Development of State-and-Transition Models (STM): Integrating Ecosystem Function, Structure and Energy to STM

The main objective of an ecosystem sustainable management is to preserve its capacity to respond and adapt to current disturbances and/or future changes, and maintain the provision of environmental goods and services. Two very important properties linked to this objective are the ecosystem resilience and resistance to disturbance factors. The objective of this paper is to recommend conceptual modifications to the integration of key ecological concepts such as dynamic equilibrium, resistance and resilience to the ‘State and Transition Model’ (STM) in order to apply them in a more feasible way for rangeland management. Ecological resilience describes the amount of change or disruption required to transform a system from being maintained by one set of mutually reinforcing processes and structures to a different set of processes and structures. STMs integrated to concepts of structure, function and energy provides greater opportunities to incorporate adaptive management, more accurate forecasts and a better and easier comparison between rangeland ecosystem types than traditional STMs. We propose to enhance the STM considering four principal axes (ecosystem functions and/or processes, natural disturbances and/or negative management activities, required energy to return to the previous state, and structural ecosystem changes and transition time) also simultaneously, to compare the “robust” ecosystem to “fragile” ecosystem. The recommended modifications enable STMs to identify a broader range of variables to anticipate and identify conditions which determine state resilience to better inform ecosystem managers of risk and restoration options.