SALAMANDRA 46(3) 147–166 20 AugustReptile 2010 speciesISSN of the0036–3375 Soutpansberg The reptile species assemblage of the Soutpansberg (Limpopo Province, South Africa) and its characteristics Sebastian Kirchhof1, Michael Krämer2, Jabu Linden3 & Klaus Richter4 1) Biogeography Department, Trier University, Am Wissenschaftspark 25+27, 54296 Trier, Germany 2) Wehler Weg 25, 31785 Hameln, Germany 3) P.O. Box 1536, Louis Trichardt, 0920 Limpopo Province, South Africa 4) Anhalt University of Applied Sciences, Dept. 1, Strenzfelder Allee 28, 06406 Bernburg, Germany Corresponding author: Sebastian Kirchhof, e-mail: [email protected] Manuscript received: 20 April 2010 Abstract. The Soutpansberg situated in north-eastern South Africa was investigated with respect to its reptile species di- versity, geographic range of the species and habitat utilisation. Typical inselberg characteristics are discussed in the context of the herpetofauna and compared with the Blouberg, an isolated mountain range to the west of the Soutpansberg. Possible biogeographic links between the species assemblage of the Soutpansberg and adjacent areas are discussed in the context of present geological and climatic conditions within the area. The Soutpansberg reptile community clearly shows effects of isolation. The mistbelt and the grassland on the summits, which both withstood climatic oscillations in the past, harbour the majority of species and most of the endemic taxa in particular. Hence, these areas are of significant ecological value for the reptile community. Rocky habitats and the cooler and moister climate on the mountain provide exceptional conditions within this area. Most of the Soutpansberg endemics exhibit a rupicolous lifestyle and a large number of species are adapted to mesic conditions. A high proportion of Afromontane species was detected. Furthermore, eastern coastal and Lowveld el- ements exert an influence on the species composition whereas the Kalahari elements are of lesser importance. Tropical for- est species are completely absent. The Soutpansberg harbours more endemics (nine taxa) compared to the Blouberg (three taxa) due to its larger size and the resultant decreased risk of extinction. Key words. Biogeography, checklist, endemics, inselberg, mistbelt, relicts. Introduction es, including a considerable number of relict species as a re- sult of habitats contrasting to those of the surrounding land- The poorly studied Soutpansberg mountain range is situat- scape and acting as refuges. Furthermore, inselbergs, like ed in the northern Limpopo Province of South Africa. In re- oceanic islands, often stimulate speciation processes and cent years, this area has received greater scientific attention, hence can harbour a considerable number of endemic spe- which has lead to the recognition of its exceptionally high cies (e.g., Groger & Barthlott 1996, Parmentier 2003, biodiversity and high degree of endemism (e.g., Hahn 2002, Parmentier et al. 2005). 2006, Mostert 2006, Foord et al. 2008). In May 2009, Information on the reptilian fauna of the area is limited as the area was included in the proclamation of the Vhembe no inventories have been published. Egan et al. (2005), in a Biosphere Reserve as part of UNESCO’s Man and the Bio- literature review, proposed that regional influences affecting sphere programme. The vegetation of the Soutpansberg has the reptile species composition of the Vhembe Biosphere been well studied (e.g., Hahn 2002, 2006, Mostert 2006). Reserve area comprise temperate or Afromontane, Kalahari Hahn (2006) recognized at least eight major elements that or xeric, Lowveld, eastern coastal and tropical elements. The exert an influence on the flora of the mountain range. In most extensive field study, which included the Soutpansberg terms of its floristic diversity and high degree of endemism, area, was conducted by Jacobsen (1989) who surveyed the the Soutpansberg mountain range – despite its size – has entire former Transvaal Province, cataloguing reptiles and been shown to display the typical characters of an inselberg amphibians on a quarter-degree grid square base. Also, a (Hahn 2006). Generally, inselbergs are defined as isolated long-term study of the diversity of reptiles in the Blouberg rises above a plain that consist of hard bedrock (Bremer & Nature Reserve (BNR) (9360 ha), a neighbouring moun- Sander 2000). Inselbergs are usually remnants of erosion tain situated about 20 km west of the Soutpansberg (Fig. processes and can vary greatly in size (Burke 2003). They 1), was carried out between 1993 and 2001 (Schmidt et al. include rocky outcrops of only several meters in height and 2005). Although the Soutpansberg and Blouberg belong to diameter as well as mountain massifs (Jürgens & Burke the same geological system (McCarthy & Rubidge 2005), 2000). Inselbergs often harbour unique species assemblag- they are separate, isolated mountains. Topographical links © 2010 Deutsche Gesellschaft für Herpetologie und Terrarienkunde e.V. (DGHT), Rheinbach, Germany All articles available online at http://www.salamandra-journal.com 147 Sebastian Kirchhof et al. Figure 1. Locality of the sampling sites (red dots) on the Soutpansberg including the main study area, the Lajuma Research Centre, and the neighbouring Blouberg with the Blouberg Nature Reserve (blue). between them are missing, indicating that the separation et al. 2005). Average annual rainfall ranges from around of the two mountains is an ancient one and is most likely 400 mm on the northern slopes and 550 mm in the east to to have existed in the Pliocene or even earlier (A.J. Bumby 1800 mm on the central southern slopes (Schulze 1997). pers. comm. 2007). Most of the precipitation can be classified as orographic The present study is based on an extensive survey con- rainfall, which is the result of moisture-laden air carried by ducted at the Lajuma Research Centre property in the West- the prevailing south-easterly winds from the Indian Ocean ern Soutpansberg and numerous field trips to the Eastern into the southern scarp of the Soutpansberg (Hahn 2006). Soutpansberg. The aim was to compile a preliminary species Hence, the higher parts of the Soutpansberg, especially on list of Soutpansberg reptiles and reveal endemic species. For the southern and eastern slopes, are characterised by mist- the purpose of this study, Soutpansberg endemics are de- belt areas with frequent cloud cover and mist precipitation fined as taxa restricted to the Soutpansberg sensu stricto. It (Kabanda 2003). was assumed that the reptile species assemblage of the Sout- pansberg sensu stricto displays typical characteristics of an inselberg. Special attention was also paid to habitat prefer- Vegetation ences of the recorded taxa. Possible impacts of past geologi- cal and climatic changes on the species composition of the The classification follows the latest vegetation atlas of South Soutpansberg are discussed. Finally, the reptile community Africa (Mucina & Rutherford 2006). The Soutpansberg of the Soutpansberg is compared to that of the Blouberg Na- is dominated by Soutpansberg Mountain Bushveld, which ture Reserve based on the results of Schmidt et al. (2005). is very heterogeneous and comprises a mosaic of different kinds of vegetation. Mistbelt bush clumps, characterised by the presence of orchids and other epiphytes, can be found Study area on the high crests of southern and central, east-west ori- Geography, geology and climate entated ridges, growing on outcrops with shallow sandy soils. In sheltered gorges and at the foot of vertical cliffs on The Soutpansberg with its maximum elevation of 1748 m the high southern and eastern slopes of the Soutpansberg, a.s.l. is situated in the arid northern region of the Limpopo Northern Mistbelt Forest with tree species such as Podocar­ Province in north-eastern South Africa (Fig. 1). It is sur- pus latifolius and Xymalos monospora occurs. Soutpansberg rounded by slightly undulating plains and lowlands of 400 Summit Sourveld occurs on the summits of the mountain to 900 m a.s.l., including the dry Limpopo River valley in range, bordering the pockets of Northern Mistbelt Forest. the north. The appearance of the Soutpansberg topographi- This vegetation type is restricted to the high altitudes of the cal feature most probably has been sculpted by erosion proc- Blouberg and Soutpansberg above 1200 m a.s.l. where frost esses (Partridge & Maud 1987). The mountain is situated is not uncommon. The mistbelt and the high-altitude grass- within the summer rainfall region of Southern Africa. As a land withstood climatic oscillations in the past and pro- result of its east-west orientation, the mountain range rep- vided cool and moist conditions throughout the Neogene resents an effective barrier between the south-eastern mari- (Hendey 1983, Coetzee 1986, Mucina & Rutherford time climate and the northern continental climate (Egan 2006). 148 Reptile species of the Soutpansberg Lajuma Research Centre Northern Mistbelt Forest (regrowth), Soutpansberg Moun- tain Bushveld, Soutpansberg Mountain Bushveld (Coleo­ The main survey over the course of this study was conduct- chloa association), Soutpansberg Mountain Bushveld ed at the Lajuma Research Centre property, situated on the (Mistbelt bush clumps), Soutpansberg Mountain Bushveld southern slopes of the Western Soutpansberg (farm Berg- (Patches), Soutpansberg Summit Sourveld and Wetland plaats 40LS, quarter-degree grid square 2329AB; hence- (Fig. 2). forth simply called Lajuma) (Fig. 1). The area includes al-