Overview

Crocidura mariquensis – (A. Smith, 1844)

ANIMALIA – CHORDATA – MAMMALIA – EULIPOTYPHLA – SORICIDAE – Crocidura – mariquensis 

Common Names: Swamp Musk Shrew, Marico Musk Shrew (English), Vleiskeerbek (Afrikaans)

Synonyms: No Synonyms 

Taxonomic Note: Meester et al. (1986) recognised two subspecies in southern Africa: C. m. mariquensis occurring in KwaZulu-Natal, northern Free State, North West, Limpopo, Gauteng and Mpumalanga provinces and Mozambique; and C. m. shortridgei, occurring from north-eastern Namibia to northwestern Zimbabwe. Additionally, morphometric data reveal the KwaZulu-Natal population to be distinct from all others (Dippenaar 1979; Taylor 1998). Thus, this species may represent a species complex, but until new research provides further evidence, we retain the species status. 

Red List Status: NT – Near Threatened, B2ab(ii,iii,iv,v) (IUCN version 3.1) 

Assessment Information

Assessor: Russo, I.M.¹ & da Silva, J.² 

Reviewer: Patel, T.³ 

Institutions: ¹Cardiff University, ²South African National Biodiversity Institute,³Endangered Wildlife Trust  

Previous Assessors: Taylor, P., Baxter, R., Monadjem, A. & Power, J. 

Previous Reviewers: Harvey, J. & Child, M.F. 

Previous Contributors: Avery, M., MacFadyen, D., Avenant, N., Wilson, B., Palmer, G. & Roxburgh, L. 

Assessment Rationale 

This species has a wide distribution across the assessment region and occurs in many protected areas but is restricted to wetlands and waterlogged areas, thus leading to a patchy area of occupancy (AOO). Wetlands were used as a proxy for suitable habitat and the amount of natural habitat remaining within buffer strips around wetlands as the inferred area of occupancy (AOO) was calculated. This yielded 2,395–2,794 km² using a 32 m buffer strip. Habitat patches for this species are severely fragmented due to the poor dispersal ability of shrews in general. In addition, the continuing rates of urban and rural expansion may have increased overgrazing and water abstraction which may reduce the suitability of patches and the corridors between habitat patches. Similarly, a continuing population decline based on high rates of habitat loss in all provinces, especially the KwaZulu-Natal and North West Provinces (1.2% per annum from 1994–2011 and 0.5% per annum from 2006–2010 respectively) has been inferred. Additionally, climate change may cause a range contraction as arid areas expand towards the east. The species is therefore listed as Near Threatened B2ab(ii,iii,iv,v) because, although the AOO estimate is > 2,000 km², not all suitable habitats will be occupied. Further field studies and research should assess the species’ distribution more accurately and examine whether artificial wetlands can compensate for the loss of natural areas. The species is reliant on natural vegetation and wet, muddy substrates. Managers and landowners should therefore restore and maintain buffers of natural vegetation around wetlands and keep stocking densities at ecological carrying capacity to ensure the persistence of this species.  

Regional population effects: Habitats are presumably fragmented between regions, and the species is too small to disperse over long distances so rescue from neighbouring regions is not thought to be possible. 

Reasons for Change 

Reason(s) for Change in Red List Category from the Previous Assessment: No change 

Red List Index 

Red List Index: No change

Recommended citation:  Russo IM & da Silva JM. 2025. A conservation assessment of Crocidura mariquensis. In Patel T, Smith C, Roxburgh L, da Silva JM & Raimondo D, editors. The Red List of Mammals of South Africa, Eswatini and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

Regional Distribution and occurrence

Geographic Range 

This widely but patchily distributed species occurs in the south-eastern part of the Democratic Republic of Congo, Zambia, Angola, north-eastern Namibia, north-western Botswana (the Okavango Delta), Zimbabwe, southern Mozambique, Eswatini and north-eastern South Africa. There is a disjunction between the subspecies occurring within the assessment region (C. m. mariquensis) and the more northern subspecies (C. m. shortridgei). If the latter is revealed to be a full species through molecular research, C. m. mariquensis will become endemic to the assessment region. 

Within the assessment region, the species occurs in wetlands and waterlogged grasslands (both post-1999 and pre-2000 records) in the KwaZulu-Natal, Mpumalanga, Limpopo, Gauteng and eastern North West Provinces. Marginal populations occur in the northern reaches of the Free State Province (Fuller & Perrin 2001; Wandrag et al. 2002) at Seekoeivlei and Tussen-die-Riviere Nature Reserves with a single isolated record from the University of Free State, Bloemfontein (N. Avenant unpubl. data). Although no data for Kruger National Park is available, the species presumably occurs in the park. In the North West Province, new records were obtained from Mafikeng and Bloemhof (Power 2014), which extends the range westwards and confirms anecdotal suggestions of its presence in the area (Rautenbach 1982). The distribution of the species will track waterlogged environments and will most likely shift east to reflect the east-west aridity gradient across the country. Climate change is predicted to make the western regions drier (Erasmus et al. 2002). In Eswatini, it occurs in the Highveld and Middleveld regions (Monadjem 1998). 

Based on the records available, the extent of occurrence (EOO) was calculated to be 397,992 km². However, the species is distributed patchily and fragmented within the assessment area due to its reliance on moist habitats. Within the EOO, the amount of natural habitat remaining within buffer strips around wetlands as the inferred area of occupancy (AOO) was calculated at 50,377–63,440 km² (using 500 m buffer strip) or 2,395–2,794 km² (using 32 m buffer strip). Although this is still a large area, the lower estimates are more plausible. Given that this AOO estimate is uncertain, the species falls within the thresholds for Near Threatened (IUCN Standards and Petitions Subcommittee 2014).  

Elevation / Depth / Depth Zones 

Elevation Lower Limit (in metres above sea level): (Not specified) 

Elevation Upper Limit (in metres above sea level): (Not specified) 

Depth Lower Limit (in metres below sea level): (Not specified) 

Depth Upper Limit (in metres below sea level): (Not specified) 

Depth Zone: (Not specified) 

Map

Figure 1. Distribution records for  Swamp Musk Shrew (Crocidura mariquensis) within the assessment region (South Africa, Eswatini and Lesotho). Note that distribution data is obtained from multiple sources and records have not all been individually verified.

Biogeographic Realms 

Biogeographic Realm: Afrotropical 

Occurrence 

Countries of Occurrence 

Large Marine Ecosystems (LME) Occurrence 

Large Marine Ecosystems: (Not specified) 

FAO Area Occurrence 

FAO Marine Areas: (Not specified) 

Climate change

Climate change may cause a range contraction as arid areas expand. It is predicted to make the western regions drier (Erasmus et al. 2002). The distribution of the species will therefore track waterlogged environments and will most likely shift east to reflect the east-west aridity gradient across the country.  

Population information

This can be a common and locally abundant species in suitable habitat, for example, it occurs in higher numbers than Rhabdomys pumilio at Lajuma in the Soutpansberg Mountains, Limpopo Province (R. Baxter and P. Taylor unpubl. data) and at Seekoeivlei Nature Reserve in the Free State Province it was the most abundant small mammal sampled,  constituting 41% of samples collected while R. pumilio and Myosorex varius accounted for 28% and 22%, respectively (Wandrag et al. 2002). However, due to the species patchy distribution, the total population size of the species is unlikely to compare to that of more widespread and generalist species. Power (2014) reported that the species is only locally common in wetlands in the mesic parts of the North West Province and it appears to be localised or patchily distributed in KwaZulu-Natal (J.Harvey unpubl. data). 

Population Information 

Current population trend: Declining. Inferred from wetland habitat loss and degradation across its range. 

Number of mature individuals in population: Unknown  

Number of mature individuals in largest subpopulation: Unknown  

Number of subpopulations: Unknown  

Severely fragmented: Yes, considering the poor dispersal ability of the species and the fragmented nature of wetlands within its range. 

Extreme fluctuations in the number of subpopulations: (Not specified) 

Continuing decline in number of subpopulations: (Not specified) 

All individuals in one subpopulation: (Not specified) 

Quantitative Analysis 

Probability of extinction in the wild within 3 generations or 10 years, whichever is longer, maximum 100 years: (Not specified) 

Probability of extinction in the wild within 5 generations or 20 years, whichever is longer, maximum 100 years: (Not specified) 

Probability of extinction in the wild within 100 years: (Not specified) 

Population genetics

No population genetics study has been conducted on this species; however, it is expected that genetically distinct subpopulations exist within the assessment region given the patchy distribution of its habitat and its poor dispersal capabilities. A molecular study is highly recommended to uncover the extent of this structure and to investigate the genetic health of each distinct group (e.g., effective population size (Ne). 

Habitats and ecology

This species has specific habitat requirements and occurs only close to open water with intact riverine and semi-aquatic vegetation such as reedbeds, wetlands and the thick grass along riverbanks (Monadjem 1999; Skinner & Chimimba 2005). Individuals are found both in wet substrates and drier grassland away from the water edge (Taylor 1998). The species are often sampled in waterlogged areas, such as inundated grasslands and vleis (Rautenbach 1982; Monadjem 1998; Taylor 1998; Fuller & Perrin 2001). Observations from Eswatini and Telperion Nature Reserve (auteng Province) suggest that the species can occur within a variety of land covers (A. Monadjem pers. obs.) 

The species is active at night and during the day but is primarily nocturnal (Baxter et al. 1979). Individuals use the paths made by Vlei Rats (Otomys spp.) and Marsh Rats (Dasymys spp.; Skinner & Chimimba 2005). The hind feet are splayed which may be an adaptation to marshy conditions. When moving the tail is often curved slightly upwards (Baxter & Meester 1980). It shows little agnostic behaviour to conspecifics (Baxter et al. 1979; Baxter & Meester 1980). Insects constituted 92% of the diet in Umvoti Vlei Conservancy, the KwaZulu-Natal Province (Fuller & Perrin 2001). 

Ecosystem and cultural services: This species could be a candidate flagship species in the wetland biodiversity stewardship schemes. It is an important prey species of African Grass Owls (Tyto capensis) (Vernon 1972). 

IUCN Habitats Classification Scheme 

Life History 

Generation Length: (Not specified) 

Age at Maturity: Female or unspecified: (Not specified) 

Age at Maturity: Male: (Not specified) 

Size at Maturity (in cms): Female: (Not specified) 

Size at Maturity (in cms): Male: (Not specified) 

Longevity: (Not specified) 

Average Reproductive Age: (Not specified) 

Maximum Size (in cms): (Not specified) 

Size at Birth (in cms): (Not specified) 

Gestation Time: (Not specified) 

Reproductive Periodicity: (Not specified) 

Average Annual Fecundity or Litter Size: (Not specified) 

Natural Mortality: (Not specified) 

Does the species lay eggs? (Not specified) 

Does the species give birth to live young: (Not specified) 

Does the species exhibit parthenogenesis: (Not specified) 

Does the species have a free-living larval stage? (Not specified) 

Does the species require water for breeding? (Not specified) 

Movement Patterns 

Movement Patterns: (Not specified) 

Congregatory: (Not specified) 

Systems 

System: Terrestrial 

General Use and Trade Information

There is no known subsistence or commercial use of this species. 

Local Livelihood: (Not specified) 

National Commercial Value: (Not specified) 

International Commercial Value: (Not specified) 

End Use: (Not specified) 

Is there harvest from captive/cultivated sources of this species? (Not specified) 

Harvest Trend Comments: (Not specified) 

Threats

The main threat to shrews is the loss or degradation of moist, productive areas such as wetlands and rank grasslands within suitable habitat. The two main drivers behind this are abstraction of surface water and draining of wetlands through industrial, agricultural, afforestation and residential expansion, and overgrazing of moist grasslands, which leads to the loss of ground cover (reduces habitat structural complexity) and decreases small mammal diversity and abundance (Bowland & Perrin 1989, 1993). Overgrazing is particularly threatening this species as it relies on medium to tall grass cover. Suppression of natural ecosystem processes, such as severe fire, can also lead to habitat degradation through bush encroachment or loss of plant diversity through alien invasives, and is increasing with human settlement expansion. There are also clear overlaps and synergistic effects between these threats. A continuing population decline based on loss of natural habitat is inferred. 

Wetlands are the most threatened ecosystem, with 65% of wetland ecosystem types threatened (48% of all wetland types are Critically Endangered, 12% are Endangered and 5% are Vulnerable) because they are highly productive and hence become transformed for agriculture (Driver et al. 2012). Overall, 45% of our remaining wetland area exists in a heavily modified condition due primarily to on-site modification from crop cultivation, coal mining, urban development, dam construction, and overgrazing (and thus erosion) and off-site modifications from disruptions to the flow regime and deterioration of water quality (Driver et al. 2012). Although this species may occur in artificial wetlands, it is reliant on natural vegetation and wet, muddy substrates. 

Current habitat trend: Habitat loss and degradation across the range of the species is caused primarily by agricultural expansion (including overgrazing), urban and rural settlement expansion, aforestation and mining. Overall, there was a 19.7% loss of natural habitat in KwaZulu-Natal Province from 1994 to 2011, with an average loss of 1.2% per annum (Jewitt et al. 2015). If this rate of loss continues into the future, there will be an estimated 12% loss of habitat over 10 years. In Gauteng Province, 13% of natural habitat was lost between 1995 and 2009 (Driver et al. 2012). In North West Province, 2% of natural habitat was lost just between 2006 and 2010 (Desmet & Schaller 2015). Similarly, although not formally quantified, there is ongoing habitat loss in both Mpumalanga and Limpopo provinces, especially from settlement expansion and mining. New land cover data from 2000 and 2013 show that Gauteng, Limpopo, Mpumalanga and North West provinces experienced rural expansion of 39%, 9%, 7% and 6.5% respectively (GeoTerraImage 2015), while urban expansion proceeded at 8%, 15%, 11% and 14% for the same provinces (GeoTerraImage 2015). Such settlement expansion indicates both a loss of habitat and an increase in human encroachment on grassland and wetland resources, which we infer as increasing habitat degradation. Erasmus et al. (2002) modelled the effects of a 2°C increase in temperature and projected a range shift from west to east and an absolute reduction in total occupancy for most species. Presumably, this range shift and reduction, that tracks the east-west aridity gradient, would apply to this species too, and thus represents an emerging threat. 

Conservation

This species occurs in several protected areas. Although the loss of wetlands may be in part compensated by its ability to exploit man-made waterbodies (farm dams), natural vegetation is key to species survival. The main intervention for this species is thus the protection and restoration of rank vegetation around wetlands. Biodiversity stewardship schemes should be promoted if landowners possess wetlands close to core protected areas or remaining habitat patches, and the effects on small mammal subpopulations should be monitored. Protecting such habitats may create dispersal corridors between patches that will restore connectivity between habitat patches. Landowners and managers should be educated, encouraged and incentivised to conserve the habitats on which shrews and small mammals depend. Retaining ground cover is the most important management tool to increase small mammal diversity and abundance. This can be achieved through reduced grazing pressure (Bowland & Perrin 1989), or by maintaining buffer strips of natural vegetation around wetlands (Driver et al. 2012). Small mammal diversity and abundance is also higher in more complex or heterogeneous landscapes where periodic burning is an important tool to achieve this (Bowland & Perrin 1993). Removing alien vegetation from watersheds, watercourses and wetlands is also an important intervention to improve flow and water quality, and thus habitat quality for shrews. Education and awareness campaigns should be employed to teach landowners and local communities about the importance of conserving wetlands and moist grasslands. 

Recommendations for land managers and practitioners:  

• Landowners and communities should be incentivised to stock livestock or wildlife at ecological carrying capacity to avoid overgrazing and to maintain buffers of natural vegetation around wetlands and riverine habitats. 

• Enforce regulations on developments that could potentially impact on the habitat integrity of grasslands and wetlands. 

Research priorities:  

• Additional field surveys are needed to clarify and confirm the distribution of this species, particularly around artificial waterbodies, agricultural landscapes and urban/rural gardens. 

• The effects of climate change on the distribution and abundance of the species should be modelled. 

Encouraged citizen actions:  

• Citizens are requested to submit any shrews killed by cats or drowned in pools to a museum or a provincial conservation authority for identification, thereby enhancing our knowledge of shrew distribution (carcasses can be placed in a ziplock bag and frozen with the locality recorded). 

• Practice indigenous gardening to sustain small mammals. 

Bibliography

Baxter R.M. and Meester J. 1980. Notes on the captive behaviour of five species of southern African shrews. Säugetierkundliche Mitteilungen 26: 55–62. 

Baxter RM, Goulden EA, Meester J. 1979. The activity patterns of some southern African Crocidura in captivity. Acta Theriologica 24: 61-68. 

Bowland, A.E. and Perrin, M.R. 1989. The effect of overgrazing on the small mammals in Umfolozi Game Reserve. Zeitschrift für Säugetierkunde 54: 251–260. 

Bowland, J.M. and Perrin, M.E. 1993. Wetlands as reservoirs of small-mammal populations in the Natal Drakensberg. South African Journal of Wildlife Research 23: 39–43. 

Desmet PG, Schaller R. 2015. North West Biodiversity Sector Plan Technical Report. North West Department of Rural, Environment and Agricultural Development, Mahikeng, South Africa. 

Dippenaar NJ. 1979. Variation in Crocidura mariquensis (A. Smith, 1844) in southern Africa, Part 2 (Mammalia: Soricidae). Annals of the Transvaal Museum 32: 1-34. 

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. 2012. National Biodiversity Assessment 2011: An assessment of South Africa’s biodiversity and ecosystems. Synthesis Report. South African National Biodiversity Institute and Department of Environmental Affairs, Pretoria, South Africa. 

Erasmus, B.F.N., van Jaarsveld, A.S., Chown, S.L., Kshatriya, M. and Wessels, K.J. 2002. Vulnerability of South African animal taxa to climate change. Global Change Biology 8: 679-693. 

Fuller, J.A. and Perrin, M.R. 2001. Habitat assessment of small mammals in the Umvoti Vlei Conservancy, KwaZulu-Natal, South Africa. South African Journal of Wildlife Research 31: 1-12. 

GeoTerraImage. 2015. Quantifying settlement and built-up land use change in South Africa. Pretoria. 

IUCN Standards and Petitions Subcommittee. 2014. Guidelines for Using the IUCN Red List Categories and Criteria. Version 11. 

Jewitt, D., Goodman, P.S., Erasmus, B.F.N., O’Connor, T.G. and Witkowski, E.T.F. 2015. Systematic land-cover change in KwaZulu-Natal, South Africa: Implications for biodiversity. South African Journal of Science 111: 1-9. 

Meester, J.A.J., Rautenbach, I.L., Dippenaar, N.J. and Baker, C.M. 1986. Classification of Southern African Mammals. Monograph number 5. Transvaal Museum , Pretoria, South Africa. 

Monadjem A. 1998. The mammals of Swaziland. Conservation Trust of Swaziland and Big Games Parks, Mbabane, Swaziland. 

Monadjem A. 1999. Geographic distribution patterns of small mammals in Swaziland in relation to abiotic factors and human land-use activity. Biodiversity & Conservation 8: 223-237. 

Power, R.J. 2014. The distribution and status of mammals in the North West Province. Department of Economic Development, Environment, Conservation & Tourism, North West Provincial Government, Mahikeng. 

Rautenbach, I. L. 1982. Mammals of the Transvaal. Ecoplan monograph, N.S. Supplemento 1: 111-211. 

Skinner, J.D. and Chimimba, C.T. (eds). 2005. The Mammals of the Southern African Subregion. Cambridge University Press, United Kingdom, Cambridge. 

Taylor, P. 1998. The Smaller Mammals of KwaZulu-Natal. University of Natal Press, Pietermaritzburg, South Africa. 

Vernon CJ. 1972. An analysis of owl pellets collected in southern Africa. Ostrich 43: 109-124. 

Wandrag, G.F., Watson, J.P. and Collins, N.B. 2002. Rodent and insectivore species diversity of Seekoeivlei Provincial Nature Reserve, Free State province, South Africa. South African Journal of Wildlife Research 32: 137–143.