Hydrobiology Lab., Freshwater & Lakes Division, National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt.
Chemistry Lab., Freshwater & Lakes Division, National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt.
Environ Sci Pollut Res Int. 2023 Mar;30(11):28803-28817. doi: 10.1007/s11356-022-24140-z. Epub 2022 Nov 19.
Macrobenthic invertebrate communities serve as markers of anthropogenic stress in freshwater ecosystems. In this study, 17 sampling sites were selected from two Nile river subbranches (El-Rayah El-Behery and El-Rayah El-Nassery) and subjected to different anthropogenic influences to explore the ecological environment and characteristics of macrobenthos communities. Macrobenthos were studied using taxonomic diversity and biological trait analysis to investigate how human activity and variation in water quality affect their structure and function. A total of 37 taxa represented by 43,389 individuals were recognized. The communities are composed chiefly of Oligochaeta and aquatic insects. Multivariate statistical analyses found that the most influential environmental variables in the structural and functional community were sodium, dissolved oxygen, silicate, pH, calcium, and cadmium. At high levels of pollution, notably sewage and industrial pollution in the northern part of El-Rayah El-Behery, characteristics such as larger body size, detritus feeders, burrowers, and high tolerance to pollution predominated, whereas at low levels of pollution, features such as small body sizes, scraper and predator feeders, intolerant and fairly tolerant of pollution, and climber and swimmer mobility are predominant. The results confirm our prediction that the distribution of macroinvertebrate traits varies spatially in response to environmental changes. The diversity-based method distinguished impacted sewage and industrial sites from thermal effluent sites, while the trait-based approach illustrated an apparent variance between the ecological status of contaminated regions. Therefore, the biological features should be employed in addition to structural aspects for assessing the biodiversity of macroinvertebrate communities under environmental stressors.
底栖无脊椎动物群落是淡水生态系统人为压力的标志物。本研究在尼罗河两个支流（El-Rayah El-Behery 和 El-Rayah El-Nassery）选择了 17 个采样点，这些采样点受到不同人为影响，旨在探索底栖无脊椎动物群落的生态环境和特征。通过分类多样性和生物特征分析来研究人类活动和水质变化如何影响它们的结构和功能。共识别出 37 个分类单元，代表 43389 个个体。这些群落主要由寡毛纲和水生昆虫组成。多变量统计分析发现，对结构和功能群落影响最大的环境变量是钠、溶解氧、硅酸盐、pH 值、钙和镉。在污染水平较高的情况下，特别是在 El-Rayah El-Behery 的北部存在污水和工业污染，特征为体型较大、碎屑食者、掘穴者和对污染具有较高耐受性；在污染水平较低的情况下，特征为体型较小、刮食者和捕食者食者、不耐受和相当耐受污染以及攀援者和游泳者移动性。结果证实了我们的预测，即大型底栖无脊椎动物特征的分布随环境变化而在空间上发生变化。基于多样性的方法将受影响的污水和工业地点与热废水地点区分开来，而基于特征的方法则说明了受污染地区生态状况之间的明显差异。因此，在评估环境胁迫下大型底栖无脊椎动物群落的生物多样性时，除了结构方面，还应采用生物特征。
