Effects of past and current drought on the composition and diversity of soil microbial communities

摘要

Drought is well known to have strong effects on the composition and activity of soil microbial communities, and may be determined by drought history and drought duration, but the characterisation and prediction of these effects remains challenging. This is because soil microbial communities that have previously been exposed to drought may change less in response to subsequent drought events, due to the selection of drought-resistant taxa. We set up a 10-level drought experiment to test the effect of water stress on the composition and diversity of soil bacterial and fungal communities. We also investigated the effect of a previous long-term drought on communities in soils with different historical precipitation regimes. Saplings of the holm oak, Quercus ilex L., were included to assess the impact of plant presence on the effects of the drought treatment. The composition and diversity of the soil microbial communities were analysed using DNA amplicon sequencing of bacterial and fungal markers and the measurement of phospholipid fatty acids. The experimental drought affected the bacterial community much more than the fungal community, decreasing alpha diversity and proportion of total biomass, whereas fungal diversity tended to increase.