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应用生态学报 ›› 2018, Vol. 29 ›› Issue (7): 2129-2138.doi: 10.13287/j.1001-9332.201807.025

• 研究报告 • 上一篇    下一篇

冠层结构和光环境的时空变化对紫耳箭竹种群特征的影响

黄慧敏, 董蓉, 何丹妮, 向运蓉, 张小晶, 陈娟, 陶建平*   

  1. 西南大学生命科学学院, 三峡库区生态环境教育部重点实验室/重庆市三峡库区植物生态与资源重点实验室, 重庆 400715)
  • 收稿日期:2018-01-11 出版日期:2018-07-18 发布日期:2018-07-18
  • 通讯作者: *E-mail: taojianping@163.com
  • 作者简介:黄慧敏, 女, 1989年生, 硕士研究生. 主要从事群落生态学、种群生态学研究. E-mail: 673727393@qq.com
  • 基金资助:

    本文由国家自然科学基金项目(31570612)资助.

Effects of temporal and spatial variation of canopy structures and light conditions on population characteristics of Fargesia decurvata.

HUANG Hui-min, DONG Rong, HE Dan-ni, XIANG Yun-rong, ZHANG Xiao-jing, CHEN Juan, TAO Jian-ping*   

  1. Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education/Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
  • Received:2018-01-11 Online:2018-07-18 Published:2018-07-18
  • Contact: *E-mail: taojianping@163.com
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (31570612).

摘要: 选择金佛山国家自然保护区内落叶阔叶林、常绿落叶阔叶混交林、常绿阔叶林3种典型群落类型,研究冠层结构和光环境特征,以及林下优势种——紫耳箭竹的种群特征.结果表明: 随着落叶阔叶林→常绿落叶阔叶混交林→常绿阔叶林的演替,Shannon多样性指数、Simpson优势度指数和Pielou指数呈增加趋势,表明群落趋于稳定发展的状态;冠层结构特征也发生了显著改变,冠层开度和平均叶倾角减小,叶面积指数增加,冠层的消光能力增强,林下光照水平降低.上层林冠是造成林型郁闭的主要原因,其中冠层厚度和冠层面积是2个主要的影响因素.冠层结构与林下光照指标显著相关,对林下散射光的影响最大.冠层开度、林下光照条件均随着生长季的到来而下降,而叶面积指数呈现增长的趋势,峰值出现在6、7月;平均叶倾角在春季达到最大值,在夏季为最小值.紫耳箭竹的生长与冠层结构和光环境密切相关,其在光照适中的常绿落叶阔叶混交林中生长得最好,分株粗壮、密度大(29.69±1.68株·m-2),地下茎拓展能力强;落叶阔叶林中的强光环境可能造成土壤水分缺失,从而对其生长产生影响;而在常绿阔叶林的低光环境下紫耳箭竹分株矮小,密度小(5.80±1.16株·m-2),克隆扩展能力降低.在森林结构演变的过程中,冠层结构发生了明显的改变,显著影响林下光环境,过度的低光环境对紫耳箭竹种群的更新和发展有限制作用.

Abstract: The canopy structures and light conditions and the population characteristics of Fargesia decurvata, a dominant understory species, were investigated in three typical communities, i.e., deciduous broad-leaved forest, evergreen and deciduous broad-leaved mixed forest, evergreen broad-leaved forest. The results showed that with the succession from deciduous broad-leaved forest to evergreen and deciduous broad-leaved mixed forest and to evergreen broad-leaved forest, the Shannon index, Simpson index and Pielou index were increased, suggesting that the development of communities in Jinfo Mountains tended to be stable. Moreover, canopy structures were significantly changed, in that the canopy openness and mean leaf angle decreased, leaf area index increased, and canopy extinction ability enhanced, resulting in the decrease of light intensity under the canopy. The upper canopy was the main contributor for canopy closure, with the crown depth and crown area of canopy being the two main influencing factors. Moreover, canopy structures were significantly correlated with light conditions in the forest, with the greatest influence on the diffuse solar radiation. With the growth season coming, canopy openness and understory light conditions were decreased, while leaf area index increased, and their maximum values appeared in June or July in the three forest types. The maximum and minimum value of mean leaf angle appeared in spring and summer, respectively. Clonal growth of F. decurvata was closely related to canopy structures and light conditions. In evergreen and deciduous broad-leaved mixed forest with moderate light, F. decurvata grew best, with high and thick ramets, high ramet density (29.69±1.68 ind·m-2) and high ability to expand rhizomes. In deciduous broad-leaved forest, the strong light condition caused the reduction of soil water might have effects on the growth of F. decurvata. However, in the evergreen broad-leaved forest with low light condition, ramets of F. decurvata tended to be short and thin, with low ramet density (5.80±1.16 ind·m-2) and the clonal expansion ability. Those results suggested that forest succession would change canopy structures and understory light conditions. Low understory light conditions prohibited the regeneration and development of F. decurvata population.