Unravelling environmental and temporal patterns in South African Middle to Later Stone Age micromammals

Abstract

This study reviews and compares palaeoecological information derived from fossil micromammal assemblages spanning the last ~100 ka BP from South African Middle and Later Stone Age contexts. Multiple statistical approaches were used to assess how micromammal assemblage composition is structured across sites and whether broader chronological patterns can be recognised within the Cape region and the South African interior, two regions currently characterised by markedly different biomes. Furthermore, we explored the impact of local environmental heterogeneity, assemblage size and taphonomic processes on taxon abundance. Results indicate that micromammal composition is strongly structured by site identity in both regions, although the degree of within-site variability differs between them. The interior assemblages generally form coherent site-specific groups, whereas some Cape sequences show greater internal compositional variability. The ordination and clustering analyses provide only limited evidence for broader chronological organisation across sites. Palaeoecological reconstructions reveal that interior sites show pronounced shifts between forest and semi-arid weighted components, some of which align with climatic pulses inferred from local pollen records. In contrast, Cape sequences show variable degrees of internal environmental change, with some shifts corresponding broadly to climatic episodes such as the Last Glacial Maximum and, potentially, the 4.2 ka event. These results demonstrate that using micromammals as palaeoecological indicators may be more complex than previously appreciated as they provide reliable information on local palaeoenvironmental trajectories and important contextual evidence for human–environment interactions, but less consistently record coherent regional change through time.