عنوان مقاله [English]
Concurrent with increasing peoples’ knowledge of the links between human and environment, understanding the importance of ecosystems in human well-being has also increased. The relationship between human well-being and ecology under the title of "ecosystem services" has been intensively studied over the past decades. Despite the general consensus on the overall concept of ecosystem services, there are now significant differences in the presented definitions. Given that many studies refer to the proposed framework definition for the Millennium Ecosystem Assessment (MEA), in this research, other major studies have been selected before and after the MEA framework. Many of these studies for explaining the concept of ecosystem services have taken different approaches in expressing key concepts such as structure, process, function, services and ecosystem benefits. Understanding the position and role of each of these concepts in the definition of ecosystem services is discussed in this study. However, it is hardly possible to determine the exact boundary between different approaches. The discussion of what constitutes the term of ecosystem services may seem to be very theoretical and scientific, but in practice when it comes to quantitatively assessing ecosystem services such as spatial planning, it will be very important to distinguish between the intermediate and final services because it helps researchers not to double count these services.