habitat_narrative
Terrestrial
As the common and generic names suggest, there is a large number of mammae present, between eight and 12 pairs from the sternum to inguinal region. Both species are terrestrial and nocturnal with a diet that varies from granivorous to omnivorous, sometimes including arthropods and carrion (Monadjem et al. 2015). For example, in Umvoti Vlei Conservancy, KwaZulu-Natal Province, while Rhabdomys pumilio was primarily granivorous, M. natalensis preferred green plant foods (Fuller & Perrin 2001), where its diet changed from predominantly plant material in summer to mainly seeds in winter. They are to some extent dependent on water but occur in areas where water is only seasonally available, such as along the Orange River valley in the Northern Cape (Skinner & Chimimba 2005). They have also been observed to swim (Hickman & Machiné 1986; Power 2014).Mastomys coucha demonstrates a wide habitat tolerance (Skinner & Chimimba 2005; Leirs 2013a; Power 2014) in high altitude/moderate rainfall regions (Venturi et al. 2004). It is often associated with human-dominated landscapes and is regularly found inside and around human dwellings (Skinner & Chimimba 2005; Leirs 2013a). It is abundant in human disturbed areas or in areas that are recovering from a natural disturbance. In disturbed areas, its abundance generally decreases, although it never disappears as succession proceeds (Avenant et al. 2008; MacFadyen et al. 2012). For example, it may stay on in an area during and directly after a fire (Avenant 2011). Similarly, M. natalensis is typically associated with agricultural fields and homes, but also occurs in natural savannahs and grasslands (Leirs 2013b). Mastomys natalensis tolerates disturbance well and can be abundant in Aristida and disturbed grasslands (Fuller & Perrin 2001). It is a generalist species that rapidly colonises areas following disturbance, such as fire, overgrazing and cultivation (Meester et al. 1979; Monadjem 1997). Home ranges of M. natalensis in Swaziland were 626 ± 86 m2 for males and 718 ± 88 m2 for females (Monadjem & Perrin 1998). Leirs et al. (1996) reported home ranges of > 1,000 m2 for M. natalensis.
Due to its high abundance in agricultural landscapes, M. natalensis is a significant crop pest and frequently digs up newly-planted maize seeds or climbs maize stalks to feed on the seeds (Leirs 2013b), as well as feeding on stored grains inside dwellings. Although the specific impact of M. coucha on agricultural crops has not yet been assessed, it is widely accepted that it may cause extensive losses similar to that observed for M. natalensis (Skinner & Chimimba 2005; Leirs 2013a). According to Mulungu et al. (2011), damages to maize by M. natalensis during population outbreaks may exceed 80% of the harvest in some areas.
Both M. coucha and M. natalensis are opportunistic breeders that have the ability to breed throughout the year whenever conditions are favourable, and breeding is strongly correlated with rainfall. In most areas, however, reproduction does not occur during winter. They are known as prolific breeders and, although this rarely happens, they can carry up to 24 foetuses at once, under favourable conditions. Their gestational periods and the interval between litters are also relatively short, with litter sizes varying from 1â27 young (Monadjem et al. 2015). Due to their reproductive characteristics, multimammate mice populations are known to erupt under favourable conditions (Skinner & Chimimba 2005; Leirs 2013a, 2013b).
Ecosystem and cultural services: Mastomys spp. are indicators of poor ecosystem integrity as they become the dominant small mammals in a community during and after a disturbance (Avenant & Kuyler 2002; Avenant et al. 2008; Avenant 2011). They are also vectors of disease, where M. coucha is more susceptible to experimental plague infection than M. natalensis, and thus more implicated in plague epidemiology (Isaäcson et al. 1981; Venturi et al. 2004). Both species may act as seed dispersers, pollinators, and form a forage resource for carnivores, especially in post-fire landscapes, as they do not vacate the area following fires.
