Effects of human activities on benthic macroinvertebrate community composition and water quality in the upper catchment of the Mara River Basin, Kenya

摘要: Land-use changes in the upper reaches of Mara River Basin have modified their biophysical and hydrological processes, resulting water quality degradation streams. This study was conducted to investigate effects human activities on macroinvertebrates along Nyangores River, one main tributaries Kenya. Seven sampling sites were chosen correspond loss riparian cover, livestock watering (e.g. laundry washing, bathing, cultivation, wastewater inputs, dumping solid wastes from urban areas settlements river). Physical–chemical variables samples for nutrient analyses collected monthly February July 2012. Benthic also at same as samples. Two-way analysis variance tested significant differences each variable among sites. Similarity percentages (SIMPER) used identify key taxa contributing between minimally disturbed most conditions area. The results indicated increased concentrations agricultural settlement areas. Significant (P < 0.05) spatial–temporal variations observed. A total 42 macroinvertebrate genera encountered, with Ephemeroptera, Plecoptera Trichoptera orders dominating areas, Diptera receiving point nopoint liquid wastes, including nutrients, settlements. Canonical correspondence (CCA) revealed relationships communities measured physicochemical variables. this indicate need protection zones treatment sewerage before release into waterways. near streams rivers is discouraged, maintain surface waters aquatic organisms.