Superior dispersal ability leads to persistent ecological dominance by Candida pseudoglaebosa in the Sarracenia purpurea metacommunity

Abstract

A large number of descriptive surveys document changes in microbial communities over time, but direct evidence for the ecological processes mediating succession or causing ecological dominance remains rare. Differential dispersal may be a key mechanism. We surveyed microbial diversity within a metacommunity of pitchers of the model carnivorous plant Sarracenia purpurea and discovered the yeast Candida pseudoglaebosa as ecologically dominant. Its frequency in the metacommunity increased over the growing season, and it was not replaced by other taxa. We next measured its competitive ability in a manipulative laboratory experiment and tracked its dispersal over time in nature. Despite its dominance, C. pseudoglaebosa is not a superior competitor. Instead, it is a superior disperser: it arrives in pitchers earlier, and disperses into more pitchers, than other taxa. Differential dispersal across the spatially structured metacommunity of individual pitchers emerges as a key driver of the continuous dominance of C. pseudoglaebosa during succession.