Forest transformation and human impact in pearl river delta, south China, during the last 6000 cal yr BP

Despite numerous Holocene studies in the Pearl River Delta (PRD), extensive, high-resolution investigations of peatlands containing buried ancient Glyptostrobus forests remain limited, hindering a full understanding of vegetation evolution and human activity there. This study, conducted in a wood-rich peatland within PRD of South China, utilized magnetic susceptibility, humification, pollen, and microcharcoal indicators to elucidate substantial environmental and vegetational shifts over the last 6000 cal yr BP, capturing the entire process of wetland formation, development, and disappearance, as well as vegetation transitions from dense forests to open habitats. The Glyptostrobus forests initially developed around 5000 cal yr BP and thrived between 4100 and 2800 cal yr BP. This period coincided with the expansion of freshwater wetlands in the PRD, as strong monsoon-driven freshwater discharge progressively advanced the shoreline seaward, creating numerous freshwater wetlands in the lower reaches of the Pearl River. These newly formed wetlands provided suitable habitats for Glyptostrobus to thrive. Concurrently, the relatively strong Asian Summer Monsoon maintained a warm and wet climate, which was conducive to the prosperity of Glyptostrobus forests. Agricultural activities were identified as the main driver in the degradation and ultimate disappearance of natural Glyptostrobus forest after 3000 cal yr BP. Our findings suggesting primary human activities dating back to approximately 3500 cal yr BP ago, with intensive impacts on local vegetation by 2800 cal yr BP. This research provides crucial evidence for understanding palaeoecosystem‌ changes in the context of deltaic evolution and human activities in this densely populated region.