Climate Change Impact on Spatiotemporal Hotspots of Hydrologic Ecosystem Services: A Case Study of Chinan Catchment, Taiwan

Hydrologic ecosystem services are greatly affected by the changing climate. In this study, the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was used to quantify hydrologic ecosystem services. Five general circulation models (GCMs) and two representative concentration pathways (RCPs) were selected to estimate hydrologic ecosystem services. The Local Indicators of Spatial Association (LISA) index was used to identify hydrologic ecosystem hotspots. The hotspots were used to evaluate the impact of climate change on the services. Results indicate that annual water yields vary from −17% to 8%, with significant intra-year fluctuation. Compared to baseline data, the CESM1-CAM5 predicts an increase of 45% in June, but HadGEM2-AO predicts a drop to only 12% in January. Sediment export results show a similar trend to water yield, with sediment export increasing significantly under RCP 8.5, and monthly sediment export increases concentrated from June and October. Nitrogen and phosphorous exports both show less significant changes but obvious intra-year variations. The CESM1-CAM5 predicts strong seasonal and spatial variation of the hydrologic ecosystem services. Our proposed approach successfully identifies annual and monthly hotspot spatial changes of hydrologic ecosystem services under climate change.