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Restoration Conservation at Kirstenbosch National Botanical Gardens
Anthony Hitchcock
Kirstenbosch NBG.


Introduction

In 1999, the XVI International Botanical Congress called for plant conservation to be recognised as an outstanding global priority in biodiversity conservation. Following this, the Global Strategy for Plant Conservation was developed and adopted by the Conference of the Parties to the Convention on Biological Diversity in 2002 to be achieved by 2010. Target 8 of the Global Strategy for Plant Conservation focuses on ex situ conservation and reads as follows:

“60 per cent of threatened plants in accessible ex situ collections, preferably in the country of origin, and 10 per cent of them included in recovery and restoration programmes” The purpose of this article is to show how the Threatened Plants Program at Kirstenbosch has developed and been refined over the years and to highlight the progress that has been made in recent years with the help of our partners.
Background to Conservation at Kirstenbosch Gardens

Kirstenbosch National Botanical Garden is one of eight botanical gardens that form part of the South African National Biodiversity Institute (SANBI). The gardens are situated throughout South Africa with each being responsible for its own area of jurisdiction. The Karoo Desert Botanical Garden, for example, grows xerophytic plants from the winter rainfall Karoo region extending from the western to the northern-Cape. Kirstenbosch Gardens is unique as it collects and displays plants from all over South Africa and should therefore by definition collect, grow and restore threatened species from the whole country. There are over 20 500 higher plants in South Africa of which well over 2000 species are listed as threatened making this an onerous and possibly unattainable task.

Kirstenbosch Gardens has attempted to build up collections of threatened plant species within its target plant families and groups over the last few decades. The targeted families are Proteaceae, Zamiaceae, Ericaceae, Rutaceae, Restionaceae, Geraniaceae, and also include some broad groups such as trees, shrubs, medicinal plants, herbaceous perennials, geophytes and xerophytic plants.

Our success in conserving threatened plants has been limited mainly to those groups that are long-lasting such as cycads, bulbs and trees. The majority of fynbos species are however short-lived, can be difficult to grow and pose other problems such as susceptibility to various pathogens such as phytopthora.

We therefore asked ourselves the following questions when reviewing our conservation efforts:

  • How do we effectively conserve so many threatened plant species?
  • How do we preserve a good representation of the gene pool of each threatened species in ex-situ collections?
  • Where should we focus our efforts?
  • For how long can we keep these plants in effective ex-situ conservation?
  • How do we accommodate these ever increasing ex-situ collections?
  • Do we have enough staff and resources?
  • How do we get the conservation message through to policy and decision makers, the public and school learners?
Clearly there is a need to plan our conservation efforts to focus on certain key areas if we are to be effective.

Focussing our Conservation Efforts The first exercise involved looking at the conservation status of the flora in South Africa and to use available information to focus and target our efforts in conservation.

Kirstenbosch Botanical Gardens is situated in the middle of the Cape Floristic Kingdom, which is one of the world’s richest regions in biological diversity. It is estimated to have about 9000 species of vascular plants of which about 69% are endemic. (Goldblatt & Manning 2000) In addition to its high plant species diversity and endemism it is also the part of the country with the most threatened ecosystems. The western Cape lowlands near Cape Town and immediately to the east have been assessed as the most threatened ecosystems in South Africa (Rouget et al, 2004).

A comparison between lowland habitats verses mountainous or higher areas clearly shows that the Cape lowlands are the most threatened and therefore in most need of our conservation attention.

To illustrate this a comparison was made between the Cape Peninsula mountain chain and the acid sand-plain fynbos on the Cape lowlands. At the time of publication in 2004 approximately 94% of the Cape Peninsula mountain habitat still existed and of this 90% was protected whereas only 19% of acid sand-plain fynbos remained of which none is protected. (Rouget et al 2004)


Selected habitats showing remaining natural areas and levels of protection

Integrated Conservation Research done by Mathieu Rouget and his team in Geographical Information Systems (GIS), the Conservation Biology Unit including the Protea Atlas Project and the Threatened Species Project has been most useful in helping us develop a new Integrated Threatened Plant Strategy for Kirstenbosch Gardens. The new strategy still embraces the conservation targets set by the GSP, but with focus on the areas of greatest conservation need. The basic conservation strategy being implemented at Kirstenbosch Gardens is the following:

  • To target threatened habitats for conservation efforts such as the lowland areas near Cape Town
  • To target threatened species within these habitats
  • To prioritise in-situ conservation by implementing restoration where possible
  • To increase our ability to be effective by working together with researchers at Kirstenbosch and local universities, Cape Nature Conservation, Millennium Seed Bank and South African National Parks
  • To practise ex-situ conservation at Kirstenbosch Gardens in combination and collaboration with the Millennium Seed Bank Project
In this way we focus on the areas of immediate need in threatened habitats. At the same time we are expanding our ability through collaborative projects to effectively preserve a greater portion of the gene pool in the Millennium Seed Bank.

Case Studies in Restoration Two case studies are highlighted in restoration work on the Cape lowlands near Cape Town. The first involves a pilot project that was initiated some years ago between Mr Dalton Gibbs, Conservation Officer for the City of Cape Town and Kirstenbosch Gardens. This project involves the restoration of one of our ‘Flagship’ conservation species, Erica verticillata, to the Rondevlei Nature Reserve.

Erica verticillata is extinct in the wild with its most recent wild collection dating back to 1908. Two seed-producing clones have been planted at Rondevlei.


Map showing position of Rondevlei Nature Reserve and Kenilworth

Rondevlei Pilot Project

Rondevlei is a nature reserve situated within the southern suburbs of Cape Town and consists of lakes, wetlands, acid sand-plane fynbos and coastal dune vegetation. Early herbarium records indicate that Erica verticillata grew in seasonally moist acidic soils in the area and was once harvested as a cut flower.

Erica verticillata is extinct in the wild with its’ most recent wild collection dating back to 1908. Only two of the known clones produce seed, both of which have been planted at Rondevlei. The restoration was preceded by removal of invasive Acacia species. The presence of Acacias resulted in the normally nutrient poor soils been enriched, which is thought to have inhibited the initial restoration process. Plants grew much better in areas where Acacias had not invaded or where the annual grasses were first allowed to grow and use up some of the nitrogen. Harvesting and removal of large quantities of this grass by the local hippopotami also appears to have helped lower the nitrogen levels.

The Ericas were planted in a transect ranging from wet to dry soils about ten years ago. Only one of the first planting of about 20 plants survived. This plant grew well in the damp soils between the wet and dry areas. The second planting was done after the area was left for about two years. The Ericas were planted in the moist zone that had proved suitable and have since thrived in the area. They flower freely every summer and attract a range of pollinators including sunbirds.


The author with restored Erica verticillata at Rondevlei Nature Reserve

The successful restoration at Rondevlei encouraged us to pursue further restoration projects. The impetus for this came from the Millennium Seed Bank Project, which encourages the implementation of restoration programs as part of its initiative.

The Kenilworth Restoration Project

The Conservation Value of Kenilworth Race Course Habitat

Kenilworth Racecourse was established in the 1882 and the central area has been for the most part preserved since then. It was chosen as a worthwhile conservation and restoration project as it satisfied the requirements of our conservation strategy. The high concentration of threatened species and the rarity of the habitat type give the natural area of Kenilworth Racecourse a very high conservation priority. This natural remnant comprises by far the best example of Sand Plain Fynbos remaining in either the Cape Peninsula or Cape Flats. This vegetation type has been virtually eliminated by urban and agricultural development and by alien invasive vegetation. A separate study has shown that the nine natural seasonal wetlands on the centre of the racecourse are among those of the highest quality in the southwestern Cape (Silberbauer and King). The main reason for this phenomenon is probably linked to the low level of disturbance and lack of inflow of water-borne pollution into the Kenilworth Racecourse wetlands. The water originates largely from natural seepage points in the centre of the racecourse.

The natural area is about 42 hectares in size and contains about 271 plant species of which at least 19 are red listed. It used to be home for two Extinct in the Wild species namely, Erica verticillata and Erica turgida, which are fortunately preserved in the ex situ collections at Kirstenbosch.

Erica verticillata is recorded in the herbarium to have grown in the Kenilworth area and well-known fynbos botanist Elsie Esterhuizen collected Erica turgida from the racecourse for Kirstenbosch in 1970.

In addition to floral richness Kenilworth is home to a comprehensive faunal component. The management plan lists 7 mammals, 66 bird species (1 red listed), 17 reptiles, 11 amphibians (3 red listed) and 13 aquatic invertebrates.


Erica turgida ‘Extinct in the Wild’

Status of Kenilworth Racecourse Habitat

The company Gold Circle owns the racecourse and the natural area in the centre. A management agreement was established between Gold Circle and Cape Nature Conservation, also known as ‘Cape Nature’, where both parties agreed to collaborate in preserving the conservation area. This land unfortunately has no conservation status at the moment, but Cape Nature would like to establish it as a contractual reserve. This is very important because the natural area at the racecourse is a threatened habitat of international conservation value.

Successful Restoration Depends Upon Collaboration

Collaboration is the recipe for success in restoration projects. The Kenilworth project involves close collaboration between the South African National Biodiversity Institute (SANBI), the Millennium Seed Bank Project and Cape Nature. Within SANBI, researchers in conservation biology, systematics and molecular systematics are working together with Kirstenbosch horticulturists. The Millennium Seed Bank Project is also involved in the Kenilworth Project through banking seed from the conservation area and providing much needed funding and hands on support for the restoration work.

We are working with the Cape Nature to put the restoration process into effect. Cape Nature is the essential catalyst for restoration as they are the custodians of natural areas and it is through them that we carry out our restoration work.

Memoranda of Understanding

Our experience when working with other organizations or departments is that there is the potential for misunderstandings and confusion given different priorities and staff systems. For this reason we recommend formalising collaborative projects through Memoranda of Understanding (MOU’s). In this way both parties define their respective roles and commitments. If in the unlikely event any problems or disputes arise then the MOU is the basis to which the parties fall back on to resolve the issues. The MOU serves to provide a framework within which the parties operate.

We have MOUs with the MSBP that cover the collaborative operating arrangement between SANBI and KEW. In addition there is an internal MOU between Kirstenbosch Gardens and our partners in Research, namely Custodians of Rare and Endangered Wildlife (CREW). This MOU includes agreement to work together on conservation matters of mutual interest, but also serves as an undertaking by both parties to protect sensitive information such as localities of threatened plants.

We also have a MOU with Cape Nature that covers our working relationship regarding our collaborative restoration projects. This is important as both parties commit time, money and resources to these projects. One of the most positive aspects of collaboration between these parties is the seed harvesting and cleaning training given by MSB Cape staff to Nature Conservation staff. Once trained they assist our efforts in collecting seed in designated project areas such as at Kenilworth.

Kenilworth Restoration Planning

The restoration of the natural areas at Kenilworth Racecourse has involved a planned, properly co-ordinated series of activities. The basis for the restoration is a management plan that was drawn up by Dr Clive McDowell. This report highlighted the need for proper land management. The area has been protected from natural events such as fire for over 100 years. Fynbos is fire adapted and with long term exclusion of fire there has developed senescent vegetation, resultant lack of recruitment and therefore disappearance of some short lived species. There have also been other detrimental influences such as dumping and a proliferation of alien invasive plants.

With the need to burn established we had to make some important decisions and do some planning. We also had to take into account factors such as:

  • Kenilworth Racecourse is within a city urban environment
  • The land is privately owned
  • There are horse quarantine stables within the area
  • Decide how much of the area to burn at one time (burn assessment)
  • Removal of invasive plants prior to burning
  • Rescue as much fauna as possible prior to burning
  • Atlas the threatened species prior to burning (Kenilworth Threatened Species Atlas)
  • Decide which extinct in the wild Erica verticillata and E. turgida clones to use in restoration
  • Decide what post burn monitoring needed to be done

Nature Conservation Manager, botanists and ecologists discussing restoration plans An ecologist from the University of Cape Town was brought in to do a burn assessment. He gave advice on which section to burn and the best time to do this. Plans were drawn up between Cape Nature and Kirstenbosch managers to complete invasive plant removal and an atlas of threatened species was commissioned prior to the burn. Seed was collected by Millennium Seed Bank staff for banking and a portion kept for restoration of damaged areas. The Cape Nature manager, Chrizette Kleinhans, prepared plans for burn permits, press releases and traffic and crowd control and permission from the landowner.

The burn was set for February 2004, but was postponed as there was an outbreak of horse flu and the racehorses could not be moved out of the quarantine stable, which is adjacent to the burn area. The late summer window period for burning fynbos passed so plans were put on hold until early 2005. The burn eventually took place at the end of March 2005 after some more delays.


Controlled burn at Kenilworth in March 2005

Restoration

We decided to leave the burnt area to recruit naturally with the minimum of human interference save for restoring the two ‘extinct in the wild’ Ericas. These were planted in two areas in late May and early June 2005 after good soaking early winter rains. Suitable sites were chosen with the help of Dalton Gibbs who had successfully restored them to Rondevlei Nature Reserve. One batch was planted in the un-burnt area where the ground is moist. The second batch of Erica verticillata was planted in seasonally wet areas in the burnt site. Erica turgida was planted on higher ground where it is drier and better drained.

Plants of one clone of Erica turgida was planted being the original collection from Kenilworth Racecourse in 1970. Plants from two clones of Erica verticillata were planted being the same two clones that were restored to Rondevlei Nature Reserve and that produce viable seed. The other three clones in our ex-situ collections do not produce seed in open pollination situations. The Erica verticillata clones were validated by Erica systematist, Dr Ted Oliver, and by AFLP fingerprinting by our molecular biologists prior to being used in restoration.


Kirstenbosch Horticulturists and Dalton Gibbs restoring Erica verticillata to Kenilworth

Post-burn Monitoring

The post-burn monitoring includes random plot sampling to assess plant diversity on Kenilworth Racecourse. The Kenilworth Threatened Species Atlas work continues in order to compare the status of the threatened plants prior to burning with that after the burn. We hope that the burn will stimulate the revitalization of the flora as a whole and that we will see an improvement in the condition and number of the threatened species.

Post burn monitoring also includes the alien invasive flora, which will be eradicated.

Challenges to Restoration

The projects highlighted in this article are progressing well, but there remain daunting challenges. The most immediate challenge is habitat loss and fragmentation. The city of Cape Town is growing very fast and there is an ever-increasing need for land for housing and resources to support the increasing population in the area.

Co-operation from landowners with natural vegetation on their property is not always forthcoming. There is little or no incentive to preserve natural habitats and a property owner can get substantial financial reward by selling property for development. The local community could play a significant role in lobbying to protect natural areas, but there is a great deal of indifference and lack of knowledge on the conservation value of our flora.

The Nature Conservation authorities are doing their best to preserve the remaining natural areas within their capacity and limited budgets. The intensity of management input by Nature Conservation in projects such as Kenilworth may be worth the effort, but it reduces their capacity to work on other conservation projects.

While we are attempting to conserve as much of what remains of our natural habitats the ever-increasing threat of climate change might have the final say.

Summary

A number of questions were posed about the challenges and approach to conservation at Kirstenbosch Botanical Gardens in this article. The answers to these questions are as follows:

  • Seed stored in seed banks is the only effective means of conserving genetic collections of threatened species in ex-situ collections in the long term
  • We need to focus our efforts on in-situ conservation and therefore habitat conservation as our first priority
  • Seed banks allow for long term preservation of threatened species and are far more effective in storing the large and increasing numbers of these species
  • Effective conservation requires collaboration between conservation organizations as we do not have enough staff and resources to be effective on our own
  • The conservation message can be passed on to the public and schools through high profile conservation projects using ‘flagship threatened species’ such as has been done at Rondevlei Nature Reserve and Kenilworth Racecourse
Conclusion

Our habitats are disappearing faster than we can preserve any part of them. Many Cape lowlands plant species will be lost in the next 50 years at current rates of development and land alteration. Incentives need to be created to encourage landowners to preserve some portion of their land where natural vegetation occurs. The reality is that this will probably not happen in the short term.

The South African National Biodiversity Institute can through its research make a significant contribution to conservation in South Africa. Research in geographical information, vegetation mapping, conservation biology and climate change are important in influencing government policy in land development planning. This is most important because plants are best preserved in their natural habitats.

Botanical Gardens can make a significant contribution to conservation as long as realistic and achievable goals are set. These include a greater emphasis on habitat restoration projects in collaboration with researchers and conservation organizations.

Ex-situ threatened plants collections management at Kirstenbosch, particularly with the short-lived and disease prone fynbos flora cannot effectively conserve most species. These collections are ‘genetic bottlenecks’ and should be seen as preservation rather than conservation. Ex-situ genetically representative collections can not be effectively conserved in living collections in Botanic Gardens and therefore the best alternative to restoration is long term preservation in properly managed seed banks.

Living collections displayed in botanical gardens are however very useful as an educational tool to create awareness amongst the public and school learners provided they are accompanied by effective interpretation.

References

Goldblatt, P. & Manning, J. 2000 Cape Plants. A conspectus of the Cape Flora of South Africa. Strelitzia 9.
Grindley, J. 1950. A survey of the bird species at Kenilworth Racecourse. Unpublished data.
McDowell, C. 1989a. Conservation and horse racing: the unseen connection (Part 1.) Veld & Flora 75: 36-39.
McDowell, C. 1989b. Conservation and horse racing: the unseen connection (Part 2.) Veld & Flora 75: 79.
McDowell, C., Low, A.B., and McKenzie, B. 1990. Natural remnants and corridors in Greater Cape Town: their role in threatened plant conservation. In: Nature Conservation: the Role of Corridors (Proceedings of conference held in Brusselton, Western Australia.
McDowell, C., Low, A.B. 1989. Conservation Priority Survey of the Cape Flats. Cape Town City Council, Cape Town.
McDowell, C.R. and Brown, L.B. 1991. Conservation Management Plan for the Kenilworth Racecourse Fynbos and Surrounding Area.
Rouget, M, et al (2004) South African National Spatial Biodiversity Assessment. Technical Report. Vol. 1: Terrestrial Component. South African National Biodiversity Institute, Cape Town. South Africa.
Silberbauer, M., and King, J.1990. Water quality of the wetlands in the south-west Cape.