Spatio-temporal Effects of Anthropogenic Disturbances on Macroinvertebrates in Subukia River, Kenya

Anthropogenic disturbances modify river habitat conditions and influence the distribution of biotic communities. However, the effect of anthropogenic disturbances on macroinvertebrates is unknown for the Subukia River, despite its importance as a source of water for the local people and a habitat for organisms. This study was conducted to evaluate the effect of study site locality and seasonal variability on macroinvertebrate characteristics in the Subukia River. Nine study sites were chosen to correspond with livestock watering and human activities such as laundry washing, water abstraction, cultivation, dumping of solid wastes, settlements along the riparian zone and clearance of riparian vegetation. Mean invertebrate abundance, Shannon-Wiener diversity index, a Multimetric index, Taxa richness, Ephemeroptera, Plecoptera, Trichoptera (EPT) abundance and richness and Dominance index were determined. The results of the study showed that study site locality had a significant effect on Taxa richness (p=0.003), EPT abundance (p = 0.003) and richness (p=0.02), Shannon-Wiener diversity (p=0.003) and Multimetric index (p=0.003). Seasonal variability only had a significant effect on Taxa richness (p=0.01). In conclusion, most macroinvertebrate characteristics are influenced by anthropogenic disturbances and are less influenced by seasonal variability.