Linking functional microbial groups to soil carbon cycle multifunctionality in degraded karst forests
Description
The collected research data include indicators of soil microbial communities involved in the C cycle and environmental indicators. The microbial indicators consist of species diversity, relative abundance, functional strength, and functional diversity, considering overall, rare, common, and abundant taxa separately. Based on our research hypotheses: i) soil C cycle multifunctionality will increase during the restoration process; ii) the shifts in microbial communities involved in soil C cycling will differ among abundant, common, and rare taxa across the restoration stages; and iii) the contributions of these microbial taxa to soil C cycle multifunctionality will also differ throughout the restoration chronosequence. We conducted a space-for-time sequential study across multiple restoration stages. For each stage, ten fixed plots were randomly set up, with dimensions of SB (shrubland) in both SG (secondary-growth forest) and OG (old-growth forest) systems. The results showed that the SCCM index increased significantly throughout restoration, with microbial functional traits exerting more influence than microbial diversity. Within the microbial community, functional reorganization involves a shift in functional dominance from rare to non-rare (common and abundant) taxa, indicating improved functional stability. Specifically, common taxa were the primary drivers of the enhanced SCCM, with increases in their functional diversity and strength playing a pivotal role. The concurrent recovery of plant diversity and soil properties facilitated these microbial shifts. In summary, natural restoration promotes SCCM mainly by augmenting microbial functional performance, particularly that of common taxa, a subgroup whose role in supporting soil ecological functions has historically been underestimated.