西双版纳热带季节雨林土壤氮含量对乔木树种多样性的影响  

Effects of Soil Nitrogen Content on Tree Diversity in Xishuangbanna Tropical Seasonal Rain Forest

作　　者：宋彩云[1,2] 徐武美[1,2] 李巧明[1] 

机构地区：[1]中国科学院西双版纳热带植物园植物系统发育与保护生物学实验室,昆明650223 [2]中国科学院大学,北京100049

出　　处：《植物分类与资源学报》2015年第1期99-104,共6页Plant Diversity

基　　金：国家自然科学基金面上项目(31370267);中科院研究所135研究项目(XTBG-T01)资助

摘　　要：大气氮沉降或人类活动导致生态系统氮输入增加,可能会提高土壤氮含量水平,促进优势种的生长和减少环境异质性,从而使物种共存的生态位减少,群落物种多样性降低。为研究土壤氮含量的增加对森林群落乔木树种多样性的影响,本研究在西双版纳热带季节雨林随机设置了14个1 ha的样方,对各样方土壤总氮(TN)含量、乔木树种丰富度以及西双版纳热带季节雨林20 ha动态监测样地中各样方乔木树种及建群种望天树(Parashorea chinensis)生物量进行了调查。结果表明:土壤氮含量与乔木树种丰富度具有显著负相关而与群落及建群种望天树生物量具有显著正相关。我们推测其机制可能是:土壤氮含量增加促进了建群种望天树等的生长及群落生物量的积累,减少树种共存的生态位,由于竞争排斥等原因而导致群落树种丰富度降低。因此,减少生态系统人为氮输入,对于保护西双版纳热带季节雨林乔木树种多样性具有重要意义。Atmospheric nitrogen deposition and human activities may enhance the nitrogen input into ecosystems, in- crease content of nitrogen in soil and reduce biodiversity due to promoting the growth of dominant species and decrea- sing spatial heterogeneity of environment. To study the relationship between the content of nitrogen in soil and tree diversity in Xishuangbanna tropical seasonal rainforest, we randomly setted 14 plots with each of 1 ha, investigated the tree species richness, total soil nitrogen （ TN）, biomass of the foundation species （ Parashorea chinensis ） and the whole trees of each plot. Our study showed increasing content of total soil nitrogen will promote growth of dominant species, decrease niches for species coexistence and reduce tree diversity due to competitive exclusion. The study indicated that reducing anthropogenic nitrogen supply to ecosystems would play a vital role for protecting tree diversity in Xishuangbanna tropical seasonal rainforest.

关 键 词：总氮 热带季节雨林 树种丰富度 生物量 西双版纳 

分 类 号：Q948.113[生物学—植物学]