评价漓江健康的RIVPACS预测模型研究

Health assessment based on a RIVPACS-type predictive model in Lijiang River

RIVPACS类河流健康评价模型是广泛应用的河流健康评价工具.利用漓江流域48个样点的底栖动物和环境数据,按照建立RIVPACS模型的方法和步骤,开展预测模型试点研究.48个样点中有32个参照样点,随机选取其中27个用于模型构建.余下的5个参照样点、10个轻至中度干扰样点和6个严重干扰样点用于模型验证.首先通过B ray-Curtis系数将27个参照样点分成3组,然后通过判别分析获得可最佳解释3个参照点组中底栖动物组成的5个环境变量,即溪流的平均流速、宽深比、水温、底质类型I(小于2mm)和Ⅱ(2-8mm)用于模型计算.通过建立的预测模型计算各样点的期望值(E)、观察值(O)和O/E比值.27个建模参照样点与5个验证的参照样点O/E平均值无显著差异,与10个轻至中度干扰点和6个严重干扰样点皆有显著差异,10个轻至中度干扰样点与6个严重干扰样点间也有显著差异.说明已建立的模型可靠性好.建议深入开展R IVPACS类预测模型的研究和应用示范,为我国水环境和水资源保护与可持续利用提供科学的决策依据.

RIVPACS models were widely used for river health assessment.We used the data of 48 benthic assemblages and environmental samples collected in February and September,2008 at Lijiang River,Guiling,Guangxi Autonomous Region,and developed,validated and tested a RIVPACS model.From this dataset,32 samples were indentified as reference,27 of which were used to calibrate the model,5 remain reference samples,10 slightly to moderately disturbed and 6 heavily disturbed samples were used to validate and test the model.Firstly,27 reference samples were clustered into 3 groups using Bray-Curtis coefficient.Then,5 environmental variables（mean stream velocity,width/depth,water temperature,substrate size I（2mm） and II（2-8mm）） were determined as the best discriminated variables among 3 sample groups through a stepwise discriminant function analysis.The observed（O） and expected（E） biota,and O/E ratio of all 48 samples were obtained by the model,The O/E values of 27 reference samples used in model development had no significant difference with 5 remain reference samples for validation,but had significant difference with 10 slightly to moderately and 6 heavily disturbed samples,and 10 slightly to moderately disturbed samples were also significantly different from 6 heavily disturbed samples.The validation and test results suggested that our model was robust and the potential for development and application of RIVPACS model and its role in the management and protection of water quality and water resource in China.