青海湖流域河流生态系统评价指标间的相关性

Correlation Among Evaluation Indexes of River Ecosystem in Qinghai Lake Basin

[目的]研究河岸草甸生态特征、河岸土壤性状及河流水质评价指标间的相关性,为评价青海湖流域河流生态系统提供科学依据。[方法]通过对青海湖流域内主要河流沿海拔梯度进行野外采集河流水样、河岸表层土壤和统计植被生长特征,并且结合室内试验分析。[结果]青海湖流域河流生态系统18个评价指标随着海拔梯度的变化均表现出一定规律性,河岸植被、表层土壤及河流水样各评价指标间具有明显的相关性。由相关分析和主成分分析可知,COD(化学需氧量)与Pb、盖度与有机质、生物量与丰富度间具有极显著正相关(p<0.01),河岸土壤砂粒与河流水中全氮含量、全盐量与盖度、砂粒与丰富度间具有极显著负相关(p<0.01);化学需氧量、有机质、盖度和砷元素可以作为评价河流生态系统优良状况的主要指标。[结论]人类活动对青海湖流域沿河草甸生态系统的负面影响已经显现,必须降低草场的载畜量和减少不必要的工程建设,以实现区域生态、社会和经济可持续发展。

[Objective] The objective of this study is to study correlation among the ecological characteristics of riparian meadows, riparian soil properties and river water quality, in order to provide a solid basis for the evaluation of river ecosystem in Qinghai Lake basin.[Methods] Along altitudinal gradient of main rivers in the field, we collected water samples, riparian topsoil samples and investigated vegetation characteristics, and analyzed samples in laboratory.[Results] The 18 evaluation indexes of river ecosystems exhibited the certain regularity along elevation gradient in Qinghai Lake basin. Obvious correlation existed among the evaluation indexes of the riparian vegetation, surface soil and river water quality. Significant positive correlation was found between chemical oxygen demand（COD） and Pb, coverage and soil organic matter content（SOC）, biomass and richness（p〈0.01）, while significant negative correlation found between the riparian soil sandy grains and river water nitrogen content, soil salt content and coverage, sand grains and richness（p〈0.01）. The principal component analysis indicated that the COD, soil organic matter, vegetation coverage and As can be used to evaluate river ecosystems.[Conclusion] The negative impacts of human activities had emerged on the riparian meadow ecosystem. To achieve sustainability of regional ecological, social and economic development, the grassland stocking rates must be decreased and unnecessary construction projects reduced.