太子河流域不同水生态区鱼类群落分布与环境因子的关联性

Analysis of Fish Community Distribution and Its Relationship with Environmental Factors in Different Freshwater Eco-Regions of Taizi River Basin

为了研究影响鱼类群落分布的环境因子在不同水生态区间的差异性,基于太子河流域3个水生态区,于2010年8月调查了全流域53个采样点的鱼类群落分布及水体理化环境因子,利用F-IBI(鱼类完整性指数)对河流健康进行评价,并对影响太子河流域不同水生态区鱼类群落分布和河流健康的环境因子进行筛选分析.结果表明:水生态Ⅰ区(上游山地区)整体表现为健康,Ⅱ区(中游丘陵区)以处于健康状况的采样点居多(45%),Ⅲ区(下游平原区)健康状况不佳,处于一般、差、极差等级的采样点占到90%.通过比较不同水生态区良好(F-IBI≥50.03)和不健康(F-IBI≤37.06)状况对应采样点的环境因子发现,水生态Ⅰ区内ρ(TN)差异显著(P<0.05),Ⅱ区内表现为林地面积所占比例差异显著(P<0.05),Ⅲ区内海拔、ρ(TDS)(TDS为总溶解固体)的差异显著(P<0.05).典范对应分析(canonical correspondence analysis,CCA)结果显示,影响鱼类群落分布的环境因子在水生态Ⅰ区为平均流速(F=2.75,P=0.005),在Ⅱ区为林地面积所占比例(F=2.65,P=0.003),在Ⅲ区则为ρ(COD_(Cr))(F=3.83,P=0.001)、平均流速(F=3.42,P<0.001)、ρ(TP)(F=3.46,P=0.001)和pH(F=2.90,P=0.002).研究显示,在制订流域鱼类保护方案时,应当充分考虑不同水生态区特定环境因素的影响.

An eco-region includes similar structures and functions in adjacent regions. In order to make effective conservation strategies,it is vital to identify the relationship between aquatic organisms and environmental factors. A total of 53 sites were selected in the main channel of the Taizi River Basin in August 2010. The correlation between fish community structure and environmental factors in different eco-regions was investigated. Additionally,the fish index of biological index（ F-IBI） was used to assess the river health condition,and key environmental factors affecting the fish community in each eco-region were screened. The results showed that three ecoregions（ Ι,Ⅱ and Ⅲ） were defined with F-IBI methods,and named as eco-region Ι（ mountainous in the upstream area）,which was in healthy condition, eco-region Ⅱ（ hills in the midstream area）,which was in fair condition and eco-region Ⅲ（ plain region in the downstream area）, which was in poorcondition. With comparisons of environmental factors under different health conditions（ good condition with F-IBI 50. 03 vs. poor condition with F-IBI 〈37. 06）,there were different environmental factors showing a significant discrepancy in each eco-region. The key environmental factors were ρ（ TN） in eco-region Ι（ P〈 0. 05）,percent forest（ P〈 0. 05） in eco-region Ⅱ,and altitude and ρ（ TDS）（ P〈 0. 05） eco-region Ⅲ. Based on the data of fish and environmental factors,the correlation between community structure and the environment was analyzed by canonical correspondence analysis（ CCA）. The results showed that different eco-regions had different significant environmental factors which affected the distribution characteristic of fish species and community. Average velocity（ F = 2. 75,P = 0. 005） played the key role for eco-region Ι,percent forest（ F = 2. 65,P = 0. 003） for eco-region Ⅱ,and the chemical pollutants which affected the water quality in eco-region Ⅲ,such as the ρ（ COD_（Cr））（ F = 3. 83,P = 0. 001）,ρ（ TP）（ F = 3. 46,P = 0. 001） and pH（ F = 2. 90,P = 0. 002）. To make more effective conservation strategies for fish biodiversity,it is indispensable to identify the key environmental factors which affect the fish community. Therefore,the special environmental strategies of different eco-regions should be considered during the fish protection planning.