A 2000-year paleofire record from the Tashkurgan Wetland (Pamir Plateau, China): Implications for the impact of Silk Road human activities

Reconstructing the paleofire history along the Silk Road enhances our understanding of the complex interplay between natural processes and human activities, and provides a critical perspective on the long-term ecological and environmental evolution of the region. This study conducts a multi-proxy analysis of a sedimentary profile from the Zoroastrian wetland (STCN) on the Pamir Plateau, China, integrating fossil pollen, magnetic susceptibility, and microscopic charcoal records to examine paleofire patterns and anthropogenic influence over the past two millennia. Results indicate that paleofire activity was relatively low from approximately 1900 to 1300 years ago. Beginning around 1300 cal a BP, however, a rise in synanthropic plant pollen occurred alongside increased concentrations of macro-charcoal particles (>125 μm) and higher magnetic susceptibility. These shifts correlated with the development of the Western Regions during the Tang Dynasty and the spread of Zoroastrian fire-worship practices. Between 670 and 540 cal aBP (corresponding to the Yuan-Ming period), secondary peaks in macro-charcoal concentration and magnetic susceptibility, alongside a rise in synanthropic plant pollen and low large Poaceae (>45 μm) content, coincided with agricultural and military activities under the Chagatai Khanate. Since 140 cal a BP, the concentrations of macro-charcoal and the abundance of large Poaceae and synanthropic plant pollen have reached their highest recorded levels, likely driven by population growth, intensified agricultural development, and recurrent warfare. Significant correlations among large Poaceae, Taraxacum pollen, and macro-charcoal particles suggest fire regimes linked to the burning of agricultural crops or anthropogenic weeds, further underscoring the role of human activity. Multi-proxy evidences indicate that human activities along the Silk Road, such as agricultural practices, ritual fire use, and military conflicts, were important factors driving paleofire activity in the region. Particularly during the Yuan–Ming period and the Qing Dynasty, the intensity of human activities showed a synchronous increase with fire frequency, macro-charcoal particle concentrations, pollen content of anthropogenic plants, and magnetic susceptibility values. This research reveals the complex interactions within the human–fire–vegetation system along the Silk Road, providing important insights into the long-term responses of arid ecosystems to human activities.