By 2011, habitat transformation in KwaZulu-Natal was estimated at 46.4% with an average transformation of 1.2% per annum since 1994 (Jewitt et al. 2015). Land cover maps (Driver et al. 2012, Schoeman et al. 2013, Jewitt et al. 2015) show that apart from conservation areas, most habitat over the range of this species is anthropogenically transformed by forestry and cultivation. These negative influences on the species are compounded by pollution and the filling-in or drainage of swamps, marshes, pans and vleis (R.C. Boycott pers. obs.). Habitat inside conservation areas may also deteriorate in future due to climate change, which is expected to have an adverse effect on the Indian Ocean Coastal Belt Bioregion (DEA 2013), the prime habitat of the species. Based on land cover maps, we estimate that at least 20% of the species’ original range has been destroyed or degraded over the past 30 years (1.5 generations). An estimated population decline of 10-20% over the next 30 years (1.5 generations) will result in a total decline in excess of 30%, qualifying the species to be listed as Vulnerable on a regional basis according to A4ac. The regional EOO for P. castanoides falls within the limit for Vulnerable (B1). Although this listing is supported by a continuing decline in habitat quality, we do not have sufficient information about fragmentation or number of locations to support a B1 listing.
Distribution
The species occurs in tropical eastern Africa from southeastern Kenya through Tanzania, Malawi and Mozambique into South Africa (Turtle Taxonomy Working Group 2014). It is also present in Madagascar and Seychelles. Its range in South Africa is restricted to northeastern KwaZulu-Natal from the northern border with Mozambique to just south of St Lucia. The range was extended recently when an individual was found further south along the coast, near the Crestholme Conservancy. This find warrants investigation to determine if it represents an escapee or a relict population.
There is no information currently available for the populations within South Africa.
Threats
In KwaZulu-Natal the habitat of this species has probably been reduced by man through the filling-in or drainage of swamps, marshes, pans and vleis. At some localities pollution of the habitat undoubtedly affects terrapins. The long-term effect of insecticide spraying for the control of mosquitoes is unknown and poses an additional threat to survival. Veld fires in the dry season could affect hibernating terrapins if they are shallowly buried.
Uses and trade
No utilization observed in South Africa. Although a few specimens have found their way into museum collections, the offtake is probably negligible.
Conservation
The species is listed under CITES Appendix III. General conservation of the wetland habitats that it inhabits is recommended (Boycott and Bourquin 2000). Research into biology, population numbers and habitat status is needed.
[@techreport{5228,
address = {Pretoria, South Africa},
author = {Driver, A., Sink, K.J., Nel, J.N., Holness, S., Van Niekerk, L., Daniels, F., Jonas, Z., Majiedt, P.A., Harris, L. and Maze, K.},
institution = {South African National Biodiversity Institute and Department of Environmental Affairs},
title = {National Biodiversity Assessment 2011: An assessment of South Africa’s biodiversity and ecosystems. Synthesis Report},
year = {2012}
}
,@article{9077,
author = {Jewitt, D., Goodman, P.S., Erasmus, B.F.N., O’Connor, T.G. and Witkowski, E.T.F.},
journal = {South African Journal of Science },
pages = {1--9},
title = {Systematic land-cover change in KwaZulu-Natal, South Africa: Implications for biodiversity},
volume = {111},
year = {2015}
}
,@article{41662,
author = {Schoeman, F., Newby, T.S., Thompson, M.W. and Van den Berg, E.C.},
journal = {South African Journal of Geomatics},
number = {2},
pages = {94--105},
title = {South African national land-cover change map},
volume = {2},
year = {2013}
}
,@article{5336,
author = {Bourquin, O.},
journal = {Durban Museum Novitates},
pages = {57--103},
title = {Reptiles (Reptilia) in KwaZulu-Natal: 1 - diversity and distribution},
volume = {29},
year = {2004}
}
,@book{10241,
address = {Hilton, South Africa},
author = {Boycott, R.C. and Bourquin, O.},
publisher = {O. Borquin},
title = {The Southern African Tortoise Book: A Guide to Southern African Tortoises, Terrapins and Turtles},
year = {2000}
}
,@inbook{10241,
author = {Rhodin and Iverson and Dijk and Saumure and Buhlmann and Pritchard and Mittermeier },
booktitle = {Turtles of the World: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status (8th Ed.)},
editor = {TTWG (Turtle Taxonomy Working Group: Rhodin, A.G.J., Iverson, J.B., Bour, R. Fritz, U., Georges, A., Shaffer, H.B. and van Dijk, P.P.)},
pages = {1--292},
publisher = {Chelonian Research Monographs},
title = {Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group},
year = {2017}
}
,@article{11004,
author = {TTWG [Turtle Taxonomy Working Group: van Dijk, P.P., Iverson, J.B., Rhodin, A.G.J., Shaffer, H.B. and Bour, R.]},
journal = {Chelonian Research Monographs},
number = {7},
pages = {000.329--479, doi:10.3854/crm.5.000.checklist.v7.2014},
title = {Turtles of the world, 7th edition: annotated checklist of taxonomy, synonymy, distribution with maps, and conservation status},
volume = {5},
year = {2014}
}
,@techreport{170521,
address = {Pretoria},
author = {DEA (Department of Environmental Affairs)},
title = {Long-Term Adaptation Scenarios Flagship Research Programme (LTAS) for South Africa},
year = {2013}
}
,@article{16530,
author = {Fritz, U., Branch, W.R., Hofmeyr, M., Maran, J., Prokop, H., Schleicher, A., Široký, P., Stuckas, H., Vargas-Ramírez, M., Vences, M. and Hundsdörfer, A.K.},
journal = {Zoologica Scripta},
pages = {115--125},
title = {Molecular phylogeny of African hinged and helmeted terrapins (Testudines: Pelomedusidae: <i>Pelusios</i> and <i>Pelomedusa</i>).},
volume = {40},
year = {2011}
}
,@article{41601,
author = {Fritz, U., Branch, W.R., Gehring, P-S., Harvey, J., Kindler, C., Meyer, L., Du Preez, L., Široký, P., Vieites, D.R. and Vences, M.},
journal = {Organisms, Diversity & Evolution },
pages = {215--224},
title = {Weak divergence among African, Malagasy and Seychellois hinged terrapins (<i>Pelusios castanoides, P. subniger</i>) and evidence for human-mediated oversea dispersal},
volume = {13},
year = {2013}
}
,]
