Ecological status of a newly impounded sub-saharan reservoir based on benthic macroinvertebrates community (Burkina Faso, West Africa)

---

Résumé

In West Africa, particularly in Burkina Faso, the aquatic ecosystems are under human pressures.
Therefore, for long term management of these ecosystems, the managers need baseline data for regular
assessment of ecological health condition. In this regard, the structure of the benthic macroinvertebrate
community was investigated and the relationship between the environmental variables and biotic
indices of the Samandéni reservoir from January to December 2018, after one-year impoundment was
explored. The macroinvertebrates were collected with a hand net (25 × 25 cm 2 coverage area and 500
μm mesh) according to the multi-habitat sampling method. Key environmental variables such as
temperature, conductivity, dissolved oxygen, pH and total dissolve solids (TDS) were measured in situ.
High diversity of macroinvertebrates was reported and thirty-four (34) taxa were determined belonging
to eight (8) orders dominated by insects (79.41% of all taxa). Good ecological quality of the reservoir
was testified by the presence of several sensitive taxa like Ephemeroptera and Trichoptera. The trends
of environmental variables also reflect good habitat conditions. The results revealed a strong and
negative relationship between some abiotic variables and biotic indices. The finding of this study is of
big importance for sustainable management of the Samandéni Reservoir.

Mots-clés

Burkina Faso, macroinvertebrates, monitoring, reservoir, status.