Microbial spatial distribution was mostly studied at global scales (i.e. ecosystemic scale) while
studying spatial organization at small scales (i.e. centimeter to millimeter scales) represented a
challenge to understand how structure could impact functions at these scales. Community ecology
approaches, such as the core and satellite theory hypothesis and/or abundance-occupancy relationships,
were classically used to investigate macroorganisms spatial distributions and far less microbial ones.
Previous work showed that microbial communities spatial structure existed at the small scale but never
extended the observation to contrasted and geographically distant soils. In the present work, a focus was
made on bacterial diversity (i.e.16SrRNA gene sequencing) occurring in micro-samples from a variety of
locations presenting various pedo-climatic histories (i.e. from semi-arid, alpine and temperate climates)
and thus differing physicochemical properties. The forms of ecological spatial relationships in bacterial
communities (i.e. frequency-occupancy and abundance-occupancy) and taxa distribution (i.e. habitat
generalists and specialists) were investigated. The results showed a segregation of bacterial diversity
in the four soils at the small scale. Moreover, one soil presented core mode distribution, another a
satellite mode distribution whereas the two others presented bimodal distributions. Interestingly,
numerous core taxa were present in the four soils among which 8 OTUs were common to the four sites. These
results confirm that analyses of the small scale spatial distribution are necessary to understand
consequent functional processes taking place in soils, affecting thus ecosystem functioning.