| 摘要: |
| 草海作为我国亚热带高原湿地生态系统的典型代表，具有丰富的水生动植物资源和极高的生态价值。然而，近年来草海水体富营养化状态加剧，沉水植物大量消亡，正逐步由草型湖泊向藻型湖泊转变，这一变化对草海生态系统功能和生物多样性产生了深远影响。本文基于2022-2023年的野外调查，系统研究了草海大型底栖动物群落的现状和特征，并比较了其与草海草型湖泊期间（1983年和2014年）的差异，揭示了草-藻型稳态转换过程中草海大型底栖动物群落的响应机制。结果显示，现阶段，草海大型底栖动物平均密度为146.49 ± 16.62 ind./m2，平均生物量为15.93 ± 14.02 g/m2，Shannon-Weiner多样性指数均值为0.73 ± 0.06，Margalef丰富度指数均值为0.37 ± 0.03，Pielou均匀度指数均值为0.66 ± 0.04，功能摄食类群相对丰度占比分别为收集者94.69%、捕食者2.81%、刮食者1.58%、滤食者0.92%。研究发现，大型底栖动物群落空间分布特征与沉水植物分布格局基本一致，生物量呈现出秋季和冬季显著高于春季和夏季的季节特征（p < 0.05），大型底栖动物的其他群落结构特征在季节间差异不显著。冗余分析结果表明，溶解氧（DO）、水深（WD）、pH值、高锰酸盐指数（CODMn）、透明度（SD）和电导率（Cond）是影响草海大型底栖动物群落结构变化的主要环境因子。草海近20年来 CODMn持续升高，稳态转换后Chl.a浓度上升，SD逐年下降。比较研究发现，草海大型底栖动物群落在草型清水态时以刮食者（腹足纲）为主，而藻型浊水态时则以收集者（颤蚓科和摇蚊科）为主，且草型湖泊阶段大型底栖动物的物种数、密度、生物量和物种多样性指数均高于藻型湖泊阶段。本研究为全面评估草海水生态系统现状，了解高原淡水湖泊稳态转换过程中大型底栖动物群落的响应，开展针对性的生态修复工作提供了重要的科学依据，也为草海后续水生态修复工作提出了科学建议。 |
| 关键词: 大型底栖动物 草海 群落演替 湖泊稳态转换 水生态修复 |
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| Community structure of macroinvertebrate and its response to the regime shift from macrophyte- to phytoplankton-dominated states in Caohai Lake, Guizhou |
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Zhang Hanwen,Zhou Ting,Kuang Chenyi,Zhang Ping,Dang Anzhi,Guo Chuanbo
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1.College of Fisheries and Life Science,Dalian Ocean University;2.Institute of Hydrobiology, Chinese Academy of Sciences
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| Abstract: |
| As a representative subtropical plateau wetland ecosystem in China, Caohai Lake is characterized by abundant aquatic flora and fauna resources and high ecological value. However, recent intensification of eutrophication has triggered massive decline of submerged macrophytes, driving the gradual regime shift from a macrophyte-dominated clear-water state to an algae-dominated turbid-water state, profoundly impacting ecosystem functions and biodiversity. Based on field investigations conducted during 2022-2023, this study systematically examined the current status and characteristics of macroinvertebrate communities in Caohai Lake, comparing differences with historical data from macrophyte-dominated periods (1983 and 2014), thereby revealing the response mechanisms of macroinvertebrate communities during the regime shift. Results showed that current macroinvertebrate communities exhibited a mean density of 146.49 ± 16.62 ind./m2 and biomass of 15.93 ± 14.02 g/m2, with Shannon-Weiner diversity index (0.73 ± 0.06), Margalef richness index (0.37 ± 0.03), and Pielou evenness index (0.66 ± 0.04). Functional feeding groups comprised 94.69% collectors, 2.81% predators, 1.58% scrapers, and 0.92% filter-feeders. Spatial distribution patterns of macroinvertebrate communities corresponded with submerged macrophyte distribution. Biomass showed significant seasonal variation (p < 0.05), being higher in autumn and winter than spring and summer, while other community characteristics exhibited no significant seasonal differences. Redundancy analysis identified dissolved oxygen (DO), water depth (WD), pH, permanganate index (CODMn), transparency (SD), and conductivity (Cond) as key environmental drivers. Over two decades, CODMn showed persistent increase while Chl.a concentration rose and SD declined annually post-regime shift. Comparative analysis revealed dominance of scrapers (Gastropoda) during the clear-water state versus gather-collectors (Tubificidae and Chironomidae) in the turbid-water state, with higher species richness, density, biomass, and diversity indices observed during the macrophyte-dominated phase. This study provides critical scientific basis for comprehensive assessment of Caohai Lake"s aquatic ecosystem status, understanding macroinvertebrate responses during plateau lake regime shifts, and implementing targeted ecological restoration measures. |
| Key words: Macroinvertebrate Caohai Lake Community succession Regime shift Aquatic ecosystem restoration |
