The effects of different grazing regimes on the population dynamics of small mammals in the eastern cape

Four permanent trapping grids on predominantly sweet grass-bush study plots and subjected to different grazing regimes, were monitored from June 1991 to July 1992. The diversity and population density of small mammals on these grids were affected by the pattern of animal stocking and grazing types. Only two species, Rhabdomys pumilio and Mastomys natalensis were trapped. Sites undergoing rotational resting, and those grazed by cattle, supported more rodents than constantly grazed ones and those grazed by sheep. Other environmental factors, excepting drought, had lesser impacts on the small mammal populations. The seasonal recruitment and breeding of the small mammals was affected by grazing whereas sex ratios appeared unaffected. The drought of 1991-92 was obviously a contributory factor to low small mammal numbers.