Influence of micro-habitats on the distribution of macroinvertebrates in Burkina Faso (West Africa)

In this work, we assessed micro-habitat's influence on the distribution of macroinvertebrates in lake Ziga in Burkina Faso from July to December 2016. The water quality variables were measured in situ and the macroinvertebrates were collected with a hand net. The organisms were identified to the lower taxonomic resolution as possible. The results show that the temperature is globally warm, characteristic of tropical area, with a good oxygen content and pH close to neutral. We found five micro-habitats, mainly dominated by fine substrates (32.5%) and aquatic plants (25.83%). The stone, roots and dead woods represented less than 20%. In total, 3,773 individuals of macroinvertebrates were collected. These individuals belong to 33 taxa and three classes. The insects class is the most abundant (88.22%) and the most diversified (24 taxa, 72.72%). The highest taxonomic richness is observed in aquatic plants and root zones. The diversity and density of the macroinvertebrate community varies according to micro-habitats but not according to the size of their surface area. The results showed that coleopterans and hemipterans were strongly and positively correlated to transparency and conductivity (adjusted r>60%, P <0.05). In the local area, the results showed that macroinvertebrates' diversity and distribution are more linked to habitat availability. Our findings reveal a good habitat condition of the lake, and can be served as reference site and hostpot of aquatic biodiversity in the area.