Millennial-scale societal shifts drive the widespread loss of a marine ecosystem

Degradation of marine ecosystems by human activities is a global problem, with only recent recognition that exploitation of ecosystems over millennia can result in their functional extinction and loss from human memory. To reconstruct the historical distribution of oyster reefs in China, and the context behind loss, we extracted information from archaeological records and historical documents (pre-modern Chinese literature, administration reports, art, maps, newspapers) spanning ∼7600 years, then constrained records with past coastlines and habitable environmental conditions. Oyster reefs were extensively distributed along >750 km of coastline in the Pearl River Delta, and their exploitation underpinned the region’s development into China’s first economic hub in the 6 th century. Millennial-scale overexploitation alongside societal shifts were central in their regional extirpation by the 19 th century, but the enduring cultural importance of oysters is maintained by aquaculture expansion. Informed conservation practices can be developed from reconstructing the temporal interplay between human societies and the natural environment.