To conserve the strategic integrity of its environment, China has drawn up a system of 'Red Lines'. These denote the total minimum areas of various land-use types nationally and regionally, without specifying their exact locations.

Coming after Red Lines that were created to protect cropland and forest habitats, the latest Red Line will safeguard China's vast biodiversity, environmental resources and ecosystem services. This could consolidate the shift in the country's environmental strategy, which is moving away from networks of protected areas and short-term ecological restoration towards longer-term conservation of entire landscapes.

We propose that the area marked by the latest Red Line (see go.nature.com/na6ry6; in Chinese) should equal at least 496 million hectares. This would incorporate the areas covered by China's existing nature-reserve network and three recent, overlapping, landscape-scale conservation schemes. Within these, 'priority biodiversity conservation areas', 'important ecosystem-function areas' and 'key ecosystem-service function areas' have been designated for flood protection, erosion control, biodiversity conservation and ecosystem-service provision.

Direct government payments for ecosystem-service provisions and adjustments to imbalances in designations, particularly in China's eastern provinces, should underpin this initiative.