Rationale

The Least Dwarf Shrew is widespread within the assessment region, occurring across many habitat types, including gardens, and is regularly sampled in suitable habitats. It is common and can be overlooked due to its small size. It is present in several protected areas and there is no evidence for net population decline. Thus we evaluate the species as Least Concern. However, we caution that, pending molecular research, the species may be split into several species and most likely represents one or more endemic taxa. This requires reassessment once the taxonomy has been resolved. Key interventions include protected area expansion of moist grassland and riverine woodland habitats, as well as providing incentives for landowners to sustain natural vegetation around wetlands and keep livestock or wildlife at ecological carrying capacity.

Regional population effects: There is a disjunct distribution between populations in the assessment region and the rest of its range. This species is also a poor disperser. Thus there is not suspected to be a significant rescue effect.

Distribution

The Least Dwarf Shrew has a seemingly wide African distribution: It is found in South Africa and Kenya (Rumruti and Rongai), with additional isolated records from Central African Republic and Cameroon. It possibly occurs in Uganda, however, this needs to be confirmed. Thus, it has a disjunct distribution between the South African population and populations in east and central Africa. Additionally, it is thought to be a species complex and molecular research may reveal the South African population to be an endemic species. Thus, we call this species Near Endemic currently.

Within the assessment region, it occurs extensively in Gauteng, Mpumalanga, KwaZulu-Natal and Eastern Cape provinces, and marginally in the North West, Free State, and Western Cape provinces (Skinner & Chimimba 2005). A single specimen has been collected from Malolotja Nature Reserve in the highveld region of Swaziland (Monadjem 1998).

Habitat View more ecological information

Population trend

Trend

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 and residential expansion, and overgrazing of moist grasslands, which leads to the loss of ground cover and decreases small mammal diversity and abundance (Bowland & Perrin 1989, 1993). Suppression of natural ecosystem processes, such as fire, can also lead to habitat degradation through bush encroachment or loss of plant diversity through alien invasives, and is suspected to be increasing with human settlement expansion. There are also clear overlaps and synergistic effects between these threats. Across South Africa, 65% of wetland ecosystem types are threatened (48% of all wetland types Critically Endangered, 12% Endangered and 5% Vulnerable; Driver et al. 2012).

Climate change is considered to be the principal emerging threat to this species (Ogony 2014), both due to loss of habitat and habitat degradation from drying out of wetlands and because shrews cannot tolerate extremes of temperature for long and thus their foraging time will be reduced. Because of their high metabolism, low dispersal capacity and short life spans, climate change may reduce the amount of suitable habitat available.

Uses and trade

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

Conservation

The Least Dwarf Shrew is present in several protected areas across its range within the assessment region. The main intervention for this species is the protection and restoration of grasslands and wetlands. Biodiversity stewardship schemes should be promoted if landowners possess wetlands or grasslands 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 grassland patches that will enable adaptation to climate change. At the local scale, 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 lowering 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 and to maintain a buffer of natural vegetation around wetlands.

Research priorities:

• Further molecular research is needed to ascertain the validity of the putative species complex.
• Additional field surveys are needed to clarify and confirm the distribution of this species.

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).