片段化热带森林优势植物叶虫食及其影响因素研究

Study on insect herbivory of dominant plants and its influencing factors in tropical forest fragments

植食性昆虫取食叶片(叶虫食)不仅影响植物种群结构、群落组成和生态系统的功能,还影响食物网内物种的相互关系。但是有关叶虫食在人为干扰的片段化森林中的情况还研究甚少。本研究以西双版纳纳板河保护区两种森林类型(雨林和常绿阔叶林)各4个片段森林作为研究对象,通过树冠的叶片采样分析了每种片段森林共有优势树种的虫食率和虫食频度,并调查了各片段森林的面积和树种多样性。结果表明:(1)雨林片段和常绿阔叶林片段的优势树种平均虫食率分别为7.6%和6.7%,雨林片段的优势树种平均虫食频度(77.0%)显著高于常绿阔叶林片段的(67.5%)(P<0.05);(2)雨林片段的树种多样性显著高于常绿阔叶林片段的(P<0.05);(3)两种片段森林的优势树种叶虫食与片段面积和树种多样性之间均没有显著相关关系。因此,影响片段森林中优势树种叶虫食的因素与片段面积和树种多样性没有直接关系,可能与植食性昆虫和捕食者的散布有关,有待于进一步的研究。

Insect herbivory largely affects plant population structure, community organization, and ecosystem functioning, and it also affects the relationship among species within the food web, but little is known on how insect herbivory is altered in human-modified landscapes. Four rain forest fragments and four evergreen broad-leaved forest fragments were sampled from Nabanhe national reserve, Xishuangbanna. Leaves of shared dominant tree species of each forest type of fragments were collected from canopy to analyze insect herbivory （ including herbivory and herbivory frequency ）, meanwhile tree diversity and fragment area were also measured. The results were as follows： （1） Mean herbivory of dominant tree species of rain forest fragments and evergreen broad-leaved forest fragments were 7.6% and 6.7% respectively, mean herbivory frequency （77.0%） of dominant tree species of rain forest fragments was significant higher than that of evergreen broad-leaved forest fragments （67.5%） （P 〈 0.05）. （2） The tree diversity of rain forest fragments was significant higher than that of evergreen broad-leaved forest fragments （P 〈 0.05）. （3） Insect herbivory of dominant tree species both in rain forest fragments and evergreen broad-leaved forest fragments had no correlation with tree diversity and fragment area. Therefore, Tree diversity and fragment area have no effect on insect herbivory of dominant tree species in forest fragments directly. Future studies should evaluate whether dispersal ability of predators and herbivores can cause change of insect herbivory in forest fragments.