Assessing high impacts of climate change: spatial characteristics and relationships of hydrological ecosystem services in northern Japan (Teshio River watershed)

Ecosystem services (ESs) provide information on the tendency of ecosystems to reach and form a state of equilibrium. The process of ES changes is important in order to identify the climate change-related causes that occur regionally to globally. ES-based management plays an important role in mitigation strategies for the negative impact of global climate change on ecosystem. Therefore, it is necessary to evaluate spatial characteristics and relationships among these multiple services from different spatial scales which could aid in multiple ES sustainable development from local to global scales. In this study, we developed a framework for analyzing the spatial characteristics and interactive relationships of multiple ESs. We analyzed the spatial distributions of six hydrological ESs that are important in the northernmost part of Japan (Teshio River watershed) by using hydrology and nutrient model (Soil and Water Assessment Tool, SWAT) under baseline climate conditions and climate change derived from the global circulation model (GCM). We then explored the spatial characteristic scales of ESs by multiscale analysis (lacunarity estimation) to reveal provision flow and spatial distribution characteristics for hydrological ESs. We observed a strong relationship between the spatial characteristics of land uses and ES provision. The spatial characteristics of individual hydrological ESs were totally different and had different spatial homogeneity and cluster (indicated by initial lacunarity index and lacunarity dimension). The results also showed trade-offs between inorganic nutrient retention (provision ESs) and organic nutrient and sediment retentions (regulating ESs), and synergies between organic nutrient retention and sediment retention under all climate change scenarios. The different stakeholders will take different mitigation programs (e.g., establishing riparian vegetation, planning nutrient management practices, and integrating climate change model into systematic conservation planning of ESs) to avoid negative impacts of climate change on ESs. Application of this proposed framework to study the spatial characteristics and relationships of hydrological ESs under climate change could provide understanding on the impact of climate change on ES changes and solutions to mitigate strategies to cope with those changes in the future.