A chief cybernetic feature of natural living systems is the recycling of nutrients, which tends to enhance stability and is one of the principal causes of ecosystem complexity. In 1976, Finn proposed a simple and effective measure (later known as the Finn cycling index [FCI]) to assess the quantitative importance of cycles in ecosystems. This index was successfully applied as a gauge of ecosystem health and maturity in a wide variety of studies. It turns out, however, that FCI is biased as a measure of cycling in ecosystems, because it does not include all flows engaged in recycling. A new, more inclusive version of the index is possible. What is called the comprehensive cycling index (CCI) accounts for all of the fluxes generated by cycling. Computing the new measure requires a large amount of time, however, even with ad-hoc software. To obviate the necessity for such heavy computation, a linear transformation of the FCI into the CCI is proposed.
['Stefano Allesina', 'Robert E. Ulanowicz']
Cycling in ecological networks: Finn's index revisited