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林业科学 ›› 2019, Vol. 55 ›› Issue (12): 140-150.doi: 10.11707/j.1001-7488.20191215

• 研究简报 • 上一篇    下一篇

绍兴淡水湿地人工林优势树种水分利用策略

马迎宾1,2,张蓓蓓1,徐庆1,*,高德强1,郝玉光2,黄雅茹2   

  1. 1. 中国林业科学研究院森林生态环境与保护研究所 国家林业和草原局森林生态环境重点实验室 北京 100091
    2. 中国林业科学研究院沙漠林业实验中心 磴口 015200
  • 收稿日期:2018-12-10 出版日期:2019-12-25 发布日期:2020-01-02
  • 通讯作者: 徐庆
  • 基金资助:
    林业公益性行业专项(201504423);国家自然科学基金项目(31670720);国家自然科学基金项目(31170661)

Water Use Strategy of Dominant Tree Species in Freshwater Wetland Plantations in Shaoxing

Yingbin Ma1,2,Beibei Zhang1,Qing Xu1,*,Deqiang Gao1,Yuguang Hao2,Yaru Huang2   

  1. 1. Research Institute of Forest Ecology Environment and Protection, CAF Key Laboratory of Forest Ecology and Environment of the National Forestry and Grassland Administration Beijing 100091
    2. Experimental Center of Desert Forestry, CAF Dengkou 015200
  • Received:2018-12-10 Online:2019-12-25 Published:2020-01-02
  • Contact: Qing Xu
  • Supported by:
    林业公益性行业专项(201504423);国家自然科学基金项目(31670720);国家自然科学基金项目(31170661)

摘要:

目的: 以浙江省绍兴市汤浦水库库区3种15~20年生湿地人工林(阔叶林、针阔混交林、针叶林)中的优势树种美洲黑杨、北美枫香、柳叶栎、河桦和池杉为研究对象,分析3次不同量级降水后9天内各树种植物水δD组成,定量阐明不同量级降水对各树种植物水的贡献率及各树种的水分利用策略,为该地区湿地人工林生态系统水循环过程的定量研究、水资源合理利用及管理提供理论依据。方法: 利用氢氧稳定同位素技术,分析植物茎(木质部)水δD随采样时间(雨后9天内)的动态变化,并将植物水δD与潜在水源(大气降水、雨前土壤水和浅层地下水等)的δD值进行比较,判断各树种水分来源,并运用贝叶斯混合模型(MixSIAR)计算不同量级降水对各树种植物水的贡献率。结果: 汤浦水库库区淡水湿地人工林优势植物水主要来源于大气降水、雨前土壤水和浅层地下水;降水事件是影响植物水δD以及该次降水对植物水贡献率的主要因子;降水后9天内,小雨(7.5 mm)对阔叶林中各树种植物水的贡献率表现为北美枫香(45.2%~1.5%)>美洲黑杨(38.0%~0.6%)>柳叶栎(31.2%~0.8%),小雨对针阔混交林中各树种植物水的贡献率表现为河桦(39.0%~0.6%)>池杉(32.4%~0.8%)>柳叶栎(25.5%~0.6%);中雨(14.5 mm)和大雨(35.0 mm)对阔叶林中各树种植物水的贡献率表现为美洲黑杨>柳叶栎>北美枫香,中雨和大雨对针阔混交林中河桦植物水的贡献率皆最高;小雨、中雨和大雨对针叶林中池杉植物水的贡献率分别为40.2%~2.6%,58.2%~2.7%和67.4%~20.9%。结论: 汤浦水库库区淡水湿地人工林各优势树种能够快速吸收利用当次降水;小雨对浅根(0~20 cm)树种植物水的贡献率较高,而中雨和大雨对根系分布较深树种植物水的贡献率更高,该库区针阔混交林和阔叶林中的深根和浅根树种具有不同的水分利用策略,有利于该湿地人工林群落的稳定和各树种共存。建议今后在我国长三角地区进行淡水湿地植被恢复过程中,应考虑选择根系分布不同的树种混种,以合理利用水资源、维持湿地森林生态系统的稳定性。

关键词: 植物水分利用, 稳定同位素, 淡水湿地人工林, 根系分布, 汤浦水库

Abstract:

Objectve: The dominant species including Populus deltoides, Liquidambar styraciflua, Quercus phellos, Betula nigra, and Taxodium ascendens in the three freshwater wetland plantations(broad-leaved plantation, coniferous and broad-leaved mixed plantation, coniferous plantation) in the Tangpu Reservoir area of Shaoxing City, Zhejiang Province were used to study the composition of δD of plant stem water within nine days after three different magnitudes of rainfall, and the contribution rate of different magnitudes of rainfall to plant stem water of every arbor species and use strategy of plant species was quantitatively clarified, providing scientific theoretical basis for quantitative research of water cycle process, rational utilization and management of water resources in the reservoir area. Method: Hydrogen and oxygen stable isotopes technique were used to study the dynamic change of water δD of dominant plants during the sampling time (within 9 days after each rainfall) and its comparison with δD values of precipitation, soil water before rainfall, and shallow underground water, etc., to determine the water source of the species. On this basis, Bayesian isotope mixing model MixSIAR (version 3.1.7) was used to calculate the contribution rate of three magnitudes of rainfall to plant stem water of dominant arbor species. Result: For the dominant plant water was mainly obtained from atmospheric precipitation, soil water before rainfall and shallow underground water in freshwater wetland plantation in the Tangpu Reservoir area, rainfall event was the main factor affecting the water δD and the water contribution rate of the plant. Within 9 days after rainfall, the sequence of contribution rate of light rain (7.5 mm) to plant stem water of dominant plants in broad-leaved plantation was L. styraciflua (45.2%-1.5%) > P. deltoides (38.0%-0.6%) > Q. phellos (31.2%-0.8%), the sequence of contribution rate of light rain to plant stem water of dominant plants in the coniferous and broad-leaved mixed plantation was B. nigra (39.0%-0.6%) >T. ascendens (32.4%-0.8%) > Q. phellos (25.5%-0.6%). The order of contribution rate of moderate rain (14.5 mm) and heavy rain (35.0 mm) to plant stem water of tree species in the broad-leaved plantation was P. deltoides > Q. phellos > L. styraciflua, and contribution rate of moderate rain and heavy rain to plant stem water of B. nigra was the highest in the coniferous and broad-leaved mixed plantation. The contribution rate of light rain, moderate rain and heavy rain to plant stem water to T. ascendens in the coniferous plantation were 40.2%-2.6%, 58.2%-2.7%, and 67.4%-20.9%, respectively. Conclusion: The dominant tree species can quickly absorb the precipitation in the freshwater wetland plantation in the Tangpu Reservoir area. The contribution rate of light rain to plant stem water of trees with abundant roots at surface layer (0-20 cm) is higher, while the contribution rate of moderate rain and heavy rain to plant stem water of trees with deeper root distribution is higher. Trees with deep root and shallow root in the coniferous and broad-leaved mixed plantation and in the broad-leaved plantation of Tangpu Reservoir area have different water use strategies, which is conducive to the stability of the wetland plantation community and the coexistence of various tree species in the wetland plantation. It was suggested that tree species with different root distribution should be selected to achieve the rational use of water resources, and maintain the stability of wetland plantation ecosystems in the process of vegetation restoration in freshwater wetlands in the Yangtze River Delta region of China.

Key words: plant water use, stable isotope, freshwater wetland plantation, root distribution, Tangpu Reservoir

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