Parotomys brantsii – Brants’ Whistling Rat Goegap Nature Reserve and Tswalu Kalahari Reserve), and because there are no major documented threats that could cause range-wide decline. They are also not exploited by humans. However, this is a species we need to flag as being potentially threatened due to projected aridification from climate change and overgrazing in some areas. This may affect the forage resources on which this species depends, and may be exacerbated by the sensitivity of this rodent to high ambient temperatures that may limit foraging behaviour under hotter conditions. Given that this species displays a patchy distribution and undergoes population irruptions, it may qualify for listing under the C criterion in the future, and will need to be Derek Keats reassessed once more data are generated. We recommend that more research and long-term monitoring of subpopulation trends, geographic distribution and Regional Red List status (2016) Least Concern* threat level are undertaken. National Red List status (2004) Least Concern Regional population effects: The bulk of the population Reasons for change No change exists in South Africa, so extra-regional rescue effect is minimal. It is a rapid disperser over short distances Global Red List status (2016) Least Concern (< 1 km), especially into areas that were recently TOPS listing (NEMBA) (2007) None overgrazed. Long distance dispersal ability is unknown, and would be dependent on corridors of suitable habitat. None CITES listing The successful colonisation of poorly vegetated mine Endemic Near dumps (Desmet & Cowling 1999) suggests an ability to establish in harsh habitats provided deep soils are *Watch-list Threat available. Evidence suggests that this species may facilitate the rehabilitation of mine dumps through the creation of nutrient-rich patches around its Distribution burrows (Desmet & Cowling 1999). This species is restricted to the arid regions of southern Africa occurring in southwestern South Africa, southern Namibia and extreme southwestern Botswana (Skinner & Chimimba 2005). It is associated with open habitats and hard, sandy substrates throughout the arid Karoo and Taxonomy southern Kalahari regions (Monadjem et al. 2015). It prefers dry, coarse, sandy soils with adequate forage in Parotomys brantsii (A. Smith 1834) the more arid parts of the Nama-Karoo and Succulent ANIMALIA - CHORDATA - MAMMALIA - RODENTIA - Karoo biomes (Skinner & Chimimba 2005). It occurs from MURIDAE - Parotomys - brantsii sea level up to 1,000 m asl and generally inhabits regions with an annual rainfall of 300–500 mm. Common names: Brants’ Whistling Rat (English), Brants se Fluitrot (Afrikaans) The species distribution marginally abuts the North West Province, and it has been tentatively mentioned in Taxonomic status: Species provincial documents, but during a recent mammal Taxonomic notes: Molecular data suggest that Parotomys survey, Power (2014) found no evidence of their existence should be synonymised with Otomys (Taylor et al. 2011, in the province. Similarly, there are no recent records from 2014), but the genera are recognised as distinct pending a the Free State except for a handful of historical records final phylogenetic analysis of species relationships within from the southwestern corner of the province the Otomyinae (Monadjem et al. 2015). This species is (N.L. Avenant pers. comm. 2014). Historically, it was also similar to P. littledalei, but distinguishable, both by its recorded 15 km west of Steytlerville, Eastern Cape dental morphology (grooved upper incisors) and by its Province, but is no longer present (G.I.H. Kerley unpubl. whistle frequency and length (Le Roux et al. 2002; data). Monadjem et al. 2015). Population Assessment Rationale It can be very common locally, as it undergoes population Listed as Least Concern because of its wide distribution irruptions in response to environmental conditions within the assessment region, its occurrence in several (Jackson 2013), and has a patchy distribution, linked to protected areas (including Kgalagadi Transfrontier Park, the distribution of deep sandy soils. This reflects its Recommended citation: Schradin C, Malan G, Kerley GIH, Child MF. 2016. A conservation assessment of Parotomys brantsii. In Child MF, Roxburgh L, Do Linh San E, Raimondo D, Davies-Mostert HT, editors. The Red List of Mammals of South Africa, Swaziland and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa. The Red List of Mammals of South Africa, Lesotho and Swaziland Parotomys brantsii | 1 Figure 1. Distribution records for Brants’ Whistling Rat (Parotomys brantsii) within the assessment region Table 1. Countries of occurrence within southern Africa (G. Malan unpubl. data). In the central Little Karoo (study site 108 km2 in size), low densities were categorised by Country Presence Origin isolated pockets of active warrens, and moderate Botswana Extant Native densities had animals evenly spread across the study area (G. Malan unpubl. data). At high densities, the whistling Lesotho Absent - rats were so abundant that they even burrowed in road Mozambique Absent - verges and open disturbed areas (and commonly ran Namibia Extant Native across roads), and their piercing whistles reverberated through the veld (G. Malan unpubl. data). In high-density South Africa Extant Native years, in Karroid Broken Veld, the density was estimated Swaziland Absent - at 128 active warrens / km2 (range 76–212 warrens / km2) (Malan 2001). In the neighbouring and more open Zimbabwe Absent - Succulent Karoo, the density was estimated at 192 active warrens / km2 (range 96–388) (Malan 2001). In a low- density year (1991) in Karroid Broken Veld, the estimated requirements for burrowing as the Brants’ Whistling Rat is density decreased to 40 active warrens / km2 (standard an obligate burrower and uses burrows to avoid deviation = 28 warrens) (recalculated from Malan 2004). physiological extremes and predators (du Plessis & Kerley Jackson (2013) reports densities exceeding 50 1991). Thus, detecting a population trend is difficult, and individuals / ha in favourable conditions. At one adult per long-term, systematic monitoring is necessary. warren, the biomass estimate was 16 kg / km2 (Malan Population data from Goegap Nature Reserve, Northern 2001). Cape Province, indicate that this species is generally more Current population trend: Stable resilient and stable than P. littledalei, with densities of 2–10 individuals / ha remaining stable and consistent between Continuing decline in mature individuals: No 2001 and 2014 (C. Schradin unpubl. data). This compares Number of mature individuals in population: Unknown to a density of 15 individuals / ha being recorded for P. littledalei at the same site in 2001, and subsequently, Number of mature individuals in largest subpopulation: not having been recorded until 2014, at a density of one Unknown individual / ha (C. Schradin unpubl. data). Similarly, in the Number of subpopulations: Unknown Little Karoo, (33°30'–33°37'S; 21°43'–21°52'E) over 14 years (1988–2001), their numbers peaked in 1989 and 1990, but Severely fragmented: No thereafter fluctuated between moderate and low densities Parotomys brantsii | 2 The Red List of Mammals of South Africa, Lesotho and Swaziland of mine dumps. This should be interpreted with some Habitats and Ecology caution as the rats require forage and would only Brants’ Whistling Rat is a largely crepuscular species recolonise areas where there is at least some plant cover. (Jackson 1998), with additional short bouts of activity It is a key prey species for Pale Chanting Goshawks during the night and day (du Plessis 1989). It has a patchy (Melierax canorus) and Booted Eagles (Aquila pennatus) habitat distribution (reflecting forage availability and the in the Little Karoo, where the reproductive fitness of the need for deep soils). It is restricted to areas with latter is associated with the Karoo Broken Veld vegetation consolidated sands in semi-desert landscapes, with a low type that contains the tall shrubs and heuweltjies percentage plant cover (plant cover = 34–40%) (du necessary for high Otomyine density (Malan 2001). Pale Plessis & Kerley 1991; Malan 2001). These open areas Chanting Goshawks catch P. brantsii individuals in probably provide it with a clear view of approaching aerial proportion to the warren densities, as the birds may find it and terrestrial predators. In the Kalahari, it occurs in dune easier to catch P. brantsii on or near their warrens that are swales associated with Driedoring (Rhigozum normally devoid of any vegetation (Malan 2001). At high trichotomum) (Jackson 2013). It is not associated with rodent densities, Jackal Buzzard (Buteo rufofuscus), Black grass patches in Goegap Nature Reserve (C. Schradin Harrier (Circus maurus) and Lanner Falcon (Falco unpubl. data). It can also occur in rangelands or old fields. biarmicus) move into the area to hunt P. brantsii (Malan It feeds on a variety of annuals in spring, and mostly 2000). Reptiles found in warrens include the Cape Cobra perennial succulents, grasses and shrubs in summer and (Naja nivea) and Mole Snake (Pseudaspis cana) (G. Malan winter (Jackson 1998, 2001). Perennial succulents may pers. obs. 2014). function as key resource areas for this species and it is thus potentially sensitive to destruction of these areas. It is a central place forager; smaller food items are eaten in situ Use and Trade whilst larger items are eaten at burrow entrances or stored This species