Identification of Key Indicators for Drinking Water Protection Services in the Urban Forests of Ljubljana

Abstract

Background and Purpose: The importance of forest ecosystem services, related to provisioning of fresh water and water purification are of increasing importance, especially in urbanized areas. This study investigates key indicators for ecosystem services, related to drinking water protection, provided by urban and peri-urban forests. Material and Methods: Seven different monitoring programs, projects or directives, assessing water quality variables were analysed. We determined which indicators, describing the drinking water protection services in forest ecosystems, can be applied to urban forests. A list of core indicators sensitive to the specifics of the drinking water supply and urban forest ecosystems in Ljubljana were suggested. Results and Conclusion: Analysis included over 86 potential indicators related to nutrient regulation, storage capacity and water purification in forest canopies, forest soils, surface streams, lakes and groundwater. Through scientific review and the application of “necessary” and “feasible” criteria to urban forests the number of indicators was reduced to 62. According to the specifics of drinking water supply and urban forest in Ljubljana 52 core indicators have been selected. Due to the influence of urbanization on water bodies, special emphasis should be given to indicators for storage capacity and water purification capacity of urban forest ecosystems for hazardous substances. This might increase the willingness of decision and policy makers to acknowledge the water protection capacity of urban forests.

Keywords

• urban forests
• ecosystem services
• drinking water protection
• Ljubljana
• Slovenia