Potential Distribution Shifts and Ecological Implications of Two Invasive Xanthium Species in China Under Climate Warming Scenarios

Predicting the potential climatic suitability of invasive plants under global warming is essential for understanding invasion mechanisms and developing targeted management and control strategies. Here, we used MaxEnt and biomod2 (incorporating 10 individual algorithm models) to project potential suitable habitats for two invasive Xanthium species, Xanthium chinense and Xanthium orientale, across China. Projections were run for baseline climate conditions and two future time windows (2040–2060 and 2080–2100) across four Shared Socioeconomic Pathway scenarios: SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. Under baseline climate conditions, the random-forest model predicted that X. orientale possessed the largest suitable habitat area, reaching 22.79 × 105 km2, whereas the MaxEnt model estimated the suitable-habitat area of X. chinense at 17.56 × 105 km2. Under all future climate scenarios, both species exhibit northward range expansion into higher-latitude regions of China. Under high-emission scenarios (SSP3-7.0 and SSP5-8.5), suitable habitat for X. chinense is projected to increase across North and Northeast China, whereas X. orientale shows range gains in Northwest and Northeast China. Temperature seasonality, mean temperature of the driest quarter, and population density were identified as the key environmental drivers shaping the distribution of X. orientale. Rising temperatures are expected to render high-latitude provinces such as Jilin and Heilongjiang climatically suitable for the species. Conversely, the extreme heat and humidity in southern China may constrain its suitable range by impairing growth and reproductive output. For X. chinense, annual precipitation, precipitation seasonality, mean minimum temperature in June, and population density serve as the primary environmental drivers of its distribution. Mirroring the pattern seen in X. orientale, high-latitude areas of China are projected to become core suitable habitats for X. chinense under future climates. X. chinense frequently co-occurs with X. orientale, a pattern that suggests both taxa are strongly influenced by human activity and are capable of sustaining stable populations in economically developed areas. Overall, climate warming is projected to expand the total suitable habitat for both invasive Xanthium species, with high-latitude regions in northern China emerging as newly suitable areas. This shift could amplify competitive pressure on native plant communities in these high-latitude regions.