Page 6 - 《广西植物》2020年第6期
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7 5 2                                 广  西  植  物                                         40 卷
  ( 1. Key Laboratory of Karst Dynamicsꎬ MNR & Guangxi Key Laboratory of Karst Ecosystem and Treatment of Rocky Desertificationꎬ MNRꎬ Institute
   of Karst Geologyꎬ Chinese Academy of Geological Sciencesꎬ Guilin 541004ꎬ Guangxiꎬ Chinaꎻ 2. Key Laboratory of Karst Ecology and Environment
   Change of Guangxi Department of Educationꎬ College of Environment and Resourcesꎬ Guangxi Normal Universityꎬ Guilin 541006ꎬ Guangxiꎬ Chinaꎻ
      3. Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrainꎬ Guangxi Institute of Botanyꎬ Guangxi Zhuang
         Autonomous Region and Chinese Academy of Sciencesꎬ Guilin 541006ꎬ Guangxiꎬ Chinaꎻ 4. Guangxi Key Laboratory of Traditional

            Chinese Medicine Quality Standardsꎬ Guangxi Institute of Chinese Medicine & Pharmaceutical Scienceꎬ Nanning 530022ꎬ
                   Chinaꎻ 5. College of Life Sciencesꎬ Guangxi Normal Universityꎬ Guilin 541006ꎬ Guangxiꎬ China )

       Abstract: Dashiwei Karst Tiankeng Groupꎬ which lies in Leye Countyꎬ Guangxi (Global GeoPark)ꎬ is the most typical
       collapsing Tiankeng group. Many species survived in the relative isolated habitats in karst Tiankeng group. Howeverꎬ the
       flora of the area left insufficiently known because some of the karst Tiankeng groups are difficult to reach. Based on
       available data and further field surveys including transect lines and quadrats covering the whole area and interior of main
       karst Tiankengsꎬ the characteristics of the flora of seed plants were analyzed. The result were as follows: Native seed
       plants in Dashiwei Karst Tainkeng Group was abundant and variousꎬ including 863 species belonging to 445 genera and
       137 families. In terms of genus and family levelꎬ tropical element was the main floristic geographical components. Species
       endemic to China were rather poor. Either the ratio of tropical families to temperate families or the ratio of tropical genera
       to temperate genera was smaller in Dashiwei Karst Tiankeng Group than that of the whole Leye ̄Fengshan Global
       Geopark. The seed plant composition of Dashiwei Karst Tiankeng Group can better reflect the original composition of the
       past. Temperate floristic components used to be more abundant than they are todayꎬ which is a persuasive evidence of
       global warming. In light of 82 species of rare and endangered plants conserved (including 67 wild orchids belonging to 30
       genera)ꎬ Tiankeng group has become a “refuge”for the existing rare and endangered species.
       Key words: Dashiwei Karst Tiankeng Groupꎬ flora of seed plantsꎬ evidence of global warmingꎬ refuge


       天坑是碳酸盐岩地区由溶洞大厅形成的深度                           性组成、形成与演化等开展了系列调查研究ꎮ 第三
   和口径不小于 100 m 或者容积大于 100 万 m 的特                    纪孢粉证据揭示天坑发育早期该区属于亚热带温
                                            3
   大型漏斗ꎬ其四周或大部分周壁陡崖环绕ꎬ曾经或                            暖湿润气候ꎬ主要植被为森林( 刘金荣等ꎬ2004)ꎮ
   者现在仍然与地下河溶洞相通( White & David ꎬ                    现存维管植物多样性、植被类型组成及其特征、观
   2012)ꎮ 随着奉节小寨天坑、武隆箐口“ 漩坑”、广                       赏资源植物的调查研究在一定程度上阐明了天坑
   西乐业“大石围” 天坑等的相继发现ꎬ引发了天坑                           植物组成的特点ꎬ揭示了植物多样性与天坑生境的
   研究的热潮ꎮ 国际学者从天坑的形态、成因、发育                           密切关系(和太平等ꎬ2004ꎻ林宇ꎬ2005ꎻ 苏仕林等ꎬ
   等方面进行了研究和讨论( Walthamꎬ 2005)ꎬ朱学                    2012)ꎬ以及天坑相对孤立的负地形对生物多样性

   稳研究团队于 2003 年初步建立了天坑理论体系                          具有的保育作用(苏宇乔等ꎬ2016)ꎮ 冯慧喆(2015)
   (朱学稳和黄保健ꎬ 2003)ꎮ                                  结合天坑发育特点和区系组成特征将天坑区系的
       天坑是岩溶地区最壮观奇特的负地形景观ꎬ吸                          发展划分为发育的前期、中期和后期三个阶段ꎬ进
   引了地质、地理、景观、生物、环境、旅游、探险等方                          一步揭示了植物多样性和天坑发育之间的关系ꎮ
   面的研究者ꎬ并不断取得新的研究成果和进展ꎮ 大                           然而ꎬ由于天坑险峻ꎬ绝壁表面积大ꎬ风化时间长ꎬ
   石围天坑 群 是 研 究 最 早 也 最 系 统 的 天 坑 群ꎮ 自               相当部分天坑均需借助绳降才能进入坑底ꎬ滚石很

   1998 年以来ꎬ大石围天坑群地区的地质地貌调查、                         多ꎬ坑底开展工作危险且困难ꎬ所以大多已有调查
   植物资源调查与旅游开发同步进行ꎮ 地质地貌调                            局限在容易进入的部分天坑ꎬ尽管有时集中了进入
   查研究以朱学稳团队为主ꎬ逐渐阐明了天坑的形成                            天坑的力量却也只能选择重点少量调查ꎬ从而导致
   条件、发育过程、景观旅游与科研价值(邓亚东等ꎬ                           不同时期调查统计的植物数量变动很大ꎬ如 2004 年
   2012)ꎮ 因此ꎬ对天坑这一独特生境中的生物多样                         调查报道的兰科植物为 15 属 27 种 ( 黄保健等ꎬ
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