Driving mechanisms of adaptive strategies and heavy metal remediation potential in Artemisia lavandulaefolia during succession of abandoned Pb-Zn mining areas.

Phytoremediation is a cost-effective and environmentally friendly remediation technology that uses plants to treat contaminated sites, thereby restoring ecosystems and reclaiming degraded land. Plant remediation efficiency is influenced by multiple factors, often leading to inconsistent outcomes. This study was conducted on Artemisia lavandulaefolia, a pioneer plant with remediation potential. A space-for-time substitution approach was employed to investigate its adaptive strategies to contaminated environments, heavy metal remediation potential, and the underlying driving mechanisms during natural succession in an abandoned Pb-Zn mining area. It was observed that A. lavandulaefolia transitioned from a stress-tolerant pioneer to an active rhizosphere regulator as succession progressed. Its cadmium (Cd) enrichment coefficient was found to peak at 20.86 under intense interspecific competition during the late successional stage. Partial least squares path modeling (GoF = 0.60) revealed that soil properties significantly influenced the niche parameters (path coefficient = 0.84, R2 = 0.71), functional traits, and tissue elemental composition of A. lavandulaefolia (path coefficient = 0.98, R2 = 0.95), thereby shaping the rhizosphere soil environment (path coefficients = 0.46 and 0.57, R2 = 0.96). The resulting rhizosphere effects were found to largely determine the heavy metal enrichment and transfer coefficients (path coefficient = 1.13, R2 = 0.96). At the 25-year site, the rhizosphere effects of β-glucosidase (802.98%), available manganese (613.29%), available phosphorus (1243.66%), and available cadmium (1123.63%) were observed to peak simultaneously. Through combined random forest and Spearman correlation analyses, it was demonstrated that rhizosphere β-glucosidase activity, available manganese, and available phosphorus were key factors driving the Cd enrichment coefficient of A. lavandulaefolia. Our findings identify key rhizosphere regulators (phosphorus, manganese, and β-glucosidase activity) for maximizing cadmium enrichment in A. lavandulaefolia, offering a targeted strategy for precision ecological restoration in mining areas.