Economic evaluation of hydrological ecosystem services in Mediterranean river basins applied to a case study in southern Italy

Land use affects the eco-hydrological processes with consequences on extreme events such as floods and droughts. Changes in land use affect terrestrial ecosystems and their hydrological services. Spatial planning integrates the water resources governance in order to achieve the objectives of the water and floods European directives. The objective of this paper is the study of hydrological ecosystem services through the quantification of water resources, pollutant loads, land retention capacity and soil erosion. This evaluation allows assignment of an economic value to the ecosystemic services, and then the programming of compensatory actions to climatic or anthropogenic alterations. By assigning an economic value to natural resources (water and soil) and hydraulic system, the authors quantified the hydrological services provided by ecosystems of catchments using climate, hydrological and land use parameters. The proposed methodology to the basin "Bonis" (Calabria Region, Italy) has been applied. The authors have formulated three scenarios: variation between cultivated and forest areas, insertion of impermeable areas and alteration of the vegetation vigor. The simulations prove that the variations of the state of forest areas has a considerable influence on the quantity of water, and then on the economic value provided. Small economic changes occur in the introduction of reduced impermeable areas. A 50% rise of agricultural areas to the detriment of forest areas, increases soil erosion and reduces the storage capacity of the water. The proposed methodology can be a guideline for land planning choices.