Red List of South African Species

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Least Concern (LC)
Assessors: Nigel Bennett Sarita Maree Jenny Jarvis
Contributors: Claire Relton Matthew Child Nico Avenant Margaret Avery Rod Baxter Duncan MacFadyen Ara Monadjem Guy Palmer Peter Taylor Beryl Wilson
Reviewers: Nigel Bennett Sarita Maree Jenny Jarvis

Rationale

The Namaqua Dune Mole-rat was previously listed as Near Threatened due to the threat of continued habitat destruction of three isolated subpopulations. It is currently listed as Least Concern because there is no evidence for population decline and it occupies habitats that are highly protected and restricted from the public. However, the presumed lack of dispersal and increasing habitat destruction remain major concerns for subpopulations of this species. This is especially true along the coastal regions, where the threat of diamond mining is yet to be quantified. If the mines are rehabilitated, the species may still not be able to recolonize these sites. Resultantly, this species should be reassessed when data on the impact of mining become available.

Regional population effects: Due to disjunctions in the distribution, dispersal is impossible.

Distribution

This species ranges from the north-western regions of the Northern Cape (near Rondawel) northwards along the coast to about 90 km into southern Namibia (Faulkes et al. 2004, Jarvis 2013). Inland, it extends from Springbok and Kamieskroon to Ezelfontein in the Kamiesberg Mountains (Roberts 1951, De Graaff 1981, Jarvis 2013). It is restricted primarily to sandy soils in coastal dunes. A number of isolated populations have been identified in the following areas of South Africa: Alexander Bay on the Orange River, from Port Nolloth to Groenrivier, from Steinkop to Kamieskroon, and in the red dunes of Klawer. Although this species rarely occurs above an altitude of 300 m, in the Kamiesberg it has been found at heights of 1,350 m asl (Skinner and Chimimba 2005). North of the Orange River, in the Sperrgebiet (Diamond mining area), Namibia, it occurs on seepage areas and inselbergs (isolated hills), where precipitation is higher than lower lying areas. Much of its distribution in Namaqualand overlaps with Cryptomys hottentotus, and towards Groenriviersmond and Rondawel, in the south of its range, it occurs sympatrically with B. suillus (Skinner and Chimimba 2005, Jarvis 2013). The estimated extent of occurrence within the assessment region is 10,234 km2.

Population trend

Trend

Namaqua Dune Mole-rats are found commonly within their range. However, their habitat is highly fragmented and their distribution is restricted. Their patchy distribution is especially prominent in the most arid parts of the range where they are often associated with seepage lines where geophytes are found (Jarvis 2013). Their population density increases further inland where rainfall is higher, with up to 44 individuals / km² recorded (Herbst et al. 2004, Jarvis 2013).

Threats

Habitat loss through diamond mining threatens the subpopulations along the coastal belts of southern Namibia and the north-western parts of South Africa. Fortunately, the general public is entirely prohibited from entering these regions, therefore limiting the threats of human disturbance. However, data are needed on the impact of diamond mining on this species. To a lesser extent, overgrazing by goats and sheep threatens to reduce the quality of above ground vegetation on which they forage. Finally, climate change could present an increasing threat to this species by reducing habitat quality and availability, as the geophytes on which these animals feed could dry out and disappear (Hoffman et al. 2009).

Uses and trade

This species is not known to be traded or utilised in any form.

Conservation

Although this species lacks formal protection in many areas, it occurs within the Namaqua National Park (South Africa), the |Ai-|Ais/Richtersveld Transfrontier Park (South Africa and Namibia), and Sperrgebiet (Namibia), which have extremely low levels of human disturbance and contain key habitats for this species. Although locally abundant, subpopulations of this species are fragmented and reintroductions are not possible. No current conservation interventions are in place for this species. Data on the impact of diamond mining should be collected before a conservation strategy can be formulated.

Recommendations for land managers and practitioners:
  • Livestock farmers should reduce stocking rates to conserve ground cover.
Research priorities:
  • Investigating the current extent of distribution and number of subpopulations.
  • Long-term monitoring of population dynamics to establish baseline information.
  • Determining the impact of diamond mining.
Encouraged citizen actions:
  • Report sightings on virtual museum platforms (e.g., iSpot and MammalMAP), especially outside protected areas.

References 

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 author = {Skinner, J.D. and Chimimba, C.T.},
 publisher = {Cambridge University Press, United Kingdom},
 title = {The Mammals of the Southern African Subregion},
 year = {2005}
}
,@article{2620,
 author = {Faulkes, C.G., Verheyen, E., Verheyen, W., Jarvis, J.U.M. and Bennett, N.C.},
 journal = {Molecular Ecology},
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 title = {Phylogeographical patterns of genetic divergence and speciation in African mole-rats (Family: Bathyergidae)},
 volume = {13},
 year = {2004}
}
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,@article{2619,
 author = {Hagenah N, Bennett NC},
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 pages = {19–26},
 title = {Mole rats act as ecosystem engineers within a biodiversity hotspot, the Cape Fynbos.},
 volume = {289},
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,@phdthesis{2619,
 author = {Herbst M},
 school = {University of Pretoria},
 title = {The biology and reproductive ecology of the Namaqua dune mole-rat, <i>Bathyergus janetta</i> from the Northern Cape Province, South Africa. M.Sc. Thesis},
 year = {2002}
}
,@article{2619,
 author = {Herbst M, Jarvis JUM, Bennett NC},
 journal = {Journal of Zoology},
 pages = {259–268},
 title = {A field assessment of reproductive seasonality in the threatened wild Namaqua dune mole-rat (<i>Bathyergus janetta</i>)},
 volume = {263},
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}
,@article{2619,
 author = {Hoffman MT, Carrick PJ, Gillson L, West AG},
 journal = {South African Journal of Science},
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 title = {Drought, climate change and vegetation response in the succulent karoo, South Africa},
 volume = {105},
 year = {2009}
}
,@book{2619,
 address = {London, UK},
 author = {Jarvis JUM},
 publisher = {Bloomsbury Publishing},
 title = {<i>Bathyergus janetta</i> Namaqua Dune Mole-rat. Pages 644–646in D. C. D. Happold, editor.Mammals of Africa. Volume III: Rodents, Hares and Rabbits.},
 year = {2013}
}
,]
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