Identifying spatial mismatches between the supply and demand of ecosystem services to achieve a sustainable management regime in the Ionian Islands (Western Greece)

By accounting for both the supply and demand of ecosystem services (ES), it is possible to identify where ES are not able to satisfy human needs. In addition, human demands for natural resources continue to grow rapidly, risking the short supply of ES. Consequently, understanding the balance between ES supply and demand can facilitate sustainable spatial planning and enhance the quality of life. The ES framework followed in this study allowed us to identify spatial similarities and mismatches between the biophysical capacity of ecosystems to provide benefits and societal needs. Specifically, this study revealed the spatial mismatches between the supply and demand of three ES (food provision, climate regulation, and recreation), through identifying zones where excess supply and demand occur on the Ionian Islands (Western Greece). ES supply was quantified from biophysical indicators, while ES demand was estimated through economic valuation. Due to the complexity of ES and the different type of values (direct and indirect use values), a combination of two valuation methods, namely the market prices and the benefit transfer method, was employed to map ES demand. To reveal the spatial relationship between the supply of services and societal demand, a supply-demand ratio was used. The results showed that cropland and urban areas presented high demand for all three ES, due to the high presence of the human population, along with tourism activities. In comparison, more than 50% of the Ionian Islands are characterized by natural forests and olive orchards, leading large areas to be dominated by excess ES supply or by similar amounts of both ES supply and demand. The hot spot analysis (Getis-Ord Gi* statistic) that was used, delineated zones with high connectivity, which could facilitate the prioritization of conservation areas. For areas where an unsustainable regime exists, we suggested how to maintain or shift current spatial policies to improve the decision-making process. In conclusion, the framework used identified compact ES zones in which diverse landscapes of the Ionian Islands allowed the existence of a balanced situation, signifying that human's demands for ES were for the most part fulfilled.