Native Species Responses to Lantana camara Allelopathy: Implications for Restoring Invaded Forest Landscapes

The allelochemicals released by Lantana camara negatively influence the phytosociological characteristics of native plant communities, with the severity of its impact increasing in relation to the density of Lantana invasion. These compounds hinder the growth, establishment, and survival of native species, thereby reducing forest biodiversity and disrupting ecosystem balance. Hence, to evaluate the vulnerability of tree species to the allelopathic effects of Lantana, we performed a greenhouse-based experiment using aqueous Lantana root and leaf extracts at different concentrations and assessed various germination and phytotoxicity parameters across five important native tree species. A Composite Performance Index (CPI) was developed to identify best-performing and resilient species suitable for ecological restoration in Lantana-invaded landscapes. Results indicated that both extract type and concentration significantly influenced all measured growth parameters, and the responses were species-specific. A strong linear relationship (r2 = 0.87) was observed between treatment concentration and germination. The species Tinospora cordifolia demonstrated the highest tolerance (CPI = 0.75), followed by Thespesia populnea (CPI = 0.56). Azadirachta indica (CPI = 0.50) showed moderate tolerance, while Sapindus mukorossi (CPI = 0.42) and Caesalpinia bonduc (CPI = 0.37) exhibited low tolerance. Species with higher CPI values are promising candidates and may be recommended to forest managers for future restoration initiatives in Lantana-invaded ecosystems.