海南中部山区天然林物种组成与群落特征变化

为了揭示受20世纪50年代砍伐影响的热带天然林在自然恢复过程中物种组成与群落特征变化趋势，以海南中部山区山地雨林原始林、低地雨林次生林、山地雨林次生林、云雾林次生林4个森林动态样地为对象，基于2012—2020年2次植被调查，从物种组成、区系组成、群落外貌特征等方面分析群落动态特点。结果表明:2012—2020年，（1）山地雨林原始林S?rensen群落相似度为0.960，物种组成最稳定；低地雨林次生林为0.921；山地雨林次生林为0.889；云雾林次生林为0.794，物种更替最明显。随着短期演替进行，各群落间S?rensen群落相似度升高，多年来有更多相同的物种。（2）各群落排名第1的优势种重要值均降低，云雾林次生林优势种重要值下降明显，向更为混合的多优势种群落发展。（3）随着短期演替进行，群落郁闭度增加，喜阳的前中期树种逐渐被耐荫的演替中后期种替代，分布区窄的海南特有种作为补员树种进入群落。（4）各群落均以热带区分布为绝对优势，并以热带亚洲（印度?马来西亚）分布为主。随海拔升高，温度降低，呈现出热带性减弱、温带性加强的特点。8年间，植物区系地理成分更加复杂。（5）叶性质呈现出以中型叶、单叶、革质叶、全缘叶为主的热带地区典型特点；8年间，中型叶比例增加。通过有效的封山育林，受干扰的生态系统均得到较好的恢复。

Changes of species composition and community characteristics of tropical natural forests in the central area of Hainan Island

In order to study the changes of species composition and community characteristics of tropical natural forests in the central area of Hainan Island, two vegetation surveys were conducted in the primary forest of montane rain forest, secondary forest of lowland rain forest, secondary forest of mountain rain forest and secondary forest of cloud forest from 2012 to 2020. The community dynamic characteristics of the tropical natural forests in the recovery process were analyzed in terms of species composition, flora composition and leaf characteristics. The results showed that from 2012 to 2020 the Srensen index was 0.960 for the primary forest of montane rain forest, with the species composition being the most stable, 0.921 for the secondary forest of lowland rain forest, 0.889 for the secondary forest of the mountain rain forest, and 0.794 for the secondary forest of the cloud forest, with the species replacement being the most obvious during succession. With the succession the Srensen index among communities increased, and more species were the same over years. The importance value of the first dominant species decreased in each community. The important value of the dominant species of the secondary forest of the cloud forest decreased significantly, and the secondary forest of the cloud forest tended to develop into communities of multi-dominant species. With the short-term succession, the canopy density of the communities increased. Sun-loving species were gradually replaced by shade-tolerant species. Pioneer species were gradually replaced by transitional species. Hainan endemic species entered into the communities as a supplementary species. The dominant floristic elements of all the forests at the generic levels of woody plants were the tropical distribution, mainly the tropical Asia distribution (India-Malaysia). With the increase of altitude, the temperature decreases and the dominant floristic elements were low in tropical distribution and high in temperate distribution. During the period of eight years, the geographical components of flora were more complex. The leaves of the tropical natural forests showed obvious indigenous characteristics in tropical regions, and they are mainly medium leaves, single leaves, leathery leaves and entire leaves. During the period of 8 years the proportion of the forests with medium leaves increased, which indicates that the tropical natural forests under survey have been restored to some extent due to reduced human disturbance.