Co-invasion of daisy fleabane and Canada goldenrod pose synergistic impacts on soil bacterial richness

Abstract

Understanding the impacts of co-invasion of multiple invaders on soil bacterial communities is significant in understanding the mechanisms driving successful invasion. This study aimed to determine the response of soil bacterial communities to co-invasion of two invaders daisy fleabane (Erigeron annuus) and Canada goldenrod (Solidago canadensis). Daisy fleabane and/or Canada goldenrod invasion significantly enhanced the operational taxonomic unit richness, Shannon index, and Chao1 index of soil bacterial communities. Canada goldenrod under light degree of invasion and co-invasion of daisy fleabane and Canada goldenrod regardless of invasion degree signally improved the ACE index of soil bacterial communities. Thus, the two invaders can enhance soil bacterial diversity and richness to facilitating subsequent invasion due to the fact that higher soil bacterial diversity and richness can enhance the levels of soil function and nutrients acquisition of plant species. ACE index of soil bacterial communities subjected to co-invasion of daisy fleabane and Canada goldenrod regardless of invasion degree was greater than that under the independent invasion of either daisy fleabane or Canada goldenrod. Hence, co-invasion of the two invaders can impose synergistic impacts on soil bacterial richness, which may build a preferable soil micro-environment via the intensified soil bacterial communities, which is contributive to their following invasion.