BIOMES OF SOUTH AFRICA
Polokwane
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Johannesburg
Upington
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Bloemfontein
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Durban
Biomes
Forest
Fynbos
Grassland
Nama Karoo
Savanna
Succulent Karoo
Thicket
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Cape Town
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Port Elizabeth
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E
900 Kilometers
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Dominant life forms in SA biomes:
Savanna:
• Herbaceous perennial
• Woody perennial
Grassland:
• Herbaceous perennial, biennial
Forest:
• Woody perennial
Fynbos:
• Woody perennial,
• Herbaceous perennial,
• Shrubs
Succulent Karoo
• Shrubs
• Succulents
Nama Karoo
• Herbaceous perennial
• Shrubs
Desert (see the first map of SA biomes a few pages back)
• Annuals
• Below ground
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More in detail when we look at each biome separately – this is just to give you an idea of the
different life forms in the different biomes.
The other thing I want you to understand is that dominant forms occur in particular regions
because of the advantage they have in that particular environment.
Remember how we said that climate does influence the distribution of biomes? Well that
does not only apply globally but to South Africa’s biomes as well. Look at the following
maps:
Mean annual precipitation: for example you note how savanna is localised to areas that are
dry but not too dry; too little rain and it becomes karoo, too much and woody vegetation
begins to dominate.
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Variation in precipitation: high variation  karoo; low variation grassland, thicket and
forest; savanna  intermediate.
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You can see from previous figure how we can distinguish between areas with summer
rainfall encompassing mainly savanna, grassland, forest ; very late summer rainfall in the
Nama Karoo and winter rainfall in the succulent Karoo and fynbos
Let’s now look in more detail at each of the South African biomes with the focus being on
their vegetation characteristics and plant adaptations to the prevailing environmental
conditions, plant and animal diversity, some charismatic species (both plants and animals)
and the impact humans have in each.
FYNBOS
The two major vegetation types in the region are fynbos and renosterveld.
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The fynbos, above all the mountain area part, is quite well conserved, with several
conservation areas having been established.
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Renosterveld is limited to low lying fertile areas. It once hosted herds of herbivores
and their predators. Most large animals (including the bluebuck, cape lion, quagga
and Cape warthog) where shot to extinction by 1800. Less than 5% of coastal
Renosterveld remains today: the rest has been transformed to produce wheat and
wine.
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This biome is one of the 3 biodiversity hotspots in SA. Remember the definition of
biodiversity hotspot: an area with high species diversity, a high concentration of
endemic species and a large number of endangered and threatened species and
under serious threat. The other two biodiversity hotspots are the Succulent Karoo
and the Maputuland – Pondoland – Albany centre of endemism.
FYNBOS ECOLOGY
Flora
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Incredible diversity (9000 spp, 70% endemic)
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Winter rainfall, summer drought.
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Nutrient poor soils
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FIRE is key
Fire in the fynbos
Most plants are geared towards coping with fire! They flower and produce seed before the
fire; the seed release is largely stimulated by fire; germination: cued by chemicals in smoke
Season: Autumn fires
Fauna
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A part from the Rinosterveld, where large animals used to live because of the high
soil fertility and hence good forage quality but that are now extirpated, in the
mountain areas, even historically, there are few large animals. As a consequence of
poor soils the vegetation is of scarce nutritive quality for herbivores
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Many small:
– Baboons, many rodents, many reptiles
– High diversity of frogs (1/2 of SA spp, 29 endemic!)
FYNBOS THREATS
Despite being one of the 3 biodiversity hotspots of global importance the fynbos is highly
threatened. More than 20% of plant species are threatened with extinction.
Major threats:
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Habitat transformation (clearing of veg for housing and agriculture like wheat, fruit
and vines) in the low lying areas
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Afforestation (commercial forestry) above all in mountain areas
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Invasive aliens above all in the mountains. These outcompete the indigenous plants.
FYNBOS: FLAGSHIP SPECIES
Marsh rose:
• Member of the Protea family
• Only on south slopes of Kogelberg Biosphere Reserve
• In 1968 only 10 plants were left. Accordingly protection measures were taken and
research undertaken. Results showed that an appropriate fire regime was the key to
the survival of this species. As consequence, fire policies were modified. One fire
resulted in more than 1,800 plants germinating
• Population numbers are now maintained by burning different colonies on different
cycles
Bontebok
• Endemic to the renosterveld
• Threats include:
• Habitat loss due to agriculture
• Encroachment by alien vegetation
• Hybridization with blesbok
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•
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Historically number got low because of over hunting
Strict protection since the 1940s
Current population more than 2,500
Stag beetle:
• All species in the genus are wingless and have very localized distribution on high
mountains in the fynbos biome.
• Highly prized by collectors because of their rarity
• Only African insect group to be CITES listed which is likely to increase the black
market
Micro frog (watch the video):
• Also called Cape Flats frog
• Its less than 2 cm long
• Most threatened lowland amphibian in SA
• Fragmented distribution of less than 10 square km
• Endemic to certain fynbos wetlands
• Most of remaining habitat in unprotected private land
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SUCCULENT KAROO
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The succulent Karoo is one of only two arid hotspots in the world (the other one is
the Horn of Africa)
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Confined to the western parts of Africa and extends into Namibia; areas with limited
winter rainfall and hot, dry summers. Rainfall about 250 mm / year
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High levels of endemic plants (69%) – richest variety of succulents on earth. These
drought-adapted plants have thick, fleshy leaves or stems for water storage.
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High level of endemic fauna as well: a number of specialized insects feed only on
specific local plants + endemic mammals (small ones) and reptiles.
•
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High number of rare and red data plant species
ECOLOGY
Species living here are adapted to arid environments.
Animals
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They either migrate in the hottest months (e.g. antelopes, birds) or they hide under
the ground (e.g. Meerkats, desert rain frog that survives by hiding under the dune
sand).
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Mobility is the secret of success for antelopes that move nomadically between
rainfall patches, away from adverse veld conditions because of drought. Treks are in
the direction of localised rainfall patches and new growth.
Plants
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Ephemerals (annuals):
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Ephemeral means transitory or quickly fading.
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These are plants that avoid drought and temperature extremes by
completing their lifecycle in just two or three weeks. Shortly after a period
of extensive rain, the seeds germinate, grow very quickly, and bloom. They
survive the dry and hot season through seed dormancy.
•
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Geophytes (Seasonal bulbs - perennials):
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Above ground portion of plant dies off during the dry season
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Storage organ are left in the soil storing food reserves and the plant is able to
re-sprout when environmental conditions are appropriate again
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Therefore are able to have perennial life cycles
Other plants are able to tolerate the stress e.g succulents
These drought-adapted plants have thick, fleshy leaves
or stems for water storage
Largest diversity of succulents in the worlds
THREATS
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Farming (wheat, potato, winter grazing for stock)
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Mining (largest diamond mines in the country), especially for diamonds and heavy
metals.
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Ecotourism (massive floral displays + collecting & artificial fields = threat)
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Inadequately represented in protected areas, but the Succulent Karoo Ecosystem
Planning Strategy (SKEP) was launched, which aims at rectifying the situation
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FLAGSHIP SPECIES
Namaqua Pollen Wasp
• SA has the highest diversity of pollen wasps in the world
• Often they are the sole pollinators of the flower they visit
• Disappeared from most areas due to land degradation
• Three isolated, refuge populations, in three localities in Namaqualand
Desert Rain Frog
• Survives by lying under the dune surface during the day. Here moisture from periodic
coastal fog is trapped beneath the surface of the dunes.
• Serious threat: strip mining for diamonds that entails systematic removal of all
surface soil
Granulated thick-tailed Scorpion
• Size: 11.5 cm (large!)
• Most venomous scorpion spp in SA
• Common in the drier Succulent Karoo
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NAMA KAROO
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The Nama Karoo makes up 25% of the land surface of SA
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Hot summers cold winters – extreme temperature ranges and unpredictable rainfall
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Wide variety of life forms: small trees (drainage lines and rocky hillsides), low shrubs
mixed with grasses, succulents, geophytes and annual forbs (plains)
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Grassiness changes in time, increasing in times of above average summer rainfall and
decreasing in periods when summers are drier than winters.
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Termites are important as they are responsible for much of the nutrient cycling in
the Nama Karoo and are also the staple food of many other species
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Centre of endemism for ground dwelling birds
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Ranches, industrial mining, citrus, olives, deciduous fruit and wine grapes are farmed
in the major river valleys
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Threats to the fauna include overgrazing (desertification and increase of unpalatable
shrubs) and land transformation by mining, agriculture (grapes, fruit, grains e.g.
Orange river valley) and development
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Springbok where the inhabitants of the region: there has been extensive removal of
springboks to alleviate competition with livestock  change in dynamics
•
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Less than 1% of this area is conserved in formal areas
FLAGSHIP SPECIES
Riverine Rabbit
• Endemic to the Nama Karoo, it is the most endangered mammal in SA
• In the 1950s, cultivation of wheat in particular, led to complete alteration of an
estimated 60% of the original habitat
• No riverine rabbits are found in formally protected areas
• Total pop size < 1,500 individuals
The Karoo Padloper
• There are 43 land tortoise species in the world: ¼ are in SA
• Small, cryptic, rock dwelling, 100 mm in length
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Endemic
Threat: poor veld management (over-grazing)
Namaqua Sandgrouse
• Adapted to desert existence, carrying water to its chicks in specially designed breast
feathers
• Numbers have decreased since the 1940s
• Results of increased dispersion as a consequence on increases numbers of artificial
water points
• Breeding success is now < 10% because of egg predation  predators can survive
arid conditions because of the increased number of water points
• The population may well not be able to survive in the long term
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FORESTS
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Smallest and most vulnerable biome in SA
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Small, isolated remaining areas (< 500 ha) making them highly vulnerable to impacts
from surrounding land use
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Forests are restricted to frost-free areas
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Main threats: clearing, strip-mining, urban development, uncontrolled harvesting,
aliens
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Distinguished between:
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Afromontane forest (oldest one)
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Coastal forest
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Sand forest
Coastal Forest (eastern Cape, KZN):
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Where rainfall is > 700 mm/year and mostly in areas with summer rainfall.
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Economic use: Trees are utilized mainly for firewood and structural timber.
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The main threat is due to holiday resort expansion along parts of the coastline, dune
mining in some limited localities, and the use of firewood, building materials and
muti plants in rural regions
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Conservation status: Coastal Forest is well-conserved in some reserves in KwaZuiuNatal and Eastern Cape.
Afromontane forest
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Along the mountain chains (altitudes from sea level up to 1500 m) from Northern
Province through Swaziland and KwaZulu-Natal to Western Cape.
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Rainfall is generally greater than 700 mm per year, and can exceed 2000 mm in some
regions, occurring throughout the year, or during winter or summer, depending on
the region. Temperatures can be extreme in some of the higher altitudes where
snowfalls may occasionally occur.
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The forest is confined to kloofs and gullies, water is a key limiting factor. However,
Afromontane Forest would certainly spread into both grasslands and fynbos were it
not for fires - all forest patches are in fire-safe habitats with the largest stands
occurring in the moist valleys of the Garden Route where they are protected by the
sea and the Cape Fold Belt mountains.
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Economic use: timber, firewood
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Conservation status: Afromontane Forest is well conserved in a number of areas, and
many stands are safe from exploitation by their isolation in remote areas.
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Plantations of pine threaten the water supply to the indigenous forests in many
regions.
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Afromontane forests are older and more species poor than the younger and more
tropical coastal forests. Most endemics are in the coastal forests but these are also
the most threatened ones.
Sand forest
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•
•
•
•
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Confined to the tropical and subtropical coastal belt of KwaZulu-Natal as far south as
Port Shepstone, although some elements may reach the Great Kei River. It is only
extensive in the north-east of KwaZulu-Natal.
Hot tropical with summer rainfall
The tropical climate could explain the differences in structure and species
composition between this and the other forest types. Species diversity declines
southwards, as the number of more tropical elements decreases.
Economic use: Mainly cleared for firewood and grazing.
Conservation status: About half of the forests have been destroyed, but some
substantial stands occur in nature reserves. The Dukuduku forest, Ndumu and Mkuze
Game Reserves, Sodwana State Forest and Tembe Elephant Park contain examples of
Sand Forest.
Indigenous forest of Dlinza, next to Eshowe in Zululand. Note the small fragment,
surrounded by a developing town and agricultural fields
FORESTS: FLAGSHIP SPECIES
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Samango Monkey
• Coastal belt forest of KZN and afromontane forest of Limpopo to Eastern Cape
• Population decline because of fragmentation of forest patches hence limited
movements
• Now sufficient forest is conserved to ensure their survival in the medium term
Cape Parrot
• Endemic
• < 500 birds in the wild
• Depends on yellowwood trees for feeding, roosting and nesting sites
• Threats: forest degradation, logging of yellowwood trees, poor breeding success,
removal from wild for cage bird trade, beak and feather viruses
Pink Velvet Worm
• Living fossils – have changed very little in more than 400 million years
• Only occurs in one Forest in southern KZN
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THICKET
Another highly fragmented ecoregion is the thicket biome
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Characterised by a sparse to dense, spiny, evergreen shrub vegetation, with varying
proportions of tree cover.
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The thicket biome is an area of transition and contains elements of all other biomes
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High carbon dioxide storage ability  important area to buffer the effect of climate
change
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Because it contains elements of all 7 other biomes, it will provide genetic material to
buffer the effects of climate change  it has to become a conservation priority.
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Part of this biome is the Maputaland – Pondoland – Albany biodiversity hotspot. Do
you remember what the other two hotspots present in SA are?
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The thicket biome in the Eastern Cape has the most species-rich formations of
woody plants in SA. So not the forest but the thicket is richest in woody plants.
THREATS
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Transformation for agriculture
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Urbanization
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Invasion by alien vegetation
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Clearing and overgrazing is of main concern. Extensive clearing and overgrazing have
led to large areas becoming totally transformed or degraded, in some areas leading
to desertification. By 1981, 9% of this biome had been permanently transformed an
50% was seriously overgrazed.
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Addo Elephant National Park is an example of an area conserving this biome.
However this biome is underrepresented in conservation areas, with only less than
5% being protected.
FLAGSHIP SPECIES
Tree Dassie
• A solitary, arboreal browser
• Nocturnal
• Uses cavities of trees for dens
• Population decline due to loss and structural modification of their habitat caused by
human activities
• Highly threatened
Addo Dung beetle
• Once widespread in SA
• Now restricted to few isolate fragments in protected areas: one is the population in
the Addo Elephant National Park
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•
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Needs large herbivores dung e.g. elephant
Lowest fecundity recorded for dung beetles: maximum of two progeny produced per
year
IUCN status: vulnerable
Albany cycad
• Only 70 specimens in the wild
• Plants more than 1 km apart
• Sex ratio 4:1 in favour of males
• Specialist pollinators are extinct
•  poor seed set
• It’s decline went hand in hand with thicket habitat decline due to bush clearing in
the 19th century and remaining populations have been decimated by plant collectors
over the past 50 years
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SAVANNA
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This biome occurs in the north-eastern parts of the country, stretching southwards in
the lowland areas of KZN and extending into the Eastern cape. It is also prominent in
Botswana, Zimbabwe and Namibia.
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Savannas cover 46% of the country and it is therefore the largest ecoregion of South
Africa.
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The term savanna describes a vegetation type with a well-developed grassy layer,
and with a prominent woody layer of trees and or shrubs that may be deciduous or
evergreen. The woody plants may be more or less scattered. Intermediate grade
between grassland and forest, with wide variability in tree : grass cover ratio
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The rainfall varies from 235 mm in the Kalahari savanna in the west (dry savanna) to
over 1000 mm in some moist savanna types in the east.
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Altitude varies from sea level to 2700 m resulting in high variation in geology and
associated soil types  different vegetation types.
SAVANNA AND FIRE
A number of factors predispose this biome to fire:
•
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Dry season lasting at least 3 months
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•
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Adequate fuel
Thunderstorms with lightning
People with fire
Fire impact on grasses
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Dead biomass removed
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Vulnerable parts at ground level or below hence protected
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Grass regenerates with next rainfall
Fire impact on trees
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Frequent/intense fire prevents tree recruitment because fire kills seedlings and small
saplings
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Herbivory maintain young trees in a “fire trap”
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Exclusion of fires  encroachment
Picture of a bush encroached savanna
Herbivores can influence fire regimes by altering the quality and quantity of fuels available
for combustion. Through their reduction in the standing crop biomass they can reduce the
extent, frequency and intensity of fires. It can be the switch between fire prone and fire
resistant grasslands. Example, in Serengeti when <600,000 wildebeest then most of
Serengeti burns. When >600,000 only 20% burns.
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THREATS
Much of the areas is used for game farming and big game hunting and illustrates that
conservation and utilization of an area are not mutually exclusive.
Threats include expanding of settlements  increased need for firewood and building
materials; reduced water supply, agriculture (Sugar cane) and overgrazing.
FLAGSHIP SPECIES
Starburst horned baboon spider
• Baboon spiders are the largest in SA
• Belong to a group of spiders regarded as primitive : oldest fossil record dates from
the Triassic Period
• Long lived they can live to 20 yy
• This one only lives in the savanna biome
• They are nocturnal and live in silk- lined burrows where they wait by the entrance
for the passing prey
• Great demand as pets hence commercially threatened
Wild dog
• SA most endangered carnivore vulnerable to habitat destruction, persecution,
disease (rabies) and competition from other large carnivores
• Currently only viable population is in KNP
• Attempts are being made to form a second population through establishment of a
series of sub-populations in scattered reserves, and to manage them as a single metapopulation
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GRASSLAND
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The grassland biome includes both montane grassland and highveld grassland.
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Because of the different climatic conditions and the high altitude of the montane
grasslands they have a very different florist composition; the cool wet summer to
cold dry winter climatic conditions on the high altitude mountains causes a varied
floristic composition, with an extraordinary high biodiversity including rare and
endemic plants and animal species.
•
The montane grassland is entirely restricted to the high mountains of the Great
Escarpment.
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The grassland biome covers 30% of the country’s surface area and of this 26% is
covered by highveld grassland.
•
Characterized by summer rainfall mostly in the form of thunderstorms and frost in
winter.
GRASSLAND AND FIRE
Trees are scare and fire plays an important role in the ecology:
•
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Vegetation which climatically could be savanna
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Maintained as grassland by frequent fires because fire prevents establishment of
seedlings
N.B. FIRE AND SOUTH AFRICAN BIOMES
Pattern, behaviour differs by biome:
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African forests: catastrophic and infrequent
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Savannas, fynbos, grassland: important and necessary
TREATHS
•
It is one of the most threatened biomes in SA, with 60-80% of land been irreversibly
transformed and only 2.8% formally conserved.
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Enormous economic importance. It includes most of the country’s gold and coal
mining industries and associate extensive urban and industrial development.
•
The climate is ideal for agriculture  more that 40% converted to fields
•
Johannesburg in in the grassland biome! Would you believe it?
FLAGSHIP SPECIES
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Giant bullfrog
• Largest frog of SA
• Adult males can reach over 250 mm in body length and weighting more than 1 kg
• They need shallow rain-filled pans for breeding and large areas of grassland for
foraging and dispersal
• Dramatic decline
• Because of habitat destruction, habitat degradation, human persecution and illegal
collection for pet trade
• The pictures show the grassland habitat loss for this species in the Midrand area
Zooming in:
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Karkloof blue butterfly
• Its habitat is under pressure from alien invasive plants that transform their habitat.
• This butterfly is classified as Vulnerable and only five colonies of the species have
ever been recorded, one of which no longer exists presumably because its habitat has
been transformed by alien plants. The butterfly only occurs in the Moist Midlands
Mistbelt.
• The Midlands Meander route has made the Karkloof Blue their symbol and has
funded a research project in the hope that they are successful in ensuring its survival.
Blue crane
• Endemic to SA
• Most restricted global range of all crane species
• It is SA national bird
• It has declined drastically over large areas of its range during the last two decades due
to direct poisoning and indirect loss of grassland breeding habitat
• Other significant threats are the removal of the crane chicks for per trade or to sell to
birds breeders, power line collisions.
• They are mainly restricted to privately owned farmland  conservation relies on
landowner management participation
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FRESHWATER ECOREGION
•
SA is a semi-arid country with the average annual rainfall of 497 mm being well
below the global average of 860 mm.
•
Most freshwater systems have been overexploited and are highly transformed
•
The pressure will grow as population grows therefore SA faces a water shortage and
water supply crisis that threatens the future development of the country.
•
As with mammals number of species of freshwater fish are higher in the warmer
savanna regions in the north and east and endemicty is higher towards the south
and west
•
Freshwater fish are threatened by habitat degradation, dams, pollution and
introduction of alien species
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FLAGSHIP SPECIES
Cape Clawless Otter
• Predominantly aquatic even if not totally restricted to water
• Relies on fresh water daily
• Diet: crabs and fish and frogs
• Threats: water extraction, dams and invasion by alien plants
• Steady decline in their numbers with some local extinction cause by progressive loss
and degradation of habitat
African jacana
• Associated with aquatic habitats with floating water plants
• Usually found on seasonal pans and wetlands in the warmer parts of SA
• Suitable wetlands are becoming less
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ESTUARINE ECOREGION
•
Estuaries are located between rivers and sea and thereforear e a unique habitat.
•
Present a unique chemical environment resulting from the mix of fresh and sea
water.
•
The plants and animals respond directly and indirectly to these physical and chemical
processes.
•
A preliminary assessment of 258 estuaries in SA has revealed that 15% were in poor
conditions, 23% in fair conditions, 31 % in good and 31% in excellent conditions.
•
Increased human impact will place growing pressures on the ecological functioning
of these systems.
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FLAGSHIP SPECIES
Knysna seahorse
• Endemic to SA
• Most threatened sea horse species in the world
• Threat comes from his limited distribution, habitat degradation
Peringuey’s leaf-toed gecko
• Only discovered in 1992 after having been lost to science for 80 years
• Only gecko in world to live in salt marshes
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MARINE ECOREGION
Aghulas current: transport of also many coral and fishes
Benguela current: characterized by frequent upwelling (you know what an upwelling is as
we did it the first week – now you can link back to the theory done in class).  those coasts
are rich in species: 15% of coastal marine species known worldwide
Stocks of linefish, abalone and lobster are declining
Abalone facing extinction through poaching
FLAGSHIP SPECIES
African penguin
• Number crashed in the 20th century
• In the past impacted by guano collection (which destroyed their breeding habitat)
and egg collection
• Today the major threat they face are oil pollution and commercial overfishing of
their food supply
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