Abstract

HOLMES, M.; CAMPBELL, E.E.; DE WIT, M.  and  TAYLOR, J.C.. Preliminary checklist for freshwater diatom species of the Karoo, South Africa. Bothalia (Online) [online]. 2025, vol.55, n.1, pp.1-19. ISSN 3078-8056.  https://doi.org/10.38201/abc.v55.3.

BACKGROUND: Species checklists are a way in which local biodiversity can be monitored. There is no readily accessible database or checklist of diatom flora of South Africa. This publication gives an account of the diatom taxa encountered during two survey projects (2010-2012 and 2015-2017) within the Eastern Karoo. OBJECTIVES: This list has been compiled to allow for: (1) comparisons with future research in the geographical area; (2) comparison with ecological data from other countries; (3) monitoring the occurrence of new species; and (4) documentation of the disappearance of 'clean water' indicator species. METHODS: Sampling took place in the area known as the Eastern Karoo during the two projects. Samples were scrubbed, cleaned and checked for live cells. Permanent slides were made and diatoms identified using light and electron microscopy. Each species was assigned a four-letter code from the software Omnidia version 6. RESULTS: A total of 474 taxa were encountered, some of which are, as yet, un-described. This list contains taxonomic rank currently assigned as well as the Omnidia codes as this software is commonly used throughout the world and in South Africa for diatom assessment protocols. CONCLUSION: The National Environmental Management: Biodiversity Act does not cover the protection of diatom species, which can only realistically be conserved if the habitats in which they are found are also conserved. This species checklist can serve as a catalyst for a move towards legislation accepting the use of diatoms as bioindicators for freshwater within South Africa.

Keywords : diatoms; freshwater; bioindicator; Karoo.

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