Ecosystem services in Mediterranean river basin: Climate change impact on water provisioning and erosion control

• Mediterranean hydrological ecosystem services (HES) are threatened by climate change.
• Provisioning (water) services are expected to decrease between 3 and 49%.
• Regulating (erosion control) services are expected to decrease between 5 and 43%.
• Pyrenees mountains are a significant contributor in Llobregat basin's water yield.
• The mean sediment retention is decreasing from upper to lower part of the basin.

The Mediterranean basin is considered one of the most vulnerable regions of the world to climate change and such changes impact the capacity of ecosystems to provide goods and services to human society. The predicted future scenarios for this region present an increased frequency of floods and extended droughts, especially at the Iberian Peninsula. This paper evaluates the impacts of climate change on the water provisioning and erosion control services in the densely populated Mediterranean Llobregat river basin of. The assessment of ecosystem services and their mapping at the basin scale identify the current pressures on the river basin including the source area in the Pyrenees Mountains. Drinking water provisioning is expected to decrease between 3 and 49%, while total hydropower production will decrease between 5 and 43%. Erosion control will be reduced by up to 23%, indicating that costs for dredging the reservoirs as well as for treating drinking water will also increase. Based on these data, the concept for an appropriate quantification and related spatial visualization of ecosystem service is elaborated and discussed.