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中国沙漠 ›› 2024, Vol. 44 ›› Issue (4): 1-13.DOI: 10.7522/j.issn.1000-694X.2024.00010

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生长季降水格局变化对科尔沁沙地典型生境植物群落结构、功能和地上生物量的影响

张晶(), 左小安(), 吕朋   

  1. 中国科学院西北生态环境资源研究院,甘肃 兰州 730000
  • 收稿日期:2023-09-15 修回日期:2024-01-15 出版日期:2024-07-20 发布日期:2024-08-29
  • 通讯作者: 左小安
  • 作者简介:左小安(E-mail: zuoxa@lzb.ac
    张晶(1988—),女,甘肃榆中人,博士,主要从事生态政策、恢复生态学等方面的研究。E-mail: zhangj@llas.ac.cn
  • 基金资助:
    国家自然科学基金项目(42001110)

Effects of changes in growing season precipitation regimes on plant community structure, function and aboveground biomass in typical habitats in the Horqin Sandy Land

Jing Zhang(), Xiaoan Zuo(), Peng Lv   

  1. Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
  • Received:2023-09-15 Revised:2024-01-15 Online:2024-07-20 Published:2024-08-29
  • Contact: Xiaoan Zuo

摘要:

为探究中国干旱、半干旱草地在生长季降水格局变化下植物群落结构、功能和地上生物量的变化规律,以科尔沁沙地为研究对象,于2022年分别在固定沙丘和沙质草地设立5—9月减水60%(P60-)、5—9月增水60%(P60+)、5—6月减水100%(P100-)和5—6月增水100%(P100+)野外模拟控制试验,分析了生长季降水格局变化下植物群落特征(物种多样性、植被盖度、植物密度、地上生物量)、植物群落功能性状(高度、叶片厚度、比叶面积、叶干物质含量、叶片碳氮含量)以及土壤理化性质(土壤含水量、pH、电导率、机械组成、碳氮含量)等指标的变化规律和与地上生物量的相关关系。结果表明:干旱(P60-和P100-)提高了科尔沁沙地中虎尾草和蒺藜等一年生C4植物的重要值(P<0.05),降低了糙隐子草等多年生植物的重要值(P<0.05);对于固定沙丘而言,生长季前期极端干旱(P100-)提高了Simpson优势度指数(P<0.05),降低了Shannon-Wiener多样性指数(P<0.05),整个生长季持续干旱(P60-)提高了地上生物量(P<0.05);对于沙质草地而言,干旱(P60-和P100-)降低了植被盖度和植物密度(P<0.05);干旱处理下地上生物量的提高主要是由单株生物量较大物种优势度的提高所导致,固定沙丘和沙质草地间土壤含水量和细砂含量的差异会通过影响Shannon-Wiener多样性指数和植物群落高度对地上生物量产生影响。因此,生长季降水格局变化改变了科尔沁沙地草地植物群落的物种组成、植被特征和土壤理化性质,影响地上生物量的同时改变了该区域草地生态系统的结构和功能。

关键词: 降水格局, 植被特征, 功能性状, 土壤理化性质, 科尔沁沙地

Abstract:

To explore change rule of plant community structure, function and aboveground biomass within arid and semi-arid grasslands in China, particularly under changing precipitation regimes during the growing season, field simulation control experiments were conducted in fixed sand dunes and sandy grasslands in 2022. The experimental treatments included: a reduction of water by 60% from May to September (P60-), an increase of water by 60% during the same period (P60+), a 100% water reduction from May to June (P100-) and a 100% water increase in the same two months (P100+). This study analyzed changes in plant community characteristics (species diversity, vegetation coverage, plant density, and aboveground biomass), plant community functional traits (height, leaf thickness, specific leaf area, leaf dry matter content, and leaf carbon and nitrogen content), and soil physical and chemical properties (soil water content, pH, conductivity, mechanical composition, and carbon and nitrogen content). The correlations with aboveground biomass were also examined. The results indicated that drought conditions (P60- and P100-) increased the prominence of annual C4 plants such as Chloris virgate and Tribulus terrestrisP<0.05), while diminishing the role of perennial plants like Cleistogenes squarrosaP<0.05). In fixed dunes, extreme early-season drought (P100-) led to an increase in the Simpson dominance index (P<0.05) and a decrease in the Shannon-Wiener diversity index (P<0.05). Conversely, drought throughout the growing season (P60-) increased aboveground biomass(P<0.05). In sandy grasslands, drought (P60- and P100-) reduced vegetation cover and plant density(P<0.05). The increase in aboveground biomass under drought conditions was primarily due to the increased dominance of species with larger biomass. Moreover, differences in soil water content and fine sand content between the fixed sand dunes and sandy grasslands could negatively or positively impact aboveground biomass. This effect is mediated through influences on the Shannon-Wiener diversity index and plant community height. Therefore, shifts in precipitation regimes during the growing season altered species composition, vegetation characteristics, and soil physicochemical properties in the grassland communities of the Horqin Sandy Land. These changes affected aboveground biomass and consequently transformed the structure and function of the grassland ecosystem in this region.

Key words: precipitation regime, vegetation characteristic, functional trait, soil physicochemical property, Horqin Sandy Land

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