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应用生态学报 ›› 2023, Vol. 34 ›› Issue (2): 305-314.doi: 10.13287/j.1001-9332.202302.008

• 研究论文 • 上一篇    下一篇

黄土高原刺槐人工林郁闭度对林下植物多样性特征的影响

王依瑞1,2, 王彦辉2, 段文标1*, 李平平1,2, 于澎涛2, 甄理1,2, 李志鑫3, 尚会军3   

  1. 1东北林业大学林学院, 哈尔滨 150040;
    2中国林业科学研究院森林生态环境与自然保护研究所/国家林业和草原局森林生态环境重点实验室, 北京 100091;
    3甘肃省平凉市泾川县官山林场, 甘肃平凉 744306
  • 收稿日期:2022-09-25 接受日期:2022-12-26 出版日期:2023-02-15 发布日期:2023-08-15
  • 通讯作者: *E-mail: dwbiao88@163.com
  • 作者简介:王依瑞, 女, 1999年生, 硕士研究生。主要从事黄土高原森林植被生态恢复效应研究。E-mail: 2995830568@qq.com
  • 基金资助:
    本文由国家自然科学基金项目(U20A2085,U21A2005)和中央级公益性科研院所基本科研业务费专项(CAFYBB2021ZW002)资助。

Effects of canopy density on understory plant diversity in Robinia pseudoacacia plantations on the Loess Plateau of China

WANG Yirui1,2, WANG Yanhui2, DUAN Wenbiao1*, LI Pingping1,2, YU Pengtao2, ZHEN Li1,2, LI Zhixin3, SHANG Huijun3   

  1. 1College of Forestry, Northeast Forestry University, Harbin 150040, China;
    2Ecology and Nature Conservation Institute, Chinese Academy of Forestry/Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Beijing 100091, China;
    3Guanshan Forest Farm of Jingchuan County of Gansu Province, Pingliang 744306, Gansu, China
  • Received:2022-09-25 Accepted:2022-12-26 Online:2023-02-15 Published:2023-08-15

摘要: 为解决黄土高原刺槐人工林因林木过密而导致林下植物缺乏和物种多样性低等问题,基于野外调查和文献收集数据,开展上外包线分析,确定林冠郁闭度对林下植物多样性的影响。结果表明: 在甘肃省泾川县官山林场的调查中,刺槐林下植物的物种数量(91)高于天然草地(78),其优势种随郁闭度而变化且与天然草地截然不同。对文献数据与本研究调查数据的综合分析表明,在年均降水量<550 mm或>550 mm时,郁闭度增加会导致林下植物的盖度呈先基本平稳后大幅或小幅下降的变化,生物量呈大幅下降或小幅度先升后降的变化;而林下植物的物种丰富度指数、Shannon指数、Simpson指数和Pielou指数都呈先升后降的变化,其变幅也是年降水量低时较大。综合来看,刺槐人工林的林下植物生长特征(盖度、生物量和多样性指数等)受郁闭度影响较大,且年降水量低时更敏感,总体上存在一个0.45~0.6的郁闭度阈值,超过或低于这个阈值范围会使这些林下植物生长特征中的多数指标快速降低。因此,若想将林下植物的上述特征同时维持在较高水平,就需在刺槐林经营中维持郁闭度为0.45~0.6。

关键词: 黄土高原, 刺槐人工林, 郁闭度, 林下植物, 物种多样性

Abstract: To solve the problems of understory plant shortage and biodiversity reduction caused by high tree density of Robinia pseudoacacia plantations on the Loess Plateau in northwest China, we analyzed the data collected by field survey and from literatures. We used the upper boundary line method to examine the impacts of canopy density on understory plant diversity. Based on field survey at the Guanshan Forest Farm of Jingchuan County of Gansu Pro-vince, the species number of understory plants in R. pseudoacacia plantations was higher than that in natural grassland (91 vs. 78). The dominant species varied with canopy density, which was completely different from that of natural grassland. A comprehensive analysis of both literature data and field survey data showed that, when mean annual precipitation (MAP) <550 mm or >550 mm, the increases in canopy density first led to a stable understory plant coverage and then a sharp or slight decrease, and understory plant biomass showed a sharp and continuous decrease or a slight increase and then decrease. Understory plant species richness and other diversity indices (Shannon, Simpson, and Pielou indices) first increase and then decrease, with bigger variation range under lower MAP. In all, the characteristics (coverage, biomass and species diversity, etc.) of understory plant community in R. pseudoacacia plantations were strongly affected by canopy density, with higher sensitivity under lower MAP. There was a general threshold range of canopy density of 0.45-0.6. When canopy density was above or below this thre-shold range, it would lead to a rapid decrease of the most characteristics of understory plant community. Therefore, keeping canopy density within the rational range of 0.45-0.6 in the management of R. pseudoacacia plantations is the key to make all the above-mentioned understory plant characteristics at relatively high level.

Key words: Loess Plateau, Robinia pseudoacacia plantation, canopy density, understory plant, species diversity