UC Davis

We evaluated the bacterial and archaeal community dynamics and assembly in soils under forest, grassland and no-till cropping, using a high-throughput shotgun metagenomics approach. No significant alterations in alpha diversity were observed among different land uses, but beta diversity in grassland was lower than that observed in forest and no-till soils. Grassland communities showed assembly that predominantly followed the neutral model, i.e. high homogenizing selection with moderate dispersion, leading to biotic homogenization. Both no-till and forest soil communities were found to have assembly that predominantly followed a niche model, i.e. low rates of dispersal and weak homogenizing selection, resulting in maintenance of higher beta diversity relative to grasslands, indicating niche specialization or variable selection. Taken together, our results indicate that the patterns of assembly and their governing processes are dependent on the land use employed after deforestation, with consequences for taxa turnover and microbial functional potential.