Screening and mitigating major threats of regional development to water ecosystems using ecosystem services as endpoints.

Coordinating the coercion of human activities to the ecosystem is a continuous strategic concern. A practical way to conceptualize socioeconomic development and link it to ecosystem response is urgently needed. This study proposed a two-staged method to reveal the threats concealed in socioeconomic development and show the return of water ecosystem services to regulation measures. Eight threat indexes referring to scale, structure and efficiencies of industrial, agriculture and domestic sectors were designed to assess the threats caused by unsustainable development features, while four indexes for evaluating water supply, habitat provision, regulation and quality purification service of ecosystem were set up. For each threat index, the evaluation result is a relative value derived from comparison with a reasonable level. The major threats could be screened out by ranking threat indexes, so that unreasonable development dimension could be identified and subsequent regulation scheme be prepared. On this basis, with the targeted adjustment of socioeconomic development, corresponding improvements in water ecosystem could be expected and quantified. In the case study of Beijing-Tianjin-Hebei District, the most remarkable threats include production inefficiency of the industrial sector and oversized population, of which degrees of deviation from reasonable levels exceed 70%. When all development dimensions were dragged to the suggested levels, the habitat provision and water supply service would witness the largest progress among four services, with the values rising from 0.49 to nearly 1. This method helps discover the critical defect of socioeconomic development in terms of ecosystem response and facilitate the decision maker to establish more sustainable initiatives.