Red List of South African Species

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Least Concern (LC)
Assessors: Beryl Wilson Claire Relton
Contributors: Matthew Child Nico Avenant Margaret Avery Rod Baxter Duncan MacFadyen Ara Mondajem Guy Palmer Peter Taylor
Reviewers: Beryl Wilson Claire Relton

Rationale

The Brukkaros Pygmy Rock Mouse is listed as Least Concern because of its relatively wide distribution (although only scattered records are available) including a few protected areas, presumed large population, and because its population is not believed to be declining at present. It occurs on flat plains or open rocky areas, and is not found in mountainous terrain. There are no major threats as its habitat is unlikely to be rapidly transformed. However, climate change and renewable energy projects in some areas may represent emerging threats. Additionally, habitat disturbance by domestic sheep and goats may be a problem, particularly during drought periods. More research needs to be conducted and further field surveys are required to estimate extent and occupancy more accurately. This species should be reassessed once its taxonomy has been resolved.

Regional population effects: Occasional dispersal of this species across the Orange River between South Africa and Namibia is likely, thus rescue effect is possible.

Distribution

This species was originally collected from a rocky koppie at the base of the Great Brukkaros Mountain in southern Namibia, from where it gets its name (Skinner & Chimimba 2005). Although the extent of its range is uncertain, this species is probably limited to arid, rocky habitats of southern Namibia, extending into the Northern Cape Province of South Africa (Skinner & Chimimba 2005; Monadjem et al. 2015). Further vetting of museum records is necessary to delimit distribution more accurately. For example, Monadjem et al. (2015) only list one verified record within South Africa. It is predicted to occur from 100 m to 2,000 m asl.

Population trend

Trend

Although originally considered to be rare when it was known from only one locality in southern Namibia (Coetzee 2013), this species is now believed to be relatively common in some portions of its range. No population estimates are available for this species.

Threats

No major threats have been identified for this species. However, in association with global climate change, the projected vegetation shift in the semi-arid Succulent Karoo may represent a future threat to this species (Rutherford et al. 1999). Increased temperatures, in conjunction with an enhanced frequency and duration of drought, is predicted to have negative effects on resource availability for small herbivorous mammals in the arid regions of southern Africa (Hoffman et al. 2009). Similarly to P. collinus, prolonged droughts and concomitant shortages of food resources during summer, such as climate change-exacerbated droughts, are likely to have severe energetic consequences for this species (Bragg 2000).

The rapidly expanding construction of renewable (in particular solar) energy projects in the Northern Cape may signify an emerging threat to this species as its range partially overlaps with earmarked areas (van der Westhuizen 2013). Additionally, habitat degradation through overgrazing by domestic sheep and goats may be a threat, particularly during drought periods (Coetzee 2013).

Uses and trade

This species does not appear to be utilised or traded in any form.

Conservation

No specific conservation initiatives have been identified for the Brukkaros Pygmy Rock Mouse. The range of this species extends into a number of protected areas, including Augrabies Falls National Park, Richtersveld National Park, and possibly into Namaqua National Park. Further research is needed into the potential threat of enhanced aridity associated with climate change, and how this may affect food resources, as well as potential habitat loss from renewable energy projects.

Recommendations for land managers and practitioners:
  • Systematic field surveys needed to gather information on population size and trends.
Research priorities:
  • Population size, distribution and trends.
  • Analysis of potential impacts of renewable energy projects.
  • Taxonomic resolution using molecular techniques and vetting of museum records.
  • Analysis of potential impacts of increased resource constraints and increased temperature extremes on energetics of the species under climate change scenarios.
  • Ecological niche modelling to identify areas to focus sampling.
Encouraged citizen actions:
  • Report sightings on virtual museum platforms (for example, iSpot and MammalMAP), especially outside protected areas. However, due to their morphological similarities, misidentification of this species with other Petromyscus species is common. See Taxonomic notes for distinguishing characteristics.
  • Encourage the inclusion of mitigation measures specific to the species in the Environmental Management Plans for new renewable energy developments overlapping with this species’ distribution.

References 

[@book{14262,
 address = {Berlin, Germany},
 author = {Monadjem, A., Taylor, P.J., Denys, C. and Cotterill, F.P.D.},
 publisher = {De Gruyter},
 title = {Rodents of Sub-Saharan Africa: A Biogeographic and Taxonomic Synthesis. },
 year = {2015}
}
,@inbook{21693,
 address = {London},
 author = {},
 booktitle = {<i>Thallomys shortridgei</i> Shortridge’s Acacia Rat (Shortridge’s Thallomys)},
 editor = {Nel, J.A.J.},
 pages = {562–563},
 publisher = {Bloomsbury Publishing},
 title = {Mammals of Africa. Volume III: Rodents, Hares and Rabbits},
 year = {2013}
}
,@article{2619,
 author = {Hoffman MT, Carrick PJ, Gillson L, West AG},
 journal = {South African Journal of Science},
 pages = {54–60},
 title = {Drought, climate change and vegetation response in the succulent karoo, South Africa},
 volume = {105},
 year = {2009}
}
,@article{16776,
 author = {Rutherford MC, Powrie LW, Schulze RE.},
 journal = {Diversity and Distributions },
 pages = {253–262},
 title = {Climate change in conservation areas of South Africa and its potential impact on floristic composition: a first assessment.},
 volume = {5},
 year = {1999}
}
,@phdthesis{16778,
 author = {Bragg CJ.},
 school = {University of KwaZulu-Natal},
 title = {Thermoregulation and torpor in the pygmy rock mouse, Petromyscus collinus - energy-conservative traits in a desert subject to the unpredictability of El Nino Southern Oscillations. Honours Thesis.},
 year = {2000}
}
,@article{16779,
 author = {Schenk, J., Rowe, K. and Steppan, S. . },
 journal = {Systematic Biology},
 number = {6},
 pages = {837--864},
 title = {Ecological Opportunity and Incumbency in the Diversification of Repeated Continental Colonizations by Muroid Rodents},
 volume = {62},
 year = {2013}
}
,]
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