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.