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Biological invasions are a major driver of biodiversity loss, but no study has described the scope of threats to bats (Chiroptera) by invasive species., We reviewed the literature for negative effects of invasive species to bats and summarised threats according to four categories: predation, disease, competition, and indirect interactions. We identified threats of 37 invasive species to 40 bat species. Ten bat species were threatened by more than one invasion pathway., About 38 percent of cases are speculative and 18 percent circumstantial, many attributed to overlapping ranges, and most accounts do not quantify effects needed to forecast bat population impacts., Evidence of cat predation is frequently cited, constituting the greatest incidence of observational data. Other direct and indirect impacts were documented from goats, dogs, brown tree snake, rainbow lorikeet, rose-ringed parakeet, yellow crazy ant, giant centipede, palm, burdock, avian cholera, and white-nose syndrome. Circumstantial evidence suggests impacts by rats, stoats, coqui frog, common wolf snake, little fire ant, kudzu, and Lantana camara. Other impacts by giant centipede, yellow crazy ant, cats, goats, rats, and avian cholera are speculative, as are those from pigs, deer, white eye, common starling, house sparrow, rock dove, barn and little owls, brush-tailed possum, honeybee, wasp, phytophagous insects, tamarisk, Cinnamomum verum, and Tabebuia pallida., Over 60 percent of bat species reviewed are island-dwelling, corresponding with evidence indicating that most extinctions occur on islands and invasive species' impacts are worse for island than mainland populations., Although appreciable bat population reductions owing to invasive species are often unproven, invasions are likely to exacerbate effects of other vulnerabilities. Multiple invaders and synergistic interactions may ultimately lead to species losses., Managers should exercise the precautionary principle by taking action against non-native species when first detected, even if new species do not appear to be detrimental. [ABSTRACT FROM AUTHOR]

• The hemlock canopy is maintained in forests managed for hemlock woolly adelgid. • Microenvironmental conditions are similar in managed and un-managed hemlock forests. • Montane salamanders are less abundant in forests invaded by hemlock woolly adelgid. • Arthropod order richness is greater in managed eastern hemlock forests. • Forest management predicts montane salamander abundance. • Long-term outcomes of insecticide use in natural systems are unknown. Hemlock woolly adelgid (Adelges tsugae ; HWA), an invasive aphid-like insect, was first documented on the East Coast of the United States in the 1950 s. Hemlock woolly adelgid is an herbivore which primarily feeds at the needle base of hemlock tree species (Pinaceae: Tsuga). With no evolutionary defenses and few biotic controls, the eastern and Carolina hemlock (Tsuga canadensis and Tsuga carolinensis) serve as the primary diet of HWA in eastern North America. The invasive pest began to spread rapidly throughout the hemlock's range causing defoliation and death of the trees within 4 – 10 years. With the loss of the foundational species, Tsuga canadensis , several microenvironmental changes were documented. Microenvironmental changes in response to biological invasions and anthropogenic forestry practices can lead to shifts in populations of physiologically sensitive taxa such as salamanders and their prey, terrestrial arthropods. National Park Service (NPS) staff at Great Smoky Mountains National Park manage HWA by treating eastern hemlocks with the neonicotinoid pesticides, imidacloprid and dinotefuran. To measure indirect effects of eastern hemlock mortality, and HWA management, this study collected data on several parameters in hemlock-dominated stands that have been repeatedly managed by the NPS and stands which were un-managed and where HWA has reduced the hemlock canopy. Our major objectives were to assess microenvironmental, vegetative, and arthropod community differences between managed and un-managed eastern hemlock stands and analyze those differences with respect to woodland salamander abundance. Answering these questions should provide insight into indirect impacts of the invasive species, HWA, on indicator species, terrestrial salamanders, through changes in prey availability and microenvironmental parameters. A mixed effects linear model using elevation range as a random effect or block was used to model salamander abundance with prey availability, microenvironmental parameters, and HWA management as a factor. Our results indicate that HWA management was the strongest predictor of total salamander abundance and for Plethodon jordani and Desmognathus wrighti abundance individually. We found over five times the relative salamander abundance in sites which had been managed for HWA compared to sites which had been left un-managed. Funding: This work was supported by the University of Tennessee, Knoxville Department of Earth and Planetary Sciences, Knoxville, TN. [ABSTRACT FROM AUTHOR]