Establishment of an invasive snail Melanoides tuberculata (Müller, 1774) in a Sahelian urban reservoir in Ouagadougou, Burkina Faso

Abstract

Human land-use plays an important role in the distribution of aquatic invasive species. The establishment of these species may have an unpredictable impact on their new environment. We analyzed the establishment of M. tuberculata, an invasive species, and its effect on the mollusc community in Ouagadougou’s reservoir No.3. Mollusc samples were collected using an Ekman grab through sampling points randomly distributed across the whole reservoir. Collected specimens were sorted, preserved in alcohol at the field site and transported to the laboratory for identification. Species diversity, abundance and distribution were analyzed. Among the five species encountered, M. tuberculata and L. varicus were identified for the first time in this reservoir. M. tuberculata had the highest relative abundance (60.83%) and the highest density. The evenness was less than 0.5 for 72.5% (i.e. 21) of sampling points, reflecting the relative dominance of a single species, M. tuberculata . In terms of spatial distribution, the most widespread species in the study reservoir was M. tuberculata , followed by C. aegyptiaca and B. unicolor. M. tuberculata distribution in the reservoir mostly overlaps that of B. unicolor (0.45). Renewed monitoring efforts are needed to better understand the evolution of mollusc species in freshwaters of Burkina Faso to understand species extinction risks as well as the potential use of mollusk diversity measures as water quality indicators.