Rodent population fluctuations in three ecologically heterogeneous locations in northeast, central and southwest Tanzania

Rodent population fluctuations and breeding patterns were investigated at localities in South-west, Central and North-east Tanzania. The three localities are ecologically heterogeneous ill vegetation types, rodent species diversity, rainfall pattern and altitude. Capture -Mark-Release studies were conducted in 2001-2003 to compare rodent species composition and Population trends. In North-castern Tanzania, species composition is diverse and includes Mastomys natalensis, Lophuromys flavopunctatus, Grammomys dolichurus, Arvicanthis nairobae, Praomys delectorum and Mus sp.. Five species were recorded in South-western Tanzania namely, M. natalensis, Graphiurus murinus, Saccostomus elegans, Tatera leucogaster and Steatomys pratensis. In Central Tanzania M. natalensis was dominant, but a few Lemniscomys griselda were captured. Rodent abundance fluctuations were distinctively seasonal, especially for M. natalensis in the three localities and T. leucogaster in South-west Tanzania. In North-eastern Tanzania, L. flavopunctatus, G dolichurus, A. nairobae and P delectorum had low, but relatively stable Populations throughout the year. Ill South-west Tanzania, population peaks of M. natalensis and T leucogaster were reached in the dry season (June-September). In Central Tanzania, breeding of M natalensis was seasonal, with highest population abundance during July-November. Female M. natalensis were reproductively active in January-May and males had scrotal testes in December-June. No males were sexually active during July-November. Female T leucogaster in South-western Tanzania were reproductively active during November-April/May whereas sexually active males appeared in the Population during November-March. In view of the observed rodent population fluctuations and breeding patterns, recommendations are given for pragmatic rodent control in South-west and Central Tanzania and for plague in North-eastern Tanzania.