Turnover of soil bacterial diversity driven by wide-scale environmental heterogeneity

Spatial scaling and determinism of the wide-scale distribution of macroorganism diversity has been largely demonstrated over a century. For microorganisms, and especially for soil bacteria, this fundamental question requires more thorough investigation, as little information has been reported to date. Here by applying the taxa–area relationship to the largest spatially explicit soil sampling available in France (2,085 soils, area covered ~5.3 × 10 5 km 2 ) and developing an innovative evaluation of the habitat–area relationship, we show that the turnover rate of bacterial diversity in soils on a wide scale is highly significant and strongly correlated with the turnover rate of soil habitat. As the diversity of micro- and macroorganisms appears to be driven by similar processes (dispersal and selection), maintaining diverse and spatially structured habitats is essential for soil biological patrimony and the resulting ecosystem services. In microbial biogeography, little is known about processes involved in soil bacterial diversity turnover. By conducting a wide-scale investigation, this study shows that dispersal limitation and environmental selection of bacteria are not mutually exclusive, highlighting the importance of landscape diversity.