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中国沙漠 ›› 2015, Vol. 35 ›› Issue (6): 1520-1526.DOI: 10.7522/j.issn.1000-694X.2015.00001

• 生物与土壤 • 上一篇    下一篇

毛乌素沙地南缘沙柳(Salix psammophila)丛生枝年龄结构与动态特征

陈国鹏1,2, 赵文智1,3   

  1. 1. 甘肃农业大学林学院, 甘肃 兰州 730070;
    2. 甘肃省白龙江林业管理局林业科学研究所, 甘肃 兰州 730070;
    3. 中国科学院寒区旱区环境与工程研究所中国生态系统研究网络临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室, 甘肃 兰州 730000
  • 收稿日期:2014-11-10 修回日期:2015-01-04 出版日期:2015-11-20 发布日期:2015-11-20
  • 通讯作者: 赵文智(Email:zhaowzh@lzb.ac.cn)
  • 作者简介:陈国鹏(1986-),男,甘肃武威人,博士研究生,主要从事生态系统过程研究。Email:chgp1986@gmail.com
  • 基金资助:
    国家基础研究发展计划项目(2013CB429903);甘肃省青-科技基金计划项目(145RJYK278);陇原青-创新人才扶持计划项目

Age Structure and Dynamics of Salix psammophila Branches in Southern Edge of the Mu Us Sandy Land

Chen Guopeng1,2, Zhao Wenzhi1,3   

  1. 1. College of Forestry, Gansu Agricultural University, Lanzhou 730070, China;
    2. Institute of Forestry Sciences, Bailongjiang Forestry Management Bureau of Gansu Province, Lanzhou 730070, China;
    3. Linze Inland River Basin Research Station/Key Laboratory Inland River Ecohydrology, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2014-11-10 Revised:2015-01-04 Online:2015-11-20 Published:2015-11-20

摘要: 沙柳(Salix psammophila)是毛乌素沙地典型的优势灌木,对维持沙区生态系统稳定起着重要作用。在自然生长过程中,随着年龄增加,沙柳死亡枝条数增多,植株生命活力衰退,沙区生态系统的稳定受到挑战。研究沙柳丛生枝结构随年龄增加的变化规律对保育沙柳生命活力、保障沙区生态系统稳定具有重要意义。本研究通过对沙柳丛生枝分枝收获,查数年轮计数枝龄,绘制丛生枝的年龄结构图,编制静态生命表,分析存活曲线、生存函数等参数变化,并运用时间序列模型预测丛生枝的年龄结构动态。结果表明:沙柳丛生枝中以3 a生枝条最多,年龄结构呈两头小中间大的纺锤型;当年生的枝条生命期望最高、5 a生枝条的死亡率和消失率最高,存活曲线趋于Deevey-Ⅱ型;枝条生长4 a时死亡密度开始下降,生长5 a后的累计死亡率和危险率稳定,枝条动态为前期衰退、后期稳定;丛生枝动态指数趋近于0,趋于稳定型;在未来的2、4、6、8 a时间后沙柳丛生枝数量逐渐增多,但幼龄枝条补充不足,沙柳稳定性难以长期维持。因此,在沙柳生长4 a后需要通过适当的平茬抚育来调整丛生枝的年龄结构以维持沙柳生命活力。

关键词: 沙柳, 丛生枝年龄结构, 生命表, 存活曲线, 时间序列预测

Abstract: Salix psammophila is a pioneer species in the Mu Us Sandy Land. Understanding the age structure and survival status of branches can provide insight into the senescence process of S. psammonphila. We surveyed and analyzed 342 branches of S. psammonphila in southern Mu Us Sandy Land. We estimated the survival curve, mortality curve, life expectancy of the branches, and other parameters of age structure. The results showed that the branches were characterized by the abundance of 3-year-old branches, and the age structure of branches was spindle shaped. The stationary life table of S. psammonphila branches indicated that the observed life expectancies were the highest in 1-year-old branches, while the mortality rate and disappearance rate were the highest in 5-year-old branches. The survival curve of S. psammonphila branches tended to be of Deevey-Ⅱ type. The survivability of the branches declined at young age and fluctuated at old age. The dynamic index of population size of Vpi' was close to zero under random disturbance, indicating that the age structure of the branches tended to be stable and was very sensitive to environment disturbance. The time sequence model predicted that the number of individuals increased in the coming 2, 4, 6 and 8 age classes, but the number in young individual deceased. It was assumed that S. psammonphila population would decline from a lack of recruitment of young individuals if appropriate action is not taken to protect and foster these plants. Therefore, we encourage appropriate pruning to rejuvenate S. psammonphila.

Key words: Salix psammophila, branch age structure, life table, survival curve, time sequence analysis

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