Global assessment of invasion risk: Ardisia elliptica, one of the most noxious tropical shrubs in the world

Abstract Background Global risk assessment of invasive weeds is a proactive strategy for identifying high-risk species and regions, predicting invasion rates and extents, and evaluating harmful impacts on native biodiversity, agriculture, and ecosystems. In this study, species distribution modeling was used to assess the global invasion risk of Ardisia elliptica , a highly invasive tropical shrub native to South and Southeast Asia that is harmful in other parts of the world, under the current climate and future climate change scenarios [shared socioeconomic pathways (SSPs) SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5] and other environmental variables, including land use and land cover change, soil moisture, soil carbon, soil pH, and human influence index. Results Our study revealed that annual precipitation, human influence index, and precipitation in the wettest month contributed significantly to the MaxEnt model, with estimated contributions of 31.35%, 22.76%, and 14.77%, respectively. These findings suggest that the global distribution of A. elliptica is limited primarily by climatic variables, whereas anthropogenic factors also play an important role in its habitat expansion. The current invasion risk was highest in South America, Oceania (east), and Africa, affecting up to 24.51% of the total land surface area. A risk assessment of 165 countries revealed a risk of invasion in 41 countries with no records of species occurrence. Under future climate change scenarios, a significant global expansion of the distribution was predicted, with invasion in South America covering up to 48.97% of the land surface area by 2061–2080. Habitat suitability analysis revealed that 21 countries under the current climate and 47 countries under SSP5-8.5 had extremely suitable habitats for A. elliptica . Additionally, the species has already invaded at least 115 countries, while 15 countries, including Benin, Burundi, Japan, Uruguay, Swaziland, and South Korea, are predicted to shift categories from having unsuitable or poor invasion risk to having high invasion risk. Conclusions These findings are crucial for understanding the global invasion risk of A. elliptica under substantial climate change and anthropogenic activities and support the development of effective biosecurity measures and sustainable management strategies for this harmful species at the global and national levels.