Shenzhen Evaluation of the Impact of Urbanization on the Benthic Macroinvertebrate Community Structure and Diversity in Longgang River of Guangdong Greater Bay Area Station

Channelization is the most common hydraulic modification of urban rivers. In this study, we evaluated the impact of urban river morphology on benthic communities by conducting an analysis of benthic community characteristics at various sites in channelized and natural rivers within the Longgang River system in southern China. Our survey identified 4 species of Clitellata, 5 species of Oligochaeta, 1 species of Polychaeta, 10 genera/species of Gastropoda, 2 genera/species of Bivalvia, 2 genera/species of Crustacea, and 14 genera/species of Insecta. Insecta and Oligochaeta were the dominant classes in both the wet and dry seasons, with Chironomus plumosus being the most prevalent species. The density of Clitellata was notably lower in channelized rivers compared to natural rivers. Additionally, the Shannon’s diversity index was significantly lower in channelized rivers than in natural rivers during both the wet and dry seasons. These results suggest that river channel morphology has an impact on benthic faunal structure and diversity, with the effects varying across different seasons. Limiting channelization can help prevent the loss of aquatic biodiversity in subtropical urban rivers, as can the preservation of natural rivers.

河道渠化（Channelization）是城市河流最常见的水力改造方式。本研究以中国南方龙岗河水系内渠化及天然河流的多个采样点位为研究对象，通过分析底栖生物群落（benthic community）特征，探究城市河流形态对底栖生物群落的影响。本次调查共记录到环带纲（Clitellata）4种、寡毛纲（Oligochaeta）5种、多毛纲（Polychaeta）1种、腹足纲（Gastropoda）10个属/种、双壳纲（Bivalvia）2个属/种、甲壳纲（Crustacea）2个属/种以及昆虫纲（Insecta）14个属/种。昆虫纲与寡毛纲为湿季与旱季的优势类群，其中羽摇蚊（Chironomus plumosus）为最优势物种。渠化河段的环带纲密度显著低于天然河段。此外，无论湿季还是旱季，渠化河段的香农多样性指数（Shannon’s diversity index）均显著低于天然河段。上述结果表明，河流河道形态对底栖动物群落结构与多样性具有显著影响，且该影响随季节变化存在差异。限制河道渠化与保护天然河流，均有助于遏制亚热带城市河流的水生生物多样性丧失。