Forces driving ecological degradation in southern China during the MIS3: Natural or anthropogenic?

The role of natural forces in ecological degradation remains controversial owing to the scarcity of records of past land cover destruction with no or less anthropogenic disturbance. Here, we reconstructed land cover changes during the Marine Isotope Stage 3 (MIS3) in the Nanling Mountains in southern China using the delta C-13 and saturation magnetisation (M-s) records of a speleothem from Zuixian Cave. The persistently positive delta C-13 values since 51.9 ka B.P. suggest vegetation reduction and karst rocky desertification in the Nanling Mountains. This prolonged ecological degradation was exposed to reduced precipitation, weak pedogenesis (as indicated by less depleted delta O-18 ratios and low M-s values), and recurring forest fires. Our results highlight the critical role of natural forces in ecosystem degradation, challenging the view of human domination on environmental change. These findings could improve our understanding of the drivers of current ecological evolution and global change.