Abstract:

Aims: Cathaya argyrophylla is the only extant species of the genus Cathaya in the family Pinaceae and has great evolutionary significance. As a typical ectomycorrhizal-dependent tree species, its ex situ conservation and artificial propagation are often constrained by low seedling survival and slow population regeneration. These limitations may be associated with disturbances to the rhizosphere microecosystem under artificial cultivation. This study aimed to reveal the effects of artificial cultivation on the soil microecology of C. argyrophylla and to provide a scientific basis for improving conservation strategies. 

Methods: Using high-throughput sequencing of the 16S rRNA gene and ITS regions, we characterized soil microbial communities and evaluated differences in soil physicochemical properties, microbial diversity, community assembly processes, co-occurrence network characteristics, and functional potential between C. argyrophylla plantations and natural forests. 

Results: Compared with natural forests, plantation soils had significantly higher available phosphorus, available potassium, nitrate nitrogen, and pH, but lower total carbon and soil organic matter contents. Bacterial α diversity was significantly higher in plantation soils, whereas the connectivity and stability of microbial co-occurrence networks markedly decreased. Community assembly shifted from deterministic selection-dominated processes in natural forests to increased stochastic processes in plantations. In terms of taxonomic composition, natural forests were enriched with acid-tolerant and symbiotic taxa such as Acidothermus and Oidiodendron, whereas plantations were dominated by copiotrophic taxa such as Bacillus and Trichoderma. 

Conclusion: Current plantation management practices may enhance soil nutrient availability and bacterial diversity in the short term, but they are also associated with fragmented microbial network structures, loss of key symbiotic taxa, and degradation of functional potential. These changes may constrain the long-term recovery and self-maintenance of C. argyrophylla populations by weakening mycorrhizal nutrient acquisition and the buffering capacity of soil ecosystems. Therefore, ex situ conservation of C. argyrophylla should shift from a sole focus on plant survival to the maintenance of soil microecological network integrity. Management practices such as reducing chemical fertilizer inputs, promoting litter return, maintaining moderately acidic soil conditions, and introducing indigenous keystone symbiotic taxa may help reconstruct a functionally stable and mutualism-dominated rhizosphere interaction system, thereby providing microecological support for the sustainable conservation of C. argyrophylla and other mycorrhizal-dependent rare species.

Key words: Cathaya argyrophylla, soil microbiome communities, microbial network stability, community assembly, sustainable management, ex situ conservation