Invasive mammals disrupt native dung beetle community coexistence

Biological invasions are among the major drivers of biodiversity and are increasing worldwide. Among the invasive species, mammals have a particularly profound impact on native ecosystems. As primary decomposers of mammalian feces, dung beetles are critical in ecosystem functioning, and their community structure is closely linked to their services. However, the introduction of invasive mammals threatens these beetles and potentially disrupts their ecosystem services. Therefore, it is necessary to understand the resulting changes in communities. We developed a novel population dynamics model focusing on the interactions among mammals, feces, and dung beetles. Our results indicate that such invasions increase the risk of extinction of specialist dung beetles that cannot utilize the feces of invasive mammals. The risk of extinction is particularly high when generalist dung beetles show a preference for native feces, leading to intensified interspecific competition for resources. Additionally, the extinction risk of specialist dung beetles increases when invasive mammals display irruptive population dynamics. In conclusion, our findings demonstrated that non-native mammalian invasions disrupt the coexistence of native dung beetle communities, potentially leading to losses in biodiversity and ecosystem function. These risks should be considered in future empirical studies to evaluate the impact of invasive mammals on dung beetle communities.