云南纳板河热带季节雨林20 ha动态监测样地的树种组成与群落分类

Species composition and community classification of the 20-ha tropical seasonal rainforest dynamics monitoring plot in the Naban River, Yunnan

大型森林动态监测样地是研究物种共存、群落演替等生态学核心问题的重要平台。纳板河流域国家级自然保护区管理局与中国科学院西双版纳热带植物园合作, 于2016–2017年参照美国史密森热带森林科学中心的技术标准, 在纳板河流域国家级自然保护区内建立了一块热带季节雨林20 ha动态监测样地。本研究分析了该样地的树种组成特征, 并进行了群落数量分类。结果表明: 该样地中DBH ≥ 1 cm的木本植物个体共有59,498株, 分属63科197属296种;个体数超过1,000株的常见物种有15个, 个体数小于20株的稀有物种有126个。科的区系分布型以热带成分为主, 占总科数的65.08%, 温带成分占17.46%。属的区系分布型以热带成分为主, 占总属数的88.32%, 温带成分占10.66%。该样地群落类型的形成主要受海拔和凹凸度这两个地形因子的影响, 500个20m×20m的样方可以分为4个群丛, 分别为: (1)灰毛浆果楝+粗糠柴-假山萝+番龙眼群丛(Cipadessa baccifera+Mallotus philippensis-Harpullia cupanioides+Pometia pinnata Association);(2)长梗三宝木+腋球苎麻–顶果木+番龙眼群丛(Trigonostemon thyrsoideus+Boehmeria glomerulifera-Acrocarpus fraxinifolius+Pometia pinnata Association);(3)云南银柴+大果山香圆-湄公锥+普文楠群丛(Aporusa yunnanensis+Turpinia pomifera-Castanopsis mekongensis+Phoebe puwenensis Association);(4)歪叶榕+密花火筒树-毒药树+番龙眼群丛(Ficus cyrtophylla+Leea compactiflora-Sladenia celastrifolia+Pometia pinnata Association)。

Aims: The large forest dynamics monitoring plot is an important research platform for answering key questions in ecology, such as species coexistence and community succession. This study reported the tree species composition and community types of the 20-ha tropical seasonal rainforest dynamics monitoring plot in the Naban River, Yunnan, which will lay a foundation for the study on species coexistence mechanism for tropical seasonal rainforests, and provide scientific basis for the management and protection of tropical seasonal rainforests. Methods: According to the protocol set forth by CTFS-ForestGEO, a 20-ha tropical seasonal rainforest dynamics monitoring plot was established by the Administration Bureau of the Naban River Watershed National Nature Reserve and the Xishuangbanna Tropical Botanical Garden of Chinese Academy of Sciences between 2016–2017. Here, we analyzed the species composition and classified community types for this large forest dynamics monitoring plot, where all free-standing woody plants with diameter at breast height(DBH) ≥ 1 cm were tagged, measured, and identified to the species level. Results: There were 59,498 individuals with DBH ≥ 1 cm belonging to 296 species, 197 genera, and 63 families. There were 15 species designated as common with individuals numbering more than 1,000 and 126 rare species with fewer than 20 individuals in the plot. At the family level, tropical-associated families were dominant, accounting for 65.08% of the total family;temperate-associated families only accounted for 17.46% of the total family. At the genus level, the tropical-associated genera were dominant, accounting for 88.32% of the total genus;temperate genera only accounted for 10.66%. Elevation and convexity are the key topographical factors underlying the formation of community types in this plot. There were four distinct associations identified among 500 quadrates(20 m × 20 m) as follows:(1) Cipadessa baccifera + Mallotus philippensis – Harpullia cupanioides + Pometia pinnata Association;(2) Trigonostemon thyrsoideus + Boehmeria glomerulifera – Acrocarpus fraxinifolius + Pometia pinnata Association;(3) Aporusa yunnanensis + Turpinia pomifera – Castanopsis mekongensis + Phoebe puwenensis Association;(4) Ficus cyrtophylla + Leea compactiflora – Sladenia celastrifolia + Pometia pinnata Association. Conclusions: The main vegetation type is tropical seasonal rainforest and the flora belongs to the type of tropical north edge in the 20-ha tropical seasonal rainforest dynamics monitoring plot in the Naban River, Yunnan. In the plot, there are four forest community types, on which the topography plays a key role.