Endangered plant growth was influenced by soil microbial life-history strategies across elevations

Elevations can influence belowground microbial diversity, network complexity, life history strategy, and the growth of endangered plants. However, how elevation affects endangered plant growth by modulating soil microbial network complexity and life-history strategies remains poorly understood. This study focused on Abies yuanbaoshanensis and systematically examined tree height, diameter at breast height (DBH), soil physicochemical properties, enzyme activity, and microbial communities at different elevations (1,750 m, 1,850 m, 1,950 m, and 2,050 m). The results showed that tree height and DBH were highest at 1,750 m and lowest at 1,850 m compared to other elevations. At an elevation of 1,850 m, soil total phosphorus (TP), total potassium content, and fungal and bacterial diversity were the lowest, while soil water content and fungal oligotrophs/copiotrophs ratios were the highest. The complexity of bacterial-fungal networks increased with elevation. Structural equation modeling suggests a potential chained correlative pathway, wherein elevation was associated with shifts in soil water content, which in turn correlated with alterations in TP content, subsequently showing associative relationships with the abundance of oligotrophic fungi and microbial network complexity, and finally exhibiting links to changes in plant growth. These findings underscore that soil physicochemical properties and microbial communities jointly determine the growth of endangered mountain plants along altitudinal gradients. Although bacterial and fungal diversity exert distinct effects on the growth of endangered plants, their life history strategies should be considered a critical factor in the management of these species. This research provides a new perspective for the ex situ conservation and in situ management of endangered plants.