扬州市河网大型底栖动物群落结构及其生境特征研究

构建适用于城市大型底栖动物的生境适宜性模型，探究大型底栖动物与生境因子间的响应关系，对城市河流生态系统恢复具有重要指示意义.本文以长江下游北岸扬州市城市河网为研究对象，基于丰水期（2018年8月）和枯水期（2019年1月）的大型底栖动物调查数据，利用典范对应分析与相关性分析筛选城市河网生态健康的关键生境因子，采用GAM模型拟合关键生境因子与大型底栖动物优势种的关系，构建城市大型底栖动物生境特征研究模型.结果表明，本次调查共获得大型底栖动物48个物种，隶属3门6纲13目20科40属，其中，水生昆虫为优势类群，霍甫水丝蚓（Limnodrilus hoffmeisteri）为研究区域优势种.影响优势种霍甫水丝蚓的主要生境因子为溶解氧（DO）、COD_Mn、NH₃-N、电导率（Cond），当霍甫水丝蚓生境适宜度为1.0时，水体中NH₃-N含量界限值为0.554 mg·L^-1，COD_Mn界限值为2.23 mg·L^-1，DO界限值为7.87 mg·L^-1，Cond界限值为272.5 S·m^-1.GAM模型能识别城市水环境关键问题，有效解释城市大型底栖动物与生境因子间的响应关系，可为城市河网水生态修复提供参考依据.

Community structure and habitat characteristics of macrobenthos in river network of Yangzhou City

Constructing a habitat suitability model suitable for urban macrobenthos and exploring the response relationship between macrobenthos and habitat factors are of great significance to the restoration of urban river ecosystems. This paper takes the urban river network of Yangzhou City on the north bank of the lower reaches of the Yangtze River as the research object. Based on the large-scale benthic survey data in the wet season (August 2018) and the dry season (January 2019), canonical correspondence analysis and correlation analysis were applied to screen the key habitat factors for the ecological health of urban rivers. The GAM model was used to fit the relationship between the key habitat factors and the dominant macrobenthos species in order to construct the urban macrobenthos habitat characteristic research model. The results showed a total of 48 species of macrobenthos were obtained from the survey, belonging to 3 phyla, 6 classes, 13 orders, 20 families and 40 genera. Insecta was the dominant population and Limnodrilus hoffmeisteri was the dominant species in the study area. The main habitat factors affecting dominant species Limnodrilus hoffmeisteri were DO, COD_Mn, NH₃-N, Cond. The habitat suitability of Limnodrilus hoffmeisteri was 1.0, while the limit value of NH₃-N, COD_Mn, DO and Cond were 0.554, 2.23, 7.87 mg·L^-1 and 272.5 S·m^-1, respectively. GAM model can identify the key problems of urban water environment, effectively explaining the response relationship between urban macrobenthos and habitat factors, and providing a reference basis for the ecological restoration of urban river network water.