Guinean biodiversity at the edge: Rodents in forest patches of southern Mali

Southern Mali mainly belongs to the Sudanian savanna bioclimatic zone, but forest patches showing botanical affinities with Guinean humid forest remain as gallery forests or ravine forests. To characterize the rodent diversity of this area and check for the presence of some species of Guinean affinities in this group, rodent assemblages were sampled in four regions of southern Mali, using trapping and observational data in forest and surrounding habitats. Twenty-four species were recorded, comprising a representative sample of the expected overall diversity in this group according to rarefaction curves. Praomys rostratus was the dominant species in the most humid, closed lowland forest. Praomys daltoni was also present in this habitat type, being all the more abundant as habitat degradation was apparent. It became the dominant species in ravine forest on rocky substrate where P. rostratus was completely absent. In Sudanian savanna habitats and in herbaceous and cultivated areas, Mastomys erythroleucus dominated a diverse rodent community. A few species were found that testified for Guinean affinities of the most humid forest patches, especially in the extreme southeast of the country (region of Sikasso). Rodent assemblages of the Bafing and Mts Mandingues areas, in the western part of the study area, showed the highest similarity, in relation with environmental characteristics of this region representing an extension of the Fouta Djallon plateau in Guinea. The results obtained highlight the high biodiversity value of this forest-savanna mosaic, and provide new arguments in favour of the preservation of West African forest patches and their surrounding habitats.