2024年7月25日 星期四
湖南八面山银杉群落特征及其残遗性和保守性分析
Analyses on community characteristics and its relict and conservation of Cathaya argyrophylla at Bamianshan in Hu’nan Province
2016年 第25卷 第4期 页码[76-86]    下载全文[1.2MB]  
摘要

为了解中国特有孑遗植物银杉(Cathaya argyrophylla Chun et Kuang)的生存现状,对位于湖南八面山脚盆辽的银杉+南方铁杉[Tsuga chinensis var. tchekiangensis (Flous) Cheng et L. K. Fu]+甜槠[ Castanopsis eyrei ( Champ.) Tutch.] -猴头杜鹃(Rhododendron simiarum Hance)群落进行调查,分析其群落特征及种群年龄结构,比较分布在不同区域的 6 个银杉群落中种子植物属的分布区类型及其相似性系数;在此基础上,讨论了银杉群落的残遗性特征。结果显示:脚盆辽银杉群落共有维管植物 66 种,包括蕨类植物 4 种和种子植物 62 种(裸子植物 4 种、被子植物 58种); 该群落乔木层的主要优势种为甜槠、 猴头杜鹃、 银杉和南方铁杉, 重要值分别为13. 12% 、 9. 28% 、 8. 86% 和7. 49% ; 该群落的 Simpson 和 Shannon-Wiener 多样性指数分别为 0. 94 和 3. 20, Pielou 均匀度指数 Jsw和 Jsi分别为0. 81 和 0. 92,说明该群落物种多样性偏低但物种分布均匀,与中亚热带山地的暖性针阔叶混交林特征一致。 从生活型谱看,该群落中各频度百分比由高至低依次为 A 级、B 级、C 级、D 级、E 级,与 Raunkiaer 标准频度图谱基本一致,表明该群落整体上处于较为稳定的亚顶极状态。 从银杉种群年龄结构看,种群中幼龄个体占一定比例,但 80 ~180 a 的中龄个体比例偏低;从该群落优势种的径级结构看,甜槠、猴头杜鹃和鹿角杜鹃( Rhododendron latoucheae Franch.)种群为增长型种群,而银杉、南方铁杉和福建柏[Fokienia hodginsii (Dunn) Henry et Thomas]种群为衰退型种群。从脚盆辽银杉群落种子植物属的分布区类型看,温带分布型属占 51.06% , 略高于热带分布型属(占48.94% ),说明该区域属于热带亚热带过渡区;除纬度外,海拔也能够在一定程度上影响其分布区类型组成。 在处于粤北、 粤桂山地和贵州高原 3 个植物区系亚地区的6个银杉群落中,种子植物属分布区类型的相似性系数为0. 35 ~ 0. 67,群落建群种所在属如铁杉属[ Tsuga ( Endlicher) Carrière]、润楠属( Machilus Nees)、水青冈属( Fagus Linn.)和福建柏属(Fokienia Henry et Thomas)等在各群落间有相似性和共通性,且多为古老成分和孑遗成分,表明现存的银杉群落具有相近的变迁历史,分布地域具有明显的亚热带山地避难所特征,体现出其演替过程的残遗性和保守性。 研究结果表明:在银杉群落中适度疏通林窗,降低林下郁闭度,有利于银杉幼树的生长,使银杉种群得到可持续更新和演替。

Abstract

In order to understand current survival status of Chinese endemic relic plant Cathaya argyrophylla Chun et Kuang, C. argyrophylla+Tsuga chinensis var. tchekiangensis (Flous) Cheng et L.K. Fu + Castanopsis eyrei ( Champ.) Tutch. - Rhododendron simiarum Hance community located at Jiaopenliao of Bamianshan in Hu’nan Province was investigated, its community characteristics and population age structure were analyzed, and generic areal-type and its similarity coefficient of spermatophytes in six communities distributing in different regions were compared. On this basis, relic characteristics of C. argyrophylla community was discussed. The results show that there are 66 species of vascular plants in C. argyrophylla community at Jiaopenliao, including 4 species of ferns and 62 species of spermatophytes (4 species of gymnosperm, 58 species of angiosperm). Main dominant species in arbor layer of the community are C. eyrei, R. simiarum, C. argyrophylla and T. chinensis var. tchekiangensis, with important values of 13. 12% , 9. 28% , 8. 86% and 7. 49% , respectively. Simpson and Shannon-Wiener diversity indexes of the community are 0. 94 and 3.20, respectively, and Pielou evenness index Jsw and Jsi are 0. 81 and 0. 92, respectively. It means that species diversity of the community is lower, but species distributes well, and its characteristics is consistent with that of warm coniferous and broad-leaved mixed forest in mid-subtropical mountainous region. Based on life-form. spectrum, percentage of frequency in the community from high to low in sequence is A class, B class, C class, D class, E class, which is consistent with Raunkiaer’s standard frequency diagram, it means that the community is totally in relatively stable subclimax state. Based on age structure of C. argyrophylla population, middle and young age individuals in population occupy a certain ratio, while ratio of middle age individuals with 80- 180 a is lower. Based on diameter-class structure of dominant species in the community, C. eyrei, R. simiarum and Rhododendron latoucheae Franch.  populations are belonged to growing type, while C. argyrophylla, T. chinensis var. tchekiangensis and Fokienia hodginsii ( Dunn ) Henry et Thomas populations are belonged to declining type. Based on generic areal-type of spermatophytes in C. argyrophylla community at Jiaopenliao, temperate areal-type genera account for 51. 06% , which is slightly higher than tropic areal-type genera ( accounting for 48. 94% ), meaning that this region is located in the transition area of tropical and subtropical. Besides latitude, altitude also has a certain effect on areal-type elements. In six C. argyrophylla communities located in three floristic subregions of North Guangdong, Guangdong and Guangxi mountainous region and Guizhou Plateau, similarity coefficient of generic areal-type of spermatophytes is 0.35 – 0.67, the genera containing constructive species in community have similarity and intercommunity among different communities, such as Tsuga (Endlicher) Carrière, Machilus Nees, Fagus Linn. and Fokienia Henry et Thomas, etc., and most of them are relic and conservative elements, indicating that existing communities of C. argyrophylla have similar vicissitude history, the distribution area has obvious characteristics of subtropical mountain shelter, showing relict and conservation of its succession process. It is suggested that moderately exploring forest gap in C. argyrophylla community and decreasing canopy density in forest understory will be beneficial to growth of young tree and keeping C. argyrophylla population continuous renewal and succession.

关键词湖南八面山脚盆辽; 银杉; 群落特征; 分布区类型; 种群年龄结构; 残遗性
Key wordsJiaopenliao of Bamianshan in Hu’nan Province; Cathaya argyrophylla Chun et Kuang; community characteristics; areal-type; population age structure; relict
作者苏乐怡1, 赵万义1, 张记军2, 杨玉鹏1, 郭远飞3, 凡强1, 廖文波1
所在单位1. 中山大学生命科学学院, 广东 广州 510275;
2. 首都师范大学资源环境与旅游学院, 北京 100048;
3. 湖南八面山国家级自然保护区管理局, 湖南 桂东 423501
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基金项目国家科技基础性工作专项(2013FY111500); 2014 年度广东省教育教学成果奖(高等教育)培育第二类项目; 2015 年广东省本科高校教学质量与教学改革工程立项建设项目