JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2024, Vol. 48 ›› Issue (6): 121-128.doi: 10.12302/j.issn.1000-2006.202306009

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Adaptation of typical mixed forest species in the southern hilly region to precipitation variation via water source changes

WU Wenjie1(), WU Chaoming2, ZHU Li2, WANG Linqi2, GE Yu2, ZHANG Tan3, LIU Ziqiang1,*()   

  1. 1. Co-Innovation Center for Sustainable Forestry in Southern China,Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, College of Soil and Water Conservation, Nanjing Forestry University, Nanjing 210037, China
    2. Wuxi Branch, Hydrology and Water Resources Survey Bureau of Jiangsu Province, Wuxi 214299, China
    3. Rizhao River and Lake Management and Protection Center, Rizhao 276826, China
  • Received:2023-06-09 Revised:2023-10-02 Online:2024-11-30 Published:2024-12-10
  • Contact: LIU Ziqiang E-mail:wuwenjie000826@163.com;liuzistrong@njfu.edu.cn

Abstract:

【Objective】The frequent extreme weather events that are likely to be associated with global climate change may have an impact on plant water use. The aim of this study was to explore how mixed forest species adapt by accessing different water sources in the southern hilly region of China under different precipitation conditions.【Method】The stable hydrogen and oxygen isotopes in the xylem, soil, and groundwater from mixed Quercus acutissima and Pinus massoniana forests in the southern hilly region were measured and multi-source linear mixed models (Iso-Source) used to compare and analyze the water use in the forest under different precipitation gradients.【Result】Q. acutissima was found to mainly use soil water from the shallow layer ([10,30) cm) under low precipitation conditions, with a utilization rate of 62.0%; however, under heavier rain the species turns to deep soil water ([80,100) cm) and groundwater, with utilization rates of 34.2% and 44.6%, respectively. P. massoniana mainly uses groundwater and deep soil water ([80,100) cm) with utilization rates of 21.2% and 21.1%, respectively, under low precipitation conditions; however, the species changes to use soil water from depths of (0,10) cm and [10,30) cm layers, with utilization rates of 27.2% and 53.3%, respectively, when precipitation increases.【Conclusion】Q. acutissima and P. massoniana adapt differently to precipitation changes in terms of the water source used, and the depth from which water is sourced changes under different precipitation gradients. The different water use patterns of these species will reduce water competition under the expected frequent extreme precipitation events expected in the future. The results of the study provide a theoretical basis for the implementation of improved forest management.

Key words: Quercus acutissima, Pinus massoniana, precipitation gradient, water source, hydrogen and oxygen isotopes

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