Lambic beers are a Belgian specialty which is still made by open-air "inoculation" by airborne microbiota first, followed by additional yeasts, LAB bacteria and more joining in at the time of transferring to used wine barrels. (No yeast is "pitched" or added intentionally.) As many as 200 organisms may play a role, and they seem to take turns, partly regulated by rising acidity and alcohol probably, but with some such as Brettanomyces seeming to simply wait their turn compared to what they will do in a single strain fermentation.
Lambic (or American Coolship Ale hereabouts) fementations can take up to 3 years. Often a thick fluffy "pellicle" or "film" forms on the top of the barrel, like "flor" on sherry, evidently in response to and protection from oxygen. (Sure seems like a bio film.)
(There have been a few studies tracking the staggered blooms of various organisms, including one done 2 years ago at Allagash and one this year at Cantillon, but no discussion about how the sequence is orchestrated. So this is a speculative question about the evolution of these beers.)
Could interspecies quorum sensing be at work? How could that be confirmed?