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Stable oxygen isotopes (δ18O) from α-cellulose of peatland plants represent a widely used tool for studying ecological processes and palaeoenvironmental evolution. However, comparison of different regions shows that the climate drivers of δ18O from peat cellulose vary by location. In addition, controversy remains about the parts of plants that are most suitable for analysis. In this study, δ18O from different parts of modern plants in the peatland of Dajiuhu (Hubei Province, China) were determined to better understand the environmental factors that influence δ18O in this area and at a seasonal scale. Results show that δ18O values do not significantly differ in different parts of the plants (whole sample, stem and leaf). Correlation analyses indicate that the major factor contributing to δ18O variability is the δ18O value of peatland water under the influence of monsoons. In addition, significant negative correlations exist between δ18O of plants and mean monthly temperature. Therefore, results demonstrate that δ18O of plants may preserve the 18O isotopic signatures of the peatland water and mean monthly temperature signals, irrespective of the plant organ analysed. Our findings provide a reference and basis for a modern process that uses α-cellulose δ18O in plants to study palaeoenvironmental changes. • The δ18O of plants in the peatland of Dajiuhu were determined. • The δ18O of plants could preserve the δ18O signatures of the source water. • The influence of the mean monthly temperature in the region was not negligible. [ABSTRACT FROM AUTHOR]

A continuous 775-cm-long sediment core (Core B) was collected from the Dajiuhu Basin in the western Shennongjia Forest Region of Central China. The core between 775 and 144 cm in depth spanning the period from 83.4 to 9.6 ka (calibrated age, throughout this study) was studied for pollen analysis. The high-resolution pollen record revealed the histories of the vegetation succession and climate changes from 83.4 to 9.6 ka in the mountainous regions at an altitude of approximately 1,700 m a.s.l. in Central China. The results show that five evident climate changes disclosed by the pollen record in Core B correspond to MIS (Marine Isotope Stage) 5a, MIS 4, MIS 3, the LGM (Last Glacial Maximum) of MIS 2, and the period from the deglacial of MIS 2 to the early Holocene, respectively. The temperature changes in the Dajiuhu Basin are consistent with the solar insolation in the Northern Hemisphere, the climate records in the Greenland and Guliya ice cores, the stalagmite, and the loess. However, the precipitation changes during the late Quaternary in the study area were roughly reversed with the temperature changes in the Northern Hemisphere. Therefore, the climatic patterns from 83.4 to 9.6 ka in the Dajiuhu Basin are cold and humid conditions and warm and dry conditions, which may be caused by the middle latitude position, the humid monsoon climate, and the steep mountainous geomorphology of the study area. [ABSTRACT FROM AUTHOR]