Reducing red-soil runoff from farmland provides heterogeneous economic benefits through coastal ecosystems

Reducing red-soil runoff from farmland to the aquatic environment is beneficial in terms of increased coastal ecosystem services. However, the benefits of countermeasures on farmland to coastal ecosystem conservation remain unclear, thus hampering effective agricultural pollution management. To address this, we quantified the economic value of the countermeasures on farmland for coastal ecosystem conservation by using a choice experiment. We also analysed the heterogeneity of the value on the basis of the type of conserved coastal ecosystem service: fishery resources, biodiversity, recreational opportunity, and aesthetic landscape. We found that the value of a 1 % point reduction in red-soil runoff depended on the conservation-targeted coastal ecosystem services and the areas where the measures were implemented. Thus, the reduction rate of red-soil runoff influenced the prioritization of countermeasure targets and locations. In particular, the conservation of coastal biodiversity by reducing red-soil runoff was more appreciated than that of fishery resources when the soil runoff reduction rate exceeded 10 %. Similarly, a runoff reduction program in national parks can provide more social benefits than that in non-protected areas when the reduction rate exceeds 30 %. Our findings highlight the importance of considering land–sea interactions during policy development and message-framing in enhancing public support.