Counts of "responder" OTU occurrences in samples from \citet{Steven_2013} and
 \citet{Garcia_Pichel_2013}. \citet{Steven_2013} collected BSC samples (25
 samples total) and samples from soil beneath BSC (17 samples total, "below"
 column in figure). \citet{Garcia_Pichel_2013} collected samples from "dark" (9
 samples total) and "light" (12 samples total) crusts in addition to "Lichen"
 (2 samples total) dominated crusts.
