Evaluating the net value of ecosystem services to support ecological engineering: Framework and a case study of the Beijing Plains afforestation project

Ecological services were initially used to quantify the benefits used in valuation of environmental protection, as they helped stakeholders to understand the benefits that ecosystems bring to people. As a result, they increased support for ecological engineering, including ecosystem restoration. However, by failing to account for costs, and particularly for indirect costs such as the tradeoffs among ecosystem services under different land uses, the analyses were incomplete and often provided poor support for policy development and land management to promote environmental conservation. In this paper, we provide a framework for assessing the net value of the benefits provided by ecosystem services (i.e., the benefit that remains after subtracting key costs), taking the Beijing Plains afforestation project as an example. Furthermore, we analyzed the importance of scale effects and marginal changes in ecosystem services assessment, and highlighted the uncertainty of evaluation results caused by basing some of the analysis on market prices, which can change unpredictably. To better support conservation activities and maximize the ecological benefits obtained from an environmental strategy, it's necessary to obtain accurate estimates of the net value of ecosystem services by accounting for an increasing range of direct and indirect costs, calculated at the same scale as the project implementation and accounting for marginal changes, thereby providing better support for policy development and implementation.