The European rabbit plays a major role in seed dispersal in its native environment. We evaluated its ecological interactions with plants through the dispersal of seeds by endozoochory in two invaded arid ecotones of Argentina. We found 855 whole seeds in 1283 fecal pellets, belonging to one non-native (Sesuvium portulacastrum) and five native plants (Arjona sp., Fabiana denudata, Frankenia juniperoides, Lycium chilensis, Poa sp.). Our results indicate that the European rabbit is a legitimate disperser of F. juniperoides, L. chilensis, and S. portulacastrum by the consumption and dissemination of viable seeds. Contrastingly, the rabbit is an illegitimate disperser of Arjona sp., F. denudata, and Poa sp. Our study identifies new interactions between an invasive herbivore and sympatric plants in the arid ecosystems of Argentina. We put forth that the mutualistic interaction between the European rabbit and both native and non-native plants highlights the complexity of trophic networks in invaded environments.