Soil faunal diversity as an indicator of Ginseng cultivation duration in Northeast China

Background and aims Continuous cultivation in temperate "ginseng-forest" systems leads to progressive soil degradation, yet the response of soil fauna - a key bioindicator - to cultivation chronosequences remains poorly understood. This study investigates the response patterns of soil faunal communities to ginseng cultivation duration and identifies the key environmental drivers at different stages. Methods Selected forest-cultivated ginseng sites with cultivation durations of 5, 10, and 15 years in a temperate broad-leaved forest of Northeast China. Within plots of each duration, we systematically collected soil fauna and soil samples to analyze community composition, diversity, and physicochemical properties. Results Soil fauna diversity and richness declined significantly with prolonged cultivation, accompanied by structural simplification and functional homogenization. Dominant taxa were mainly small-to-medium sized (300–400 µm in length, 100–200 µm in width). Redundancy analysis revealed a temporal shift in key environmental drivers: from soil moisture in 5-year habitats, to ammonium nitrogen and pH in 10-year habitats, and finally to nitrate nitrogen limitation in long-term (15-year) habitats. Prolonged cultivation also induced progressive soil acidification and nutrient depletion. Conclusions Our findings underscore that soil faunal diversity serves as a sensitive indicator of cultivation-induced soil change and highlight the stage-specific environmental constraints in "ginseng-forest" ecosystems. This study provides a scientific basis for developing temporally tailored soil management strategies to enhance the sustainability of ginseng cultivation.