西双版纳山黄麻林鸟类群落结构及功能分析

Analysis on the structure and function of the bird communities in Trema orientalis forest in Xishuangbanna, Yunnan

山黄麻 (Tremaorientalis)林是西双版纳热带森林次生演替的初级阶段 ,鸟类与山黄麻林的相互关系对森林更新和生物多样性保护有重要意义。我们采用样带观测法 ,在山黄麻林内设 10条观测带 (各带 10 0m长 ,10m宽 ,合计面积 1hm2 )观测记录鸟类 ,网捕鸟类了解摄食情况。观测到的鸟类隶属 7个营养生态位集团 ,涉及 11科、2 4属、4 5种 ;这些鸟类除 5种主要以虫为食 ,4种主要吃草籽外 ,绝大多数都摄食山黄麻果实 ,因而山黄麻果实大量成熟期鸟类较多。山黄麻林鸟类群落的季节动态与山黄麻物候关系密切 ,随山黄麻林的花果量而变动 ,鸟类集中在果熟的山黄麻树上摄食 ,在山黄麻果熟的高峰期 ,鸟类群落呈现出种群数量丰富 ,多样性高而均匀度低的分布格局。 36种食果鸟类的种群数量直接与山黄麻果实丰盛度有关 ,食虫、食草籽的鸟类与山黄麻林结构和食用山黄麻花果的昆虫数量均相关 ,山黄麻林维持了相应的鸟类群落 ,同时鸟类也控制了林内害虫 ,帮助山黄麻传授花粉、散播种子。在植被演替的过程中 ,山黄麻林与鸟类群落相互作用 ,协同发展 。

Trema orientalis forest is an early stage of secondary succession of tropical forest in Xishuangbanna. The relationship between birds and Trema orientalis forest is important to biodiversity conservation and forest regeneration. We used the line transect method to study the structure and function of the bird community in the T. orientalis forest. Within T. orientalis forest, 10 line transects were established, each 100 m long and 10 m wide, to give a total area of one hectare. Within each line, those trees with abundant flowers or fruits were used as focal points for netting birds. Forty five species of birds from seven trophic groups, belonging to 24 genera and 11 families, have been recorded in the T. orientalis forest. All of these bird species ate fruits of T. orientalis except five species of insectivore and four species of seed/insect eaters. The richness of bird species increased with the quantity of T. orientalis fruits. There was also a close relationship between the phenological stages of the T. orientalis and the composition of the bird community associated with it. Furthermore, the parameter of bird diversity ( H′ ) increased, and the parameter of evenness ( J ) decreased during the peak in ripe fruit abundance of T. orientalis , because the birds were attracted by the fruits and concentrated at those trees that were rich with ripe fruits. Occurrence of insectivorous and seed/insect eating bird species was related to the structure of the forest; they were attracted by insects that feed on the fruits of T. orientali. The T. orientalis forest supports the bird community, and in return, the birds help to pollinate the flowers, disperse the seeds and control insects. As the pioneer trees of T. orientalis are short lived, after a few years successional woody trees will replace them. Therefore, diverse birds associated with the trees of the T. orientalis forest may be helpful to natural succession in this ecosystem. It is important to consider the role of birds in the dynamic process of ecological succession.