Threatened Plants
Programmes: Kirstenbosch NBG
Cape Flats Fynbos
After a shift in focus, the Kirstenbosch Threatened Plants Programme (TPP) is concentrating its efforts, in collaboration with Cape Nature Conservation, on threatened species of fynbos on the Cape Flats near Cape Town.
Background
The Kirstenbosch
TPP has undergone considerable changes over the last few years. Up until
2000, the approach was to identify rare plants from published Red Data lists
and to target and collect as many of these as possible. The ‘fynbos’ families
were the main focus, particularly the Proteas and Ericas. The aim was to
collect as many ‘rare’ species as possible and to grow them in pots or for
the garden, depending on where they were most likely to survive. Little
or no thought was given to critical factors such as how representative these
collections were of the gene pool, whether the habitat was threatened, or
whether we could manage all these collections properly and keep the plants
alive.
Many
of the rare fynbos species are very difficult to keep alive because they
are susceptible to numerous diseases and are short-lived. The truth of the
matter is that the gene pool of each species was poorly represented in our
‘rare’ collections, rendering them insignificant in terms of conservation
value. The challenge therefore was to develop a TPP that would be practical
in its implementation and that would yield tangible results.
We
decided that we would focus our attention on those threatened species that
grow in threatened habitats, particularly in the Cape Floristic Kingdom.
Consequently, the areas that qualify most for our attention are those under
pressure on the Cape Flats near Cape Town. Rare species that are relatively
safe on mountain tops or in reserves are regarded as less of a priority
as their habitats are not directly threatened.
Implementation
We decided that two main conservation areas
(Core Conservation Sites) were to receive attention under our TPP. In addition,
we had to focus on the species that deserved our special attention. This
required meeting local representatives of Nature Conservation authorities
responsible for the areas to draw up a strategy for conserving the habitat
and the threatened plants.
We
decided on two main areas, namely Plattekloof National Heritage Site, about
20 km outside Cape Town and Rondevlei Nature Reserve near Muizenberg. Plattekloof
has some of the last natural populations of Serruria aemula and a
number of other red data species, such as Leucadendron levisanus.
Rondevlei also has some very rare lowlands fynbos and is the habitat for
the ‘extinct in the wild’ Erica verticillata.
Fortunately,
there were management plans already in place for these areas. The local
Conservation Officers are very keen that we form partnerships with them.
They need Kirstenbosch plant and horticultural knowledge to assist in the
restoration of damaged areas within their reserves.
Plattekloof
National Heritage Site
The Plattekloof Natural Heritage Site falls
under the main ESKOM power lines that supply the city. Eskom was supposed
to manage the heritage site, but the management plans that professional
conservation ecologists drew up were not adhered to. The area now falls
under the management of the City Nature Conservation authorities with whom
we collaborate. Steyn Marais is the manager in charge of the area.
Two
Red Data species were earmarked for restoration at Plattekloof, namely the
endangered Serruria aemula and the rare Leucadendron levisanus.
Cuttings
were collected from these plants and rooted at the Kirstenbosch nursery.
These were grown on in steam-sterilized soil until the plants were ready
for planting and conditions were suitable. Planting took place on 12 June
2003 after the first winter rains. Kirstenbosch horticulturists were present
to show Nature Conservation the correct method of planting.
Monitoring
Trevor Adams (Plant Propagator) and I followed
up planting by visiting the site every two months. The plants grew steadily
until the end of October. I visited Plattekloof again on 18 December 2003.
Unfortunately, the majority of both species have died since the end of October
even though they were showing active growth then. I assume that this is
the natural loss associated with certain susceptible fynbos species. This
makes me think that we should concentrate on broadcasting seed of these
species as well as planting to achieve success. Perhaps the very dry winter
also played a role in the losses. Natural regeneration of a range of species
has been quite good in some areas. I have suggested we involve the Millennium
Seed Bank in a project to assist rehabilitation as part of the next 5-year
plan, starting in 2005.
Rondevlei
Nature Reserve Restoration
We have been working with Nature Conservation
Officer, Dalton Gibbs, on the restoration of ‘extinct in the wild’ Erica
verticillata. We supplied Rondevlei with plants of one clone of this
species for initial trial on the site. The trial planting showed us the
niche habitat where the Erica would survive. More plants were supplied and
these have established and thrived in the habitat. A second clone of this
species was planted in July/August 2002 and has been established successfully.
Long-term
Survival
The different clones of Erica verticillata
are very poor producers of seed. The reason for this low viability is
unknown, as Erica usually produces copious quantities of seed. Flower heads
collected from plants at Rondevlei are open-pollinated by a range of pollinators
including sunbirds, long probiscid flies, moths, and bees. Seed set is still
low despite active pollination, but it has been noticed that it is a bit
higher where the two different Erica verticillata clones exist together.
Conservation
Genetics
I approached Dr Gail Reeves at the Hill Molecular
Laboratory for her assistance in establishing the validity of the genetic
material of our Erica verticillata clones. This will indicate to
us whether they are different clones or if there is some duplication.
The
Hill Laboratory has done primary genetic fingerprinting of Erica verticillata
clones and established that there are currently five distinct clones in
our collections. We will use this information to plan how we are to proceed
with intra-specific hybridisation in the hope of increasing the viability
of the seed. A restoration programme using these plants will only be viable
if they produce enough seed for good recruitment after fire.
Erica
clones tested
|
Erica
verticillata |
536/84 |
Pretoria
clone |
|
|
294/90 |
Kirstenbosch
clone |
|
|
594/84 |
Kew
clone |
|
|
109/01 |
Vienna
clone |
|
|
110/01 |
Vienna
clone |
Although
Erica turgida does not officially form part of this programme, we
are planning to plant it at Rondevlei as it has become extinct at the Kenilworth
site. This is possibly due to poor land management. We have also been asked
by Cape Nature Conservation to grow plants of Erica turgida and Erica
verticillata for restoration at Kenilworth Race Course where they have
taken on a monitoring role. A collaborative project with Nature Conservation,
incorporating the management and restoration of the Kenilworth Race Course
site, which is of high value in conservation terms, is in the planning stage.
Garden
of Extinction
The “Garden
of Extinction” is being developed at the new Centre for Home Gardening at
Kirstenbosch. The idea is that we make the public more aware of the plight
of many of our plants which we are in danger of losing. The garden will
display threatened plants from around the country with emphasis on those
that are good horticultural subjects. Interpretive boards have been designed
to explain the concepts and threats.
Insurance
The Kirstenbosch
Threatened Plants Project has many challenges and is dependent on a number
of factors that could mean success or failure. To make sure that we have
a better chance of success and play a more meaningful role in the conservation
of threatened plants, we have an insurance policy.
The
insurance policy takes the form of the Millennium Seed Bank Project, which
is a global initiative emanating from the Royal Botanical Gardens Kew. The
project involves collecting and storing seeds of a wide range of our flora
under controlled environmental conditions. This ensures long-term storage
and survival of the species even if it dies out in its natural habitat.
The seed is stored for the country of origin in case it is needed to restore
plants that have been lost.
Finally
The TPP could
not progress or have a chance of success if it were not for the excellent
help and support from other directorates within the NBI
(now SANBI).
I would like to mention in particular, the Research Directorate and their
various branches, such as the Herbarium, Conservation Biology, Molecular
Lab, and the Climate Change Research Group. Outside the NBI, we have very
good relations with Cape Nature Conservation and are collaborating on conservation
projects with them.
—Anthony
Hitchcock
SABONET News 9.1: 48
