Testing applicability of an indicator of ecological network sustainability/robustness to socioeconomic systems
In 2009, Ulanowicz developed an indicator of network robustness (closely related to system sustainability) based on information-theoretic measures derived from the study of healthy ecological flow-networks (e.g., energy, carbon or nitrogen networks in non-human food webs). Emphasizing the essential systemic balance between efficiency (e.g., highly pruned networks) and redundancy (e.g., networks with multiple alternate pathways), this measure was shown to apply reliably to 17 natural ecosystem networks and was then proposed as a generic gauge for sustainability of flow-networks including socioeconomic flows of money, trade, food, energy and other currencies. We and other researchers have applied and tested this indicator of systemic robustness/sustainability since its inception in 2009. The objectives of this study were to examine the most recent test applications, synthesize results and assess successes and challenges of the application of this indicator to human systems.
We report on three tests of the indicator’s applicability to socioeconomic networks: 1) introduction of the indicator into regenerative economics, banking, investment and sustainable development in both U.S. and international settings with very positive reception by multiple organizations, 2) use of the indicator to measure robustness/sustainability of a subset of the U.S. food system, a 12 node nitrogen network within the beef supply chain in Maryland, and 3) application of a related ecosystem attribute - autocatalytic loops - as a basis for sustainable economic development in rural, low income, former coal mine communities in Appalachia. This last application has shown success for recycling of organic matter, soil fertility and carbon sequestration but mixed results for associated economic relationships. We report differences between natural ecosystem networks and human socioeconomic networks that must be addressed for further use of this indicator, including 1) a higher degree of connectivity in human networks relative to natural ecosystems and 2) differences in categorizing living vs non-living compartments and interpretation of “trophic levels”. The applications, tests and methodological issues are important for determining appropriate means of employing the Ulanowicz ecological indicator in efforts to guide sustainability in human systems.