1.With accelerating species introductions in an era of globalization, co-occurring alien species have become increasingly common. Understanding the combined ecological impacts of multiple invaders is not only crucial for wildlife managers attempting to ameliorate biodiversity loss but also provides key insights into invasion success and species coexistence mechanisms in natural ecosystems. Compared with much attentions given to single invader impacts, little is known about the impacts of multiple co-occurring invaders. 2.The American bullfrog (Lithobates catesbeianus...