Invasion and environmental drivers of Melanoides tuberculata (Müller, 1774) in the freshwater ecosystems of centre region, Burkina Faso

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Résumé

The introduction of invasive mollusc to non-native habitats can have adverse impacts on native species. This successful introduction is facilitated by habitat degradation linked to human activities. The hypothesis that it had been introduced through the importation of exotic plants was suggested after the first scientific report of Melanoides tuberculata in Reservoir No.3 of Ouagadougou. However, to date, information on the current status of its invasion and the factors favoring its establishment and dispersal in Centre Region remains unknown. This study aimed : (1) to assess Reservoir No.3 and the changes in factors that could impact the establishment of M. tuberculata at the site, (2) map the current distribution of M. tuberculata in Centre Region of Burkina Faso, and (3) identify the key environmental and anthropogenic factors driving its establishment and spread. We surveyed 12 sites from November 2020 to September 2021. At each site, molluscs were collected and physicochemical parameters were measured. We assessed the anthropogenic impacts and environmental conditions at each site. Collected molluscs were taken to the laboratory for identification and counting. The relationships between species occurrence and variables were analysed using the random forest algorithm. The findings indicate that from 1993 to 2021, temperature, precipitation, and conductivity have increased, while dissolved oxygen has decreased significantly in the reservoir. We found that M. tuberculata has successfully colonised 10 out of the 12 surveyed sites since 2017.
Its occurrence was significantly associated with habitat type, specific richness, substrate type, atmospheric temperature, and fishing activities. Furthermore, M. tuberculata demonstrated tolerance to a range of abiotic stressors. Our findings suggest that habitat type, anthropogenic activities, and connectivity play a more important role in the spread of M. tuberculata in Centre Region than physicochemical parameters. This study provides a critical baseline for monitoring and managing the invasive species in this region

Mots-clés

Melanoides tuberculata; invasive species management; random forest; biological invasion; Burkina Faso