Figure 1: Schematic drawing of an individual-based
rarefaction (IBR) curve and the corresponding effective number of
species (ENS) curve. The IBR curve is constrained by the values of n
(i.e. it is bound to start at the x=y=1), whereas the ENS curve is
unconstrained on the vertical axis. The ENS value for a standardized
number of individuals En reflects the “SAD component”
in our framework. The difference between the total diversity
(EN ) and the SAD-component (En)
results from the fact that samples usually exceed the number of
individuals nmin used for standardization. As this
portion of the total diversity change reflects abundance variation, we
call it “N-component”.
Table 1: Comparing Hill numbers, Individual-based rarefaction, and ENS
rarefaction frameworks for quantifying diversity.