Quantifying realized ecosystem services from the supply-flow-demand perspective and understanding the management implications: a case study of the Chengdu Prefecture, China

• A realized ecosystem service (ES) evaluation framework was proposed. • The realized ESs and ES supplies of crop pollination, flood regulation and natural recreation showed different distributions. • The trade-offs/synergies of realized ES pairs help managers avoid overestimating the ES synergy. • The ES management zone scheme is influenced by the adoption of the realized ES or ES supply in bundle analysis. • The hotspot of the realized ES can identify the areas crucial for providing the actual benefit. To efficiently improve human wellbeing by managing ecosystem services (ESs), decision-makers have shown more interest in how many ESs are used by humans (realized service, RS) over how many ESs are provided by ecosystems (service supply, SS). However, the RS is determined by ecosystems, social systems and their complex interactions simultaneously, so RS evaluation is still challenging. In this study, we constructed an RS evaluation framework from the supply-flow-demand perspective, and applied this framework to four typical ESs in the Chengdu Prefecture, China. We quantified the SS and RS of the four ESs, and then compared the trade-offs/synergies and hotspots of the SS and RS to discuss how the RS adoption influences management decision-making. Our results show that: (1) Except for carbon sequestration, the SS and RS of the other three ESs exhibited different distributions. (2) For ES synergies/trade-offs, all the ES pairs showed synergies from the SS perspective, while such synergies were weakened or even converted into trade-offs from the RS perspective. This implies the risk of overrating ES synergies based on the SS. Moreover, the SS and RS bundles showed different distributions and ES compositions, which indicated that the ES management zoning scheme (including spatial layout and management strategies) formulated with the SS will be changed when RSs are management targets. (3) SS and RS hotspots exhibited different spatial patterns, and only less than half of SS hotspots were identified as RS hotspots. The RS adaptation in ES hotspot analysis can help identify the areas crucial for providing actual benefits as the conservation priority. This study can not only deepen the understanding of actual natural contributions to humans, but can also support ES management aimed at human wellbeing improvement.