A hotspot of large branchiopod diversity in south-eastern Zimbabwe

Abstract

Large branchiopods are considered threatened across much of their global range. However, because several regions, including Zimbabwe in general and its south-eastern lowveld in particular, remain largely unstudied, interpretations of species distribution patterns are often based on limited data. A detailed study of large branchiopods was carried out, with repeated sampling of 36 seasonal pans, in 2004–2008 in the Save Valley Conservancy, south-eastern lowveld. Sixteen large branchiopod species were collected, comprising eight Anostraca, one Notostraca, two Laevicaudata, four Spinicaudata and one cyclestherid species, representing 33% of all species known in southern Africa. Most species were new records for Zimbabwe. The enigmatic morphotype, Streptocephalus cf. bidentatus, was encountered for the first time in Zimbabwe, presenting an opportunity to resolve its taxonomic status. Streptocephalus wirminghausi, a species endemic to Zimbabwe, was also recorded. Large endorheic pans had higher species richness (an average of eight species) than small endorheic pans (average of six species), whilst floodplain pans housed fewest species (average of four species), probably due to predation by fish after floods. Since regional diversity and coexistence levels in the Save Conservancy were high, compared to other regions, this area should be considered a hotspot of large branchiopod diversity.

Keywords: Anostraca, coexistence, temporary ponds, Notostraca, southern Africa, Spinicaudata

African Journal of Aquatic Science 2014, 39(1): 57–65