The flora of the Bontebok National Park in regional perspective

Abstract

Six-hundred-and-fifty plant species from 280 genera and 85 families have been recorded as indigenous to the Bontebok National Park (BNP), which lies 5 km south of Swellendam, in the Western Cape. Twenty-nine of these plant species are globally threatened with extinction and another 23 are species of conservation concern. Three species ( Aspalathus burchelliana, Diosma fallax, Erica filamentosa) are endemic to the park. The Asteraceae, Iridaceae and Fabaceae ranked high as speciose families, in line with the Cape Floristic Region (CFR) as a whole, while the Asphodelaceae, Crassulaceae, Poaceae and Cyperaceae were overrepresented, and the Rutaceae, Proteaceae and Ericaceae underrepresented at BNP. The largest genera were Aspalathus (19 species), Crassula (17), Pelargonium (16), Erica (15), Oxalis (12), Moraea (11), Helichrysum (10) and Hermannia (10). Geophytes were the dominant growth form (23% of species recorded), followed by dwarf shrubs (20%), herbs (16%), graminoids (15%), shrubs (13%), succulents (8%), trees (3%) and climbers (2%). Forty alien plant species were recorded (likely an underestimate of true numbers) with the Poaceae most speciose and arguably the biggest invasive threat at the park. With 20 plant species/km 2, the flora of BNP is richer than expected based on its location within the south-eastern CFR. Similarity with floras of other lowland and montane protected areas in the region is low (< 33% and < 20% respectively), demonstrating that a large component of BNP's flora is not conserved elsewhere. Within a landscape context, BNP forms part of a cluster of connected core sites for Renosterveld conservation. This work confirms the high importance of BNP for flora conservation nationally and even globally.