A Biodiversity Hotspot
The Baviaanskloof has been designated as a World Heritage Site because of its outstanding natural beauty and globally important biodiversity. The uniqueness of the area is that it is geographically located in a transition zone between various ecosystems. It hosts seven of the eight national biomes, which are: Fynbos, Nama Karoo, Succulent Karoo, Subtropical Thicket, Grasslands, Savannah and Forest. Additionally, it is home to three globally recognized hotspots: Maputaland-Pondoland-Albany, Succulent Karoo and the Cape Floristic Region. The Desert biome and the Indian Ocean Coastal Belt are the only ones that are lacking. The Fynbos biome has the largest extent (46%), followed by Albany Thicket (27%) and Succulent Karoo (12%). The Fynbos biome has its major occurrence on poor and well-drained soils in the mountains, with a preference for south-facing slopes. Albany Thicket is bound to somewhat drier and more fertile soils in fire protected valleys; it is found in the eastern parts of the area (where seasonal differences are lower than in the west), as well as in the relatively dry northern mountain ranges. The Succulent Karoo occupies semi-arid flats in the north of the Mega Reserve, with its major extent in the Little Karoo.The diversity of biomes of the area creates a high degree of habitat complexity which leads to a wildlife community characterized by diversity and high endemicity. Although large mammal species have become extinct in the area, reintroductions aimed at restoring the original community have been largely successful, especially in the nature reserve.The remarkable variation in vegetation types is associated with the wide geological variety and strong climatic gradients at relatively short distances. Topography ranges from mountain tops to deep valleys (kloofs), soils from nutrient rich to nutrient poor, and climate from dry conditions to very wet conditions. When zooming in to a more micro scale, further diversity can be recognized, represented by a whole set of plant communities, each recognized by its own floristic composition. The richness of the flora can be illustrated by a variety of statistics. For example, in only the Little Karoo almost 3,200 species are found. Euston-Brown (2006) distinguished 59 vegetation units, including estuaries and wetlands, sand dunes and duneveld, temperate, afromontane and subtropical forest, valley and spekboom thicket, grassy, restioid and arid fynbos, sweet and sour grassland, different types of succulent and nama karoo (e.g. Apronveld, Gannaveld and Doringveld), as well as transitions to renosterveld, strandveld and savanna. Most of these types are zonal, which does not imply that the azonal ecosystems are less important. The latter, for instance, include freshwater wetlands along the rivers, that play an important role in the water management of the whole area.
Authors: Joop Schaminée & John Janssen (2012)