Cape Floristic Region – a global hotspot
Located at the southern tip of Africa, the Cape Floristic Region (CFR) is by far the smallest of the world’s six floral kingdoms. It has also been listed as one of 34 internationally recognised biodiversity hotspots. The CFR is one of the richest parts of the world in terms of floristic diversity and endemism. Around 9 000 plant species occur within an area of 87 892 km2 and around 70% of these are endemic, meaning that they are found nowhere else on earth. This degree of endemism is among the highest in the world. There are few endemics to Renosterveld vegetation alone, many of the species occurring in Fynbos as well. However, species endemic to the CFR comprise about one-third of Renosterveld plant species.
What is Renosterveld?
Along with Fynbos, Renosterveld is a dominant vegetation type in the CFR and the most threatened. While Fynbos grows on sandy nutrient-poor soils, Renosterveld tends to occur on more fertile and fine-grained shale, granite or silcrete derived soils where rainfall is a moderate 350 to 650 mm/year. At rainfall levels above about 800 mm/year soils are leached and Renosterveld vegetation becomes dominated by Fynbos elements. Where the rainfall is less than 250 mm it is replaced by one of the Succulent Karoo vegetation types. Both vegetation types are characterised by very high species diversity. When differentiating between Renosterveld and Fynbos, it is usually easiest to refer to habitat (which considers geology and rainfall) rather than species composition. A rule of thumb is that the typical Fynbos families Ericaceae, Proteaceae and Restios tend to be uncommon in Renosterveld.
The Bottelary Hills Conservancy flora is primarily made up of Renosterveld, characterized by the dominance of members of the Daisy Family (Asteraceae), specifically one species Renosterbos (Elytropappus rhinocerotis), from which the vegetation type gets its name. Although Renosterbos is the characteristic dominant, many other plants are also prominent – the Daisy Family (Asteraceae): Eriocephalus, Felicia, Helichrysum, Pteronia, Relhania; Pea Family (Fabaceae): Aspalathus; Gardenia Family (Rubiaceae): Anthospermum; Cocoa Family (Sterculiaceae): Hermannia; Thyme Family (Thymelaeaceae): Passerina. All these shrubs are characterized by their small, tough, grey leaves.
Another feature of Renosterveld is the high species richness of geophytic plants (chiefly in the Iris Family (Iridaceae) and Lily Family (Liliaceae), but also in the Orchid Family (Orchidaceae).
Various grasses can also be abundant. In fact, it is alleged that the high shrub cover is a result of continuous grazing. Early records suggest that Renosterveld had abundant grasses, and that game and Khoi cattle migrated over the region. With the establishment of European stock farmers, continuous grazing and the elimination of the diverse grazing-browsing fauna, the shrubby element was promoted. This theory is not universally accepted, but proponents argue to the sudden decline of hay near Cape Town in the early 1700’s, and the many historical records of early explorers claiming that Renosterbos was taking over and that grass was becoming scarce.