A measure to quantify maturity in ecosystems is proposed. The index is based on the analysis of flows of biomass. A measure of the uncertainty of the determination of the route of a given particle of matter will follow through a system and the ability of the system to recycle matter from detritus were used as estimators of maturity. The index was tested by comparing the index values against those of 17 maturity attributes in each ecosystem. We found a significant correlation in 16 of them. With the index, we can determine the maturity and stability of any ecosystem
