Application of Biotic Indices and Pollution Tolerance Index in Assessing Macro-Invertebrate Assemblage of Ediba River, Cross River State, Nigeria

Andem AB Esenowo IK

doi:10.4172/2161-0525.s7-007

Abstract

The study of the macro-invertebrates community of Ediba River in Cross River State was carried out from October to December, 2014 using Pollution Tolerance Index (PTI). Macro-invertebrate fauna were sampled with sweeping net using kick sampling methods. Sixteen genera, belonging to nine orders and a total of 289 individuals were encountered. The dominant groups in the order were Oligochaeta (29.1%)>Diptera (24.62%)>Odonata (20.3%), showing insignificant difference between the three stations at p>0.05. Taxa richness was highest in Station 1 (2.985) and least in Station 3 (1.008) showing insignificant differences across station (p>0.05). Evenness ranges from 0.337 to 0.369 showing significant difference across stations (p<0.05). Station 1 had a PTI value of 39 indicating good quality water status, while Stations 2 and Station 3 had PTI values of 6 and 4 respectively indicating poor quality water status. The abundance of pollution tolerance species of the orders, Odonata Zygoptera, Oligochaeta, Diptera and the absence of pollution sensitive species of the orders, Ephemeroptera and Trichoptera in Stations 2 and 3 indicated the poor waters quality, coupled with the low PTI values in both stations, hence need for proper management of the river.

Highlights

Macro-invertebrates communities are widely used as indicators of river ecosystem health status because they include a wide range of species, each with relatively well- known sensitivity or tolerance to river conditions [1]
The Ediba River in Abi Local Government Area of Cross River State, Nigeria is located in latitude 05 ̊ 52” 49.7” N and longitude 07 ̊ 59’56.7E’’ and latitude 05 ̊ 53’29.0”N and longitude 07 ̊ 58’41.3”E (Figure 1)
The relative abundance of macroinvertebrates taxa encountered at the different sampling stations is presented in Table 1, while Table 2 shows the percentage composition of macro-invertebrate taxa in the Ediba River

Summary

Introduction

Macro-invertebrates communities are widely used as indicators of river ecosystem health status because they include a wide range of species, each with relatively well- known sensitivity or tolerance to river conditions [1]. They are useful in understanding the ecological health of an aquatic ecosystem, rather than using chemical and microbiological data, which at least give short-term fluctuations [2]. The use of pollution tolerance index (PTI) as a method of measuring the overall health status of aquatic bodies through the use of macro-invertebrates remains the most reliable and effective method [7,8,9]. This study is undertaken to investigate the composition, abundance and distribution of macro-invertebrate community and using pollution tolerance index to assess the health status of Ediba River

Methods

Results

Conclusion