Vegetation and Plants of Prince Albert

This is an introduction to the vegetation types and plants that characterise the vegetation within a 20 kilometre radius of Prince Albert. We will start by describing how the environment of a plant is affected by altitude, rainfall, geology and soil, and how these factors in turn influence the challenges (cold, heat, wind nutrient stress, aridity, herbivory) and disruptions (fire, flood, prolonged drought) that plants face over their lifetimes. In order to describe the plants and their responses and ways of life we need to use a few botanical and other scientific terms that some might be unfamiliar with. For your convenience these terms are defined simply in Appendix 1.

How geology, altitude and rainfall shape the vegetation

The vegetation in the area from the top of the Swartberg to the plains around Prince Albert is highly diverse because there is a huge range in altitude, rainfall, soil and geology over a relatively short distance. The six main vegetation types are closely linked with altitude, geology, vegetation and water availability. They are Fynbos, Fynbos Rivers, Renosterveld, Spekboom Thicket, Succulent Karoo, and Karoo River woodland (Figure 1).

Topography and geology is the template on which vegetation develops. The more shapely the landscape, and the more varied the geology, the more diverse vegetation is likely to be. Prince Albert lies on the foot-slopes of the low hills that flank the inland slopes of the Swartberg. The geology is very diverse because this area lies within the Cape Fold Belt. The altitude ranges from 2,000 metres above sea level on the summit of the Swartberg Pass to 560 metres on the banks of the Swart River just 5 km north of the village. The rocks of the Swartberg are acidic quartzite and the soils are nutrient poor because the upper slopes of the mountain have a fairly generous rainfall (ca. 800 mm/year). The village backs onto the Gordon Koppie, a landscape feature 700 m above sea level and comprising Dwyka Tillite, a glacial Moraine deposited in an inland sea some 350 million years ago long before the evolution of dinosaurs and birds. The lower hills to the north of the village are Ecca Mudstone some 300 million years old and their rocks include fossil trees once washed from the tree-fern covered landscape into the deep inland sea that covered the area we now call the Karoo. A scatter of round white river stones flanks the downstream banks of the Dorps and other rivers that rise in the Swartberg. These pebbles are thought to have been carried from the mountain by the rivers during the great floods some 15,000 years ago that signalled the end of the most recent ice age and wide-scale warming of our planet.

The 1500 m altitudinal range and the many different geological formations as well as differences in the aspects of hills slopes and the decrease in rainfall from the mountain tops to the desert conditions on the plains to the north of the mountain, enable many types of vegetation to meet close to Prince Albert. 

Figure 1. The distribution of vegetation types (upper layer) in relation to rainfall, topography and geology Vegetation types

Fynbos is the dense shrubby vegetation covering the upper parts of the mountain and the dominant plants are Cape Reeds, Proteas and Ericas. The top of the Swartberg receives an annual rainfall of around 800 mm. Clouds often rest on the summit and conditions are frequently cool and windy as any hiker or cyclist will know. The soils are acid, pale sand, derived from the quartzite rock that makes up much of the Swartberg. Narrow belts of Forest grow along the rocky gorges and banks of rivers that flow out of the mountain – and include a mixture of Cape willow (Salix), Cape holly (Ilex mitis), kiepersol (Cussonia spicata), mountain sage Buddleja, honey bells (Freylinia), fountain bush (Psoralea pinnata) and many sorts of wild malvas (Pelargoniums). The cold, clear rivers flowing down the Swartberg via gorges to the plains, have vegetation that differs from the surrounding Fynbos.

Lower down the Swartberg, the south-facing quartzite or shale slopes such as those in the Gamkas Kloof and Prince Albert valleys are covered with a dense fine-leaved shrubland known as Renosterveld where most of the small shrubs including “Renosterbos” (Dicerothamnus rhinocerotis), belong to the daisy family (Asteraceae), and grasses are abundant in well-managed veld. The warmer and frost-free north-facing slopes of these valleys support Spekboom thicket, a dense tall shrubland of succulents such as spekboom (Portulacaria), aloes, plakkies (Crassula, Cotyledon, Tylecodon), vygies (Mesembryanthema) and scattered small trees, mainly gwarrie (Euclea undulata), kunibos (Searsia undulata) and numnum (Carissa haematocarpa).

As the rainfall decreases away from the mountains and the landscape flattens out forming the extensive Ecca Mudstone plains and low ridges between Prince Albert and the N1 low sparse, Karoo Veld forms a low and sparse cover made up of dwarf succulent and non-succulent shrubs and grasses that appear after rain. Succulents include steekvy (Ruschia spinosa), sjambokbos (Kleinia longiflora), melkbos (Euphorbia), daisies (Kleinia, Curio), and plakkies (Cotyledon and Crassula). Common non-succulent small shrubs are karoo bietou (Osteospermum sinuatum), gombossies (Pteronia), kriedoring (Lycium), and Karoo gold (Rhigozum obovatum). Wind-blown sand patches are found near major rivers and on low-lying plains. Unlike the rocky and silty ground, sand is usually covered in bushman grasses (Stipagrostis) that bear masses of silvery seeds after rains. Silty valley bottoms have saline soils and their plants, although taller and denser are salt specialists that include gannabos (Salsola), ourambos (Zygophylllum retrofractum), volstruisganna (Augea) springbok vygie (Malephora), and skaapvygie (Drosanthemum). 

Karoo riparian woodland follows the major drainage lines or rivers, most of which run only after heavy rain. Typical woodland trees are soetdoring (Vachellia karroo), rooi karee (Searsia lancea), taaibosse (Searsia longispina and others), bloubos (Diospyros lycioides), with an understory of rivierganna (Salsola aphylla) and tall grasses such as steekkweek (Stipagrostis namaquensis) and bloubuffel (Cenchrus ciliaris).

Plant adaptations to fire, wind, floods, drought and grazing

Although the Fynbos, Renosterveld, Thicket, Karoo veld and riparian woodland vegetation types are very close to one another as the crow flies, they are made up of plants that evolved to cope with very different types of challenges and disturbances. In this section we explain in some detail how the plains in the various vegetation types have adapted to cope with fire, wind, snow, floods, droughts, heat and herbivory.

FYNBOS (Figure 2a) grows where there is ample rainfall or snow particularly in winter, where soils are nutrient poor and summers may be dry. Every day is windy near the top of the Swartberg. The chance of lightning strikes increases towards the end of summer and this is the time when the mountain vegetation is likely to be at its driest. Adaptation to wind, snow and fire are all essential for plants that make up Fynbos. When you walk on the hiking trails on the Swartberg have a look at the structure of the plants. Many of the shrubs have small leaves and are tall and spindly – an adaptation to cope with high wind speeds. The larger shrubs are evergreen and have leaves that are as hard as cardboard; moreover they hold onto their old seed heads for many years. These woody seed heads do not burn completely when fire kills the bushes. The heat of a fire causes them to open up slowly and to release years of stored seed onto a fertile bed of ashes after the fire so that, when the winter rains arrive, the new seedlings can grow rapidly and fill the gaps left by the incineration of their parents (Figure 2b). In recently-burned areas you will notice many grasses, reeds and bulb plants. These have all survived the fire by using nutrients stored in bulbs and roots to regrow their leaves, and until the shrubs grow large enough to compete with them for light and water, these re-sprouters can thrive in the post-fire landscape. There are only low densities of browsing mammals such as Klipspringer in Fynbos, and the vegetation has little value for grazing, so is seldom used for farming with livestock. For this reason there are hardly any poisonous plants, and thorns or spines are very small and designed to protect seeds from mice rather than leaves from grazers. Succulents are confined to fuel-free, rocky outcrops seldom ever touched by fire.

Figure 2a. FYNBOS on the Swartberg. Note the clouds (A), pale quartzite rocks, the leathery leaves of Protea, the abundance of Cape Reeds or Restios (B), and the reds and pinks of the Erica (C), geophyte (D) and Protea flowers (E).

Figure 2b. Fynbos one month after fire (A) and in the recovery phase about two years after fire (B). Note the old seed heads on the burned Protea and the young Protea plants among the grasses and reeds after two years

FYNBOS RIVERS (Figure 3) such as the Dorps River are the result of rain, snow and cloud cover that precipitates gently into the mountain vegetation and seeps into rocky ravines eventually forming streams. The quartzitic rocks of the Swartberg produces very little silt so that the water is typically crystal clear and acidic. Organic acids leached from Fynbos give the water a slightly amber colour. Unlike the Fynbos vegetation through which they travel, the woodlands and wetlands along the mountain gorges are generally protected from fire. For this reason the plants are taller, have few adaptations to deal with drought, and few if any adaptations to survive or recover from fire.

The steep, shady mountain gorges are lined with trees such as African Holly (Ilex), wild peach (Kiggelaria africana), rock fig (Ficus Burtt-davy) and kiepersol (Cussonia spicata). The rocky beds of these rivers and their narrow sandy banks are typically covered with Cape Willow (Salix muronata), honey bells (Freylinia lanceolata) and mountain sage Buddleja salvifolia. The flexible willowy structure of riverbed trees enables them to bend when hit by floods and to re-sprout from the roots and stems if buried under rocks and sediment. Herbaceous plants on the river banks typically include long-leaved mint (Mentha longifolia), cancer bush (Sutherlandia microphylla), travellers’ joy (Clematis brachyphylla), fountain bush (Psoralea aphlla), and the scented pelargoniums

(Pelargonium glutinosum, P. hispidum, P. scabrum). These are periodically destroyed by floods but rapidly regenerate from roots or when exposure to light stimulates germination of their buried seeds.

Figure 3 Fynbos rivers: Typical plants are from left to right are (B) Cussonia spicata,  (C) Salix mucronata and (D) Pelargonium scabrum.

RENOSTERVELD (Figure 4) shrubs are also mostly evergreen and have small leaves that are often grey and hairy to conserve water. There are few succulent plants in this vegetation type because the south-facing slopes where it occurs are cold and frosty in winter, and low temperatures can kill succulents by freezing the water stores and bursting their cells. Renosterveld plants grow in drier environments than Fynbos so the soil is generally less leached and more nutrient rich, and often fine-textured being derived from Mudstone. In well managed renosterveld there are usually many grasses, particularly after fires. Not only does Renosterveld occasionally burn but its greater nutritional value attracts herbivores. Some Renosterveld plant species such as kapok (Eriocephalus) and malvas (Pelargonium) contain aromatic oils, and other such as  harpuis (Euryops), contain resins or tannins that discourage grazers. Over-grazing results in an increase in less palatable and poisonous plants. A few woody renosterveld plants re-sprout from the roots after fires, but many depend on soil-stored seeds for postfire recovery. For the first few years after a fire Renosterveld may be more grassy – however if it is grazed at this time it will be dominated by unpalatable yellow-green kraalbos (Galenia africana). Whereas in Fynbos the predominant flower colours are pinks and reds, in Ronosterveld they are yellow and purple.

Figure 4. RENOSTERVELD on the foothills of the Swartberg near Klaarstroom (A) and in the Gamkaskloof valley (B). Note the grey and ochre fine-leaves shrubs and predominance of yellow flowers

SPEKBOOM THICKET (Figure 5) found on the north-facing foothills of the Swartberg is tolerant of heat and drought, but not frost. The best-known plant in this vegetation type is spekboom (Portulacaria afra), a species that features in carbon sequestration restoration planting because its large size, very long life expectancy (many centuries), evergreen habit, inflammable juicy leaves and stems, and spreading succulent root system, make it a reliable and significant carbon sink. Other familiar garden succulents that are at home in thicket include striped aloe (Aloe striata), plakkies (Cotyledon orbiculata), sosaties (Crassula rupestris), karkai (Crassula arborescens), melkbos (Euphorbia) and many types of vygies (Drosanthemum, Lampranthus, Ruschia). All these plants store water so as to cope with the hot, dry conditions on north-facing hill slopes. Although some reduce desiccation risk in summer by shedding leaves (nenta, botterboom, succulent pelargoniums), many of them are evergreen. To conserve water some species have waxy coatings and avoid sun burn by turning the narrow red-tinted edges of their leaves to the sun. To protect the water stored in their succulent leaves or stems from excessive browsing by herbivores many have developed spines and poisons. The risk of freezing, being snapped by strong winds or burned is very low for plants in Spekboom thicket. Many have long life spans. Most produce small dry seeds that germinate only in sheltered places among rocks and in exceptionally wet years. Their reproduction is often vegetative, meaning that bits that drop off during drought take root in more favourable weather. Their food and water storage is in their juicy stems and leaves rather than in bulbs and roots – and if these are crushed (for example by being driven over) the plant is likely to die.

Figure 5. SPEKBOOM THICKET showing the dense green hedge-like growth of spekboom clumps (A) in the north-facing hill-slopes around Prince Albert. Note how pink the leaves of some succulents such as Aloe striata (B) become in summer – this is a sign of heat or drought stress. Below are (C) Euphorbia heptagona, (D) plakkie (Cotyledon) and  (E) botterboom (Tylecodon); these are all poisonous to herbivores

KAROO VELD of three kinds is found on the low ridges and extensive plains to the north of Prince Albert. These are Prince Albert Succulent Karoo, Nama Karoo shrubland and sandy grassland. The three types often co-exist as distinctive patches in the same landscape, separated mainly by soil depth, texture and chemistry. 

Prince Albert Succulent Karoo shrubland is the vegetation type on the plains closest to the village (Figure 6a). It is usually on reddish, fine-textured soils on moderately deep stony soil and is sparse, covering only 25% of the soil. As indicated by its name, this vegetation boasts a very high diversity of dwarf succulent plants. Some species of the dwarf succulents in the genera Antimima, Astroloba, Bijlia, Braunsia, Cylindrophllum, Glottiphyllum, Haworthiopsis, and Pleiospilos are found only in this vegetation type. In addition to succulents, there are non-succulent dwarf shrubs such as scholtzbos (Pteronia pallens), karoo bietou (Osteospermum sinuatum) and vanwyksbos (Galenia fruticosa) in this vegetation.

Whereas most the Nama Karoo receives rain mainly in late summer, the Prince Albert Succulent Karoo has non-seasonal rainfall and sometimes benefits in winter from light rain drifting from the clouds on the Swartberg. Plants in this environment seldom, if ever, experience nutrient limitation or fire. Their challenges are mainly the very hot dry conditions (rainfall less than 200 mm/year and summer temperatures up to 45°C) Herbivory is by small herbivores such as hares, steenbok and common duiker. 

Dwarf succulents (Figure 6a) cope with heat and aridity by being small, storing water in very fat leaves that are often also waxy, and having a fine and shallow (100 mm deep) root system that can absorb the lightest rain or dew. They conserve water in many ingenious ways including growing beneath taller plants and embedding themselves in the soil, covering themselves with UV-reflecting hairs, waxes or scales, absorbing and retaining salt in their cell fluids, and having stomata and flowers that open at night rather than in the heat of the day. The non-succulent shrubs (Figure 6b) cope with drought in a variety of ways. Some such as Asparagus store water and nutrient in their roots whereas others including Berkheya, Lycium and Osteospermum drop all their leaves and become dormant after six weeks or so without rain. The regrow of leaves and flower and seed opportunistically any time of the year when drought is broken by 10mm of more rainfall.

To reduce damage from herbivores, many succulent karoo plants are unpalatable because of tannins, alkaloids or high concentrations of salts in their leaves. Some are even deadly poisonous containing neurotoxins (Euphorbia), alkaloids that destroy liver cells (scholtzbos), or other lethal toxins (Dipcadi, Moraea). Even the more palatable plants reduces herbivore damage by such cunning ploys such as having fine spines on their leaves ( for example geel dissel Berkheya and scorpion bush Blepharis), or on their stems (Hoodia, Lycium), or being so brittle that a hungry animal can pull off only a small amount at one time (Justicia also known as maklikbreek).

Figure 6a. Prince Albert Succulent Karoo on the stony foothills and plains on the inland side of the Swartberg is short and sparse with many succulents (A-C). These can be grouped as vygies (Aizoaceae D,F, G, I), daisies (Asteraceae K), plakkies (Crassulaceae E, J) and melkbos (Euphorbiaceae H) families.

Figure 6b. Non-succulent shrubs in Prince Albert Succulent Karoo reduce herbivore damage by having (A) starch stores in their roots bietou (Osteospermum sinuatum), (B) thorny leaves (Macledium relhanoides), or (C) poisonous alkaloids in their leaves Scholtzbos (Pteronia pallens).

Nama Karoo shrubland (Figure 6c) shrubland is typically found on exposed dark

Mudstones and becomes the dominant vegetation as one travels northward from Prince Albert towards Beaufort West or westward towards Laingsburg. Most of the plant species are droughthardy, non-succulent shrubs or grasses that lose their leaves during droughts to conserve water. The taller woody shrubs such as Karoo gold (Rhigozum obovatum) and kriedoring (Lycium) have very deep roots that penetrate through cracks in bedrock to find ground water. The small karoo bossies have leaves rich in aromatic oils – and kapok (Eriocephalus), skaapbossie (Pentzia incana), and kerriebos (Helichrysum) are among the most well-known of these and contribute to the regional character of Karoo lamb. The oily leaves also enable herbivores to grow fat rapidly despite the dry and sparse look of the veld. Their defence against drought and herbivory seems to be one and the same – shut down all activity, feign death – cover yourself with dry brown leaves and look as unappetising as possible. But within three days of rain these bossies burst into life again, shedding the dry leaves and pushing out green shoots and flowers. Before the days of high electric fences the wild herbivores of the Karoo, mainly Eland, Gemsbok and Springbok, and the indigenous herders and their fat-tailed sheep, would have moved out of desiccated veld toward better grazing during drought, and gradually retuned after rains giving the plants time to recover from both grazing and drought.

Figure 6c. Nama Karoo shrubland comprises small shrubs with fine leaves. Many are in the daisy family examples of which as kapok (Eriocephalus ericoides), skaapbossie (Pentzia incana) and bloublommetjie (Felicia muricata)

Sandy arid grassland (Figure 6d) is on deep sand – sometimes confined to hollows and valleys bottoms and in other places covering vast flat plains. Bushman grass (Stipagrostis), a desert specialist dominates sandy patches. These are long-lives plants that avoid drought by becoming dormant. The flower and seed abundantly after good rains, turning the veld silver white with their abundant feather flower heads. The seeds have a barbed tip and feathered tail so that wind movement can drive the seeds deep into the sandy soil. The buried seeds may survive for many years until a succession of good rains stimulates germination. Herbaceous legumes such as skaapertjie (Lessertia), Lotononis, Melolobium and Tephrosia are important temporary components of this vegetation and add greatly to its nutritional value of wildlife and livestock. Like the grasses they have long-lived seeds that can wait for years buried in sand until rains arrive. 

The rains that bring this veld type to life attract nomadic seed-eating birds such as Greybacked and Black-eared Sparrowlarks, Lark-like Buntings, Namaqua doves and Namaqua Sandgrouse that feed their chicks in the nest with caterpillars and termites until the nestlings can eat seeds.

Figure 6d. Sand plains covered in bushman grasses (Stipagrostis ciliata and S. obtusa two months after drought-breaking rains (A). The barbed seeds of these grasses (B) stay dormant in the sand during dry times but when fresh are food for sparrowlarks that arrive and nest as the grass starts to flower (C: Grey-backed Sparrowlark nest). Annual legumes (D) are common in this grassland.

KAROO RIVER WOODLAND AND FLOOD PLAINS. The rivers that arise in the

Swartberg and in the hills of the Prince Albert valley and Sandrivier valley eventually flow onto the Karoo plains, losing water to evaporation and percolating into the soil as they go. The river beds on the plains are broad and sandy filled with alkaline or salty sediments washed from the hills and plains via the many small drainage lines that run only for a few minutes during heavy rains. Between violent flash floods that take place every few years, the wide sandy beds of Karoo rivers are dry above ground and generally covered with a spiky grass (steekkweek Stipagrostis namaquensis). The banks are flanked with a woodland of soetdoring (Vachelia karroo), rooi karee (Searsia lancea), kunibos (Searsia burchellii) and jackals bessie (Diospyros lycioides) (Figure 7a). 

The floodplains where saline silt has been deposited over many years have a specialised salt-tolerant vegetation (Figure 7b) of gannabos (Salsola aphylla) and tamarisk (Tamarix usneoides). Salt-tolerant succulents such as asbos (Mesembranthemum utile), soutslaai (M. crystallinum), skaap suuring (Hypertelis salsoiloides), springbok vygie (Malephora lutea) and ou rambos (Zygophllum retrofractum) are common on flood plains of Karoo rivers. Where there is no fresh drinking water, the high salt content in the cells of these plants makes them unpalatable to most herbivores.

Figure 7a. The Swart (Sand) River where it crosses the Kruitfontein road (R353) is a typical Karoo River with a grassy, sandy bed and flanking sweet thorn woodland (A). Occasional flash floods reshape the riverbed (B).

Figure 7b. Plants of the salty, silty floodplains of Karoo rivers include (A) gannabos (Salsola aphylla), (B) volstruisganna (Augea capensis), (C) springbok vygie (Malephora lutea)

Pollination and seed dispersal

Pollination and dispersal are important for keeping all plants up to date and relevant in changing conditions and landscapes. Pollination in plants, in common with sexual reproduction in animals, produces offspring that has a mixture of their parent genes. Genetic diversity is important for species survival because every generation faces different challenges. Seed dispersal, like travel in animals, gives plants opportunities to find new places to live that may be free of competition from parents and relatives and free of pests and diseases.

Fynbos fires result in a mosaic of vegetation of various ages since the last burn. Newly burned patches are grassy with showy red and pink geophytes such as Watsonia, Tritonia and orchids. Older Fynbos patches are taller and shrubbier, often with flowering Erica and Protea. Pollinators may need to travel large distances under cold windy conditions to find nectar and places to breed. Not surprising then that Fynbos pollinators are large bodied. In addition to large beetles, bees and butterflies, there are many flower-visiting birds and rodents in Fynbos. The Cape Sugar Bird and OrangeBreasted Sunbird are specialists at pollinating showy but odourless red and orange Protea and Erica flowers (Figure 8 upper). Rock rat (Michaelmys), vlei rat (Otomys), climbing mouse (Dendromys), mini-mouse (Mus) and striped mouse (Rhabdomys) visit ground Proteas to drink nectar, and in so doing pollinate these brown, musky-smelling flowers. 

Seed dispersal has evolved with fire in Fynbos. Plants that shed seeds in mature vegetation often have oily seed attachments known as elaiosomes that are attractive as food for ants. When they fall, the seeds are collected by ants and carried underground. The ants eat the energy rich attachment and abandon the seed where it remains underground safe from insect, rodent and bird predators until stimulated to germinate. Germination is triggered by the heat of a fire and so seedling emerge in synchrony after competition from old plants has been cleared by fire and the soil enriched by ash. Proteas and their relatives store each years seed in a very hard woody seed head. When the plant eventually burns hairy seeds are released onto a bed of ash and are further moved over the landscape by tumbling across the soil surface (Figure 8 lower).

Fynbos rivers (Figure 9) are flanked by trees, shrubs and creepers with white, blue, yellow and pink flowers. Many shrubs such as butterfly bush (Buddleja salviifolia) and honey bells (Freylinia lanceolata) have scented flowers that attract butterflies and moths. Cape Willows (Salix mucronata), reeds and grasses have dry pollen dispersed by the wind so no butterflies and moths (or any other) are needed.

Seed dispersal of trees such as wild peach (Kiggelaria africana), kiepersol (Cussonia spicata), Cape holly (Ilex mitis) and rock fig (Ficus burtt-davii) that grow in shady gorges is mainly by birds. Starlings, bulbuls, white eyes, robin chats, and mousebirds all feed on fleshy fruits and disperse seed in their droppings, often to perches near water. Willows and Clematis have light, fluffy seeds that can float on water, blow in the wind and are also collected and dispersed by birds as nest lining materials. A few riverside plants such as cancer bush (Sutherlandia) and klapperbos/lantern bush (Nymannia capensis) pack their seeds in boat-like bubbles that can float down the stream.

Figure 8. Large insects (A) and long-beaked Cape Sugarbird (B) and Orange-breasted Sunbird (C) are specialised Fynbos pollinators. Seeds are stored underground by ants (D) or above ground on the parent plants until fire stimulates release (E) and dispersal (F) 

Figure 9. Along Fynbos rivers (A) butterfly bush and (B) travellers joy are pollinated by insects. Lesser-double-collared Sunbirds visit (C) honey bells. Seeds of cancer bush (D) float on water like boats, wild peach seeds (E) are moved to new sites by fruit-eating birds and (F) travellers joy seeds have the option of using wind or water for transport.

Renosterveld (Figure 10) is vegetation dominated by grasses and fine-leaved shrubs of the daisy family. Most of the bushes have yellow flowers although September bossie (Polygala) and legume species have purple flowers. The main pollinators are flies, bees, beetles and butterflies. After fires geophytes such as fire lily (Haemanthus) attract sunbirds birds with their red flowers. Some Renosterveld plants use ants to bury their seeds, but most have wind-dispersed parachutes that are blown to freshly-burned sites or roll over the ground.

Figure 10. (A) Red fire lilies (Haemanthus) flower after fires in Renosterveld attract birds, but in general flowers are small, yellow such as (B) harpuis (Euryops) and (C) kouterbos (Athanasia) and are pollinated bees, beetles, flies and butterflies. (D) Purple Polygala teretifolia is pollinated by bees and its seed (E) is dispersed by ants that bury the seed and eat the elaiosome attached to it. Most renosterveld shrubs such as (F) kraakbos (Pteronia) and (G) Renosterbos (Dicerothamnus) have wind-dispersed seeds

Spekboom Thicket pollinators are mainly flies, bees (Figure 11). The exceptions are the red and orange-flowered aloes and cotyledon which are pollinated by Malachite and Southern Double-collared Sunbirds. Succulent thicket does not burn so fires are neither opportunities for germination nor threats to the seed bank, so above and below-ground seed storage is not a feature of this vegetation. Most of thicket succulents have winddispersed seeds that are either winged (Spekboom Portulacaria afra, aloes and stapeliads) or very small and shaken out of their pepper-pot capsules by the wind (Crassula, Cotyledon, Tylecodon). Self-propulsion via exploding dry capsules is practised by skietpit (Blepharis and Justicia) and melkbos (Euphorbia). Seeds of woody shrubs such as ghwarrie (Euclea undulata), Karoo numnum (Carissa haematocarpa) and kunibos (Searsia) have juicy fruits that are eaten by birds and mammals such as monkeys, baboons, jackals and mongooses, all of which deposit seeds in nutrientenriched and usually shady sites. 

Figure 11. Pollination in Spekboom Thicket is mainly by flies as in euphorbia (A,B) and Crassula (C). Dispersal by wind (E) for Crassula and Cotyledon and by birds for numnum (F), ghwarrie (G) and other plants with fleshy fruits.

Karoo Veld shrubs and succulents are pollinated mainly by small insects including flies, specialised flies such as bee flies, solitary bees, beetles, lycaenid butterflies, and moths (Figure 12a). A number of kinds of vygies (Mesembryanthemums) have flowers that open in the late afternoon or after dark. To attract their pollinators (moths), these vygies produce a variety of fruity and honey-scented aromas. There are a few bird-pollinated plants in Karoo veld types – notably kriedoring (Lycium) and aloes. Elephant shrews (also known as sengis) visit aloes at night and probably also pollinate the flowers as they drink the nectar. Grasses produces masses of pollen that blows in the wind so do not need animal pollinators. 

Figure 12a, showing pollination of common Karoo shrubs and succulents by moths (A) bee-flies (B, D), beetles (C), bees (E, F), butterflies ( G, H) and moths (I). Sunbirds visit nectar-rich flowers of (I) volstruis druiwe (Augea capensis) and (J) Aloe claviflora. Elephant Shrews (sengis) visit aloe flowers at night.

Fire is no threat to Karoo Veld seeds, however, high soil temperatures in summer and drought conditions unsuitable for germination are major challenges that have shaped seed dispersal in this vegetation type (Figure 12b). Seed dispersal is by wind for most dwarf shrubs, geophytes and grasses. To make the most of the wind the seeds are enclosed in papery wings, bristles, silky plumes or fluff. This enables the seeds to be rolled over the ground by the wind, or to fly short distances until they are intercepted by rocks, plants or holes dug by porcupines or aardvark (Figure 12c). These obstacles are “safe sites” for wind-dispersed seeds because they offer shelter from damaging UV light and hot soil surfaces. 

All the vygies (Mesembryanthemaceae) hold their seeds in closed woody capsules throughout dry times. Capsules swell and open only when wet, releasing seeds during rain showers. In this way the plants reduces seed loss to ants and birds and increase the probability of germination of their seeds that are splashed by raindrops onto wet soil. 

Some shrubs such as kriedoring (Lycium) have red berries that are eaten by mousebirds and bulbuls that disperse the seed to beneath the bushes where they perch, but seed harvester ants (Messor capensis) also collect seeds and fruits with the intention of storing the seeds for later consumption. Many Karoo ground-nesting birds such as sparrowlarks, lark-like buntings, larks and wheatears build nests on the south-sides of shrubs to protect the eggs and young from heat (Figure 12d). They line their nests with plant down, wool and plumes and later the seeds attached to the nest lining will germinate in these protected sites. Small herbivores including tortoises, hares and antelope disperse small seeds of skaapsuuring (Kewa salsoloides), koggelmandervoetkaroo (Limeum aethiopicum), van wyksopslag (Galenia) and other herbs in their dung.

Figure 12b showing seeds adapted for dispersal by wind (upper row) including (A) Eriospermum, (B) Kleinia and (C) Augea. Vygie capsules open when wet so that rain drops can disperse their seeds. Our examples are (D) Hereroa, (E) Mesembryanthemum and (F) Cylindrophyllum.

Figure 12c. Porcupine (A) and aardvark (B) diggings intercept wind-blown seeds and trap water and litter. They are often safe sites for plant establishment

Figure 12d Seeds designed for dispersal by birds or wind may also be dispersed by ants as food (A, B) or by nesting birds as nest lining as in (C) this nest of a Black-eared Sparrowlark. 

Karoo river beds and river banks (Figure 13) are lined by wind-pollinated grasses, and trees and shrubs with flowers pollinated mainly by bees, flies and wasps. The woody shrubs along river banks are often parasitized by mistletoes. Some mistletoes such as vuurhoutjies (Moquinella rubra) have orange tubular flowers and attract sunbirds for pollination, whereas voëlent (Viscum) have small yellow flowers and are pollinated by flies.

Seed dispersal of flesh-fruited plants and mistletoes that have berries is by mousebirds, bulbuls, starlings and white-eyes. Letting seeds fall to the ground is also an option for dispersal in river beds as occasional flash floods move silt and seed over long distances. Kruitjie-roer-my-niet (Melianthus comosus) and cancer bush (Sutherlandia frutescens) produce bladder-like fruits that float on the surface of the flooding rivers and are washed onto the banks. 

Figure 13. Karoo rivers are flanked by Sweetthorn (Vachellia karroo) woodland. Sweet thorn flowers (A) are pollinated by bees and their seeds (B) fall from the pods into the river bed. The mistletoes that parasitise riverside trees include (C) vuurhoutjies (Moquinella), the match-like, firey-orange flowers of which are pollinated by sunbirds. The red

Moquinella (D) and yellow Viscum (E) mistletoe berries are eaten by birds, that wipe off the sticky seeds on branches of trees and shrubs where the seeds root directly (F) into tree bark.


The many plant species within a 10 kilometre radius of Prince Albert have not yet all been documented and photographed. It will take a lifetime to identify them all and much longer to discover their life histories and links with pollinators, seed dispersers and symbionts.

Further reading

The most useful references to the Fynbos, Renoserveld and Karoo vegetation, plants and their pollinators and dispersers are as follows:

Chittenden H, Weiersbye I, Davies G 2018. Robert’s Bird Guide, 2nd edition. Jacana Media.

Curtis-Scott O 2020. Field Guide to Renosterveld of the Overberg. Penguin-random House.

Esler KJ, Milton SJ & Dean WRJ 2006. Karoo Veld Ecology and Management. Briza Press.

Esler KJ, Pierce SM & de Villiers C 2014. Fynbos ecology and management. Briza Press.

Picker M, Griffiths A & Weaving A 2019. Field guide to insects of South Africa, 3rd edn. Struik.

Shearing D 1994 Karoo – south African Wild Flower Guide 6. Botanical Society of South Africa.

Scholtz C, Scholtz J, de Klerk H  2020 Pollinators, Predators & Parasites – The Ecological Roles Of Insects In Southern Africa. Penguin-random House.

Vlok J and Schutte-Vlok AL 2010 Plants of the Klein Karoo. Umdaus, Pretoria

Unfortunately some of the above are out of press but the Fransie Pienaar Museum in

Prince Albert still has a few copies for sale. Also try Tru-Karoo Art shop in Church Street, Prince Albert

Seeds and Plants for Karoo gardens

Renu-Karoo Nursery in Prince Albert grows indigenous plants typical of the Karoo and

Renosterveld vegetation types. This nursery does not supply Fynbos plants (such as Proteas, Buchu and Cape Reeds) as the soil and climate conditions in Prince Albert are unsuitable for plants that need cool wet conditions and acid soils. For more information see or phone Bertus Fourie 082 650 9792

Appendix 1. Explanations of terms used in this article

Term Explanation
Alkaloid A nitrogen-based molecule giving plants a bitter flavour and having an effect on animal physiology. Examples include caffeine, morphine, strychnine, quinine, mesembrine and nicotine.
Vegetation The compass direction of a hill slope. The direction in which a hill slope faces affects the amount of sunlight and heat received by the plants. North-and westfacing slopes are hotter than south and east-facing slopes
Carbon sequestration The storage of carbon by plants involves conversion of carbon dioxide gas to carbohydrates (starch, sugar). When plans are eaten, burned or left to decay, the carbon is released again as gas. Carbon dioxide is a “greenhouse gas” that traps heat in the Earth’s atmosphere and leads to to climate change.
Dispersal The movement of seed away from the parent plant to another place where it might have a better chance of germination and survival 
Family A grouping for plants with similar physical characteristics. For example, a plant in the Legume family all produce seeds in fruits known as pods (beans, peas, thorn trees).
Fruit The structure produced by a plant after flowering and which contains the seeds. Fruits can be flesh (e.g. berries) or dry (pods, capsules)
Geophyte A plant with underground storage organs such as bulbs, tubers, rhizomes and corms. Garden examples are beetroot, onions and ginger, and wild examples are kambro (Fockea), Gladiolus and bulrush (Typha)
Herbs or herbaceous plants Soft plants without woody stems that grow from seed after rain and die in drought. Also known as opslag, ephemerals or annuals
Herbivore An animal that eats only plants
Mudstone A layer of sedimentary rock made by accumulation and compaction of layers of mud usually in deep water
Moraine The material carried and eventually deposited by a glacier
Non-succulent A plants that does not store water
Pollination The deposition of pollen onto the female part of a flower causing an ovary to be fertilized and a seed to be formed
Quartzite Sandstone melted by compression during mountain building and folding
Species Individuals of the same kind that can exchange pollen, and produce viable seeds following the pollen exchange.
Stomata Small holes in leaves that allow for the intact or release of carbon, oxygen and water vapour
Succulent A plant that stores water in its swollen leaves or stems
Vegetation, vegetation type The mixture of plant species and growth forms (grasses, succulents, shrubs, trees) growing together in a particular area. Vegetation type is a particular mixture of plant species predictably found in a particular region or habitat