塔里木河中游不同水文条件下维管束植物物种多样性研究

Study on characteristics of vascular bundle species diversity influenced by water in the middle reaches of Tarim River

根据塔里木河中游地区输水堤防有生态闸断面(乌斯满和阿其河断面)和无生态闸断面(沙子河断面)的地下水位、土壤养分以及植被的监测调查资料,分析了塔里木河中游河岸林水土空间分布特征及其特征与物种多样性的关系。结果表明,水分是影响该区域植物多样性的主导因子。由于生态闸的定期放水,乌斯满和阿其河断面水分条件明显好于沙子河断面,而不同断面间其他环境因子(土壤有机质、全氮、全磷、全钾、全盐含量和pH值)的差异不显著。草本植物多样性受水分的影响最为明显,其丰富度随土壤含水率的增加而增加,随地下水埋深的增加而减小。木本植物多样性受环境因子的影响不明显。群落物种的丰富度决定于草本植物的丰富度,同一断面,水分条件较好的近河道处物种丰富度并不高。距堤防100m的不同断面,乌斯满断面形成高丰富度与低均匀度组合的群落特征,沙子河断面则形成低丰富度与高均匀度组合的群落特征。输水堤防的修建明显影响塔里木河中游地区的土壤含水率,进而影响地表植被尤其是草本植物的物种多样性。生态闸的设置可以在一定程度上减少堤防建设引起的负面生态影响。

The present paper is inclined to introduce our investigation and analysis of the characteristic features of the vascular bundle species diversity under the influence by the water of the nliddle reaches of the Tarim River. In our investigation, we have collected sampies from 18 plots of the three monitoring sections in the middle reaches of tile Tarim River, Xinjiang, and analyzed the environmental variables and species diversity by using diversity tommla, with the help of ANOVA and regression analysis plant comnlunities. The result of our investigation and analysis indicate that the moisture factor of the environmental variables serves as the dominant factor in deciding the distribution of species diversity. Although the moisture content of the three monitoring sections proves to be significantly different by ANOVA, the other contents of the soil factors are significantly different. Of the faetors here mentioned, the water conditions of Wusiman section is better than the oilier two sections, while that of Shazihe section is rather poor. And, it is found that the increasing trend proves related with the variation of the richness of herbaceous plants along with the increased moisture content of soil by regression analysis. At the same time, the trends would decrease with the illcrease of the groundwater depth. However, significant variation of the richness cannot be found in tire woody with the changes on the environmental factors from our regression analysis. In addition, many species in the middle reaches of the river were photophilous, with the drastic interspecies competitions in the given environments that were provided with high gromtdwatcr level, at which some herbs can simply be hard to inake their survival due to dense coverage of some shrubs. However, at the same section of the river, not significant distribution gap was found in the area with better moisture condition near tile stream channel than in the other ordinary areas. As a result of investigation, we have found that 16 species of the total 23 plant species belong to herbs. That is to say, the richness of herbs may perhaps directly in- fluence the richness of the plant community. Comparing the distribu- tion of species diversities of the three sections in a distance 100 meters＇ away from the river bank areas, it can be found that the combination of high species richness and low evenness would be characteristic of the plant communities in the Wusiman section, while the inverse combination of species richness and evenness can be found in the Shazihe section.