New indicators for delineating priority regions for ecosystem conservation based on the criterion of cost-effectiveness

Natural and semi-natural ecosystems are increasingly threatened by human activities and their conservation conflicts with the ever-increasing spatial demands of human habitation and food production. Identifying the regions in most need of specific ecosystem conservation measures is an urgent problem in order to address this sustainability issue. However, the ambiguous definitions and methods of delineating these regions have led to difficulties in decision-making. To solve this problem of identifying priority regions, we developed new indicators (the marginal profit in terms of supplied ecosystem services and the area of land required to host permitted human activities) and rules for the determination of variable thresholds. Based on the criterion of cost-effectiveness, the concept of marginal profit was introduced and two variable thresholds were determined for its delineation: (i) the largest marginal profit with the highest efficiency and (ii) a marginal profit equal to zero as the potential upper limit. Taking four counties in the water conservation region of Beijing, China as case study areas, the proposed method was applied and tested. The results showed different spatial variations in water conservation services between the four counties, demonstrating the spatially distinct importance of services, which is strongly related to their priorities for conservation. Using the variable strategy, our new indicators and method were able to quantify these spatial characteristics and select particular areas with high-value ecosystem services for delineating priority regions for conservation. Compared to the non-variable threshold with a fixed target, our variable thresholds realized differentiated targets in the four different counties with smaller areas of land conserved for more ecosystem services. The developed indicators also avoided the likelihood of unreasonable outcomes from the use of a fixed target, which, although it could use more land, it would pay for fewer ecosystem services. Our results show the effectiveness of our developed indicators and overall method, which is easily operable and provides differentiated outcomes for priority regions for ecosystem conservation, leading to more informed decision-making