New ShadeLab article: Temporal patterns of rarity provide a more complete view of microbial diversit

Announcing a new opinion piece from the Shade Lab, available online early at Trends in Microbiology.

Highlights

• Conditionally rare taxa (CRTs) contribute to microbial community changes but their ecological roles are largely unknown.

• CRTs are difficult to observe due to their inherent rarity, technological limitations with sequencing, and modest time series data.

• Conceptualizing microbial taxa as dynamic components along species occurrence and species abundance distributions will improve understanding of CRTs and their transitions into and out of the rare biosphere.

• As CRTs are better documented, we can better pose and test hypotheses about their contributions to community resilience after perturbation and ecoevolutionary dynamics.

Recently, conditionally rare taxa (CRTs) – those taxa that are typically in very low abundance but occasionally achieve prevalence – were shown to contribute to patterns of microbial diversity because their collective dynamics explained a large proportion of temporal variability in microbial community structure. Here the benefits and challenges of characterizing the presence and interpreting the role of CRTs are further explored, along with questions about CRT ecology. We also introduce a conceptual model for thinking about microbial taxa as dynamic components along the dimensions of occurrence and abundance. Accounting for CRTs in interpretations of microbial ecological dynamics is essential if we are to understand community stability and ecoevolutionary interactions.