Summary: Computational Biology and Chemistry 28 (2004) 227233
Cycling in ecological networks: Finn's index revisited
Stefano Allesinaa,, Robert E. Ulanowiczb
a Dipartimento di Scienze Ambientali, University of Parma, Viale delle Scienze 33/A, 43100 Parma, Italy
b Chesapeake Biological Laboratory, University of Maryland System, P.O. Box 38, Solomons, MD 20688-0038, USA
Received 23 March 2004; received in revised form 19 April 2004; accepted 19 April 2004
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.
© 2004 Elsevier Ltd. All rights reserved.
Keywords: Cycle; Network analysis; Finn cycling index; Residence time; Leontief matrix
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