Disturbances induce similar shifts in arbuscular mycorrhizal fungal communities from grassland and field soils
Disturbances are increasingly important in structuring arbuscular mycorrhizal (AM) fungal communities because a wide range of habitats are influenced by human activities. However, it is unclear how the effects of disturbances vary between different types and if it is influenced by the land-use history of the habitat. In this study we examined these questions in two greenhouse experiments by applying mechanical (to simulate tillage) and chemical disturbances (fertilizer or herbicide addition) to AM fungal communities from sites with different land-use histories (field and meadow). We found soil communities significantly influenced plant growth in case of herbicide addition, while plant growth was similar among sterilized and alive soils in case of fertilizer addition. This suggests that herbicide addition has stronger effect on plant growth via AM fungi compared to fertilizer. Although the diversity and composition of AM fungal communities in meadow and field soil were distinctive, their response to disturbances was similar. We found both mechanical and chemical disturbance increase the proportion of culturable AM fungi in plant roots but no additional effect with simultaneous application of two disturbances. Nevertheless, there was no clear indication that disturbances would promote specific AM fungal families. Excepting abundance of Glomeraceae increased with herbicide addition, mechanical disturbance alone and in combination with herbicide addition decreased Claroideoglomeraceae abundance while only latter decreased Diversisporaceae abundance. Altogether, our results demonstrate that although land-use history can influence the composition of AM fungal communities, their responses to disturbances are determined mainly by disturbance types.