Effects of riparian vegetation on water quality and macro invertebrates in the Gilgel Gibe Tributaries, Southwest Ethiopia

Riparian vegetation is crucial for both terrestrial and aquatic ecosystems, providing numerous essential benefits. The absence of riparian vegetation along streams can lead to various pressures that negatively affect macroinvertebrates and their habitats. This study assessed the effect of riparian vegetation on water quality and macroinvertebrates in the Gilgel Gibe tributaries of southwestern Ethiopia. Eighteen sample sites were collected through cross-sectional studies. A total of three thousand two hundred twenty three macroinvertebrates were counted from 50 families and 75 plant species. The first-order streams had higher plant species diversity than the second and third-order streams. Studied tributaries were dominated by Ephemeroptera (42.96%), Diptera (17.49%), Odonata (15.19%) and Coleoptera (11.35%). Fabaceae were the most diverse family, with 13 Number of species, followed by Lamiaceae and Rubiaceae (each with 5 number of species). Non-parametric output diversity indexes such as Evennes, Shannon, Simpson, Margalef, % Ephemeroptera-Trichoptera, and Biological Monitoring Working Party all showed significant results. This means that these indicators showed a statistically significant difference between plant species and land use categories. These data imply that vegetation types and land use types have an impact on water quality and macroinvertebrates communities. Furthermore, vegetation types were the main factors that influenced water quality and macroinvertebrates diversity.