Mitigating invasive species using biochar derived from invasive plants in saline-alkaline wetland plant communities dominated by Amaranthus palmeri

Aims: Effective prevention and management of biological invasions are crucial. One promising approach involves introducing biochar to invaded plant communities to modify interspecific relationships among invasive and native plants, ultimately aiding in the suppression of invasive species. This study aimed to explore the effects of invasive-plant biochar on an established invaded plant community. Location: Tianjin coastal saline-alkaline wetland, China (38 degrees 46 ' N, 117 degrees 34 ' E). Methods: Invaded plant communities were established using soils from an Amaranthus palmeri-invaded wetland with an intact seed bank, incorporating invasive-plant biochar derived from A. palmeri and Spartina alterniflora into the soil at 0%, 1%, 3%, and 5% addition rates (m/m). Plant above-ground biomass, height, stem diameter, abundance, alpha/beta-diversity, niche breadth, and species co-occurrence networks were analyzed. Results: The addition of invasive-plant biochar significantly decreased the performance measures of the invaded plant community. The biochar addition rate had a more substantial impact on plant community structure than the type of biochar used. There was a decrease in the abundance of A. palmeri and an increase in native plants across most treatments, with S. alterniflora biochar exhibiting a more pronounced effect compared to A. palmeri biochar. Invasive-plant biochar affected the niche breadth of A. palmeri and other dominant native species, particularly at higher addition rates, resulting in reduced niche overlap. At a 5% addition rate, A. palmeri and S. alterniflora biochar had contrasting effects on the complexity of interspecific relationships within the plant community. Phylogenetic beta-diversities were significantly correlated with the biochar addition rate and stochastic processes primarily governed plant community assembly across all treatments. Conclusions: Our findings underscore the potential of biochar derived from invasive plants to mitigate the impact of invasive species on saline-alkaline wetland plant communities dominated by A. palmeri. This approach offers a promising avenue for managing biological invasions and restoring native plant species.