See also
Alpha diversity
Alpha diversity metrics
Novel alpha diversity metrics
Log-normal abundance distribution
The mirror estimator (R.C. Edgar and H. Flyvbjerg, manuscript in preparation) estimates total richness including unseen OTUs by calculating an octave histogram of OTU abundances. The modal (largest) bin is identified, unless this is the singleton bin in which case it is the second largest. The total richness is then estimated to be:
Mirror = M + 2R.
Here, M is the number of OTUs in the modal bin and R is the number of OTUs in bins to the right of the modal bin.
The mirror estimator gives a good estimate if (1) the distribution is symmetrical around a peak value and (2) the peak is found in the observed bins, not in the unobserved OTUs. In particular, it will give a good estimate if the distribution is approximately log-normal and the peak is visible. If the distribution is log-normal and the peak is not visible because it is to the left of the y axis, then the estimate can be considered as a lower bound on the total richness.
