We investigated the land-snail fauna in gallery forest sites along a 30-km long section of the Muvumba River in northeastern Rwanda. A total of 12,419 individuals assigned to 34 land-snail species were collected in 24 plots. Though the number of species is small compared with protected rainforests in the northern Albertine Rift, gallery forests are important as corridors for colonization for the forest fauna. Despite a strong human impact on the gallery forests, hardly any obviously introduced species were recorded. The composition of the snail assemblages was significantly affected by elevation, depth of leaf litter and the presence of dead wood. The high median abundances of the snails in the gallery forests, which are among the highest recorded from forests in the northern Albertine Rift, are probably the result of a higher average soil calcium content in these gallery forests, caused by flooding. The significant increase of land-snail species richness with elevation might be the result of a higher input of calcium into the upper part of the study area.

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