Tree species shape soil fauna energy flux in a subtropical common garden

Abstract Energy flux provides a process‐based measure of energy transfer through soil fauna food webs. While tree species with distinct life forms differ substantially in resource inputs and associated soil fauna communities, the linkages between these differences and energy flux remain poorly understood, hindering predictions of below‐ground responses to tree species selection in forest management. We conducted a common garden experiment to investigate soil fauna biomass and co‐occurrence structure and estimated soil fauna energy flux using a food web energy flux model across six subtropical tree species: castanopsis and michelia ( Castanopsis carlesii and Michelia macclurei , evergreen broadleaf), pine and fir ( Pinus massoniana and Cunninghamia lanceolata , evergreen coniferous), sweetgum and soapberry ( Liquidambar formosana and Sapindus mukorossi , deciduous broadleaf). Total soil fauna fresh biomass differed significantly among tree species, primarily reflecting variation in macro‐decomposer biomass. Co‐occurrence networks revealed tree‐species‐specific variation in taxon association patterns, whereas overall community cohesion showed comparatively limited variation among tree species. In contrast, total energy flux differed significantly among tree species and was highest under michelia, where it was 6.8–7.1 times higher than in the low‐flux sweetgum and soapberry. Mantel tests identified litter mass, soil fauna taxon richness and biomass as the strongest correlates of total energy flux, while piecewise structural equation modelling indicated that litter physical traits and soil fauna community structure were both positively associated with total energy flux. Collectively, these results highlight a stark contrast between the high sensitivity of soil fauna energy flux to tree species and the relative invariance of community‐level cohesion. Synthesis and applications : Our findings provide a food web energetic perspective for understanding below‐ground ecological responses to tree species selection. Integrating soil fauna energy channels into forest management frameworks could complement existing strategies focused on biodiversity conservation, stand productivity and local ecological objectives.