Zooplankton composition of temporary pools within the lower Nata River channel, Botswana, during dry season

Abstract

The Nata River is a seasonal system situated in the semi-arid north-eastern Botswana, where rainfall is unpredictable and drought is  ommon. The annual flow of approximately 279 million cubic meters is regionally significant and it forms an important resource for people and biota in the region. Information on the biological diversity of the Nata River is scarce and, to our knowledge, no data is available on its invertebrate fauna. The aim of the study was to provide the first record of the aquatic microinvertebrates of the lower Nata River and examine likely influences of water quality parameters on its species diversity. Physical water quality parameters were
measured and zooplankton sampled along the lowermost reaches of the Nata River in August 2012. Salinity, TDS and electrical conductivity ranged widely between sites. Remarkable differences were evident in the zooplankton species composition between the four study sites, evidently related to prevailing levels of salinity.

Keywords: Calanoida, Cladocera, diversity, ephemeral river, physical parameters, Rotifera, water quality