Variation of small mammal populations across different habitat types in the Serengeti ecosystem

Abstract

This study investigated the abundance and diversity of small mammals in cultivated land (unprotected area) and wooded grassland in the Serengeti National Park (protected area) in the Serengeti ecosystem. Small mammal populations were sampled through capture-mark-recapture trapping techniques in March-April 2010. A total of 896 trap nights covering wet season, 9 species of rodents and 1 species of soricomorphs (shrew family) were captured. Overall, Multimammate rat Mastomys natalensis (Smith) was by far the most abundant rodent in cultivated land (28%) while inside the park, shrew Crocidura sp., was high in numbers (8%). A significantly higher abundance (trap success) of small mammals was obtained in the cultivated area compared to the national park (p < 0.01). There was also a significant difference in the two diversity indices between the cultivated areas (Hꞌ = 0.84) and national park (Hꞌ= 0.57) (p < 0.01).  The differences are probably habitat related i.e. types of crops cultivated in agricultural fields that might have attracted small mammals. There was moderately high similarity in the number of species caught in the two sites (Sørensen Coefficient (CCs) = 0.57), indicating that species composition did not vary significantly between the two sites with different conservation status. Overall high abundance and diversity in the cultivated areas may have resulted from the availability of food materials to granivorous small mammals which were majority.  This high abundance and diversity  outside the national park raises doubt as to whether the protected areas can still be considered as the most feasible approach of ensuring small mammals protection.

Keywords: agriculture, habitat, small mammals, Serengeti