藏东南华山松林下灌草主要植物的生态位特征

Niche Characteristics of Main Shrub and Grass Plants under Pinus armandii Forest in Southeast Tibet

在西藏林芝市选取以华山松为建群种或优势种群落设置样地开展调查,基于Levins生态位宽度、Shannon-Wiener生态位宽度和Pianka生态位重叠度计算方法,对华山松林下灌草层主要植物进行计算,分析其生态位特征。结果表明:1)灌木层和草本层的主要植物分别为7种和12种,灌木层中小叶巧玲花的重要值最大,草本层中重要值最大的为西南草莓。2)灌木层中生态位宽度最大的物种是小叶巧玲花和陇塞忍冬,生态位宽度最小的是三桠乌药。草本层中Levins生态位宽度最大的是西南草莓、老鹳草、锦葵,Shannon-Wiener生态位宽度最大的是老鹳草和猪秧秧;最小的为桃儿七。3)灌木层重叠度最高的物种对是腺果大叶蔷薇和鲜黄小檗;重叠度最低的物种对是三桠乌药和腺果大叶蔷薇。草本层中生态位重叠度最高的物种对是高山露珠草和猪秧秧;重叠度最低的物种对是桃儿七和沿阶草。藏东南华山松林下草本层的竞争强度大于灌木层,群落物种对于资源的利用能力均较强,对华山松幼苗的生长发育产生一定影响,可在维持物种多样性的前提下优化幼苗的生长条件。

Sample plots with Pinus armandii as the constructive species or dominant species were selected for investigation in Nyingchi City,Tibet.Based on the calculation methods of Levins niche breadth,Shannon-Wiener niche breadth and Pianka niche overlap,the main plants in the shrub and grass layer under P.armandii forest were calculated and their niche characteristics were analyzed.The results showed that:1)There were 7 species and 12 species of main plants in shrub layer and herb layer,respectively.In shrub layer,the important value of Syringa pubescens was the largest,and in herb layer,the important value of Fragaria moupinensis was the largest.2)The species with the largest niche breadth in shrub layer were S.pubescens and Lonicera tangutica,and the smallest niche breadth was Lindera obtusiloba.In herb layer,the largest Levins niche breadth were F.moupinensis,Geranium wilfordii,and Malva sinensis,and the largest niche breadth of Shannon-Wiener were G.wilfordii and G.aparine var.Tenerum.The smallest was Sinopodophyllum hexandrum.3)The species pairs with the highest overlap in shrub layer were Rosa macrophyllavar.Glandulifera and Berberis diaphana.The species pairs with the lowest degree of overlap were L.obtusiloba and R.macrophyllavar.Glandulifera.The species pairs with the highest niche overlap in the herb layer were Circaea alpina and G.aparine var.Tenerum,The species pairs with the lowest degree of overlap were S.hexandrum and Ophiopogon bodinieri.The competition intensity of herb layer was greater than shrub layer in P.armandii forest in southeast Tibet.The community species had strong utilization ability for resources,which had a certain impact on the growth and development of P.armandii seedlings.The growth conditions of seedlings could be optimized under the premise of maintaining species diversity.