Nature Reviews Microbiology 10, 497-506 (July 2012) | doi:10.1038/nrmicro2795

Beyond biogeographic patterns: processes shaping the microbial landscape

China A. Hanson1, Jed A. Fuhrman2, M. Claire Horner-Devine3 & Jennifer B. H. Martiny1  About the authors


Recently, microbiologists have established the existence of biogeographic patterns among a wide range of microorganisms. The focus of the field is now shifting to identifying the mechanisms that shape these patterns. Here, we propose that four processes — selection, drift, dispersal and mutation — create and maintain microbial biogeographic patterns on inseparable ecological and evolutionary scales. We consider how the interplay of these processes affects one biogeographic pattern, the distance–decay relationship, and review evidence from the published literature for the processes driving this pattern in microorganisms. Given the limitations of inferring processes from biogeographic patterns, we suggest that studies should focus on directly testing the underlying processes.

Author affiliations

  1. Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92697 USA.
  2. Department of Biological Sciences, University of Southern California, MC0371, Los Angeles, California 90089, USA.
  3. School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA.

Correspondence to: China A. Hanson1 Email:

Correspondence to: Jennifer B. H. Martiny1 Email:

Published online 14 May 2012