Spatio-temporal macroinvertebrate multi-index of biotic integrity (MMiBI) for a coastal river basin: a case study of River Tana, Kenya

In the wake of climate change events, spatio-temporal integrated ecosystem models and indices are useful decision support tools for ecosystem management. We developed a preliminary spatio-temporal macroinvertebrate multi-index of biotic integrity (MMiBI) in a major tropical river basin in Kenya. Separation power of Mann-Whitney U test (p < 0.05) qualified 11 metrics from triplicate macroinvertebrate samples collected seasonally in 33 microhabitats into the scoring system of 1, 3 and 5. Validation and strengthening procedure compared the final MMiBI with selected (p < 0.05) physico-chemical parameters and post-MMiBI fieldwork. Seasonal alternating pattern of MMiBI scores suggested that it was highly likely that temporal scores performance might rank lower as compared to spatial significance on ecosystem health delineation. Although a case study in a single river basin is presented, the indexing holistic approach can be of general use for any other coastal river basin as a low-cost biomonitoring tool as a prerequisite towards ecosystem sustainability of water resources.