Arboreal ants are omnipresent and a dominant component of forest canopy biodiversity in tropical regions, yet anthropogenic impacts on arboreal ant diversity have not been well documented. Weaver ants, Oecophylla smaragdina, are known as one of the most dominant arboreal ants in tropical rainforests and are commonly found in disturbed habitats such as rubber plantations. The composition of other arboreal ant species is different between rainforests and rubber plantations, despite the dominance of O. smaragdina in both habitats. As past studies suggested the importance of competition driving the assembly of arboreal ant communities, we tested whether the relative importance of competition change between rainforests and rubber plantations in tropical Xishuangbanna located in Southwest China’s biodiversity hotspot. We used canopy baiting to collect ants and analyzed their community composition using Gaussian Copula Graphical Model to elucidate the relative strength of negative and positive interspecific interactions after controlling for the effects of environmental factors. We found that environmental factors primarily influenced the differences in ant assemblage composition in the rainforests, whereas negative interaction (competition) was more important in rubber plantations. Our study demonstrated that, despite the dominance of the same species, drivers of community assembly shifted from intact to modified habitats.