Does Rodent Management Impact the Distribution of Rattus rattus and Mastomys natalensis in Village Settings?

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.