Ecological status of three sub-saharan dam lakes based on macroinvertebrates community (Cote d’ivoire, West africa)

The government of Côte d'Ivoire had built numerous small dam lakes in the north of the country to irrigate crops. Today, these ecosystems are in a state of degradation. In order to provide the authorities with reliable data for decision-making on the conservation of these aquatic environments, a study was carried out to assess the ecological quality of three dam lakes in the Korhogo department. To this end, macroinvertebrate sampling was carried out from June 2023 to April 2024, using a 350 µm turban net and a Van veen grab (0.042m2). The ecological status of the three lakes was assessed using the multimetric index of lake environments in Burkina Faso (IMLB). A total of 3 phyla, 4 classes, 11 orders, 38 families, 89 species and 4,548 individuals were sampled in all three dam lakes. The insect class was the most abundant, accounting for over 70% of individuals. The multi-metric index of lake environments in Burkina Faso (IMLB) was 50.41 at Nindjo, 53.45 at Koko and 76.61 at Nangakaha. These values indicate that the ecological quality of the first two lakes is average. Lake Nangakaha, on the other hand, is in good ecological condition. This study will lead to decisions in favor of the protection of Koko and Nindjo lakes, which are under heavy anthropic pressure.