THE USE OF MACROINVERTEBRATE INDICATOR SPECIES TO MONITOR ECOLOGICAL CHANGE IN SOME STREAMS IN NORTH CENTRAL NIGERIA

Abstract

Indicator species have been employed in modern aquatic research for monitoring of environmental changes. In this study, we evaluated the possibility of developing surrogate indicator groups as tools for the conservation and management of the biodiversity of Niger state streams by surveying 15 streams in Niger state for benthic macroinvertebrates and environmental variables as data sets, over a period of 24 months (2016 and 2017). Samples were collected in two locations of reference and impacted sites for each of the streams surveyed. The statistically significant (p < 0.05; based on 1000 permutations) indicator species for each of the status classes (reference versus impacted) was detected using the Indicator species analysis/Indicator value method. Hierarchical agglomerative clustering was used to group sites for each sampling status class based on macroinvertebrate community structure. To visually access the multivariate patterns and structures of the macroinveretebrates community composition, non-metric multidimensional scaling (NMDS) ordination was performed. Indval found fifteen species for the reference, seven indicator species for the impacted streams, with Coleopteran Hydrophilus sp. Occurring as the keystone species. NMDS revealed that species assemblage had wide dispersal patterns in relation to the sites in both status classes. Canonical Correspondence Analysis revealed that the clear lack of concordance in environmental variables-requirements of the reference species versus the impacted indicator species showed that the two taxa responded to entirely different environmental factors. While this study has provided a reference point and effective tool to monitor environmental changes, community and ecosystem dynamics in Niger state streams, it is therefore advised that other components of freshwater biota be tested for possible use as surrogates in freshwater biodiversity research of these streams.