Influence of land preparation methods and vegetation cover on population abundance of Mastomys natalensis in Morogoro, Tanzania

A Capture-Mark-Release study was carried out in Morogoro, Tanzania, from April 1999 to April 2001 to investigate the effects of land preparation methods and cropping systems on population abundance of Mastomys natalensis in crop fields. Two land preparation methods (tractor ploughing; slash and burning) and two cropping systems (mono-cropping with maize; inter-cropping with maize and beans) were included in the study. The experimental design was a Complete Randomized Design with 2x2 factors, with two replicates. In slash and burn fields, rodent Population abundance and distribution were strongly influenced by vegetation cover regardless of the type of cropping system. Higher rodent population peaks occurred in dense vegetation cover in slash and burn relative to tractor ploughed fields. In contrast, there were no obvious associations between vegetation cover and population abundance in the tractor ploughed fields, particularly in the mono-cropping system. A negative correlation between vegetation cover and population abundance of M. natalensis was obtained in fallow land surrounding the crop Fields (r = -0.63; p <= 0.05). The results Show that the effect of vegetation cover on population abundance of M natalensis in crop fields is strongly influenced by the type of land preparation methods. Tractor ploughing and clearance of fallow land surrounding crop Fields could be a useful method to reduce the invasion of crops by M. natalensis.