Biogeographical design of soil microbial habitats
Résumé
Since the beginning of 21th century, soil microbial diversity is intensively studied gathering a
huge knowledge at local and global scales. Nevertheless, the microbial habitats have been
poorly investigated, limiting our ability to link biodiversity description and regulation. In our study,
we used a pyrosequencing approach targeting 16S rRNA genes directly amplified from soil DNA
to have a comprehensive view of soil bacterial and archaeal community composition across the
largest spatially explicit soil sampling available in France (2173 soils, area covered = 5.5x105
km2). Based on the multivariate regression tree (MRT) method, we designed 16 distinct
terrestrial microbial habitats at the territory scale, delineated by the association of soil pH, C:N
ratio, land use and minorly climatic conditions. The heterogeneous spatial distribution of habitats
drew up a complex mosaic across France. As for plants and animals, each habitat hosts
generalist and specialist taxa and a specific interaction network, directly or indirectly impacted by
the Human activities. Overall, our results stressed the importance of the integration of microbial
habitats for upgrading the biodiversity conservation policies in a context of global change