Diversity of African forest mollusc faunas: what we have learned since Solem (1984)

Abstract

We report on studies in Tanzania, Kenya, Uganda and South Africa over the past 22 years that have yielded estimates of land-snail diversity in the main forest types occurring in East and eastern southern Africa. When supplemented with the results of similar research in Madagascar and West Africa by other workers, the information provides a more detailed picture of the patterns of land-snail diversity on the continent than was available to Solem (1984). We describe our field methods, reexamine Solem's (1984) assessments of sympatric, allopatric and mosaic diversity patterns in African forests and provide a review of overall species number at continental, regional and country-wide scales, and in the main African forest biomes that have been studied.

Priority sites for conservation of land snails in Gabon: testing the umbrella species concept

“…However, despite increasing survey work, several species are still considered obligate calcicoles, and even small outcrops can harbour true endemic species (Schilthuizen et al ., 2005). In East Africa, among coastal forest localities, the sites having the highest single‐station diversity are on calcium‐rich soils (Seddon et al ., 2005).…”

“…Although not directly comparable with the results of Seddon et al . (2005) on molluscan diversity in East African forest sites, because of methodology discrepancies, our results show that Lastoursville is among the richest sites known in Africa, at least in number of species.…”

“…Solem, 1984). However, field studies throughout Africa (Emberton et al ., 1996; Tattersfield, 1996; De Winter & Gittenberger, 1998; Seddon et al ., 2005; Fontaine et al. , 2007), South‐East Asia (Schilthuizen & Rutjes, 2001), and tropical America (Gargominy & Ripken, 1998) have shown that previous assumptions on low sympatric diversity were wrong, and a result of biological and ecological rarity of molluscs in tropical rainforests.…”

“…Islands also show a high level of allopatric diversity: the Hawaiian archipelago has more than 750 mollusc species, 70–80% of which are single island endemics (Cowie, 1996). Other examples of high land snail allopatric diversity can be found in Van Bruggen (1978), Seddon et al . (2005), and Tattersfield (1998).…”

“…Sampling in the southern part of the Park would certainly increase the number of species found, but Lastoursville was also not completely inventoried and is undoubtedly a hotspot. The Gabonese rainforest probably shows the same pattern of high molluscan allopatric diversity as other parts of the Tropics (Solem, 1984, 1988; Cowie, 1996; Tattersfield, 1998; Seddon et al , 2005), making the design of an efficient conservation strategy for molluscs difficult.…”