Macroinvertebrate communities and physicochemical characteristics along an anthropogenic stress gradient in a southern Nigeria stream: Implications for ecological restoration

Identifying and Classifying Sites and Macroinvertebrate Taxa into Pollution Categories in an Afrotropic Riverine System: A Multivariate Approach

“…A PCA variance of between 70% and 90% has been considered good enough to decide the reliability of environmental variables used in constructing ordination plots [27]. Keke et al [38] reported 70% ordination variance for the first two axes of the PCA they constructed for a river subjected to industrial and urban activities in the southern part of Nigeria, which corroborates with the result of the current study.…”

“…From the taxa categorization and classification result, Gerridae was resistant and Hydrometridae was highly resistant, while the remaining macroinvertebrate taxa were highly vulnerable, except for Gerridae that was vulnerable. Other authors in Nigeria have reported a similar level of sensitivities in freshwater macroinvertebrates [38,43]. Furthermore, the biomonitoring significance of aquatic insects, such as Ephemeroptera, Plecoptera, Trichoptera, and Odonata, have been widely reported by several aquatic scientists globally [26,28,41,44].…”

“…On the other hand, taxa, such as Dytiscidae, Bithynidae, and Unionidae, were negatively associated with TDS and turbidity on the CCA triplot. Similar studies have reported variation in the association of organisms with environmental variables due to the level of sensitivities of the organisms and their ability to adapt to changing environmental factors [3,26,38,41,42]. For instance, taxa such as Leuctridae and Hydrometridae can be considered tolerant of environmental degradation, whereas Dytiscidae, Bithynidae, and Unionidae are vulnerable to environmental degradation.…”

“…PCA and CCA were employed for the sites and taxa categorization. The result of the PCA revealed that the first two axes of the PCA explained a total variance of 78.84%, making it a good ordination [37][38]. A PCA variance of between 70% and 90% has been considered good enough to decide the reliability of environmental variables used in constructing ordination plots [27].…”

Insights from the Niger Delta Region, Nigeria on the impacts of urban pollution on the functional organisation of Afrotropical macroinvertebrates

“…The increased nutrient concentrations in the highly disturbed sites are consistent with previous studies in urban impacted areas in the tropics 10,29,66 . Similarly, earlier studies 9,46,[67][68][69] reported a significant increase in nutrient enrichment in the Niger Delta Regions of Nigeria. Urban activities in the regions are associated with poorly managed sewage and industrial facilities 67,70 and limited access to good water delivery services, causing nutrient loading through erosion and runoffs from the surrounding catchment.…”