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The southern tip of Africa boasts a remarkable natural relic: a rich
ecological community that has enjoyed hundreds of thousands of years of
relatively undisturbed evolution. Known locally as the fynbos (‘fine bush’),
it comprises an astonishing variety of trees, evergreen shrubs, insects
and other animals, thousands of which occur nowhere else in the world. In
places, the fynbos rivals tropical rainforest for plant diversity. To many
South Africans, especially the Cape’s white middle classes, it has become
a potent symbol of the country’s natural heritage, something to be preserved
at all costs.

Today that sentiment is growing ever stronger, for the fynbos is in
trouble. Alien shrubs and trees imported at the turn of the century are
spreading across the country at a ferocious pace, threatening to displace
the indigenous plants. Agricultural scientists, intent on saving the fynbos,
have resorted to a form of biological warfare, deploying specially selected
organisms, or ‘bioherbicides’, to attack the invading plants. But this tactic
is drawing stern criticism from some sectors of South African society. There
are growing fears that the social costs of saving the fynbos might outweigh
the benefits to the Cape’s ecologists.

The affection South Africans feel for the fynbos is understandable.
From a distance it looks like a low green scrub, but closer to it can be
seen to be filled with flowers. There are heathers in red, yellow, pink
and white, and pelargoniums with bright petals and scented leaves – ancestors
to every pot geranium in the world. Most spectacular are the proteas (pictured
left), shrubs with huge flowers like multicoloured thistles, sometimes more
than 10 centimetres across. As South African botanists are fond of pointing
out, 1470 different plant species have been recorded on Table Mountain alone.
This is more than are found in the whole of the British Isles; but then
the flora of northern Europe has had only 10 000 years to re-establish itself
since the last ice age.

But the fynbos is not just beautiful. Like tropical rainforest, it is
believed to be a rich repository of natural medicines . The Khoi people,
who lived in the Cape before the Europeans came, were well aware of the
medicinal uses of some fynbos plants, as are many locals today. Yet modern
research has hardly begun. With many of its plants uncharacterised, the
fynbos is still something of an ecological black box. And although botanists
continue to discover new species, time could well be running out. Over 600
fynbos species, many endemic to the Cape, are currently thought to be threatened.

The Cape’s long dry summers make fire a perennial threat. But the fynbos
is superbly adapted to this problem. Some of its plants lock their seeds
into fireproof cones which split open after burning. Others coat their seeds
with tempting ant food; the ants bury the seeds in their burrows, safe from
the flames. The regular fires have, however, had one important effect: confining
trees to damp, shady ravines on mountainsides, such that much of the Cape
appears bare.

It is this apparent barrenness that is at the heart of the problem.
The first European colonists soon used up what timber they could find in
the tiny and slow-growing fynbos forests. Looking abroad for faster-growing
trees they began importing eucalyptus and pines for timber. For windbreaks
and hedges, and to bind the shifting sands on the flats around Cape Town,
the settlers procured fast-growing acacias from Australia, including the
long-leafed acacia (Acacia longifolia), Port Jackson willow (Acacia saligna),
rooikrans (Acacia cyclops) and black wattle (Acacia mearnsii), all of which
thrived in South Africa.

This was only to be expected. Like imported species everywhere, the
newcomers to the Cape were able to spread unchecked by natural predators
and parasites. The acacias also had the advantage of being nitrogen-fixing,
which in the Cape’s poor soils gave them the edge on their indigenous neighbours.
Today, the success of these exotics is all too visible in the many areas
of the fynbos which have been completely swamped by remorseless stretches
of green scrub. Where they have regrown after fire, the acacias form impenetrable
thickets of whippy stems.

In a brave attempt to stop the spread of the alien plants, groups of
mostly white, middle-class environmentalists spend weekends chopping down
the offending vegetation. Unfortunately, hacking cannot reverse or even
contain invasions of this scale. Mechanical weeding is not much more effective,
and the use of pesticides can leave behind some 20 years’ worth of Port
Jackson seed in the soil. As a consequence, ecologists and the Cape’s many
nature lovers are now pinning their hopes on biological control.

Research is under way at a number of institutions, including the botany
department of the University of Cape Town. To find insects or parasites
suitable for use as bioherbicides, researchers must first travel to the
homelands of the interlopers – usually Australia or South America. Any candidate
organisms must undergo lengthy screening to ensure they will attack only
the alien plant. Johnny Hoffman, an entomologist at the University of Cape
Town, explains what has to be done: ‘We look first to see if the insect
can attack the target’s nearest indigenous relatives, or any related plants
which have a commercial value. We then look at morphologically similar plants:
ones with the same size of flower bud, and so on. We go out in wider and
wider circles from the target plant until we can be reasonably sure the
bug will only attack the target. This can take several years.’

The researchers have already scored some notable successes. One is a
gall-forming wasp, Trichologaster acacialongifoliae, which South Africa
is now importing to control the long-leafed acacia. The wasp lays its eggs
in the plant’s flower buds. The larvae then hijack the buds, forcing them
to develop into galls (abnormal outgrowths) rather than flowers. Remaining
seeds are destroyed by a second bug, a seed-boring weevil.

Another victory came when Hoffman and his colleagues unleashed, in 1984,
a trio of weevils to halt the spread of an aggressive South American tree
called Sesbania punicea. At that time the tree was sweeping through the
country, blocking rivers and flooding farmland. But by 1988, says Hoffman,
the weevils had devastated entire stands of the offending vegetation, two
of them attacking its seeds and flowers, while the third burrowed under
its bark, effectively ringbarking the tree.

The researchers have deployed another predatory cocktail – this time
a moth and a weevil – against the silky hakea, an Australian shrub which
forms dense colonies on mountainsides and in forestry plantations. But the
most effective weapon has turned out to be a fungus found on one of the
hakea’s South African relatives, a protea. Foresters now treat their plantations
with a ‘mycoherbicide’ spray of the fungus, saving on the huge labour costs
of chopping hakea down by hand.

Overall, though, the alien plants do not pose much of a threat to South
African agriculture, something which ecologists eager to raise funds for
their work might almost regret. The threatened fynbos has only survived
thus far because its soils are extremely poor and the grazing virtually
nonexistent. Its only commercial value is for tourism and as a source of
wild flowers. ‘It’s a problem trying to get money for research when there
are no immediate returns,’ says Hoffman.

But lack of agricultural interest in the fynbos is by no means the only
problem facing conservationists. In some areas of South Africa the alien
trees, far from being pests, are valued as crops. One example is the black
wattle, plague of many Cape streams. A fast-growing tree which produces
plentiful timber and firewood, the wattle also provides bark as a raw material
for a very successful tanning industry in Natal, a province northeast of
the Cape. For several years the industry used its muscle to block not only
the release of organisms that attack acacias, but even research on such
organisms. A compromise has now been reached, says Hoffman, in which the
wattle growers have agreed to allow research into predators that attack
only seed. ‘When wattle growers wish to propagate their trees, they can
spray selected trees with insecticide to allow them to set seed,’ he explains.

The latest campaign in the battle to save the fynbos has generated new
resistance to biological control. This time the scientists’ target is the
infamous Port Jackson willow. In 1987 the government approved the release
of the fungus Uromycladium tepperianum, which attacks the Port Jackson’s
branches and flower buds, blocking seed production and inducing large galls.
The fungus has since been released at about 80 sites and Michael Morris
of the government’s Plant Protection Research Institute near Cape Town believes
it will spread. ‘The infection is now starting to explode. Up to two kilometres
away from the original sites you can find plants with a mass of galls, and
seed production is cut drastically. It looks very promising.’

The snag is that the Port Jackson willow is not only found spoiling
the mountain wilderness, it also grows in and around the townships and squatter
camps that surround Cape Town. There, where nothing less vigorous seems
to survive, the willow is a valuable source of timber, firewood and shade.
Further afield, farmers have come to depend on it for animal fodder.

Not surprisingly, the prospect of such a common tree succumbing to a
disfiguring and ultimately fatal disease is provoking concern. One angry
farmer is Frederick Rust, an Afrikaner who farms in the tough, dry lands
that sweep north from Cape Town. He has been feeding his sheep and cattle
on the Port Jackson for 20 years. ‘Because my soil is so sandy, I rest the
pasture for two months twice a year, and the animals graze on the Port Jackson
instead.’ Rust is dismayed that the government has allowed the release of
an agent which will eventually kill one of his essential crops. ‘When the
fungus comes and destroys the plants, it will be a disaster. Farmers were
not consulted in any way. . . I have tried a lot of plants, but none is
so well adapted to our dry seasons.’

Critics of the fungal herbicide are not confined to the farming communities.
Anthony Woods, who works in a Cape Town hospital, loves and values the fynbos
– but loves and values the acacias, too. ‘The galls are a sort of amorphous
mass, the colour of faeces and the size of my hand,’ he says. ‘What is Cape
Town going to look like when all the trees start to get sick?’ Woods sees
a political side to what he calls the ‘fanatical’ effort to save the native
fynbos: ‘There is a pro-South Africa craze here. They are even ringbarking
the English oaks in the botanical gardens at Kirstenbosch. The whole thing
is a bit ironic considering the Europeans are not indigenous here.’

What horrifies critics of the fungal herbicide most is that such a drastic
change to the local landscape could be authorised without public consultation.
According to Morris, the decision to release the fungus was authorised by
the Ministry of Agriculture after the Council for Science and Industrial
Research (CSIR) had rated Port Jackson the country’s number one problem
plant. ‘At the time of the release there wasn’t any public consultation,’
he admits. ‘A biological agent seemed necessary because of the enormous
seed load.’

Before opting for biological control the scientists did consider the
value of the Port Jackson. But, as a source of fuel, they dismissed the
tree as being ‘not as good as rooikrans’. Its value as animal fodder, they
judged even lower because of the unusually high tannin content of its leaves.
They were influenced almost exclusively by one government-funded study in
which animals had fallen sick soon after eating Port Jackson leaves. Rust
says that his animals do not get ill: they prefer the tree’s buds and seed
pods to the leaves.

Morris was surprised to hear that farmers feed their herds on the tree.
He now believes that there should have been more weighing up of the pros
and cons beforehand. When asked what would become of the people who depend
on Port Jackson for their living, he answered frankly: ‘You’ve got me there.
I don’t know if it will be possible to keep the fungus out.’

As well as prejudicing the present livelihoods of farmers and woodcutters,
the decision to infect the Port Jackson with fungus may hinder progress
in another vital area of agriculture: agroforestry, which is increasingly
being seen as the key to restoring fertility to the world’s hottest and
driest places.

Impressed by the Port Jackson’s vigour in tough conditions, Gavin Armstrong
is trying to grow it on the eroded mountain slopes of Lesotho. Armstrong
is also a horticulturist at the Malmesbury Camphill Village, a community
in which mentally handicapped and fully able people live together. The community
boasts a large organic vegetable garden, and has a commercial herd of goats.
The animals graze extensively on the Port Jackson shoots, and the milk they
produce is converted into organic yoghurt.

Armstrong is also testing the value the Port Jackson might have as a
hedge species in alley cropping. In alley cropping, crops are planted between
rows of shrubs which enrich the soil by fixing nitrogen and producing mulch
from fallen leaves. The hedge provides shade and stems soil erosion. Armstrong
is furious about the fungus: ‘Port Jackson had so much potential for helping
people in absolutely desperate circumstances.’ But Hoffman remains adamant
that the plant has little to offer: ‘There are much better plants than Port
Jackson, more nutritious and which will not damage the indigenous plants.’

Further north, at the University of Natal in Pietermaritzburg, Panga
Malihe is working with farmers in the overgrazed, eroded highlands of Kwazulu.
He, too, sees the planting of hardy alien trees as an invaluable way to
obtain mulch, fodder and firewood and to stem soil erosion. One of the most
promising species on his farm is Sesbania sesban. But because this tree
is a close relative of S. punicea, an alien persecuted as a weed in other
parts of the country, Malihe is running into official opposition and cannot
import seed.

He is incredulous that anyone could imagine sesbania ‘escaping’ from
the sites he proposes to plant it. ‘We have great difficulty getting anything
to grow. Everything has to be fenced, otherwise it is eaten instantly.’
For agriculturalists such as Hoffman, however, the chief worry is long-range
dispersal. The seeds of such plants, he fears, could be spread inadvertently
to places where conditions are easier. Ironically, the vigour which makes
an alien plant so highly prized on a dry plain or a gulley-riven hillside
crammed with hungry cattle, is also what makes it a pest elsewhere.

The fungus unleashed to save the fynbos appears in some respects the
perfect, nontoxic choice for the job – except that all Port Jackson willows
look the same to it. If it works as efficiently as its proponents hope,
there will be no reprieve for any of South Africa’s Port Jacksons.

The conflict of interests unfolding in the Cape sounds a cautionary
note for the future use of biological control agents. It also carries a
painful message – namely, that conservation sometimes means sacrificing
one environment to save another – and illustrates why, in the country’s
black townships, environmentalism still looks like a white luxury. After
all, nobody can be expected to defend an environment if doing so brings
about the destruction of their livelihood. A family cutting the Port Jackson
at a roadside near Cape Town, was incredulous when told about the release
of the fungus. ‘They can’t kill the Port Jackson,’ said the father, ‘it’s
²ú°ù±ð²¹»å’.

Kate de Selincourt is a freelance science writer based in Britain who
has travelled in South Africa.

* * *

THE CAPE’S LIVING MEDICINE CHEST

Many plants in the fynbos have long been used as herbal remedies by
locals descended from the Khoi and San people, the Cape’s original occupants.

Many of these remedies were adopted by the first European settlers,
and some are still popular among Afrikaners. Early colonial doctors were
so impressed with the effectiveness of the Cape’s herbs, they felt sure
the remedies would be adopted in Europe, says Jill Scott from the South
African National Botanical Institute, who is trained both as a botanist
and as a pharmacist.

However, just two remedies, buchu and bitter aloes, made it to the British
pharmacopoeia – bitter aloes for digestive complaints, buchu to treat infections
of the urinary tract.

Often it is fragrant plants which are used medicinally, and with good
reason. Many owe their fragrance to aromatic oils, often phenolic compounds,
which have mild antibacterial action. Aromatic oils are also valuable as
decongestants and as carminatives to relieve indigestion. Local sages, for
example, are used much as Europeans use peppermint.

Another plant much used in local medicine is the local wormwood, Artemesia
afra, a highly aromatic plant popular in the Cape for treating respiratory
and digestive problems, and as a treatment for worms. The eight-day healing
bush, Lobostemon fruticosus, is used in dressings for wounds and sores.
One fynbos plant, Asclepias crispa, appears to contain a cardiac glycoside
which can be used to stimulate a failing heart.

Why so little attention has been paid to these medicines by white doctors
and patients is rooted in the prejudices of western medicine. Revealingly,
what draws most attention from whites is allegations that overexploitation
of wild plants by herb sellers is threatening some species.

Conservationists tend to refer to traditional herbal remedies in derogatory
terms, saying the best thing would be for Africans to go to Western-style
doctors instead. They use terms such as ‘plunder’ to describe the gathering
of raw materials.

But not all botanists take this stance. Tony Cunningham, until recently
based at the University of Natal, and others in Natal, are exploring how
to cultivate medicinal plants in order to replace dwindling wild stocks.
A working party established by the Botanical Society of South Africa has
had preliminary meetings with herbal healers, known locally as sangomas
(literally ‘diviners’), who want to grow their medicines rather than take
them from the wild.

Meanwhile, at least one South African drugs firm, Noristan, considers
native plants worth investigating. The company is sending extracts from
indigenous plants overseas to be tested for pharmacological activity. Its
researchers have deliberately selected fynbos plants that are already used
as herbal remedies, though so far results have been mixed: the activity
found in the tests was not always that traditionally ascribed to the plant,
and on the whole activities have proved fairly mild.

Not everyone is convinced that expensive Western-style research, in
which active compounds are identified, tested and patented, is necessarily
the best way forward for South Africa. ‘I don’t know if in this country
we can afford to have the plant extracts all standardised and purified,’
says Scott.

She shares many people’s suspicion that there may be more to many herbal
medicines than a single active ingredient; different compounds may act in
concert and the combination may well be lost in the purification. Scott
points out that the WHO warns against holding back natural remedies until
their active compounds have been isolated and analysed. Rather, the WHO
advises doctors and researchers in developing countries to perform simple,
low-cost tests on natural extracts and make as much use as they can of indigenous
remedies – a policy, says Scott, which has not been followed in South Africa.

It is often argued that the money and interest such drugs attract could
provide an important incentive for the conservation of biodiversity. But
some scientists remain sceptical.

Two of South Africa’s leading ‘enthobotanists’, Fiona Archer and Eugene
Moll, both based at the University of Cape Town, think international pharmaceutical
interest will do more harm than good, both to the people and the plants.
‘When did the First World ever pay the Third World fair prices?’ asks Moll
bluntly.

Archer considers it imperative that the rights of the people whose knowledge
the companies use are safeguarded. ‘Pharmaceutical interest,’ she says,
‘creates a demand for harvesting of the plants, and this causes shortages.’