Venter, et al. 2015. Published in Australian Journal of Botany. 63:341-352. A preliminary survey of the diversity of soil algae and cyanoprokaryotes on mafic and ultramafic substrates in South Africa , , Arthurita Venter A C, Anatoliy Levanets A, Stefan Siebert A and Nishanta RajakarunaA B AUnit for Environmental Sciences and Management, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa. BCollege of the Atlantic, 105 Eden Street, Bar Harbor, ME 04609, USA. CCorresponding author. Email:
[email protected] Abstract. Despite a large body of work on the serpentine-substrate effect on vascular plants, little work has been undertaken to describe algal communities found on serpentine soils derived from peridotite and other ultramafic rocks. We report a preliminary study describing the occurrence of algae and cyanoprokaryotes on mafic and ultramafic substrates from South Africa. Results suggest that slope and aspect play a key role in species diversity and community composition and, although low pH, nutrients and metal content do not reduce species richness, these edaphic features also influence species composition. Further, typical soil genera such as Leptolyngbya, Microcoleus, Phormidium, Chlamydomonas, Chlorococcum and Hantzschia were found at most sites. Chroococcus sp., Scytonema ocellatum, Nostoc linckia, Chlorotetraedron sp., Hormotilopsis gelatinosa, Klebsormidium flaccidium, Pleurococcus sp. and Tetracystis elliptica were unique to one serpentine site. The preliminary survey provides directions for future research on the serpentine- substrate effect on algal and cyanoprokaryote diversity in South Africa. Additional keywords: algae, cryptogamic ecology, serpentine geoecology, species diversity. Introduction species (Siebert et al. 2002;O’Dell and Rajakaruna 2011) and A range of soils can develop from ultramafic rocks depending on are model settings for the study of plant ecology and evolution climate, time, relief, chemical composition of the parent materials (Harrison and Rajakaruna 2011).