The seaweeds of De Hoop Nature Reserve and their phytogeographical significance

• Published in: South African journal of botany Vol. 56; no. 2; pp. 233 - 238
• Main Authors: Bolton, J.J., Stegenga, H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.1990
• Subjects: ambient temperature; biogeography; botanical composition; coastal plant communities; conservation areas; macroalgae; marine science; Phytogeography; seasonal variation; seaweeds; southern Africa; temperature; South Africa; southern Africa; temperature; seaweeds; Phytogeography
• ISSN: 0254-6299; 1727-9321
• DOI: 10.1016/S0254-6299(16)31091-2

Detailed collections of the seaweeds of De Hoop Nature Reserve have produced a list of 126 taxa (12 Chlorophyta, 23 Phaeophyta, 91 Rhodophyta). The reserve is in a poorly collected area immediately to the east of a major marine biogeographic discontinuity around Cape Agulhas. An analysis of the southern African distributions of these species reveals that they have predominantly warm-water affinities, with the majority of the species occurring throughout the south coast marine province, and 40% occurring east of Durban in true tropical waters. Very few of the De Hoop species (18%) grow on the west coast proper, despite the geographic proximity. These distribution patterns are explained by a consideration of the changes in ambient sea temperatures in the region. Gedetailleerde kolleksies van die seewiere van die De Hoop-natuurreservaat lewer ’n totaal van 126 taxons (12 Chlorophyta, 23 Phaeophyta, 91 Rhodophyta). Die reservaat is geleë in ’n gebied waar daar voorheen skaars versamel is, onmiddellik oos van ’n belangrike biogeografiese diskontinuiteit om Kaap Agulhas. ’n Nadere ontleding van die Suider-Afrikaanse verspreidingspatrone van hierdie spesies toon aan dat meeste van hulle warmwater-affiniteite het en oor die hele suidkus-seeprovinsie voorkom, terwyl 40% tot oos van Durban in tropiese water deurdring. ’n Baie lae persentasie van die De Hoop-seewiere (18%) groei aan die Kaapse weskus, ondanks die geografiese nabyheid. Hierdie verspreidingspatrone word verklaar vanuit die beskouing van die verskuiwinge in omringende seewater-temperature in die streek.