Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
A female Winterberg
cycad with each stem
bearing a single cone.
O pposite.
The W interberg
cy cad growing
am ongst rocks in the
E astern Cape.
Photos: John Donaldson
THE WINTERBERG CYCAD
Surviving against the odds.
by fohn Donaldson, Conservation Biology R esearch Unit, N ational B otanical Institute
he mention of cycads
conjures up images of
primeval landscapes with
spewing volcanoes and wandering
dinosaurs. Although these images
are not strictly correct, they
present a graphic picture of a
world that was; and now the
volcanoes are quiet (except for the
occasional hiccup) and the
dinosaurs are gone and not even
the reconstructive genius of
Jurassic Park can bring them back.
But what of the cycads? These
extraordinary plants outlived the
dinosaurs and, until recently,
survived in relatively large
numbers in parts of Central and
South America, southern Africa
and Australasia. Yet, today cycads
are well known to many South
Africans for one primary reason they are going extinct!
Natural attrition has been
greatly accelerated by the relent­
less removal of cycads from the
wild and the destruction of their
habitat over the past 50 - 100
years. The sad reality is that many
T
36
cycads will inevitably share the
fate of the dinosaurs, at least as far
as their existence in nature is
concerned. But before we sink into
the mire of despair or simply sit
back and wait for the cycads to die
out, we need to be reminded that
there are some success stories of
cycads holding their own despite
the tremendous odds stacked
against them, giving us an insight
into the attributes that have
enabled them to survive for so
long. How do plants that evolved
with the seed ferns and dinosaurs
cope in a world full of
angiosperms and mammals and
what can we learn about survival
in an environment forever altered
by human influences?
A good example of a cycad
holding its own is the Winterberg
cycad, Encephalartos
cycadifolius. As its common
name implies, E. cycadifolius is
restricted to the Winterberg
mountain range of the eastern
Cape where it occurs in Karroid
mountain veld. Anyone whose
image of cycads is of stylized,
palm-like plants will probably be
disappointed by E. cycadifolius.
One of the ugly sisters of South
African cycads, it lacks the
majesty of its tall arboreal relatives
and the graceful leaves of forest
cycads. Instead, E. cycadifolius is
characterized by an underground
stem that suckers freely from the
base so that a mature plant usually
appears as a cluster of stems with
each stem protruding only slightly
above the ground and terminating
in an untidy crown of short tough
leaves. Everything about the plant
suggests that it is adapted to
survive in a harsh and uncompro­
mising environment and that its
unattractive features are the very
essence of its survival.
In a recent update of cycad
numbers throughout the world, it
was estimated that there were only
4 800 E. cycadifolius plants left in
the wild. Fortunately, this figure
appears to be conservative, as in a
study of cycad populations
sponsored by the Mazda Wildlife
Veld &■Flora June 1 9 9 5
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
The burnt rem ains of a
W interberg cy cad after a veld-fire.
Photo: John Donaldson
Fund, two colleagues and I found
more than 10 000 adult
E. cycadifolius plants in the areas
we visited. We were unable to get
to all the known populations so
the total figure may be somewhere
between 10 000 and 20 000 plants.
This places E. cycadifolius in a
select group of only 6 South
African species of Encephalartos
estimated to have more than
10 000 individuals left in the wild.
Most of the other 25 South African
species have substantially fewer.
Fire
Fire occurs frequently in the grass­
lands of the Winterberg, destroying
most of the above-ground parts of
E. cycadifolius. All that remains is
a charred stump that may some­
times be adorned by the rachi of
the burned leaves. But far from
destroying the plant, fire stimu­
lates growth and reproduction.
A flush of new leaves is produced
after a fire: the soft green foliage
standing out in stark contrast to
the blackened surroundings. The
most spectacular response
happens only a few years after a
fire when all the mature plants in
a burnt area reproduce simultane­
ously in a mass coning event that
follows several years when no
sexual reproduction takes place.
This dramatic phenomenon,
known as mast seeding, is most
evident at firebreaks where all the
mature plants on the burnt side
will produce cones whereas those
on the unburnt side will not.
38
This does not mean that all fires
are good for the Winterberg cycad.
Frequent fires are most likely to be
detrimental as seed-germination
and seedling-establishment are
notoriously slow in most cycads,
and the Winterberg cycad is no
exception. Seeds germinate over a
period of 18 months to 2 years and
seedlings may become established
only several years after the seeds
are shed from the parent plant. If
fire recurs within this critical
period the seeds and seedlings are
destroyed. A further point is that
field studies have shown that
seeds survive and germinate more
readily under low shrubs, where
they appear to be hoarded by
rodents, than in open grassland.
These shrubs may disappear when
the veld is burned too often
thereby removing potential germi­
nation sites for cycad seeds. When
this happens, the seeds are stored
under established adult cycads
where they germinate in the
pockets of soil that accumulate
between the stems of the mature
plant. But alas, these seedlings are
doomed to die when they deplete
the limited resources available in
these small pockets of soil.
Pollination
Is cycad pollen dispersed by
wind or insects? This has been a
perennial question asked about
cycad pollination at least since
1906 when Prof. Harold Pearson
wrote about the likelihood of
insect pollination in some South
African cycads. The Winterberg
cycad is the only South African
cycad of w hich there is any doubt
that insects are involved: when
insects are prevented from visiting
the female cones, fewer than 30%
of the ovules are pollinated
compared with 98% when insects
are present.
The insects responsible for
pollination are two beetles that
also have connections with cycads
elsewhere in the world: one is
M etacucujus encephalarti which
is related to the genus Paracucujus
found on cycads in Australia, and
the other is an undescribed
species in the family Lobariidae
that is related to beetles associated
with cycads in Central and North
America.
A point of concern in cycad
conservation circles is that
dependence on insect pollinators
increases the likelihood of extinc­
tion because pollinators may die
out and effectively emasculate the
population. Already there is spec­
ulation that the absence of fertile
seed in some cycad populations
(e.g. M icrocycas calocom a in
Cuba) is due to the disappearance
of specific insect pollinators.
Fortunately, this scenario does not
seem to apply to the Winterberg
cycad. Beetle pollinators abound
in the male and female cones and
the high proportion of fertile seed
(98% ) indicates that reproduction
is not limited by a shortage of
pollinators.
A further discovery that may
have implications for the survival
of other South African cycads, is
that the two beetles involved in
pollination are not restricted to the
Winterberg cycad but also occur
on several other cycads in South
Africa. This means that it may be
possible to transfer pollinators to
other cycad populations where
the beetles have declined or
disappeared.
Veld & Flora June 1995
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
Persistence
From a conservation point of view,
an important question is how long
populations of the Winterberg
cycad can survive in nature with­
out some sort of assistance? The
immediate but superficial answer
is that they w^ould survive for a
very long time. A striking feature
of E. cycadifolius populations is
the stubborn persistence of estab­
lished adult plants. Each plant
regularly produces new basal
G erm inated cy cad seeds, sco rch ed by a
veld-flre. Photo: John Donaldson
suckers that may develop their
own root systems so that estab­
lished adults can potentially live
forever; individual suckers may
die but the remainder of the plant
lives on. In a study of several large
populations, no adult mortality
was recorded over a 5 year period
although individual stems
regularly died.
The persistence of adult plants
seems to be the main reason why
the Winterberg cycad has survived
because there are almost no
seedlings or juveniles in most
populations. The average plant has
6 stems which, given the slow^
growth rate of this cycad under
natural conditions, means that
these plants may be anything up
to several hundred years old. The
largest plant we found had 67
stems and who knows how old
that must be!
An unknown factor is how long
adult plants will survive under
veld-management designed for
stock grazing, especially the
regular occurrence of fire. The
frequency of natural fires is
estimated to be 8 - 15 years and
it appears that E. cycadifolius is
Veld S' Flora June 1995
adapted to reproduce sexually
once during this period. In the
other years, resources are appar­
ently used for growth and the
production of additional suckers,
or they are stored for the produc­
tion of cones after fire. When fires
occur more frequently, the plants
may continually channel all their
resources into the production of
cones and not into vegetative
growth. This means that the old
plants will become increasingly
moribund without the addition of
new suckers while no new plants
will be added to the population
because the seeds and seedlings
are charred before they can
become established.
As with all long-lived plants,
the danger is that we may miss the
fact that they are declining
because the effect is subtle and
may take place over a long period.
A study to determine the effects of
veld management on cycad
populations would probably be
welcomed by the local farmers
who jealously guard their cycad
flora and eagerly await their
reproductive events.
The future
With so many individuals of
E. cycadifolius remaining in the
wild, we might be tempted to say
that their future is secure. But
numbers are all relative and we do
not need to look beyond southern
Africa to find several examples of
plants and animals where popula­
tion numbers have declined
spectacularly within a few
decades. Cycads themselves
provide one of the best examples.
The most important first step is to
ensure that adult plants are not
collected from the wild because
the future of the Winterberg cycad
depends almost entirely on the
survival of existing adult plants.
Fortunately, the Winterberg cycad
seems to have so far escaped the
excessive attentions of avaricious
collectors, and local farmers
certainly deserve credit for
protecting these plants which all
occur on private land.
The inaccessibility of
E. cycadifolius populations and
difficulties experienced in trans­
planting this cycad have probably
also deterred would-be collectors.
On the positive side,
E. cycadifolius is readily grown
from seed and the demand among
collectors could easily be met from
propagated plants. A vast excess of
fertile seed is produced during a
mast year and only a small propor­
tion of the seeds is dispersed to
sites suitable for germination - the
remainder lie on the ground in
their thousands where they desic­
cate and die. As long as dispersed
seeds are left alone, the remaining
seeds can probably be harvested
without affecting the viability of
the population in any way. In this
way, farmers may be able to obtain
a small return on their investment
in the well-being of the Winterberg
cycad. At the same time, inter­
ested growers and collectors can
enjoy this unusual plant while the
adult cycads in the wild can look
forward to several more centuries
in the sun. #
A cknow ledgm ents
My thanks to V ictor Pringle and Noel Ross
for their generous ad vice and support and
to the M azda W ild life Fund for its sponsor­
ship o f the Cycad C onservation P roject.
THE CYCAD
CONSERVATION PROJECT
The Cycad Conservation Project
was launched in 1992 by the
National Botanical Institute with
the aims of promoting cycad conser­
vation through the propagation and
cultivation of threatened species in
the National Botanical Gardens.
A research component will also
determine priorities for conserva­
tion, the chances of survival for
different cycad populations, and
the best management strategies to
ensure long-term survival of wild
cycad populations. As research
necessitates extensive visits to
natural populations, a vehicle
dedicated to this purpose was
provided by the Mazda Wildlife
Fund.
If you would like to help sponsor
the programme, which has developed
close links with other organizations
involved in cycad conservation
including the Botanical Society, or
would like more information,
contact Dr John Donaldson:
tel (021) 762 1166,
fax (021) 762 3229.
Wiu'ure R:np
NMl l H
-■.!*».
39