Invasion Mechanisms of the Alien Plant Datura stramonium in Xizang: Insights from Genetic Differentiation, Allelopathy, and Ecological Niche Analysis

<i>Datura stramonium</i>, which is originally native to Mexico, has been recognized as an invasive species following its introduction to China, where it has proliferated extensively. Despite its widespread impact, the mechanisms driving the invasion of <i>D. stramonium</i> remain insufficiently understood. Therefore, gaining insight into these mechanisms is essential for the development of effective strategies to prevent and control its further invasion. This study aims to elucidate the factors contributing to the successful invasion of <i>D. stramonium</i> in Tibet by examining genetic differentiation, allelopathic potential, and niche characteristics of its populations. Our findings reveal the following: (1) The genetic variation within 15 populations of <i>D. stramonium</i> is predominantly intra-populational, lacking distinct genealogical phylogeographic structure, and is indicative of recent population expansion. This suggests that human-mediated dispersal has played a significant role in the invasion of <i>D. stramonium</i> in Tibet. (2) Allelopathic assays demonstrate that extracts from various parts of <i>D. stramonium</i> exhibit significant inhibitory effects on the germination of <i>Hordeum vulgare</i> var. <i>coeleste</i> and <i>Pisum sativum</i> seeds. (3) <i>D. stramonium</i> exhibits the highest niche breadth within the plant community, coupled with a pronounced competitive ability for environmental resources. The invasion of <i>D. stramonium</i> poses a substantial threat to the diversity of local plant species. Consequently, the formulation of scientific management measures is of critical importance to prevent and control the invasion of <i>D. stramonium</i> and preserve biodiversity in the invaded area.