Data from: Developing and applying a macroinvertebrate‐based multimetric index for urban rivers in the Niger Delta, Nigeria

Urban pollution of riverine ecosystem is a serious concern in the Niger Delta region of Nigeria. No biomonitoring tool exists for the routine monitoring of effects of urban pollution on riverine systems within the region. Therefore, the aim of this study was to develop and apply a macroinvertebrate-based multimetric index for assessing water quality condition of impacted urban river systems in the Niger Delta area of Nigeria. Macroinvertebrate and physico-chemical samples were collected from 11 stations in eight river systems. Based on the physico-chemical variables, the stations were categorised into three impact categories namely; least impacted stations (LIS), moderately impacted stations (MIS) and heavily impacted stations (HIS). Seventy seven (77) candidate metrics were tested and only five: Hemiptera abundance, %Coleoptera+Hemiptera, %Chironomidae+Oligochaeta, Evenness index and Logarithm of relative abundance of very large body size (>40-80 mm) were retained and integrated into the final Niger Delta urban multimetric index (MINDU). The validation data set showed a correspondence of 83.3% between the index result and the physico-chemically-based classification for the LIS and a 75% correspondence for the MIS. A performance of 22.2% was recorded for the HIS. The newly developed MINDU proved useful as a biomonitoring tool in the Niger Delta region of Nigeria, and can thus be used by environmental managers and government officials for routine monitoring of rivers and streams subjected to urban pollution.尼日利亚尼日尔三角洲区域的河流生态系统城市污染问题，已成为当前备受关注的严峻环境议题。该区域此前尚无用于常规监测城市污染对河流系统影响的生物监测工具。因此，本研究旨在开发并应用一种基于大型底栖无脊椎动物（macroinvertebrate）的多指标指数，以评估尼日利亚尼日尔三角洲区域受城市污染影响的河流水质状况。研究人员从8个河流系统的11个监测点位采集了大型底栖无脊椎动物样本与理化检测水样。基于理化变量，研究将所有点位划分为三类污染等级：轻度污染点位（LIS）、中度污染点位（MIS）与重度污染点位（HIS）。本研究共测试了77项候选指标，最终保留5项并整合为尼日尔三角洲城市多指标指数（MINDU），分别为：半翅目（Hemiptera）个体丰度、鞘翅目+半翅目占比（%Coleoptera+Hemiptera）、摇蚊科+寡毛纲占比（%Chironomidae+Oligochaeta）、均匀度指数（Evenness index），以及体型＞40~80 mm的超大个体相对丰度的对数值。验证数据集显示，该指数结果与基于理化分类的轻度污染点位匹配度达83.3%，中度污染点位匹配度为75%，而重度污染点位匹配度仅为22.2%。本次新开发的MINDU可作为尼日利亚尼日尔三角洲区域的有效生物监测工具，可供环境管理者与政府官员用于受城市污染影响的河流与溪流的常规监测工作。