I. Introduction
SUSTAINABILITY of social-ecological systems has been a subject of considerable interest for some time [1]. However, despite its importance, sustainability of this kind is still far from being adequately defined in a rigorous context. The confusion stems directly from the definition of sustainable development itself, given by the Brundtland Commision of the World Commission on Environment and Development (WCED) [2], which leaves much room for interpretation. This has led to research spanning across multiple disciplines in search of a formal definition of the concept [3]–[5].