亚热带丘陵区人工湿地底栖动物群落特征研究

以湖南长沙亚热带丘陵区为研究区域，以处理农村综合污水（含畜禽养殖废水、农村生活污水及农田排水）为主要目的，通过野外小区控制试验，设置梭鱼草（Pontederia cordata）、绿狐尾藻（Myriophyllum elatinoides）、梭鱼草+绿狐尾藻组合（Pontederia cordata+Myriophyllum elatinoides）及无植物对照（CK）4个湿地处理，分别于2019年4、7、10、12月采集底泥样品，研究不同植物湿地底栖动物物种组成与优势种、丰度与生物量及生物多样性的季节变化特征，并探讨其与环境因子的关系.结果表明：4个季节共采集到底栖动物27种，以水生昆虫居多（22种）.耐污性较强的霍甫水丝蚓（Limnodrilus hoffmeisteri）、苏氏尾鳃蚓（Branchiura sowerbyi）和黄色羽摇蚊（Chironomus flaviplumus）为4个季节共同存在物种.与单一植物湿地相比，水质处理效果最好的梭鱼草+绿狐尾藻组合湿地的底栖动物年均丰度和生物量最低，仅为522ind/m²和52.1g/m²，而无植物对照湿地的底栖动物年均丰度和生物量最高，分别为3665ind/m²和146.3g/m².夏、秋季各处理湿地底栖动物的Shannon-Wiener多样性指数（H'）、Margalef丰富度指数（d）和Pielou均匀度指数（J）总体上高于春、冬季.其中，春季Margalef丰富度指数表现为梭鱼草、无植物对照湿地显著高于绿狐尾藻和梭鱼草+绿狐尾藻组合湿地（P<0.05），夏季Pielou均匀度指数表现为无植物对照湿地显著低于有植物配置的湿地（P<0.05），冬季Margalef丰富度指数则表现为梭鱼草、梭鱼草+绿狐尾藻组合湿地显著高于绿狐尾藻和无植物对照湿地（P<0.05）.Spearman相关分析结果表明，底栖动物物种数与pH值呈显著正相关（P<0.05），丰度与DO呈负相关，而与其他环境因子呈正相关（P<0.05）；RDA分析结果进一步表明，DO是影响腹足纲的主要环境因子，而寡毛纲和摇蚊幼虫受制环境因子较多，主要与TN、COD相关性较大.

Characteristics of zoobenthos community in constructed wetlands in subtropical hilly area

Subtropical hilly area, Changsha, Hunan Province was selected as the experimental area in the study. The main aim was to treat rural comprehensive sewage (including livestock breeding wastewater, rural domestic sewage and farmland drainage). Through field experiment, this study was set up four treatments:Pontederia cordata, Myriophyllum elatinioides, Pontederia cordata + Myriophyllum elatinioides and CK constructed wetland. Sediment samples were collected in April, July, October and December, 2019. Seasonal variation characteristics of species composition, dominant species, abundance, biomass and diversity of zoobenthos in different plants constructed wetland were studied. The relationship between diversity of zoobenthos and environmental factors was also discussed. Results showed that 27species of zoobenthos were found in four seasons, aquatic insects dominated (22species). Limnodrilus hoffmeisteri, Branchiura sowerbyi and Chironomus flaviplumus were common species in four seasons. Annual average abundance and biomass of zoobenthos in P. cordata + M. elatinioides constructed wetlands were 522ind/m² and 52.1g/m², respectively, which were the lowest, compared to single plant constructed wetland. Annual average abundance and biomass of zoobenthos in CK constructed wetlands were 3665ind/m² and 146.3g/m², respectively, which were the highest, compared to other treatments. The Shannon-Wiener diversity index (H'), Margalef richness index (d) and Pielou evenness index (J) of zoobenthos in summer and autumn were higher than those in spring and winter. In spring, Margalef richness index in CK and P. cordata constructed wetland were significantly higher than that in the other constructed wetlands (P<0.05). In summer, Pielou evenness index in CK constructed wetland was significantly lower than that in plants constructed wetland (P<0.05), while in winter, Margalef richness index in P. cordata, P. cordata+M. elatinoides constructed wetland were significantly higher than that in the other constructed wetlands (P<0.05). Spearman correlation analysis showed that the species number of zoobenthos were significantly positively correlated with pH (P<0.05). and abundance of zoobenthos were negatively correlated with DO, while abundance of zoobenthos were positively correlated with other environmental factors (P<0.05). RDA analysis further showed that DO was the major environmental factor, influencing Gastropoda, while Oligochaeta and chironomid larvae were affected by environmental factor as TN and COD.