RT Journal Article SR Electronic T1 The most efficient microbial community dominates during community coalescence JF bioRxiv FD Cold Spring Harbor Laboratory SP 101436 DO 10.1101/101436 A1 Pawel Sierocinski A1 Kim Milferstedt A1 Florian Bayer A1 Tobias Großkopf A1 Mark Alston A1 Sarah Bastkowski A1 David Swarbreck A1 Phil J Hobbs A1 Orkun S Soyer A1 Jérôme Hamelin A1 Angus Buckling YR 2017 UL http://biorxiv.org/content/early/2017/01/18/101436.abstract AB Immigration has major impacts on both the structure and function of microbial communities(1, 2) and evolutionary dynamics of populations(3). While most work on immigration in microbial ecology deals with relatively low numbers and diversity of immigrants, this does not capture the natural context, which frequently involves the coalescence of entire communities(4, 5). The consequences, if any, of such community coalescence are unclear, although existing theoretical(6–9) and empirical(10-13) studies suggest coalescence can lead to single communities dominating resulting communities. A recent extension(9) of classical ecological theory(14, 15) may provide a simple explanation for such dominance: communities that exploit niches more fully and efficiently prevent species from other communities invading. Here, we test this prediction using complex anaerobic microbial communities, for which methane production is a measure of resource use efficiency at the community scale(16). We found that the communities, which were most efficient methane producers when grown in isolation, dominated when multiple distinct communities were coalesced. As expected from this dominance effect, the total methane production increased with increased number of distinct communities mixed and was linked with the methane production of the most productive community. These results are likely to be relevant to the ecological dynamics of natural microbial communities, as well as demonstrating a simple method to predictably enhance microbial community function in biotechnology, health(17) and agriculture(18).