Mapping the distributions of ancient plant and animal lineages in Southern Africa.

Abstract

Southern Africa boasts a wealth of endemic fauna and flora. The focus of this study was to identify ancient biological lineages (faunal and floral lineages of Eocene age or older) endemic to southern Africa, and map the distributions of these lineages across the region. Seventy-four operational geographic units (OGUs) were delimited for distribution mapping. Twenty-seven ancient lineages were identified (seventeen plants and ten animals). For each of these lineages, individual distribution maps were generated. Total endemism and corrected weighted endemism maps were also generated collectively for all lineages. Four stages of cluster analysis were used to illustrate clusters of OGUs with similar lineage composition, using UPGMA agglomerative hierarchical clustering. Characteristic lineages were determined for clusters at each stage, and similarities between these clusters and previously recognised biogeographic units were discussed. A comparison between ancient endemic lineages and their sister lineages was conducted. Sister lineages were found to be often widespread and differed from ancient lineages in the types of habitat occupied and, in some cases, niche differences were noted. The mechanisms of ancient lineage survival in the region were investigated, and their importance for conservation in southern Africa emphasised.