Department of Wildlife Management

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Browsing Department of Wildlife Management by Author "Belmain, Steven R."

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    Does rodent management impact the distribution of rattus rattus and mastomys natalensis in village settings?
    (International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd., 2025-09-02) Mkomwa, Herieth; Makundi, Rhodes; Rija ,Alfan A.; Espinaze, Marcela P. A.; Belmain, Steven R.; Telfer, Sandra; Ponchon, Aurore; Selemani, Mwajabu
    Rodents are significant agricultural and public health pests in rural village settings. Traditional rodent control methods, such as poison baiting and locally made traps, are usually implemented by individual households when rodent abundance is high and often provide only short-term relief. Moreover, impacts on different pest species may vary, and changes to inter-specific interactions may have potential ecological consequences. This study examines the impact of community-wide daily trapping inside houses on the abundance and distribution of Rattus rattus and Mastomys natalensis in Kilombero District, Tanzania. In this area, R. rattus are typically found inside houses, while M. natalensis are found outside. Snap traps were deployed daily inside all houses in treatment villages, while control villages received no intervention. Rhodamine B (RhB) baits in exterior areas monitored the movements of rodents from these areas to houses. Intensive in-house trapping successfully reduced the abundance of R. rattus but not M. natalensis. M. natalensis increased its use of houses in treatment villages, with a significant rise in the proportion of individuals captured indoors and a significant increase in the proportion of these individuals that had consumed RhB compared to non- treatment villages. Our results suggest that M. natalensis benefits from the reduced presence of R. rattus by expanding its habitat use to include houses. These findings underscore the effectiveness of intensive trapping in controlling R. rattus but reveal potential ecological readjustments following community ecology principles, with habitat shifts by M. natalensis. This highlights the need for integrated, multi-species management approaches for sustainable rodent pest control.
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    Impact of contraceptive hormones on the reproductive potential of male and female commensal black rats (Rattus rattus)
    (International Society of Zoological Sciences, 2021) SelemanI, Mwajabu; Makundi, Rhodes H.; Massawe, Apia W; Mhamphi, Ginethon; Mulungu, Loth S.; Belmain, Steven R.
    The black rat is considered one of the world’s top pests. With increased restrictions on rodenticides, new alternatives to manage rats are urgently needed. Research on the use of contraceptive hormones, levonorgestrel (LE), and quinestrol (QU), have been evaluated against some rodent species, and this research is the first study to assess these on black rats. Hormones were incorporated into rodent bait at 10 and 50 ppm concentrations singly and in combination (EP-1). Groups of 10 animals of each sex were fed the baits over 7 days. Lower bait consumption was observed with slight body mass reductions. On dissection, it was observed that the uterus was in a state of edema and male reproductive organs weighed less with reduced sperm counts/motility. The 2 most promising baits, 50 ppm QU and EP-1, were used to assess impact on pregnancy and litter size. Pregnancy was reduced from 70% success when both males and females consumed untreated bait, down to 30% when males had consumed contraceptive bait but females had not, and down to 0% when females had consumed contraceptive bait, regardless of whether they had paired with a treated or untreated male. Litter size in the untreated pairs was 8 pups, but only 4 pups in those cases where the male only had consumed the contraceptive. Further studies should investigate how long the effect lasts and its reversibility. Field studies at the population level may also shed light on the practicality of using contraceptive baits for black rats in different habitats.