Subalpine peatland development since the Last Glacial Maximum in subtropical China: Predominantly controlled by monsoonal climate and local topography

Peatlands interact significantly with the global carbon cycle and climate changes. A comprehensive understanding of the development of peatlands is extremely important to help address future climate challenges. Here, we combine three total organic carbon content records with seven published records from subalpine peatlands in the monsoonal region of subtropical China, aiming to reveal the general pattern of peatland development since the Last Glacial Maximum (LGM) in this region. The synthesis showed that organic carbon contents significantly increased at approximately 16 cal kyr B.P. These ten records clearly display two distinct patterns since that time: pattern one showed three intervals of high carbon contents at ca. 16−12 cal kyr B.P., 9.5−7.5 cal kyr B.P. and 6−4 (or 4−1) cal kyr B.P., whereas pattern two reached the maximum in the early Holocene and remained high and relatively stable during the Holocene. Through comparison with pollen indicators and climate reconstructions, we demonstrated that local hydrology linked to monsoonal climates (especially precipitation) was the dominant factor controlling carbon accumulation and the development of subalpine peatlands since the LGM in subtropical China. However, two dynamic patterns that occurred under the same climatic conditions were attributed to the significant modulation of local topography, i.e., intermontane basin (pattern one) or montane (pattern two) settings. The hydrology and development of peatlands are functions of the changes in monsoonal climate and local site-specific topography. These findings provide a comprehensive understanding of past long-term development of peatlands under monsoonal climates.