广东内伶仃岛白桂木群落结构及其演替研究

Structure and succession of Artocarpus hypargyreus community in Neilingding Island,Guangdong

【目的】揭示内伶仃岛植被的演替,为中国特有珍稀濒危植物白桂木Artocarpus hypargyreus种群的保护提供科学依据。【方法】运用群落生态学方法对内伶仃岛白桂木群落进行样地调查,分析群落的组成和结构、地理成分性质以及物种多样性等,并且与其他3个热带或中亚热带植物群落进行比较。【结果】该群落共有维管植物73种,隶属于40科61属,其中蕨类植物有4科4属4种,种子植物有36科57属69种。种类组成以热带分布属占绝对优势,占总属数达98.18%,具有南亚热带成分向热带成分过渡的性质。群落垂直结构较明显,乔木层优势种主要有翻白叶树Pterospermum heterophyllum、白桂木、假柿木姜子Litsea monopetala和浙江润楠Machilus chekiangensis等,其重要值依次为43.86、31.64、12.75和10.39;灌木层则以破布叶Microcos paniculata和九节Psychotria rubra为主;层间藤本植物亦十分发达。群落中主要优势种群的分布格局皆为聚群分布,年龄结构以II级(DBH<2.5 cm)和III级(2.5 cm≤DBH<7.5 cm)立木占绝大多数,属增长型种群,但白桂木种群为衰退型种群。群落的Simpson多样性指数(E)=0.95,Shannon-Wiener多样性指数(H)=3.27,Pielou均匀度指数(EH)=0.84。【结论】内伶仃岛白桂木群落是一个处于群落演替中期的南亚热带常绿阔叶林类型。

【Objective】To reveal the succession of vegetation in Neilingding Island,and provide a scientific basis for protection of Artocarpus hypargyreus,a rare and endangered species endemic to China.【Method】Method in community ecology was used to survey the sample plots of A. hypargyreus community in Neilingding Island,Guangdong. The community composition and structure,characteristics of geographical components and species diversity were analyzed,and were compared to those of other three plant communities in tropic or mid-subtropical regions. 【Result】A total of 73 species of vascular plants belonging to 61 genera of 40 families were discovered in the A. hypargyreus community. Among them,4species of pteridophyta belong to 4 genera of 6 families,and 69 species of seed plants belong to 57 genera of 36 families. Tropical genera（ 98. 18%） occupied a foremost position in this community which shows a transitional property that range from south subtropical to tropical regions. The stratification of the commu-nity was obvious： the dominant populations in the arborous layer mainly were Pterospermum heterophyllum,A. hypargyreus,Litsea monopetala and Machilus chekiangensis,with the important values of 43. 86,31. 64,12. 75 and 10. 39 respectively,the dominant population in the shrub layer mainly were Microcos paniculata and Psychotria rubra,and the lianas were abundant among the layers. The dominant populations in this community had clustering distribution pattern,and were characterized by stumpage of level II（ DBH 2. 5 cm） and level III（ 2. 5 cm≤DBH 7. 5 cm）,indicating that they belonged to the increasing population except the A. hypargyreus population was declining. In this community,Simpson diversity index（ E） was 0. 95,Shannon-Wiener diversity index（ H） was 3. 27,and Pielou evenness index（ EH）was 0. 84. 【Conclusion】The A. hypargyreus community in Neilingding Island is a south subtropical evergreen broad-leaved forest at the middle stage of succession.