African Wildlife & Environment Issue 84 2023

FAUNA, FLORA & WILDLIFE

nutrients). Forests also occur in localized sites where a good litter layer is able to accumulate (so elevating the plant-available nutrient content in the pedoderm (= those upper few centimetres of soil that is biologically the most active).

Meanwhile the sandstone mountains to the north also became fractured as rivers like the Umtamvuma, Mdloti, Mgeni, Tugela and Pongolo cut their way through them on their way to the Indian Ocean.

The Umtamvuma River has cut a deep gash through the quartzite flats near Oribi Gorge. Typically the flats are covered in a grassy heathland and the steep slopes to the river are forested

Once the area of the CFR was limited to ‘the Cape’, and all the species in the south were isolated genetically in a much smaller region, particularly the heathland elements, giving them the opportunity to speciate locally when climates changed over time. If one now considers where there are non heathland tree endemics in the CFR , they are basically confined to three primary habitats. The first in the now isolated patches of Afromontane Forest and/or in Scrub-forest or on Rocky outcrop outliers; other habitats are Wetland and/ or Riverine species, and finally a few species are restricted to the third habitat that is areas of Coastal sands. Now for the fun part… CRF endemics in Afromontane Forest islands Firstly, we have to briefly consider the basic environmental drivers of this vegetation type. Forests are on soils that, relatively speaking, have a fairly high clay content (so generally sandy soils containing some shale and/or granite component that provides a little clay content - and thus they contain slightly more plant-available

The forest in Skeleton Gorge is an excellent example of habitat selection of Afromontane Forest in a fire shadow. Below the outcropping quartzites the geology is granite, and thus above the granite the forest is tightly restricted to the deep ravine and mostly on the south-facing side. The last fire in this area was in 1970 - and since then the forest has been able to aggressively expand into the adjacent fynbos. Kirstenbosch’s rainfall is ~1,200 mm p.a

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