Browsing by Author "Mahlaba, T. A."

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Experimental treatment-control studies of ecologically based rodent management in Africa: balancing conservation and pest management
(CSIRO PUBLISHING, 2012) Taylor, P. J.; Downs, S.; Monadjem, A.; Eiseb, S. J.; Mulungu, Loth S.; Massawe, A. W.; Mahlaba, T. A.; Kirsten, F.; Maltitz, E. V.; Malebane, P.; Makundi, Rhodes H.; Lamb, J.; Belmain, S. R.
Context. Rodent pests severely affect crop production, particularly in monocultures where one or two rodent pest species dominate. We predict higher species richness of native small mammal species in more heterogeneous mosaic (crop–fallow–bush) subsistence agro-ecosystems in Africa. Conservation and agro-ecological imperatives require that such diverse natural communities should be maintained and may benefit crop protection through limiting domination of pest species. Ecologically based rodent-management alternatives to rodenticides are urgently required and one such method (community trapping) is herein advocated. Aims. To provide baseline information on rodent and shrew communities in agro-ecosystems in three African countries and to demonstrate efficacy of ecologically based rodent management (EBRM) in Africa (e.g. community household trapping). Methods. Removal-trapping in a variety of agro-ecological habitats provided accurate small-mammal species lists. Intensive kill-trapping by rural agricultural communities was carried out experimentally where the efforts of communities were scientifically monitored by kill-trapping to measure impact on rodent numbers and the levels of post-harvest damage to stored grains. Key results. Our study revealed a high diversity of endemic species in agricultural habitats in Tanzania and Namibia (but not Swaziland) and the existence of undescribed and possibly rare species, some of which may be at risk of extinction from unchecked habitat transformation for agriculture. Treatment-control studies showed that communities in three African countries could effectively reduce pest rodent populations and rodent damage by intensive trapping on a daily basis in and around the community. Conclusions. Community trapping reduced pest rodent populations and damage to stored grains. Unlike the use of indiscriminate rodenticide, this practice is expected to have a negligible effect on beneficial non-target rodent and shrew species. Implications. Ecologically based rodent management approaches such as community trapping will conserve beneficial non-pest rodent communities and ultimately improve crop protection.
Impact of crop cycle on movement patterns of pest rodent species between ﬁelds and houses in Africa
(CSIRO Publishing, 2011) Monadjem, A.; Mahlaba, T. A.; Dlamini, N.; Eiseb, S. J.; Belmain, S. R.; Mulungu, L. S.; Massawe, A. W.; Makundi, Rhodes H.; Mohr, K.; Taylor, P. J.
Context. Rodent pests can have severe impacts on crop production in sub-Saharan Africa. In particular ,the multimammate mouse Mastomysnatalensis severely damages agricultural crops in southern and eastern Africa ,leading to signiﬁcant losses. Both its population ecology and breeding biology have been studied in agricultural and natural habitats. Population numbers erupt depending on the timing and amount of rainfall and may reach plague proportions, especially in agricultural settings, where it may become a serious pest. However, the ecology of this species, in particular its interactions with other species within the context of human settlement ,is poorly understood. It may occasionally enter houses, but the degree to which it does so and the factors inﬂuencing this movement are not known. Aims. We investigated the relationship between Rattus spp. and M. natalensis entering buildings in an agro-ecological setting. We predicted that M. natalensis would enter houses more readily when food availability was lowest in the surrounding ﬁelds, and when the larger Rattus spp. were absent. Methods. We followed 40 individuals ofM.natalensis in Swaziland and Namibia by radio-telemetry. Mice were captured in maize ﬁelds within 50m of a home stead and ﬁtted with radio-transmitters at three different times corresponding to different stages of crop development: pre-harvest, post-harvest and pre-planting. To corroborate the ﬁndings of the telemetry study, a non-toxic marker, rhodamine B, was mixed with standard bait and left at bait stations inside houses in 10 homesteads in Swaziland and Tanzania. Key results. Mice remained in the ﬁelds during the entire period of study in Swaziland, but entered buildings in Namibia during the post-harvest stage, which may represent a period of food shortage for these mice in the ﬁeld. Rodents captured after baiting with rhodamine B demonstrated that Rattus spp. predominated within the houses. A small number of rhodamine B-marked M. natalensis were captured outside the houses, the proportion declining with distance away from the houses. Conclusions. These results suggest that in a typical rural African setting dominated by subsistence agriculture, Rattus spp. (when present) competitively exclude the smaller M. natalensis from entering houses. Implications. Interactions between rodent pest species may be important in determining which rodent species enter houses in rural African landscapes. Consideration of such interactions may play an important role when developing pest management strategies.