The effects of fire and grazing pressure on vegetation cover and small mammal populations in the Maasai Mara national reserve

An extensive study of vegetation changes as a consequence of fire and grazing pressure and their effect on small mammal populations inside the Maasai Mara National Reserve, Kenya, was carried out during May-June 1997. Comparison of vegetation maps from 1979 and 1998 suggested that vegetation in 46% of the Reserve area converted from shrubland to grassland, possibly as a result of fire and grazing pressure. We tested the hypothesis that in areas with high fire and grazing impact the population of small mammals was negatively affected. A low density of rodents was recorded in all habitats except in areas of human activity, where artificial resources are constantly present. Capture efforts were unsuccessful in grasslands. Our results confirm those of Norton-Griffiths (1979) and Dublin (1995), i.e. that fire and grazing pressure impact the vegetation of the Serengeti-Mara ecosystem and limit the natural regeneration of woodlands. This indirectly affects the small mammal community, which is limited in its long-term establishment.