Bats as bioindicators of trace element pollution in an industrial estuary

Insectivorous bats are susceptible to environmental pollutants because of their mobility, longevity and trophic position, making them useful sentinels of environmental contamination. Despite their ecological importance and vulnerability, few studies have quantified multi-element exposure in bats inhabiting industrialised estuaries. Here, we compare concentrations of metals and metalloids in fur samples from bats inhabiting natural forest (reference site; n = 29) and an industrial estuary (industrial site; n = 65) in eastern Australia. Of 23 elements analysed, 11 were consistently quantifiable. Variation of trace element concentration was high among species, mostly attributable to site differences. In general, bats sampled from the industrial site had significantly higher concentrations of boron (B), manganese (Mn), molybdenum (Mb), and strontium (Sr), whereas barium (Ba), chromium (Cr), iron (Fe) and zinc (Zn) were higher at the reference site. Collectively, our results demonstrate that bats can reflect spatial variation in trace element contamination across industrialised landscapes. Therefore, insectivorous bats have strong value as bioindicators of trace element contamination in industrial areas. Further, as some individuals had concentrations of some trace elements that exceeded thresholds known to cause negative health effects, we also highlight an urgent need to monitor pollutant accumulation in bats and other wildlife inhabiting industrialised zones and assess implications for the health of bats. This evidence is critical for informing conservation strategies and regulatory policies aimed at mitigating environmental contamination.