Taxonomic status and conservation importance of the avifauna of Katanga (south-east Congo Basin) and its environs

Abstract

A re-appraisal of published knowledge of the birds recorded in Katanga (Democratic Republic of Congo) focussed on the status of 56 taxa, to reveal a high endemism (14 species of a total of at least 642). In addition, 33 taxa were also revealed as possible south-central African endemics but need thorough taxonomic appraisal. All are geographically isolated populations, with ranges restricted within, or centred on, Katanga. These taxonomic enigmas await thorough re-appraisal. The majority of these newly-recognised Katanga endemics were traditionally lumped into polytypic species in classifications based on the Biological Species Concept (BSC). These synonymised taxa have therefore been ignored repeatedly in recent conservation assessments of African birds. This failure illustrates how the BSC can obfuscate patterns of species diversity in its classifications, which lump evolutionarily-distinct lineages into imprecisely-diagnosed taxa. An unfortunate historical legacy is to forget that a distinct population exists, after it has been classified as a subspecies, synonym or race in a polytypic species. These discoveries exemplify the research opportunities that Katanga's birds present for avian systematists. The assessment of any taxon of Afrotropical birds is hamstrung by the fragmented state of taxonomic information in the literature. This constraint impinges on any taxonomic study of any African avifauna and will be removed if an accessible database summarises all published taxonomic information in an exhaustive classification, accounting for synonomy, authority and context of each described taxon. Availability of such a complete taxonomic catalogue is quintessential if phylogeographic and systematic research is to determine precisely which populations have been named, and where these occur. This is critical to compile refined biogeographical knowledge for scientifically-sound conservation plans and actions. Objective evaluation of the endemism of the Katanga avifauna requires complementary datasets for other regional avifaunas across Africa. Their unavailability exemplifies the gravity of this taxonomic impediment, given the immense effort involved in compiling and comparing such fine-grained taxonomic data. Deficiencies aside, the data compiled in this review point to a recent suite of speciation events (most likely late Cenozoic) centred on Katanga. The strident biogeographical signal in these data emphasises the hitherto poorly-appreciated significance of Katanga's unique and rich biodiversity, which ranks alongside better-known sites in Africa of global conservation importance.

Ostrich 2006, 77(1&2): 1–21