Using macroinvertebrate-based biotic indices and diversity indices to
assess water quality: A case study on the Karasu Stream (Kastamonu,
Türkiye)
Abstract
Biomonitoring is an approach that uses indicators or sentinel species to
assess the health or pollution of an environment, combining diversity
based on specific taxonomic groups with the taxa’s indicator of
pollution into a single index or score. Benthic macroinvertebrates are
among the most preferred and valuable indicators of the biotic index.
Our study aims to evaluate water quality and ecological status using
biotic and diversity indices based on benthic macroinvertebrates. The
macroinvertebrate samples used in this study were collected seasonally
from 16 stations determined in Karasu Stream. These samples consist of
14747 specimens belonging to 9 orders and 40 families of Insecta,
Malacostraca, Hirudinea and Oligochaeta. In addition, some
physicochemical parameters were measured at the stations. The data
obtained were analyzed using the Turkey-Biological Monitoring Working
Group (TR-BMWP), Average Score per Taxon (ASPT), Family Biotic Index
(FBI), Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxon richness
index, and Shannon-Wiener (SWDI), Simpson (SDI) and Hill’s diversity
indices. Our results showed that the last six stations of Karasu Stream
were under pressure due to various anthropogenic effects. According to
biotic indexes, the ecological quality status of the water in the
stations was determined to be High or Good in the first ten stations and
Average, Poor, or Bad in the last six stations. The results of our study
showed that TR-BMWP, FBI, and EPT indices are more reliable in
determining water quality than the ASPT index and reflect the
environmental situation better. Since the TR-BMWP index is adapted to
macroinvertebrate taxa distributed in Türkiye, it can be used as a
suitable tool for evaluating other rivers’ water quality in Türkiye.