塔里木河下游植物群落结构特征分析

The structure characteristic of the plant community in the lower reaches of Tarim River

对塔里木河下游经30a断流后的应急输水河畔植被进行外业调查,分析了调查区植物群落的种类组成、垂直结构、密度结构以及优势种群的格局分布,旨在了解输水后研究区植物群落在结构特征方面恢复程度。结果表明:调查样地内有植物13种,其中胡杨(Populus euphratica)、柽柳(Tamarix)、黑果枸杞(Lycium ruthenicum)、花花柴(Karelinia caspica)和疏叶骆驼刺(Alhagi sparsifolia)为优势种。不同地下水条件物种的重要值不同,表现在不同离河距离具有不同的物种组成结构,随地下水埋深不同植物群落由以胡杨和胀果甘草为主到以柽柳、黑果枸杞、花花柴和疏叶骆驼刺等抗旱耐盐碱植物为主。乔木层密度随着离河距离加大而减小,灌木层和草本层密度随离河距离加大呈先增加后减小的趋势。群落垂直结构随离河距离加大由乔-灌-草3层逐渐转变为灌-草2层,随离河距离加大趋于简单。优势种群胡杨在离河300m以内呈聚集分布,聚集强度随离河距加大而增强;柽柳灌丛在离河50m呈均匀分布,离河150m以外呈聚集分布,但离河750m段有向随机分布发展趋势。植物群落结构特征在不同的离河距离具有差异,说明经过输水下游植物群落的恢复在结构特征方面有响应,为区域生态治理和保护提供科学依据。

On the basis of the survey data on the Yingsu section that main vegetation distribute of emergency conveyance in the lower reaches of Tarim River,the plant communities species composition,the density structure,the horizontal structure and the distribution pattern of dominant populations are analyzed in the survey area,in order that know the plant community recovery on the structure in the study area after the water. The results shows there are 13 species of plants,of which Populus euphratica,Tamarix,Lycium ruthenicum,Karelinia caspica and Alhagi sparsifolia are dominant species in survey plots. the analysis of the important value of all species in different distance from the River shows there are different species composition in different sections from the river,with the depth of groundwater differing,dominant communities that P. euphratica and Glycyrrhiz inflata change to communities of anti-drought and salt-tolerant plants including Tamarix,Lycyum ruthenicum,Karelinia caspica and Alhagi sparsifolia. the vertical structure of community become three levels including tree,shrub,herbaceous layers to two levels including shrub and herbaceous layers,which tends to simple with the distance increasing from the river. Density of tree layer decreases with the distance increasing from the river,shrub and herb layer density demonstrated the trend that increases at first and decreases after that with distance increasing from the river. The distribution pattern of dominant populations is that populus population present the pattern of clustering distribution inside 300 m from the river and its aggregating intensity is higher with the distance from Tarim River increased,Tamarix shrub present he pattern of uniform distribution in 50 m from the river and which of clustering distribution outside 150 m from the river,except for 750 m from the river which tends to random distribution,in addition,its aggregating intensity is not certain regularity with the distance changing from the river. The structure of plant communities are discrepant in different distance from the river in this section,that means the plant community restoration get to response on the structure in the lower reaches of Tarim River,These results provide scientific basis for regional ecological remediation and protect.