Invasive legumes encounter similar soil fungal communities in their non-native and native ranges in Australia

Abstract

Acacias are globally one of the most successful invaders, but relatively little is known about the role of soil microbial communities, particularly fungi, in their invasion success. We assessed intra- and interspecific variation in the soil fungal communities of five legumes native to either south-east (Acacia longifolia, Acacia melanoxylon – invasive in the south-west) or south-west (Acacia cyclops, Acacia saligna, Paraserianthes lophantha – invasive in the south-east) Australia across their Australian non-native and native ranges. Soil samples were collected from around the roots (up to 5 cm) of each legume species from multiple populations and soil fungal communities were amplified and 454 pyrosequenced. Results revealed a significant interaction between host species and geographic location (i.e., south-east vs south-west) suggesting that among-population differences in fungal communities were largely driven by geographic-scale variation between south-east and south-west Australia. However, pairwise analyses of range effects within species showed that soil fungal communities were not different between non-native and native range populations for any host species except for A. cyclops, suggesting that this species may be more of a generalist than the other legumes studied. Pairwise analyses between species revealed considerable variation in soil fungal communities. Our work suggests that these legume species, introduced into novel ranges across the continent, whether south-east or south-west, generally associate with similar soil fungal communities, indicating that soil fungal communities in non-native ranges are unlikely to have constrained or facilitated the invasion success of these legumes.