西辽河流域鱼类生物完整性指数评价及与环境因子的关系

摘要

采用鱼类生物完整性指数( F-IBI)评估西辽河流域环境质量，利用相关分析筛选了影响F-IBI的环境因子，结合局部加权回归散点修匀法( LOWESS)估算了这些环境因子的保护限值.结果表明：20个候选参数指标中，鳅科鱼类物种百分比、底层鱼类物种数、耐受性鱼类个体数、杂食性鱼类物种数和筑巢产卵鱼类个体百分比适合作为西辽河流域F-IBI构建参数.采用比值法统一参数量纲，以参考点F-IBI值的95%分位数作为健康参考值，对全流域44个采样点进行健康评价，得到健康点位5个(11.4%)，亚健康点位9个(20.5%)，一般点位12个(27.3%)，差点位11个(25.0%)，极差点位7个(15.9%).电导率、氨氮浓度、碱度和泥沙比例与F-IBI呈显著负相关，坡降和草地比例与F-IBI呈显著正相关.经LOWESS和独立样本t检验发现，电导率、氨氮浓度、碱度、泥沙比例和草地比例等环境因子的保护限值分别为531μS/cm、0.55 mg/L、4.4 mmol/L、47.2%和37.0%，且限值两侧的F-IBI分值差异显著，该结果可作为西辽河流域环境管理中鱼类群落完整性保护的有益参考.%The environmental quality of Xiliao River Basin is assessed based on the fish index of biotic integrity( F-IBI) . Protection limit values of the environmental factors correlated with the F-IBI are determined by the method of locally weighted regression scat-terplot smoother( LOWESS) . The results indicated that five indices, including the percentage of the Cobitidae fish, the number of demersal fish species, the number of omnivorous fish species, the number of tolerated fish individuals and the percentage of the nests spawning fish individuals, were suitable for constructing the F-IBI assessment system. The ratio method is used to unify di-mensionless parameters. The 95% quantile of the F-IBI in all reference sites is used as the reference value of health conditions. Forty four sampling sites of Xiliao River Basin were assessed by F-IBI. The results found that five sites(11. 4%) were in excellent grade, nine sites(20. 5%) were in good grade, twelve sites(27. 3%) were in normal grade, eleven sites(25. 0%) were in poor grade, and seven sites(15. 9%) were in very poor grade. Electrical conductivity, ammonia nitrogen, alkalinity and proportion of sand were negatively correlated with F-IBI scores in the Xiliao River Basin, whereas slope and proportion of grassland were posi-tively correlated with F-IBI scores. The results of LOWESS and independent sample t test indicated that F-IBI scores significantly changed when the electrical conductivity, ammonia nitrogen concentration, alkalinity, proportion of sand and proportion of grass-land reached the protection limit value, which was 531 μS/cm, 0. 55 mg/L, 4. 4 mmol/L, 47. 2% and 37. 0%, respectively.The results of this study could provide beneficial information for the regional environmental management of fish integrity protection in the Xiliao River Basin.