黄河源区干流水生维管束植物和大型底栖动物多样性及分布特征

Study on the diversity and distribution characteristics of aquatic vascular plants and macrobenthos in the mainstream of the Yellow River Source Area

  • 摘要: 水生维管束植物和大型底栖动物作为生态指示物种,反映河流的生态环境状况。为探究黄河源区干流水生维管束植物和大型底栖动物的多样性、分布特征及其受环境和社会经济因素的影响程度,选取黄河源区内流经8个县域的黄河干流,进行水生维管束植物和大型底栖动物调查监测,计算并分析其结构特征指标(密度、生物量、物种数)和多样性指数(Shannon多样性、Pielou均匀度和Marglef丰富度),并通过冗余分析(RDA)探究环境和社会经济因素对水生维管束植物和大型底栖动物多样性的综合影响。结果表明:在黄河源区干流中共采得6种水生维管束植物、27种大型底栖动物。水生维管束植物总体多样性不高,分布具有空间异质性。其中玛多县黄河干流中水生维管束植物各项指数均最高,共采集到水生维管束植物6种,密度为(248.00±35.55)株/m2,生物量为(22.92±4.27)g/m2,除玛多县、甘德县外的其他县域干流中均无水生维管束植物生长。大型底栖动物多样性较高且分布广泛,其中摇蚊科(Chironomidae)种类最为丰富(6种),以青步甲(Chlaenius sp.)分布最为广泛,除兴海县之外的其他7个县域均有记录。达日县大型底栖动物密度〔(206.67±85.61)个/m2〕和总物种数(12种)最高,玛多县大型底栖动物生物量〔(7.04±3.31)g/m2〕最高。RDA分析结果显示,水生维管束植物和大型底栖动物多样性受到降水量(解释贡献率为31.81%)、海拔(解释贡献率为16.7%)等多重环境因素的影响,也与人口密度(解释贡献率为11.24%)、牲畜年末存栏量(解释贡献率为11.18%)等社会经济因素呈显著负相关。为系统推进黄河源区水生态保护与修复工作,从短期可操作措施和长期机制两个层面提出了建议和对策。

     

    Abstract: As ecological indicator species, aquatic vascular plants and macrobenthos continuously reflect the ecological environment of rivers. To investigate the diversity, distribution characteristics, and their responses to environmental and socio-economic factors in the mainstream of the Yellow River Source Area, field surveys were conducted across eight counties in the source region. Structural characteristics indices (density, biomass, and species number) and diversity indices (Shannon diversity, Pielou's evenness, and Margalef's richness) of aquatic vascular plants and macrobenthos were calculated and analyzed. Redundancy analysis (RDA) was used to investigate the comprehensive effects of environmental and socio-economic factors on the diversity of aquatic vascular plants and macrobenthos. The results showed that a total of 6 aquatic vascular plants and 27 macrobenthos were collected in the mainstream of the Yellow River Source Area. The overall diversity of aquatic vascular plants was not high, and their distribution exhibited spatial heterogeneity. Among the counties, Maduo County recorded the highest values across all the indices for aquatic vascular plants, with all 6 species of aquatic vascular plants found there achieving a density of (248.00±35.55)ind./m2 and a biomass of (22.92±4.27)g/m2. Except for Maduo County and Gande County, there was no growth of aquatic vascular plants in other counties in the mainstream. The diversity of macrobenthos was abundant and widely distributed, among which Chironomidae had the richest species (6 species), while Chlaenius sp. was the most widely distributed, with records in seven other counties except Xinghai County. The density of macrobenthos in Dari County (206.67±85.61)ind./m2 and the total number of species (12 species) were the highest, while the biomass of macrobenthos in Maduo County (7.04±3.31)g/m2 was the highest. The RDA analysis results showed that the diversity of aquatic vascular plants and macrobenthos was influenced by multiple environmental factors, such as precipitation (explaining 31.81% of variance) and altitude (16.7%). It was significantly negatively correlated with socio-economic factors, such as population density (11.24%) and year-end livestock inventory (11.18%). To promote the protection and restoration of water ecology in the Yellow River Source Area, this study provided suggestions and countermeasures from both short-term operational measures and long-term mechanisms.

     

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