Community ecology of a kiss and a falling leaf? Community coalescence

What do a kiss, a flooded meadow, a disintegrating soil aggregate, and leaf falling on a soil surface have in common? Not much, unless you consider the microbial communities involved. In these cases, it seems that entire microbial communities and their environment (in some cases) collide and mix; until recently there was not really a term for this. We, in a recent paper in Trends in Ecology and Evolution, coined the term “community coalescence” to describe just such situations; the mixing of entire communities.

It seems – unlike in the macroscopic world (like the Great American Interchange) – such events could be pervasive and unavoidable in microbial systems, because pieces of the environment containing entire communities are moved all the time by a large variety of forces. It’s like the Great American Interchange en miniature all around us!

It will be interesting to see if microbial ecologists become interested in such phenomena and decide to study and understand them. They could have enormous significance for understanding the staggering diversity of microbial systems, and their functioning. And perhaps there are also evolutionary consequences for members of such communities subject to coalescent events.

Are they likely to occur in your system, be it aquatic or terrestrial? What might they look like? How could they be studied? What pieces of ecological theory could be applied, adjusted or developed further? Do such events increase in a world increasingly dominated by aspects of global change?

I think it will be exciting to think about…

Experimentally, perhaps one of the first steps should be to start with very simple systems and to add complexity over time. In the meantime, it may be important to be on the look-out for situations in which community coalescence appears to play an important role, and to collate information from these.