findings challenge the simple assumption that disturbances like grazing uniformly degrade belowground ecosystems. Instead, the outcome depends on a complex interplay between soil chemistry, physical disturbance, and the competitive hierarchy within the microbial community. The authors suggest that the high sensitivity of Basidiomycota makes its relative abundance a powerful indicator for monitoring soil degradation and recovery. The rapid response of the microbial community to short-term fencing also suggests that management practices like rotational grazing could be effective tools for balancing conservation needs with local livelihoods.

Fan adds, “Our study reveals for the first time the intricate mechanism through which livestock grazing impacts the soil microbial community in this critical giant panda habitat. We found that the suppression of a single dominant fungal group can cascade through the ecosystem. This highlights the importance of understanding microbial competition when managing and restoring forest ecosystems. Our findings suggest that monitoring key microbial indicators, like the abundance of Basidiomycota, can provide a sensitive and early warning signal for assessing the health of the forest floor.”
DOI:10.1007/s42832-025-0364-5