Reconciling Spatial Conservation of Multiple Hydrological Ecosystem Services across Teshio Watershed, Northern Japan

Abstract

Ecosystem services (ESs) including provisioning, regulating, and cultural services for sustaining and fulfilling human well-being are formed based on various conditions, processes, and components of natural and artificial ecosystems. Spatial conservation planning for sustainable ecosystem development requires precise information on the local potential for providing hydrological ecosystem services in a watershed. The principal challenges in spatially conserving multiple ESs are that they are not independent of each other, and that the interactive relationships between them are in the forms of trade-offs and synergies. The rationality of spatial priority conservation on reconciling multiple ESs will be enhanced if the interactive relationships are recognized at the planning stage. Such a framework is developed by integrating a hydrology model into a systematic conservation model, and it is illustrated with data about multiple hydrological ESs in the Teshio watershed, with the aim of developing a priority conservation ranking map that reconciles competing and compromising interactive relationships among multiple services. The water yield, sediment, and organic nutrient retentions concentrated in eastern and some northern areas with higher precipitation, more forest lands, and steeper slope, but the inorganic nutrient retention concentrated in riverine and southwestern places with agricultural lands. The spatial priority conservation ranking map of an individual ES is closely related to its spatially distributed pattern. The spatial priority conservation areas for sediment and organic nutrient retentions are traded off against those for inorganic nutrient retention. There are obvious differences between the spatial priority conservation ranking maps of individual ESs and those of multiple services together. The spatial priority conservation areas for multiple ESs together simultaneously include southwestern, riverine, eastern, and some northern places of the study watershed, which can balance the conflicts existing between sediment and organic nutrient retentions and inorganic nutrient retention. The systematic priority conservation areas of hydrological ESs provide an effective tool for identifying trade-offs between environmental protection and agricultural economic development. The proposed framework in this study can be applicable to similarly structural prioritization problems of other watersheds, which can sustain ecosystem conservation and economic development.