ABSTRACT
The holistic approach highlights the emergent properties that guide natural systems in their evolution and dynamics. Goal functions and orientors have been defined and successfully utilized to study and predict ecosystem behavior. Emergy can measure the inputs to an ecosystem from the environment in equivalent units, and it is an indicator of the energy and matter that the system needs to auto-maintain and develop. Eco-exergy represents the development of ecosystems by increase in work capacity. A combination of these two orientors, i.e., the ratio of eco-exergy to emergy flow, is proposed as an indicator of ecosystem efficiency in converting inputs of resources into ecosystem work capacity. This ratio can also be used in environmental management to assess the nutrient or pollutant effect of an input to a system and to indicate the health status of an ecosystem. Some new approaches are proposed, combining the ratio of eco-exergy to emergy flow together with the concept of ecosystem services.
