2011—2016年武夷山甜槠常绿阔叶林乔木层群落动态

Community dynamics of arbor layer in the Castanopsis eyrei evergreen broadleaved forest in the Wuyi Mountains,Fujian Province,southeastern China in 2011—2016

武夷山保存了典型的中亚热带原生性森林生态系统。加强武夷山常绿阔叶林研究,对支撑武夷山生态保护实践具有重要意义。2016年,对按照美国史密森热带研究所热带森林研究中心调查技术规范建立的甜槠常绿阔叶林样地进行了首轮复查,并从物种组成、群落多样性、重要值、死亡率、补员率、胸径等方面分析了其群落动态。结果表明:2016年的乔木个体为25科44属88种,较2011年增加了2科2属7种。群落的优势种组成及其优势程度变化不大,在重要值大于1的21个常见树种中,10个树种的重要值增高,11个降低。甜槠仍为建群种,其重要值略下降。乔木个体增加到3888个,年死亡率为1.31%,年补员率为2.98%。43个树种出现死亡,46个出现补员。4个常见树种的种群数量下降,16个上升。群落的平均胸径从4.82 cm增大为4.89 cm,5个常见树种的平均胸径下降,16个上升。死亡个体的平均胸径为4.47 cm,补员个体为1.67 cm。甜槠仍然将在乔木层,马银花和鹿角杜鹃在亚乔木层保持优势地位。在短期内群落结构不会出现较大的变化,但黄绒润楠、厚皮香等阴生树种和中性树种优势度的增加可能预示群落将向中生群落(顶级群落)演替。

The Wuyi Mountains represent the primary forest ecosystem characteristic of the mid-subtropics. It is important to support biodiversity conservation in the Wuyi Mountains by strengthening research on the evergreen broad-leaved forests ofthese mountains. In 2016, relevant data was gathered in an existing research plot, which was established according to standard international protocols （Smithsonian Tropical Research Institute, Center for Tropical Forest Science, CTFS）, in a Castanopsis eyrie-evergreen broad-leaved forest. The community dynamics of the trees was analyzed based on species composition, community diversity, importance values, mortality rate, recruitment rate, and tree DBH. The results showed that the community of trees in the plot changed from 23 families, 42 genera, and 81 species in 2011 to 25 families, 44 genera, and 88 species in 2016. There was no significant change in community-dominant species composition or in the degree of dominance in the past 5 years. For the 21 common tree species with higher importance values （ 〉 1 ） in 2016, the importance values of 10 species increased, and those of 11 species decreased, when compared with their importance values in 2011. Castanopsis eyrei was still the dominant species in the plot, although its importance value declined slightly. The number of individual trees had increased to 3888 by 2016, the average annual mortality was 1.31%, and the average annual recruitment rate was 2.98%. Compared with the plants living in 2011, individual trees from 43 species had died, and those from 46 species were recruited over the past 5 years. The results also indicated that the populations of 4 common tree species declined, and the populations of 16 common tree species increased from 2011 to 2016. The average DBH of all trees in this community increased from 4.82 cm to 4.89 cm. For the 21 common tree species, the average DBHs of trees from 5 species decreased, and those of the others increased. In addition, the average DBH of dead and recruited individuals were 4.47 cm and 1.67 cm, respectively. Castanopsis eyrei was still dominant in the tree layer, and both Rhododendron ovatum and R. Machilus grijsii and Ternstroemia gymnanthera, may indicate that the succession of this C. eyrie-evergreen broad-leaved forest community will change to climax.