鼎湖山季风常绿阔叶林原锥栗-厚壳桂-荷木群落演替

Succession of the original Castanopsis chinensis-Cryptocarya chinensis-Schima superba community of monsoom evergreen broad-leaved forest in Dinghushan Nature Reserve

在对 2 0 0 0 m2 永久样地进行 5次调查的基础上 ,研究了鼎湖山季风常绿阔叶林锥栗 -厚壳桂 -荷木群落在 2 0 a演替过程中的物种组成结构和物种多样性的动态变化 ,对影响该群落演替的因素进行了分析 ,并对未来演替趋势作了探讨。结果表明 :(1)群落个体数呈现类似“W”型动态变化。(2 )在 2 0 a的演替中 ,黄果厚壳桂在群落乔木层消失 ,厚壳桂种群数量下降了 98.2 1% ,都丧失了原来的优势地位 ,樟科植物的个体数减少了 95 .35 % ;锥栗和荷木个体数都随着演替的进展在减少 ,正逐步走向衰亡 ;因此 2 0 0 2年的群落应更名为锥栗 -云南银柴 -荷木群落。 (3)群落中的阳生性树种的重要值在 18.87～ 2 7.73之间波动 ,在 2 0 0 2年达到最大。 (4 )群落物种组成结构差异随演替时间的增加在逐渐增大 ,但总体变幅较小。 (5 )群落的物种丰富度有小的起伏 ;SW指数在 3.390 4～ 3.5 72 4范围内呈现类似于群落个体数的变化格局 ,在 2 0 0 2年到达最大 ;均匀度在 0 .6 175～ 0 .6 5 4 0范围内表现与 SW指数相似的动态变化 ;生态优势度介于 0 .1837～ 0 .2 4 77之间 ,但变化趋势与 SW指数、均匀度相反。总体上看 ,群落物种组成结构、物种多样性都波动不大 ,群落仍维持相对稳定。(6 )

The monsoon evergreen broad-leaved forest (MEBF) in Dinghushan Nature Reserve (DNR) has been considered as a zonal vegetation in lower subtropical China, with a history of more than 400 years. Its community structure, species diversity and community dynamics have been studied since 1956, so a lot of data have been well accumulated, which benefits the study on community succession.Based on the data from five-time survey in a 2000m^2 permanent plot of the original Castanopsis chinensis - Cryptocarya chinensis - Schima superba community of MEBF in DNR, the community dynamics of species composition and species diversity in a twenty-year successional process,its future successional tendency and the main factors that influenced the community succession were studied in this paper. The results were showed as follows:(1) Changes of the number of individuals of community demonstrated a “W” shape tendency. (2)Due to insect irruption, the population size of Cryptocarya concinna and Cryptocarya chinensis decreased by 100%, 98.21%,respectively, which led to lose their dominant status,and the number of individuals of the Lauraceae decreased by 95.35%; Similarly, the population size of Castanopsis chinensis and Schima superba decreased with successional processes; Therefore, original community should be renamed as Castanopsis chinensis - Aporosa yunnanensis - Schima superba in 2002. (3) The important value of all Heliophytes in the community fluctuated from 18.87 to 27.73, maximized in 2002. (4) Differences in species composition among commuities increased with the community successional time, but their changes were no obvious within 20 years. (5) Species richness appeared a little fluctuation, and the values of SW index, evenness index and Simpson index of community fluctuated within the ranges of 3.3904～3.5724, 0.6175～0.6540 and 0.1837～0.2477, respectively. The maximum value of SW index occurred in 2002. The changes of SW and evenness indices were similar to that of the number of individuals in the community,but the change of Simpson index was contrary to that of evenness index. Although species composition and species diversity fluctuated slightly, the community still maintained relatively stable. (6) The main factors that influenced community succession and led to community fluctuation might include both natural disturbances (insect irruption, catastrophic weather) and human disturbances (tourism and research activities). (7) The community will approach to a climax in the future, but the opinion that the climax community of Dinghushan characterized by the dominant species of Cryptocarya concinna - Cryptocarya chinensis needs to be further testified.