Identifying ecological red lines in China's Yangtze River Economic Belt: A regional approach

'Ecological red lines' (ERL) is currently used as a national policy for protecting ecological systems for sustainable development and safeguarding ecological security. The ERL defines the scale and scope of ecosystem services, and can be applied in policy decision-making and ecological protection. This study employs three ecological models (InVEST, RUSLE, CASA) and uses GIS to consolidate five key indicators (annual available recharge, soil retention capacity, net primary productivity, protected areas, lakes and flood storage and retention areas) that measure ecosystem services and two ecological vulnerability indicators (susceptibility of geological hazards, rocky desertification) to establish a coherent framework and criteria of the ERL. The ERL is spatially delineated in China's Yangtze River Economic Belt on the regional scale. The results show that the total area of ERL amounts to 1.13 million km(2), accounting for 55.5% of the total land area within the Belt. Six ERL domains-biodiversity conservation and soil retention; soil retention; biodiversity conservation; water conservation; soil retention and carbon sequestration; and biodiversity conservation and water conservation-make up 82.8% of the total ERL. The findings suggest that implementation of ERL policy is effective when the regional authority acts as an independent and a third-party assessor and enforces the use of a cross-provincial ecological compensation strategy. The coherent framework and criteria of the ERL at the regional scale is applicable to other regions of China.