Earthworm-induced shifts in microbial diversity in soils with rare versus established invasive earthworm populations

European earthwormshave colonised many parts of Australia, although their impact on soil microbial communities remains largely uncharacterised. An experiment was conducted to contrast the responses to Aporrectodeatrapezoides introduction between soils from sites with established (Talmo, 64 A. trapezoides m-2) and rare (Glenrock, 0.6 A. trapezoides m-2) A. trapezoides populations. Our hypothesis was that earthwormintroduction would lead to similar changes in bacterial communities in both soils. The effects of earthwormintroduction ( earthwormactivity and cadaver decomposition) did not lead to a convergence of bacterial community composition between the two soils. However, in both soils, the Firmicutesdecreased in abundance and a common set of bacteria responded positively to earthworms. The increase in the abundance of Flavobacterium, Chitinophagaceae, Rhodocyclaceaeand Sphingobacterialeswere consistent with previous studies. Evidence for possible soil resistanceto earthwormswas observed, with lower earthwormsurvival in Glenrock microcosms coinciding with A. trapezoides rarity in this site, lower soil organic matterand clay content and differences in the diversity and abundance of potential earthwormmutualist bacteria. These results suggest that while the impacts of earthwormsvary between different soils, the consistent response of some bacteria may aid in predicting the impacts of earthwormson soil ecosystems.