Soil bacterial community restoration along a chronosequence of sand-fixing plantations on moving sand dunes in the Horqin sandy land in northeast China

In the desertified Horqin sandy land in northern China, sand-fixing plantations covering a large area have been gradually established by planting native shrubs or semi-shrubs on moving sand dunes to improve the degraded sandy ecosystem. Given that soil bacterial community mediates the biogeochemical cycling of essential elements, the secondary progressive succession of the soil microbial community may change with the establishment of sand-fixing plantations during the restoration process. However, the mechanism underlying the restoration of a soil bacterial community is unclear. We detected the variation in diversities and structures of soil bacterial communities by using the high-throughput Illumina MiSeq sequencing technique from a chronosequence of Caragana microphylla plantations and the natural Caragana microphylla community (NC), which is widely distributed in this region. We found that soil from a 32-year-old plantation possessed almost equal species richness to that of NC, thereby showing recovery of species richness during the stabilized process of moving sand dune. Bacterial community structure from the 9-year-old plantation was more similar to NC. The relative abundance of Sphingomonas responded to plantation age and can be an indicator of the restoration level of soil bacterial community. The changes in the soil properties caused by plantation establishment shaped the bacterial community structure at the genus level. All these findings demonstrated that the soil bacterial community structure in moving sand dunes can be restored to its native state by revegetation.