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The role of Kisantu Botanical Garden in biodiversity conservation: a first effort to sustainably manage useful plants of Bas Congo

Volume 10 Number 2 - July 2013

Introduction

The Democratic Republic of Congo is demographically in rapid evolution. The annual population growth is above 3% and according to the latest estimates, the population will increase from 73 million in 2012 to about 190 million in 2050 (Marien et al., 2013). This population increase is occurring mainly in the cities and is only poorly controlled, causing adverse effects on natural resources.

The basic needs for food and wood energy contribute to the overexploitation of resources in urban and suburban areas and the degradation of natural ecosystems in an even wider area. This is certainly the case for the city of Kinshasa, a megalopolis of 8 million inhabitants, which strongly affects the entire Bas Congo region.

To augment agricultural production, environmentally harmful practices are increasingly used. These include slash and burn agriculture, monoculture (especially cassava), shortening of the fallow period with the consequent overexploitation of soils and recurring bush fires.

In addition, the need of charcoal ("makala") to fulfil the energy needs of Kinshasa has accelerated the modification of ecosystems in the region: forest fallows have been reduced, erosion has increased and biodiversity has decreased.  Due to the lack of alternatives, even fruit trees are cut to produce charcoal for daily cooking. Important savannah plants such as Imperata cilindrica (Poaceae) for thatching roofs are disappearing at a high rate and are substituted by invasive exotic species such as Chromolaena odorata. 

Traditionally, the population of the Bas Congo used a wide variety of plants and products for their daily needs: such as leaves, fruits and seeds for food, bark for medicine and trees for construction and energy. However rapid population growth and loss of biodiversity has meant that knowledge about the traditional, sustainable use of plants is being lost and replaced by unsustainable exploitation of the natural resources.

Kisantu Botanical Garden

Located 120 km south of Kinshasa, the Botanical Garden of Kisantu (JBK) is a vast garden of 225 ha. A Jesuit Mission created the garden in 1900 in order to introduce useful and economically beneficial plants to the Democratic Republic of Congo. Initially, efforts were made to cultivate plants to feed the missionaries but these soon became part of the diet of the local population. A range of vegetables and fruits were introduced to the Bas Congo region and throughout the Democratic Republic of Congo such as potatoes, carrots, onions, tomatoes, rice, mangosteen …

Kisantu was a thriving scientific institution until 1980 when the decline of the governmental institutions began. The infrastructure was all but destroyed by lack of maintenance and by war; living collections were left untended, and the government failed to allocate financial resources to the Garden.

Despite this, a core group of devoted researchers and technicians managed, against the odds, to preserve the Garden’s potential. Thanks to these few individuals, the loss of local knowledge of Central Africa‘s rich flora has been limited and the heritage of the institution has been kept alive.

In 2004 the European Union financed the program for the rehabilitation of the protected areas of the Democratic Republic of Congo and this included the Kisantu Botanic Garden. The World Wildlife Fund (WWF) and the National Botanic Garden of Belgium (NBGB) provided technical assistance, logistical support and advice to the program.

At the Garden, progress has been swift. During the past eight years, infrastructure, paths, plantations, glasshouses, living collections, herbaria, library, and the Internet have been improved or established. The revival of scientific research has been one of the pillars of the program: this activity is absolutely necessary to fulfil the educational and conservation functions of the Garden.

Since its rehabilitation, Kisantu has become one of the most advanced botanical gardens in Central Africa and is ready to play an important role in nature conservation. The success of the restoration project can be seen in many aspects, for example in the impressive increase in visitor numbers. In 2005, 9,000 people came to the Kisantu Botanic Garden compared with 35,000 in 2011.


The role of Kisantu in the development of Bas Congo region

The Garden includes the only remaining forest in the District of Lukaya, and in the vicinity of the towns of Inkisi and Kisantu. The surrounding natural vegetation in the area of the Kisantu Garden has disappeared, as the result of human activities, only secondary vegetation remains. Even in recent times, people came to the garden to harvest leaves, fruits, medicinal plants, wood etc. in an almost uncontrolled way.

In order to support the local community, the Garden’s direction and the NBGB staff have developed activities of reforestation and plant propagation, with a focus on fuel wood, medicinal plants, host plants for caterpillars (for cultivating these protein-rich insects), plants that attract honeybees, vegetables and a range of different fruits. The ultimate goals are to provide the local communities with a supply of useful plants with which, as in the past, they can surround their homes and which are available for direct and immediate use, while at the same time, conserving the Bas Congo’s original vegetation where it still occurs.

In order to the implement this project four tasks were defined:

  • Carry out a literature review of plants traditionally used by the local communities;
  • Carry out a socio-economic and ethno-botanical analysis of resource exploitation;
  • Establish living collections of plants and study their development;
  • Test simple techniques of reproduction and domestication of useful plants in the Kisantu Botanic Garden.

These actions need trained teams in the field of plant production (hence the need to strengthen the nursery facilities) and communication and awareness raising (environmental education).
Useful plants were grouped into four categories - namely:

  1.  Host plants for caterpillars;
  2. Honey plants;
  3. Medicinal plants;
  4. “Forgotten” vegetables


Results

The literature review highlighted that for several years very few studies or research had been conducted on plants and vegetables traditionally consumed in the region.

The last author and the horticulture team of the garden of Kisantu conducted interviews with community leaders and farmers around Kisantu. The most spectacular result was the unforeseen wealth of medicinal plants and vegetables used today or in the past. In sharp contrast, the knowledge on the ecology and better cultivation methods of these useful plants were largely lacking. The garden of Kisantu therefore started a program to propagate these plants and to develop strategies for their sustainable use.

Host plants for caterpillars – Caterpillars are part of the traditional cuisine of the population and they are used in many traditional dishes. In addition they form a very important source of proteins and minerals. The survey showed that seven of the most popular caterpillar species are mainly found on seventeen indigenous plant species, belonging to eleven families. With the disappearance of these species, the caterpillars also disappear. Replanting these species in and around the villages will result in a partial restoration of the original vegetation and encourage more caterpillars, therefore providing important nutrients to the poorest families (Malaisse 1997).

Honey plants – The people of Bas Congo know about eighteen honey plants belonging to eight families. Knowledge and use of honey in this region dates back to the earliest days of its history and it is undoubtedly part of the oldest foods. In addition to its use as a food, honey is used for its healing properties and to beautify the skin.

Medicinal plants – About 25 medicinal plants belonging to 21 families are still used by local communities of the Bas Congo. Different parts of the same plant may have different uses. Plants with medicinal properties also sometimes have culinary uses.

“Forgotten” vegetables – About 35 edible plant species were identified that could be categorized as “forgotten“ vegetables. Some have been introduced a long time ago and knowledge is lost of how to cultivate them, while others are indigenous species that have become very rare as the natural habitat has been destroyed. Some species, such as Gnetum africanum, have become so rare in the area that they are now imported into the region from as far as Kisangani, more than 1,750 km from Kinshasa. (Ingram et al.,  2010)

To conserve these vegetables and the traditional dishes derived from them, fields of these plants were established within the Kisantu Botanical Garden. These were grown from seeds that were harvested in villages where the plants are still cultivated. They form a living museum to educate children and visitors about these traditionally used plants and how they can be cultivated.

Finally, the aim is to have enough seeds to distribute to interested visitors (for which there is a high demand) and to introduce these vegetables into the garden restaurant menu for a "taste" of the flavours of the past.

Conclusion

Anthropogenic disturbances in the ecosystems of the Bas Congo province are mainly related to shifting cultivation techniques and the unsustainable exploitation of forest resources. This strongly affects the quality of life and well-being of the local people. Natural resources that traditionally played an important role in the daily lives of thousands of people have become very rare and knowledge about their proper utilisation is fading quickly.

The botanical gardens in the Congo Basin have an important role to play in raising public awareness, particularly in urban areas, about the importance of natural ecosystems and the ecosystem services they provide. They should convey information about the main themes for the protection of the environment (deforestation, fuel wood, global warming, biodiversity conservation, endangered species) and promote environmental education (Ingram et al., 2010). Recent activities developed by the Kisantu Botanic Garden show how the garden contributes to this overall mission at a small scale, but with very concrete actions. Apart from the installation of a vegetable and medicinal garden, the Garden has planted 6.5ha of local and introduced tree species to highlight the role of trees in local agricultural systems and in the sustainable production of wood for fuel. It is to be hoped that the Kisantu Botanic Garden can continue its mission in the future and that it can play an even more prominent role in safeguarding indigenous plants and the local knowledge about these natural resources.

References

  • Ingram, V., Ndoye, O., Midoko Iponga, D. 2011. The forest of Congo Bassin: State of the forest 2010, chapter 7.
  • Latham, P. 2004. Useful plants of Bas Congo Provinces DRC Armée du Salut de Kinshasa, RDC.
  • Malaisse, F. 1997. Se nourrir en forêt claire africaine : Centre Technique de Coopération Agricole et Rurale (CTA), Wageningen (Netherlands).
  • Marien, J.N., Dubiez., Louppe, D. 2013. Quand la ville mange la forêt le défis du bois énergie en Afrique centrale. Ed. Quae.


Francesco Lanata, Steven Dessein
National Botanic Garden of Belgium,
Domein van Bouchout,
BE-1860 Meise, Belgium

Leopold Nsimundele
Botanic Garden of Kisantu,
D.R.Congo