西双版纳主要林型冠层球蛛多样性比较

Comparing diversity of canopy theridiids in major forest types in Xishuangbanna region

为比较西双版纳热带地区不同林型冠层蜘蛛多样性的差异,2007年7—8月,采用冠层喷雾法收集冠层蜘蛛,并以冠层球蛛科蜘蛛为代表进行多样性分析,并以球蛛的种类和数量分布为属性进行典范对应分析(CCA)和聚类分析,探讨不同类型植被与冠层蜘蛛多样性的关系。选择西双版纳勐仑镇5种主要林型(热带季节雨林、石灰山季节雨林、山地常绿阔叶林、人工纯林和橡胶林)为研究样地,每种林型设置4个样方,共计20个样方。共采集成熟球蛛标本944头121种,其中热带季节雨林66种,石灰山季节雨林63种,山地常绿阔叶林48种,人工纯林39种,橡胶林27种。研究结果表明,不同林型冠层球蛛物种数量随植被受干扰程度的增加而减少,而个体密度、多样性指数和丰富度指数随着植被群落结构的简化和人为干扰的加强而呈现出先升高再降低的趋势,说明森林简单化和严重的人为干扰会降低冠层蜘蛛的物种多样性。因此,我国热带地区橡胶林的快速增长将阻碍冠层蜘蛛物种扩散与基因交流,增加物种局部灭绝的风险,对生物多样性造成威胁。而适当增加橡胶林的植被群落结构(如:橡胶林种植茶树),保留地表植被,减少人为干扰,对保持冠层蜘蛛多样性具有重要意义。

Canopy spiders were sampled using canopy fogging method during Jul. to Aug. 2007 in Xishuangbanna, SW China, to assess the impact of forest types and habitat management on the diversity of canopy spiders. The composition and diversity of theridiids were analysed as delegate. The relationship between forest types and theridiids diversity was explored based on canonical correspondence analysis （CCA） and cluster analysis. A total of 20 plots （four for each forest type） were surveyed in five major forest types, i. e. , tropical seasonal rain forest, limestone tropical seasonal rain forest, tropical montane evergreen broad-leaved forest, artificial forest and rubber plantation. A total of 944 adult theridiids （121 species） were collected from various habitats. Among them sixty six species were collected from tropical seasonal rain forest, 63 species from limestone tropical seasonal rain forest, 48 species from tropical montane evergreen broad-leaved forest, 39 species from artificial forest, 27 species form rubber plantation. The results showed that species richness and abundance of canopy theridiids were decreased with increasing disturbance. Shannon-Wiener （Hr） index and Margalef index （D^g） were presents the trend of increased originally and then decreased. The results suggested that forest simplification and human-management have strong effects on canopy spider composition, spider diversity trend to be decreased with enhance the degree of disturbance. Species diffusion and gene exchange of canopy spiders will be hindered with the rapid increase of rubber plantations, thus the risk of local extinctions will be increased and the canopy biodiversity will be faced threat. Increasing plant community diversity （ e. g. plant tea tree in rubber plantation） and keeping the surface vegetation will be effective to conserve and restore canopy biodiversity.