Path-based Network Unfolding: A Solution for the Problem of Mixed Trophic and Non-trophic Processes in Trophic Dynamic Analysis

The purpose of this paper is to describe a quantitative method of trophic dynamic analysis derived from a systems ecology theoretical foundation. This method was devised to provide a solution for the problem of how to deal with mixed trophic and non-trophic processes in cyclic ecosystem networks, a problem that has vexed trophic ecology since Lindeman first presented a formal concept of trophic dynamics in 1942. The authorʹs initial attempt to solve this problem was presented in Whipple & Patten (1993,J. theor. Biol.163,393–411). th-based network unfolding method described in this paper provides a quantitative method for conducting trophic dynamic analysis of cyclic ecosystems containing non-living storages and non-trophic flows to produce a true energy-transformation trophic macrochain. This method solves the “trophic-level inflation” problem described in Whipple & Patten (193,J. theor. Biol.163,393–411). sults of the analysis of an oyster reef ecosystem model demonstrate that the dual trophic macrochain produced by path-based network unfolding may be used to compare the relative contribution of grazing and detrital sub-webs to the trophic dynamics of ecosystems. It was found that the standing stock and flow contribution of the detrital sub-web was quantitatively dominant in the oyster reef ecosystem model. This method might be used to compare the contribution of grazing and detrital sub-webs for models of different ecosystem types. e a true energy transformation trophic chain is produced, the progressive efficiency concept of the Lindeman–Hutchinson paradigm may be applied in comparative trophic analyses of ecosystems. In comparing the oyster reef model results of three quantitative trophic analysis methods, the path-based network unfolding method was found to produce a trophic macrochain with progressive efficiencies intermediate between those produced by the original Higashiet al. method and the Burnset al. unfolding analysis of a modified version of the oyster reef model.