China's Ecological Conservation Redline policy is a new opportunity to meet post-2020 protected area targets

Designating protected and conserved areas is a critical component of biodiversity conservation. The 10th Convention on Biological Diversity (CBD) in 2010 set global targets for the areal extent of protected areas (PAs) that were met partially in 2020, yet a new, more ambitious target is needed to halt ongoing global biodiversity loss. China recently introduced a national Ecological Conservation Redline policy, which aims to ensure no net change in land cover and no net loss of biodiversity or degradation of ecosystem services within areas that are critical for maintaining ecological safety and functions. Enacting this policy could achieve ancillary conservation outcomes even where conservation is not the primary objective, thus meeting CBD's definition of "other effective area-based conservation measures" (OECM). By comparing the Ecological Conservation Redline boundaries with important coastal waterbird sites in China, we found that three times more sites could be conserved under the new redline policy compared to the national nature reserve system alone. This indicates that considering the redline policy approach as a form of OECM is a promising pathway to expand the areal coverage of PAs and conserve biodiversity outside currently designated PAs, providing a model that could be adopted around the world.