This study quantifies habitat-specific small mammal patterns in the Caledon Nature Reserve, Free State province, South Africa. Small mammal community variables were correlated with an Ecological Index, the current method used to interpret habitat integrity in Free State nature reserves. It also reports on the seasonal abundance, species richness and diversity of small mammals present in specific habitats and addresses the most successful methods to sample these taxa, such as the duration of trapping to ensure unbiased sampling, and in which season should effort be concentrated to obtain optimal results. Our results support expectations that small mammal species richness increase with Ecological Index value, the number of specialist species in Free State grasslands increases with succession up to the climax phase, and that Mastomys coucha dominance acts as an indicator of habitat disturbance. It also supports previous studies that have shown a minimum trapping period of 3 days and nights, and best trap success and species richness at the end of autumn-early winter.
