Biodiversity of the malacological fauna of some mangroves of the Cameroonian Littoral: Influence of abiotic factors

Abstract

In order to contribute to the knowledge and conservation of the benthic macrofauna of the mangrove ecotones of Cameroon, a study was carried out in the mangrove swamps of the Cameroonian coast during the period from December 2019 to May 2020. The objective was to assess the mollusc biodiversity in relation to the abiotic factors of the environment. For this purpose, 14 sampling stations were selected. The Physico-chemical parameters of the waters were determined according to standard methods and the mollusc fauna was identified using the appropriate keys. Then, correlations were made. The results of the Physico-chemical analyses show that the mangrove waters studied are moderately oxygenated with high temperatures, are highly mineralized, have a slightly basic pH and high salinity. We also note high levels of Suspended Solids and highly turbid waters. Concerning the malacological fauna, 1644 specimens belonging to 02 classes 07 orders, 08 families, 12 genera and 15 species have been identified. The families of Thiaridae and Potamidididae were the most predominant, while the families of Lymnaeidae and Sphaeeriidae were the least represented. The species Tympanotonus fuscatus was the most regular over all study stations, followed by Pachymelania fusca and Neritina glabrata. Station S14 was the richest with 8 species while station S12 was the most diverse. The results of the statistical analyses show positive correlations between Pinaxia coronata species and salinity. Negative correlations were obtained between the species Neritina glabrata and salinity, conductivity and nitrates. On the other hand, there was a positive correlation between Pinaxia coronata species and oxidability.