A multimetric index for assessment of aquatic ecosystem health based on macroinvertebrates for the Zio river basin in Togo

---

Résumé

The use of multimetric indices as tools for assessing aquatic ecosystem health in most of the developing countries such asTogo is still lacking.To fill this gap, we developed a macroinvertebrates-based multimetric index for the Zio river basin ofTogo. Forty-two sites were assessed for thedevelopment and the validation of the Multimetric
Index of Zio River Basin (MMIZB). Thirty-nine candidate metrics belonging to four categories (composition metrics, functional feeding metrics, diversity metrics and tolerance measure metrics) were evaluated. After comprehensive multiple selection procedure, six core metrics were retained to provide the fina lMMIZB .The results showed that the MMIZB responded to a set of organic pollution (chemical oxygen demand, ammonium, total suspended solid) and hydromorphological alterations, which corresponded to a set of gradients of human pressures affectin gth eecologica lintegrit yo fZi orive rbasi nwate rbodie s( r =0.78 ,p<0.001) .Th efinal macroinvertebrate index well distinguished the reference sites and impaired sites of a validation data set (p<0.001)andshowedasignificantrelationshipbetweenwaterandhabitatqualitybasedonPrati’sindex(r=
0.73, p<0.001) and Multimetric Macroinvertebrates Index of Vietnam (MMI_Vietnam) (r = 0.88, p<0.001).
This work underlines the relevance of the MMIZB as an effectiv etoo lfo rbiologica lmonitorin gan ddecision making in water management of Zio river basin.

Mots-clés

Environmental science, Invertebrate, Water quality, Aquatic ecosystem, Drainage basin, Habitat, Ecosystem, Index (typography), Water resource management, Structural basin, Ecosystem health, Biotic index, Ecology, Hydrology (agriculture), Geography, Computer science, Biology, Ecosystem services, Cartography