Assessing the Threat of

Invasive alien species pose a significant threat to biodiversity conservation in protected areas. Ageratina riparia has been identified as a problematic invasive species in Merbabu National Park in Central Java. This study analyzed the population structure, distribution patterns, and habitat suitability of A. riparia to assess its ecological impacts on native ecosystems. Vegetation surveys were conducted using systematic sampling across different elevation zones of the park. The population density, frequency, and coverage were measured. Distribution patterns were analyzed using the Morisita Index, and habitat suitability modeling was performed using MaxEnt. riparia showed a high population density (7.85 individuals/m2) with 10.79% ground coverage and 78.67% occurrence frequency across sampling points. The species exhibited clustered distribution patterns (Morisita Index > 1) concentrated on mid-to-upper mountain slopes. MaxEnt modeling demonstrated excellent predictive performance (AUC = 0.907) and identified optimal habitat conditions in vulnerable, endemic-rich forest ecosystems. A. riparia represents a significant ecological threat to Merbabu National Park’s biodiversity through its high dominance, wide distribution, and habitat adaptability. Spatial distribution maps are essential tools for prioritizing conservation interventions and monitoring strategies.