SPATIAL DYNAMICS OF MASTOMYS-NATALENSIS IN A FIELD-FALLOW MOSAIC IN TANZANIA

The population dynamics of Mastomys natalensis rats is reported for a 3-year study of monthly CMR-trapping in a small scale maize field-fall ow land mosaic in Tanzania. The seasonal evolution of rodent presence was the same in both habitat types and it was not affected by agricult ural activities in the fields. About one week after planting, there wa s a short increase of rodent captures in the maize fields, but this di sappeared again after a few days. Recolonisation of fields was achieve d very fast after a rodent control operation. Radiotelemetry indicated that many individuals were active in the maize field as well as in th e fallow land. We concluded that, in a small scale set-up, the field a nd fallow land rodent populations are not separated and the latter sho uld not be considered as necessary refuges. This renders several roden t control approaches unsuitable.