深圳市城市区域内典型生境特征溪流大型底栖动物群落结构比较

Comparison of macroinvertebrate community structure in urban (Shenzhen City) streams with typical habitat characteristics

2020年12月在深圳市城市区域典型生境特征溪流——城市山区源头溪流金龟河、国家地质公园保护区入海溪流杨梅坑河与黑臭水体治理后溪流石溪河,开展底栖动物多样性与生境质量状况取样,通过多元统计分析探明各溪流底栖动物群落结构差异及其主要环境影响因子.结果表明:(1)金龟河底质异质性(SI)最高;杨梅坑河水质最好且流态异质性(Fr)最优,石溪河水质最差且底质异质性(Fr)最低.(2)共采集鉴定大型底栖动物118个分类单元,隶属于3门6纲14目87科.水生昆虫均占绝对优势,其中金龟河67属(81.7%),杨梅坑河62属(95.4%),石溪河12属(52.2%).金龟河中底栖动物Shannon-Wiener多样性指数、改进的Shannon-Wiener多样性指数、Pielou均匀度均高于杨梅坑河与石溪河.(3)金龟河的主要功能摄食类群是滤食者(45.5%),杨梅坑河(38.3%)与石溪河(58.7%)的主要功能摄食类群均为收集者.(4)冗余分析(RDA)结果显示,氨氮、海拔、湿宽、水温、溶氧、底质异质性(SI)、电导率和流态异质性(Fr)为影响深圳市溪流的大型底栖动物群落结构的主要环境因子.研究表明:(1)深圳市的山区溪流可作为深圳市生物多样性保护的重点区域.(2)在城市溪流生态系统中,水环境化学因子并非为主要影响因子,生境多样性发挥了重要作用.(图6表3参43)

To reveal the community structures of benthic macroinvertebrates in urban streams with typical habitat characteristics, three streams in Shenzhen City(i.e., a headwater stream in mountain — Jingui Stream, a stream flowing from the national geopark into sea: Yangmeikeng Stream, and a stream after sewage treatment:Shixi Stream) were investigated in December 2020. The diversity of benthic macroinvertebrates and habitat characteristics within the three streams were analyzed, and the main environmental factors affecting the community structure of benthic macroinvertebrates were identified using multivariate statistical analysis. The results showed that in terms of environmental quality, Jingui Stream had the best substrate index, Yangmeikeng Stream had the best water quality and the highest Fronde number, and Shixi Stream had the worst water quality and sediment heterogeneity. A total of 118 macroinvertebrate taxa, belonging to 3 phyla, 6 classes, 14 orders,and 87 families, were identified. Aquatic insect species were overwhelmingly dominant in the three streams,including 67 genera(81.7%) in the Jingui Stream, 62 genera(95.4%) in the Yangmeikeng Stream, and 12 genera(52.2%) in the Shixi Stream. The Shannon-Wiener diversity index, improved Shannon-Wiener diversity index,and Pielou evenness of macroinvertebrates in the Jingui Stream were significantly higher(P < 0.05) than those in the Yangmeikeng and Shixi streams. Filter-collectors(45.5%) were the main functional groups in the Jingui stream, whereas gather-collectors were the main functional groups in the Yangmeikeng and Shixi streams. The results of redundancy analysis(RDA with Monte Carlo, total variation of 94.7%, P < 0.05) showed that altitude,dissolved oxygen, water depth, water temperature, wetted width, electrical conductivity, and water velocity were the main factors influencing the differences in community structure. This study indicated that mountain streams within urban areas could be regarded as priority areas for biodiversity protection. In addition, chemical indicators in water bodies are not the main factors, whereas habitat diversity may play a more important role in influencing the community structure of macroinvertebrates in urban stream ecosystems.