珙桐群落种内与种间竞争研究

李

尤1

,苏智先

张素兰2,

胡进耀2,郭晓萍

2,朱利君

1

(1西华师范大学环境科学与生物多样性保护省级重点实验室,四川南充637002;

2绵阳师范学院,四川绵阳621000)

摘要:采用Hegyi的单木竞争指数模型对卧龙自然保护区的珙桐群落种内与种间竞争强度进行定量分析,并讨论了不同竞争强度下珙桐的形态变化。结果表明:珙桐受到的竞争强度随着林木径级的增大而逐渐减小,珙桐种内竞争较之与其伴生树种间的竞争剧烈;在群体水平上,珙桐种内与种间竞争强度顺序为:珙桐种内>汶川钓樟>野核桃>灯台树>光叶珙桐>白楠>总状山矾>五裂槭>稠李>蛮青冈;竞争强度和对象木胸径的关系服从幂函数关系(CI=AD-B),当珙桐的胸径达到30cm以上时,竞争强度变化很小,所得的模型能很好的预测珙桐种内与种间的竞争强度;不同竞争强度下,珙桐主干各层的逐级分枝率(R

1:2

)、分枝角度、平均枝长和当年生枝条长都有一定的差异,其中下层的分枝角度、平均枝长和当年生枝条长对邻体竞争表现出极强的可塑性。说明珙桐通过自身形态变化,提高了对资源的利用能力,增强了对不同生境的适应性。

关键词:珙桐群落;种内竞争;种间竞争;竞争强度

中图分类号:Q948文献标识码:A文章编号:0253-2700(2006)06-625-06

LI You1,SU Zhi-Xian2**,ZHANG Su-Lan2,HU Jin-Yao2,

GUO Xiao-Ping2,ZHU Li-Jun1

(1Sichuan Provincial Key Laboratory of Environmental Science and Biodiversity Conservation,China West Normal University,

Nanchong637002,China;2Mianyang Teachers College,Mianyang621000,China)

Davidia involucrata is a rare valuable and endangered plant in China.In order to study neighborhood competi-tion effects,the intraspecific and interspecific competion intensity in Davidia involucrata co mmunity in Wolong Nature Re-serve was analy zed quantitatively by using Hegyi individual tree competition index model.And the m orphological character-istics of Davidia involucrata were investigated under different neighborhood competition intensity.The results showed that the competition intensity in Davidia involucrata decreased gradually with the increasing of forest tree diameter class and the intraspecific competition in Davidia involucrata was more intensive than interspecific competition.The order of the intraspe-cific and interspecific competition intensity at the community level was:intraspecific>Lindira pulcherrima>Juglans cathay-ensis>Cornus c ontroversa>Davidia involucrata var.vilmoriniana>Phoe be neurantha>Symplocos botryantha Franch>Acer oliverianum>Prunus branchypoda>Cyclobalanopsis oxyodon.The relationship between co mpetition intensity and individual growth of objective tree closely followed the following equation:CI=AD-B.The change in co mpetition intensity is very small when the diameter of the objective tree reaches30cm.The model can stimulate and predict the intraspecific and inter-specific competition efficiently.The morphology of Davidia involucrata,such as stepwise bifurcation ratio1∶2,branching angle,average branch and current-year branch lenghth of the main stem in different strata,was modified under different 云南植物研究2006,28(6):625～630

Acta Botanica Yunnanica

通讯作者:Author for correspondence.E-mail:zxsu@

收稿日期:2006-02-14,2006-04-18接受发表

作者简介:李尤(1982-)女,硕士研究生,主要研究方向:植物生态学。E-mail:liyhome21@

基金项目:国家自然科学基金项目(30370149),四川省科技厅项目(05JY029-107)和四川省教育厅项目(2004A192)