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

clear south-east African cluster. It is placed within the continental/global zoogeographical con- text, as the SEA dominion [24] within the southern African subregion (given as southern Afri- can region in Linder et al. [45]) of the Afrotropical region (as in Procheş & Ramdhani [43], given as Afrotropical realm in Holt et al [46]). Subordinate subdominions, provinces, subpro- vinces and districts are delimited within the SEA dominion (Fig 2B, 2C and Table 1). The den- drogram recovers a land snail based biogeographical province similar to the MPA hotspot, despite extending westward from Albany to include the Knysna area. The MPA-Knysna prov- ince consequently defined in this study has 67% congruence to the MPA hotspot in terms of OGU coverage (Fig 2B). The MPA-Knysna province harbours 37 endemic species (61.7% endemicity; Table 2) in the selected land snail genera, which is higher than the 30 endemics (56.6% endemicity; Table 2) within the MPA hotspot (Fig 3). Land snail endemism in south-eastern Africa Five COEs and six CONEs derived from the UPGMA dendrogram (Fig 2A) and are illustrated in Fig 4A and 4B, respectively. Parsimony based AOEs reconfirmed all the COEs derived from phenetic clustering. The consensus tree of the PAE resulted in an area cladogram revealing five clades, among which four harboured at least two endemic species with sympatry, together with two OGUs each with two narrow endemics with congruent ranges. Hence, the PAE identified six AOEs (Fig 5). However, as the PAE area cladogram was not hierarchically well-structured, we further

tested our AOEs for consensus and congruency from a BEA. The test for clustering of distribu- tion areas indicated that the distribution ranges of land snails in south-eastern Africa show a clustering tendency (Fig 6A), as the test statistic t = 0.429, the ratio between the 25% largest and smallest distances [64, 69] for our dataset, is smaller than expected by the null model (Sim- ulated t = 0.451; ranging from 0.355 to 0.627), even though with a low level of statistical signifi- cance (p = 0.33). However, when mapped, the BEA yields nine biotic elements, seven of which supporting the six AOEs derived from PAE, and congruent with those five COEs derived from Table 1. Proposed regionalisation hierarchy for land snail zoogeography in south-eastern Africa (SEA). Dominion Subdominion Provinces Subprovinces Districts South–Eastern Africa Maputaland-Pondoland- Albany-Highveld A Maputaland-Pondoland- Albany-Knysna A1 Maputaland-Natal Extended Maputaland Natal A2 Extended Pondoland A3 Extended Albany Extended Amatolas Albany-Knysna B Bushveld B1 Sky Islands (Soutpansberg-Wolkberg) B2 Bushveld-Mpumalanga Escarpment Central Bushveld Mpumalanga Escarpment C Highveld C1 Northern Mesic Highveld & Escarpment Northern Mesic Highveld & Mpumalanga Escarpment KwaZulu-Natal Escarpment Drakensberg Plateau C2 Southern Mesic Highveld Southern Escarpment Sneeuberg Lower Karoo The SEA dominion is placed within the southern Africa subregion of the Afrotropical region (see Fig 2A for the dendrogram, 2B for the map, and the text for further details).

https://doi.org/10.1371/journal.pone.0248040.t001 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 8 / 26