Indirect impacts of invaders: A case study of the Pacific sheath-tailed bat (Emballonura semicaudata rotensis)

Although many indirect consequences of biological invasions are plausible, few studies test hypotheses for management of threatened taxa. A case study of the endangered Pacific sheath-tailed bat (Emballonura semicaudata rotensis) illustrates the importance of investigating indirect effects of invasion on species of conservation concern. We hypothesized that two invaders, feral goats and Lantana camara, would indirectly affect the bat by decreasing availability of suitable resources. Specifically, that microclimate and bat prey abundances in lantana shrub differ from native forest habitat, and that preferential browsing by goats structures forests to be less suitable for bats. Our results suggest that bats avoid lantana shrub. However, we found no evidence that preferential goat browsing influenced bat activity. Our research implies that the impact of lantana on the persistence of the bat has been underestimated and that it is unclear how goats alter bat habitat aside from reducing understory vegetation. Future managers should prioritize efforts that restore native forest and reforest areas currently dominated by lantana. We urge conservation scientists to evaluate indirect effects of invasive species and publish findings that elucidate the consequences for native populations.