Sri Lanka has a rich flora consisting of some 3,000 species of vascular plants, over a quarter of which are endemic. The number of species used in traditional medicine is estimated to be between 550 and 700. Deforestation for economic development and the increasing demand for medicinal plant material collected from the wild pose serious threats to its biodiversity. Efforts being made within the framework of the WWF Project 3320 aimed at conserving the country's biodiversity are summarised.
Every society has developed a medical system for maintaining the health of its population. F.L. Dunn, writing in "Asian Medical Systems" (Leslie, 1977), defines a medical system as "the pattern of social institutions and cultural traditions that evolves from deliberate behaviour to enhance health". In modern parlance this means that an individual's life style affects the well being of others in the community. This comes out very clearly in the word Ayurveda, the traditional Indian system, for Ayu means life or living, and Veda means science or medicine, in other words, the science of living.
Ayurveda, which reached Sri Lanka perhaps 2,500 years ago, has much to do with living in harmony with one's environment. Here environment is viewed in its totality, the interdependence of the living elements of plants with the non-living, air (including sunlight), water and soil.
My childhood in a rural community naturally exposed me to Ayurvedic physicians, or who in those colonial days were, perhaps in a derogatory sense, referred to as "native doctors". Only when I grew up did I realise that the doctor's medicines were found in nature, raised in flower pots ("pot herbs"), e.g. coriander, Iriveriya (Plectranthus), ginger (Zingiber), or gathered from the vicinity (home gardens) e.g. Adhathoda vasica, bael fruit (Aegle marmelos) or from a piece of waste land nearby, e.g. Calatropis.
Our dependence on plants was brought home more forcefully when we realised we could subsist on what grew around us: Gotukola (Centella asiatica) leaves, spinach, water cress, and the leaves and flowers of Sesbania grandiflora, would be served up at lunch time while stir-fried Amaranthus varieties and different lentils enriched dinner, all garnished, of course, with fresh ginger, garlic and cumin seed.
Realisation came later that animals shared these same delectable items. Also that the wild counterparts of similar food plants formed the bulk of a herbivore's diet. Could it be that human beings evolved their medical systems by closely observing wild animals? These surmises have been amply proven by my over 40 years of observing and studying natural history in the wilds of Sri Lanka, India, Nepal, Malaysia, Thailand and Cambodia, and through association with the ethnic populations that dwell there.
The strong cultural appeal of Ayurveda was tenaciously preserved in Sri Lanka because of its links with Buddhism, commencing with the exhortations of Lord Buddha himself. Buddhist monks and through them the ancient monarchy, practised Ayurveda, established state hospitals, nurtured herbal gardens and miniature forests, and actively encouraged the people to stay healthy. Thus it is easy to understand how a strictly traditional form of medicine steadily evolved into a science. Other factors which had and still have a bearing on the peoples' dependence and reliance on Ayurveda are, the ready availability of plants with the required therapeutic properties or, if purchased, their comparatively low cost, and very importantly, the absence of any after effects, which in many allopathic medications are warned against by the manufactures of synthetic drugs.
Despite the introduction of allopathy and 450 years of Western colonialism, Ayurveda lived on in the hearts and minds of the people of Sri Lanka. It was only after the massive deforestation that followed foreign domination with concomitant rural and urban "development", that herbal medicines were dealt some body blows and became moribund. However, soon after independence in 1948 when ethnic cultures staged a come-back, there was naturally a resurgence in Ayurveda. Once more the State elevated it to the level of Alternative Medicine, re-established hospitals and clinics in every province of the island, opened training institutes for would-be practitioners and reinstated the village physician as an approved professional.
Unfortunately the same zeal was not applied to the need to propagate or grow medicinal plants following their disappearance from home gardens and what were once village or community forests. A sudden influx of collectors into deeper forests and their irresponsible and often ruthless exploitation of nature, began to take its toll on wild populations which soon became threatened with extinction. Serious depletion of biodiversity was looming large.
It was against this backdrop that a proposal to conserve the medicinal plants of Sri Lanka was submitted to the World-wide Fund for Nature (WWF) in 1984 making use of the latter's Plants Campaign. This proposal was quickly approved in 1985, and Project 3320 - The Conservation of Medicinal Plants in Sri Lanka - was entrusted to me under the aegis of the Ministry of Indigenous Medicine and Cultural Affairs, one year later.
Before describing the project, it is necessary to look at the remarkable species diversity of the country's flora in order to appreciate the importance of plants to its people in their everyday life. Recent studies in ethnobotany have revealed an astonishing grasp of plant identification among rural people and their knowledge of the therapeutic properties these
plants developed over generations. This is another reason for present day conservationist to strive to preserve both the traditional system of medicine and the plants on which it depends for its continuity.
For a relatively small island, a little over 25,500 sq miles (65,000 sq km) in extent, its species diversity is impressive. It is generally accepted that this has been made possible because its geographical position, its mild yet variable climate, very interesting topography and soil profiles which create numerous ecological niches for the evolution of diverse biotic communities.
Eisenberg and McKay (1970), Muller-Dumbois and Sirisena (1967), and Fernando (1967), identify seven vegetational zones, indirectly determined by climate. These are:
Estimates made for the number of indigenous plant species used in medicine vary between reports. Abeywickrema (1979) puts the figure at "nearly 700" while Ekanayake (1981) lists 550. Both include about 35 species of naturalised exotics.
However, it is interesting to observe that of the indigenous plants common to Sri Lanka and India, about 305 find a place in traditional medicine. But as stated earlier, about 25% of Sri Lanka's flora is endemic, and only 3-4% of them have made their way into the local pharmacopoeias. The significance of this is two-fold: firstly that the local practitioners have faithfully followed the original system, and secondly and more importantly that at least another 20% of Sri Lanka's flora await study and research vis-à-vis the country's quest for more and perhaps better drugs.
The geographical distribution of the 550 species listed by Ekanayake (1981) is given in Table 1.
Table 1. Geographical distribution of indigenous medicinal plants of
Sri Lanka (Ekanayake, 1981).
|Biogeographical region||Number of species|
|Low country Wet zone||
|Low country Wet & Montane zone||
|Dry zone and Wet zone||
|Arid and Dry zone||
|Present in all regions||
It must be noted that Ekanayake has employed a slightly different zonal classification from the 7 zones described earlier. Be that as it may, the species distribution over a wide area tends towards an excellent gene pool which, if carefully protected, augurs well for the future.
Besides the almost inexorable removal of forest cover in the name of "economic development", in Sri Lanka medicinal plants are threatened in several other ways:
The tendency still is for collection from the wild, often on a scale detrimental to the viability of populations. This is because fresh plants fetch very low prices compelling vendors to sell in bulk, e.g. 200 plants of the herb Munronia pumila an almost universal ingredient in many prescriptions, are uprooted to produce 1 kg of material. A collector will need about 200 plants (Rs 500.00 at 25 cents a plant) to make his expedition up and down rocky terrain worthwhile. This might mean the denudation of the whole microhabitat of this endemic species.
Again taking Munronia as an example, it is the dried plant that is used in medicine and if the drying has been insufficient, the whole consignment will be attacked by fungus and rejected by the market. Such wastage is a common feature in this trade and seriously endangers the species being exploited.
Project 3320 listed the following objectives:
A large number of organisations and many interested individuals were co-opted into an Advisory Committee from which, later, a Co-ordinating Committee was formed, each member charged with an activity which would realise the objectives of the Project. Thus, the Universities of Sri Jayawardenepura and Ruhuna, the Natural Resources Energy & Science Authority (NARESA), the Bandarnaike Memorial Ayurvedic Research Institute (MBRAI), the Royal Botanic Gardens, the Conservator of Forests and the Director of Wildlife Conservation each had a part to play.
In the beginning there were some problems which arose mostly from participants running away with the idea that the Projects' principal objective was the development of Ayurveda. It took a lot of doing to steer the Project on its main axis of conserving plants and their habitats for the future.
In 1990, therefore, the Project was reviewed with the help of Dr. Alan Hamilton, the WWF Plants Conservation Officer, under whose overall direction the project was functioning. It was decided at that time to concentrate on two significant goals: the protection of representative (natural) sites for genetic reserves and the cultivation of species in decline from wild sources.
Accordingly six new components were identified to achieve these goals.
1. The establishment of a database to collate all available information and future findings in relation to the whole subject of medicinal plant conservation. The distribution and population density of species which resulted from field surveys occupy an important place in the database.
2. A market survey to determine present use and how such usage affects wild populations.
3. Field surveys covering all the major biogeographical zones.
4. Chemotaxonomic studies on medicinal plants to verify the therapeutic properties of different populations of one species and to determine the levels of genetic variability.
5. Legislation to control over-exploitation for local use as well as for export to pharmaceutical companies abroad.
6. Declaration of Special Natural Reserves for in situ conservation.
The results of components 2, 3 and 4 above provide the scientific and statistical information, hitherto seriously lacking, required to formulate conservation policy.
The market surveys revealed that ruthless extraction of fragile species from the wild was more widespread and destructive than previously thought. Nine species have been brought into a country list of endangered species for the protection of which legal provision is urgently required.
The scientific systematic surveys of representative natural sites in all the geographical zones have confirmed that the picture is not so rosy anymore. Practitioners even in rural areas complain of extirpation of certain species from their locality, notably species used in the treatment of fractures and of snake bite.
The re-survey of the hitherto jealously guarded cultural sites showed alarming depletion of immensely valuable species.
Chemotaxonomic studies have shown different genetic composition from different populations. For maintaining genetic diversity, it is essential to preserve natural populations wherever they occur, as gene banks.
A natural response to the unavailability of local herb species is to cultivate them or to introduce substitutes or, as a last resort, to import them. Cultivation has its limitations. Agronomic studies have already shown that the therapeutic value of cultivated species undergoes change with intensive cultivation practices. There have to be infusions from wild species if the therapeutic value of a medicinal herb is to be sustained. Other experiments carried out in the Botany department of the University of Matara showed that the application of agrochemicals did not directly or necessarily improve growth as occurs in other crops.
All these findings point to one goal: that of preserving species in their natural habitats.
Therefore, Project 3320 today is marching towards what could be identified as its most important goal - that of preserving biological diversity through the protection of natural habitats which support sizeable populations of either widely exploited species or those whose populations have reached critical levels. The work done so far under the Project as set out in the preceding paragraphs underscores the need for in situ conservation, providing the scientific data, the methodology and justification for establishing natural reserves.
According to the epic Asian story, the Ramayana, King Rama's beloved brother Lakshman lay gravely ill and the physician attending on him had prescribed medicines from herbs found only in the deep forests of the Himalayas. Rama therefore summoned Hanuman, the monkey-god, to fetch these herbs. Not being able to identify the herbs, Hanuman did the next best thing - he decided to carry back a piece of the forest itself. It is believed that while crossing over from the Himalayas to Lanka chunks of the forest had fallen along the way and that places like Ritigala (and Sigiriya), Dolukande in the north-west of the island and Rumassala in the south where medicinal herbs abound even today, mark some of these spots.
Even before Project 3320 was conceived, the government had decided to declare several cultural and historical sites as specially protected areas. Besides those already mentioned, Nilgala in the East-Central part of the country, Dolukande in the North-West, Rumassala in the South, and Singharaja in the West had also been earmarked. Subsequently Sigiriya and Ritigala in the North-Central Province, which are archaeological sites of great importance, were added on.
Our surveys of these sites under Project 3320 confirmed that these places were indeed very rich in medicinal plants in a natural state. Some of them like Dolukande and Rumassala had been extensively harvested and some species had reached critical levels. Dolukande has a total of 115 species while Rumassala recorded some 75. And what is more, these sites are jealously guarded by the incumbent Buddhist monks who look after the shrines at these sites. Clearly, therefore, all these sites had to be integrated into any overall plan for conservation of biological diversity and held in trust for posterity. WWF involvement at Sigiriya is a role model for integrating ex situ, in situ and cultural conservation. There, a 1-ha nursery has been progressively developed into a centre for both distributing plants to villagers and for reintroducing plants which have been extirpated. Sigiriya being a premier archaeological site for conservation under the UNESCO-aided Cultural Triangle, is the ideal location to showcase this new thinking. The herbal garden is now being extended into the adjacent forest to form a 10-acre in situ conservation site. Sigiriya is also redolent with ethnobotanical relationships which are being fully investigated only now. The herbal garden will soon be of educational value when its gates will be opened to school-children and members of the public who wish to study medicinal plants.
The present guardians of our Protected Areas as defined by IUCN, are the Forest Department and the Department of Wildlife Conservation. There are some 450 such Protected Natural Areas in the country and what better network could there be for the demarcation of Special Reserves for medicinal plants within some of them? The Protected Areas comprise Forest Reserves and Proposed Forest Reserves, National Parks, Sanctuaries and similar reserves for Wildlife, Wetlands, and Man and Biosphere (MAB) reserves.
The time is now opportune to go into partnership with the Forest Department for they are in the process of surveying selected sites for a National Conservation Register. Since these surveys concentrated only on trees of economic value, medicinal plants had been missed out. Now through discussion we have persuaded them to include herbs identified with the help of local Ayurvedic Practitioners, medicinal plant collectors and physicians from the nearest Ayurvedic Hospital. The Senior Scientist of the BMARI and Curator of the National Herbarium are also being consulted.
The Forest Department has identified 9 sites which will receive special protection under IUCN's Biological Diversity Programme. At least 5 of them have already been identified as being suitable for the protection of medicinal plant species and habitats. They are: Nilgala, Dolukande and Rumassala, already mentioned above, and Kiribathgoda and Rajawaka (Bellangala) in the Ratnapura District in the Wet Zone and the Intermediate Zone of the country.
All these sites have been established as possessing tremendous species diversity and they justify selection as Special Reserves. Nilgala, in particular, which is species rich today, is believed to have been given protection by the Sinhala kings in the past.
The Forest Department has given high priority to the declaration of the Rajawaka Proposed Forest Reserve as a Special Medicinal Plants Reserve. Besides its unusual floristics akin to that of Nilgala with a climax community of Pterocarpus marsupium, Phyllanthus emblica, Terminalia belerica and T. chebula, Rajawaka as its name implies, was the preserves of royalty (Royal Park) in ancient Sri Lanka. Today it still remains an important source of medicinal trees and plants, and is much sought after by the people in times of illness. Therefore, any form of protection will not impinge on the rights of villagers to collect material. Indeed, the Forest Department actually wishes to include participatory management by the people.
Project 3320 will be associated in the unique event of the declaration of Sri Lanka's first-ever Special Natural Reserves for medicinal plants in the following manner:
The first site which is a Proposed Forest Reserve known as Rajawaka or Bellangala has been selected and preliminary work started. This is presently a source of medicinal plants for a cluster of villages. If not properly managed, it may not remain a sustainable resource for much longer.
Project 3320 has been successful in bringing to light the exact situation with regard to the danger that awaits biological diversity in the realm of medicinal plants. The constraints identified are timely and the Government is being advised to initiate the actions proposed before it is too late.
With these scientific and cultural initiatives, it is hoped that Project 3320 will mark the beginning of a new approach to ensuring continuity of a medical science through the preservation of the natural resources on which it depends. This Project can be emulated as a model for medicinal plant conservation in both biodiversity and biocultural contexts.