Mastomys natalensis, the multimammate rat, causes serious problems in East-African agriculture. Pest management of this species can however be improved by taking into account population ecological knownledge. In this context, this Ph.D. project aims to study the spatial components of the population ecology of the multimammate rat, in maize monocultures and mosaic structures (small fields embedded in a matrix of fallow land). It is the intention to integrate these data into population-ecological models, so that these models can be used for predicting future rodent outbreaks, and simulating the efficiency of alternative control strategies.