Data from: Does evenness even exist?

The idea that diversity is a combination of species richness and the
so-called "evenness" of count distributions is a bedrock concept
in ecology. Researchers often compute stand-alone evenness indices. They
also examine Hill numbers related to Shannon's H and Simpson's D
because these metrics balance richness and "evenness" to various
degrees. But evenness is an operationally problematic abstraction, not a
thing out in the world. Evenness indices and Hill numbers in empirical
data are overly sensitive to the abundance of dominant species, poorly
replicable within communities, highly variable among similar communities,
and a weak indicator of latitudinal biodiversity trends. They are
inconsistently related to the parameters of key models that might underlie
count distributions, and they vary highly in simulation even when these
model parameters do not vary. Ecologists would benefit by instead
determining which real distributions fit which theoretical models and
using estimated parameters to understand community structure and assembly.