Plants

Plants - Southern Africa : This group includes the huge variety of plant life, from tiny algae to massive Yellowwood trees. In fact, almost everything that is green. About 24 000 species and subspecies of flowering plant have been recorded as native to southern Africa.

This group includes the huge variety of plant life, from tiny algae to massive Yellowwood trees. In fact, almost everything that is green.

About 24 000 species and subspecies of flowering plant have been recorded as native to southern Africa. The number of non-native plant species is around 2000. There are many field guides to these species.

South Africa is also home to one of the six globally recognised floral kingdoms, the Cape Floristic Region. This kingdom, the smallest of all, is found exclusively within one country (South Africa) and is regarded as the ‘hottest’ of all biodiversity hot spots in the world.

Plants are intimately associated with climate and geology, and quite different groups of plants occur in the different biomes of southern Africa. Here we summarize them: more details can be found by the links.

  • The Fynbos Biome (aka Cape Floral Kingdom) contains 9000 plant species. These are mainly found in two distinct vegetation types.

    FYNBOS

    Fynbos occurs predominantly on well leached, infertile soils with rainfall between 600 to 800 mm per annum. Fire is a major influence and Fynbos must burn between 6 and 45 years of age in order to sustain species. After fire many species resprout, but the majority rely on fire to trigger regeneration from seed. Without fire, Fynbos dies and Forest and Thicket elements begin invading.

    The major structural types of Fynbos include Grassy, Restioid, Ericaceous, Proteoid, Asteraceous, and Scrub Fynbos. Most of these are assembled into landscape units typified as Sandstone, Sand, Quartzitic (or Arid), Alluvial, Limestone, Granite and Shale Fynbos.

    Fynbos communities are characterized by having three major plant families:

    1. The Cape Reed Family (Restionaceae). These are grass analogues (shrubby grasses) that carry fire in Fynbos. These are definitive and a 5% cover of restios defines Fynbos.

    2. The Heath Family (Ericaceae). The genus Erica is the largest genus in the flora with over 800 species.

    3. The Sugarbush Family (Proteaceae). These are the dominant overstorey in Fynbos and determine dominance patterns and succession.

    RENOSTERVELD

    Renosterveld is largely confined to fine-grained soils (mainly clays and silts) and tends to occur where rainfall is between 250 (rarely to 200 mm) to 600 mm per year with at least 30% of this rainfall falling in winter. Largely confined to shale geology, it does occur on granites and infrequently on other geologies.

    Renosterveld is characterized by the dominance of members of the Daisy Family (Asteraceae), specifically the species Elytropappus rhinocerotis (Renosterbos) from which the vegetation type gets its name. Grasses are also abundant and there is a high species richness of geophytic plants (bulbs).

  • The two forest biomes (Afrotemperate Forest and Eastern Lowland Forest) cover less than 0.25% of southern Africa, making it the smallest biome on the subcontinent. Forests are found at low altitudes along the coast to over 2 100 m above sea level. Forests are confined to fire-safe habitats, but may burn on a 200-1000 year cycle under extremely hot, dry and windy conditions.

    The canopy cover of forests is continuous, comprised of mostly evergreen trees and a multi-layered understory beneath. Some 649 woody and 636 herbaceous plant species are recorded from forests. Herbaceous plants, particularly ferns, are only common in the montane forests, whereas lianas and epiphytes are common throughout. The ground layer is almost absent due to the dense shade. On the edges of the patches one finds distinctive communities, the so-called fringe and ecotonal communities, which are able to tolerate fire.

  • The Savanna Biome, or Bushveld, is the largest biome in southern Africa, occupying 46% of the area. The biome is well developed over the Lowveld and Kalahari region of South Africa and is also the dominant vegetation in Botswana, Namibia and Zimbabwe. Savanna is characterized by a grassy ground layer and a distinct upper layer of woody plants. Where this upper layer is near the ground the vegetation may be referred to as Shrubveld; where it is dense as Woodland, and the intermediate stages are locally known as Bushveld.

    A major factor delimiting the biome is the lack of sufficient rainfall which prevents trees from dominating, coupled with fires and grazing, which keep the grass layer dominant. Summer rainfall is essential for the grass dominance, which, with its fine material, fuels near-annual fires. Almost all species are adapted to survive fires, usually less than 10% of grasses and trees get killed by fire. Even with severe burning, most species resprout from stem bases.

    Savanna grasses are dominated by C4-type grasses, which are at an advantage where the growing season is hot, but where rainfall has a stronger winter component, C3-type grasses dominate.

  • The Grassland Biome is found chiefly on the high central plateau of South Africa, and the inland areas of KwaZulu-Natal and the Eastern Cape. The topography is mainly flat and rolling, but includes the escarpment itself. Altitude varies from near sea level to 2 850 m above sea level.
    Grassland (or Grassveld) is considered to have an extremely high biodiversity, second only to the Fynbos Biome. As the name suggests, grasses dominate and trees are absent, except in a few localized habitats. Rare plants are found in the grasslands, especially in the escarpment area. These rare species are often endangered, comprising mainly endemic geophytes or dicotyledonous herbaceous plants. Frosts, fire, and grazing maintain the grass dominance and prevent the establishment of trees.
  • The Nama Karoo Biome is the second-largest biome in the region and occurs on the central plateau of the western half of South Africa at altitudes between 500 and 2000 m, with most of the biome falling between 1000 and 1400 m.

    The distribution of this biome is determined primarily by summer rainfall which varies between 100 and 520 mm per year. The dominant vegetation is a grassy, dwarf shrubland. Grasses tend to be more common in depressions and on sandy soils, and less abundant on clayey soils. Grazing rapidly increases the relative abundance of shrubs. Most of the grasses are of the C4 type and, like the shrubs, are deciduous in response to rainfall events.

    The amount and nature of the fuel load is insufficient to carry fires and fires are rare within the biome. The entire flora of the Nama Karoo is less than that of the Cape Peninsula

  • The Succulent Karoo Biome is primarily determined by the presence of low winter rainfall (20 and 290 mm per year) and extreme summer aridity, with temperatures in excess of 40°C. Fog is common near the coast, frost is infrequent, and hot Berg Winds may occur year round. The landscape comprises flat to gently undulating plains with some hilly and "broken" veld mostly situated to the west and south of the escarpment and north of the Cape Fold Belt.

    The vegetation is dominated by dwarf, succulent shrubs, of which the Vygies (Mesembryanthemaceae) and Stonecrops (Crassulaceae) are particularly prominent. Mass flowering displays of annuals (mainly Daisies Asteraceae) occur in spring, often on degraded or fallow lands. Grasses are rare, except in some sandy areas, and are of the C3 type. The number of plant species, mostly succulents, is very high and unparalleled elsewhere in the world for an area of its small size.

  • The Albany Thicket Biome is a closed shrubland to low forest dominated by evergreen, sclerophyllous or succulent trees, shrubs and vines, many of which have stem spines. It is often almost impenetrable, is generally not divided into strata, and has little herbaceous cover. Because the vegetation types within this biome share floristic components with many others and lie within almost all the formal biomes, Thicket types have been referred to as "transitional thicket". Thicket types contain few endemics, most of which are succulents of Karoo origin.

  • The Namib Desert has low numbers of plants, except after heavy rains, but many species are endemic and unusual.
  • Wetlands in southern Africa, such as estuaries, lagoons, and salt pans contain a few interesting, but widespread species. The Okavango Swamps contain spectacular reed and aquatic communities, but of low endemicity.
  • Seashore plants include the Red, Green and Brown Algae, including seaweeds and especially the Kelp “forests” that occur on the rocky coastlines.

Identification

Most people start by learning to identify the more obvious plants, moving on to the less obvious ones. Those specializing in trees rapidly move on to identification by leaves and other characters, such as bark, sap and thorns. Many flowers are easy to learn, and most people can recognize at least a Daisy or a Protea, and many an Orchid, Pea, Iris and Gum. But there are many more subtle distinctions to be discovered: Sedges and Grasses will provide a challenge to the really keen. The trickiest species may require close examination of flowers, fruits and leaves under a lens, but there are plenty of flowers that can be quickly and reliably identified by careful observation.

Plant identification usually starts with shape and colour of the flowers and leaves. In some cases you have to look out for quite small details to distinguish between groups of similar species, and you'll need to get used to the different growth forms and flower types found in each plant family. The habitat, location and date of flowering can also be useful clues.

Photography for identification

Try to get several photos, showing the flower and a typical leaf in reasonable close-up, plus a shot of the whole plant, and a wider angle shot to include its habitat or setting. For Peas take a close-up of the sepals, and for Daisies the bracts. Give some indication of size, either in the photo itself or by measuring the flower/leaf and recording that information.

Useful links – these are still UK and a great starting point. We hope to have South African links soon: if you can help please send links to the “contact us” page.

Plant recording and conservation

The Botanical Society of the British Isles collate records for plants from all over Britain, via a network of volunteer county plant recorders, as well as publishing authoritative identification guides and running training courses.

The leading plant conservation society is Plantlife International.

See also:

Seaweeds

See above for the British Phycological Society.

  • Seaweeds are recorded as part of the MarLIN project, which has online identification resources and recording forms.
  • The Marine Biological Association promotes research into marine life, publishes a range of journals and other resources, and runs events and courses.
  • Seasearch works with volunteer divers to record marine habitats, as well as running projects on particular species.
  • The Marine Conservation Society promotes the conservation of marine habitats and species.
26 Sep 2008
Tony Rebelo