Ants benefit from the Japanese raisin tree invasion and favor its invasiveness in the subtropical Atlantic Rainforest.
Biological invasions are among the main drivers of biodiversity losses, which can be caused by alterations in habitat structure. Animal-plant mutualistic interactions created in recipient communities may enhance alien species invasiveness. In this study, we investigate the relationships between the Japanese raisin tree (Hovenia dulcis) and ground-foraging ant communities in the Atlantic Rainforest. Seven paired sites (n = 14) of invaded and uninvaded forests (control) were chosen. We sampled ant communities with pitfall traps in those sites during 2018 wintertime, before (June) and after H. dulcis infructescences fall on the forest floor (July). In June, leaf-litter mass of invaded sites was higher, but ant diversity and composition were not affected. In July, leaf-litter mass reduced, and infructescence offer triggered a higher ant diversity and distinct ant species composition in invaded sites. We additionally performed an experiment to understand the potential use of H. dulcis diaspores by ant species. We recorded 19 species exploiting H. dulcis diaspores, of which 18 consumed the fleshy peduncle in situ, and two removed diaspores for distances >1 cm. Our study indicates the invasion did not negatively affect ant communities by altering the leaf-litter layer. On the contrary, ant communities benefited from the high-resource availability during exposure to cold stress. Ant-H. dulcis diaspore interactions could further contribute to seed germination and propagule establishment, potentially enhancing H. dulcis invasiveness.