Land snail biogeography and endemism in south-eastern Africa: Implications for the Maputaland-Pondoland-Albany biodiversity hotspot

comprising many OGUs recently recognised as individual centres of endemism [29, 71, 72]. The incorporation of these OGUs into the MPA-Knysna province designates the greater MPA region of land snail endemism (see Figs 4–7), with 57 endemic species (82.6% endemicity; Table 2) from selected land snail genera. The greater MPA region for malacofauna, being 46.7% larger in area compared to the MPA hotspot, harbours a remarkable 78.1% greater number of endemic land snail species (57 endemic species in the greater MPA region com- pared to only 32 in the MPA hotspot; Fig 3). Moreover, spatial pattern of species richness fur- ther justifies the greater MPA region with OGUs such as southern Maputaland, Natal coastal belt, Natal Midlands, Pondoland, southern Transkei coastal belt, Albany coastal belt, Amatola- Winterberg and the Knysna transition zone (from North to South) been identified as hotspots of high species richness, while northern Mpumalanga escarpment, northern Middleveld, Ngoye, Drakensberg-KwaZulu-Natal escarpment and the Sneeuberg are also fairly speciose in land snails (Fig 7A). Discussion Land snail biogeography of south-eastern Africa The study provides a preliminary assessment of the land snail biogeography in SEA, based on a selection of the most well-known genera. The delineation of the SEA dominion separated from the Cape in south-west, Lowveld in north-east and especially the Karoo and Kalahari in the west is driven mainly by the climatic factors separating xeric areas from relatively mesic

ones, as evident in previous regionalisations for vertebrates [24, 45, 57, 73–76], higher plants [45] and bryophytes [77]. The subsequent separation of the MPA-Knysna province from more inland OGUs seems to have ecological as well as historical explanations related to the greater habitat heterogeneity Fig 5. Delineation of areas of endemism (AOEs) for land snails in south-eastern Africa based on the strict consensus tree of parsimony analysis of endemicity (PAE). Four of the five clades in the area cladogram harbour more than two sympatric endemic species, and hence identified as AOEs, together with two OGUs each with two narrow endemics with congruent ranges. All six AOEs are shaded in the map on a grey scale according to the number of endemic species, given below for each in brackets (darker shades denotes high endemism; see Table 3 for lists of endemic species): A— Soutpansberg (2), B—Wolkberg (2), C—Extended Maputaland (4), D—Natal (6), E—Extended Pondoland (7), and F— Albany-Knysna. The MPA hotspot boundary is reprinted from Hoffman et al. [26] (public domain). https://doi.org/10.1371/journal.pone.0248040.g005 PLOS ONE Land snail endemism in the Maputaland-Pondoland-Albany biodiversity hotspot PLOS ONE | https://doi.org/10.1371/journal.pone.0248040 March 4, 2021 13 / 26