Ethnobotanical Leaflets 12: 361-372. 2008.
Swertia L. (Gentianaceae) in Nepal Himalaya: Checklist, Phytogeography, Ethnobotany and Conservation Status
Kunjani Joshi* and Ananda Joshi**
*Department of Botany, Patan Campus, Tribhuvan University, Nepal
At present: Harvard University Herbaria, Cambridge, MA, USA
**President, Environmentalist’s Association of Nepal (EAN)
Email: ; [email protected]
Issued 11 June 2008
Swertia L., a morphologically diverse but taxonomically distinct genus’s circumscription has often been debated. Four problems still need to be solved: species delimitation, section delimitation, and relation with allied genera and domestication of the species for economic benefits. In the present paper an attempt has been made to prepare a checklist of Swertia species, and documentation of distribution patterns, existing ethnobotanical uses and conservation practices in Nepal. Some integrated measures, which might help to fill up the gaps in our knowledge, are also recommended.
Key words: Swertia, taxonomy, phytogeography, conservation, ethnobotany, Nepal Himalaya.
Swertia L (Gentianaceae – Gentianeae – Swertiinae) is a morphologically diverse but taxonomically distinct genus. The taxa in its present circumscription comprises ca 150 species and is annual, biennial or perennial herb ranging from 2-4 cm. to over 1.5 m in hight with 4-5 merous flowers, 1 or 2 nectaries at the base of characteristically rotate corolla lobes. The genus mostly occurs in alpine or temperate habitats in Asia, Africa and N. America. The circumscription of the genus has often been debated, resulting disagreement amongst taxonomists due to the morphological similarities (nectariferous and rotate corolla lobes) among the species of Swertia and the related genera.
Nepal, a central segment of Himalayan mountain systems, is rich in species diversity due to its transitional location between the Paleoartic and Indo-Malayan realms, and a great variety of physiographical characteristics and abundant diverse ecosystems within a short span of space. The meadow, open forest and scrub ecosystems of the mountainous regions of Eastern, Central and Western regions of the country are the suitable habitats of Swertia species (Joshi, 2007). Information on taxonomy, distribution, ethnobotany and conservation of the Swertia species are very limited (Bhattarai, 1992; Joshi, 1988, Joshi, 2000, 2004; Joshi and Joshi, 2005; Manandhar, 2002; Sacherer, 1979; Shrestha et al., 1998). Although several authors have tried to enumerate the species and varieties, systematic classification of Swertia has still been a problematic. Four problems still need to be solved: species delimitation, section delimitation, and relation with allied genera and domestication of the species for economic benefits. In the present paper an attempt has been made to prepare a checklist of Swertia species, documentation of distribution patterns, ethnobotanical uses and conservation practices and to recommend some measures which might help to fill up the gaps in our knowledge.
Materials and Methods
The plant materials were collected from the diverse habitats of various villages and adjoining areas of Rasuwa, Sindhupalchok, Dolakha, Makwanpur, Kathmandu, and Lalitpur Districts and identified with the help of local floras. Information relating to the distribution, ethnobotany and trade and conservation practices including people perception were gathered using various techniques such as interviews, discussion with local people, traders and direct observation on the way the useful plants and their parts were being collected and used (Joshi and Edington, 1990). For preparation of checklist, specimens have been checked with the herbarium specimens of the National Herbarium, and Plant Laboratories, Godavari (KATH), and Central Department of Botany, Tribhuvan University (TUCH), Nepal and Harvard University Herbaria, USA. Voucher specimens are housed in the Biodiversity Research Center, EMA Group, Nepal and in Harvard University Herbaria, Cambridge, MA, USA.
Taxonomy: Checklist of Swertia species
Although Nepal remained almost completely closed to foreigners until 1949, the flora of the country was no means entirely unknown. Many earlier workers have collected and described the plants from the different parts of the country. After 1960, major botanical expeditions, particularly from British Museum, England and Kyoto and Tokyo Universities of Japan have explored the country. The major contributions relating to the species of Swertia found in Nepal was made by national, regional and international botanists and institutions. Among the contributions on documentation of the taxa, the significant collections and studies of the species of Swertia date back to Smith (1970), who had described three new species : Swertia acaulis, collected on open slopes, foot of Wabak khola, east of Num, Arun valley, 4600m; S. gracilescens, collected on grass slopes, Kali gandaki valley, Taglung, south of Tukucha, 3700m; and S. staintonii, collected on open slopes, Arun valley, Chhoyang Khola, west of Num, 3800m. In 1976, 21 species of Swertia found in Nepal: S. acaulis, S. alata, S. angustifolia, S. bimaculata, S. chirayita, S. cordata, S. cuneata, S. dilatata, S. gracilescens, S. hispidicalyx, S. hookeri, S. kingii, S. multicaulis, S. nervosa, S. paniculata, S. pedicellata, S. petiolata, S. purpurascens, S. racemosa, S. speciosa, and S. tetragona have documented in Catalogue of Nepalese Vascular Plants (Malla et al, 1976a). Similarly, Hara et al. (1982) in Enumeration of Flowering Plants of Nepal Vol. III enumerated 27 species of Swertia along with bibliographic citation and synonyms. In 1984, Polunin and Stainton described 8 species of Swertia occurring in Nepal: S. angustifolia, S. alternifolia, S. cuneata, S. hookeri, S. multicaulis, S. petiolata, S. racemosa, S. speciosa in their book Flowers of the Himalaya. Ohba and Akiyama (1992) have reported 7 species of Swertia: S. acaulis, S. cuneata, S. dilatata, S. hookeri, S. macrosperma, S. multicaulis, and S. pseudo-hookeri.from the alpine areas of the Jaljale Himal, Eastern Nepal. In 2000, Annotated Checklist of the Flowering Plants of Nepal was published that includes 28 species and 4 varieties of Swertia (Press et al, 2000). Swertia gracilescens which was earlier reported as new species by Smith 1970, is removed and has been assigned as the synonemes of Swertia paniculata. The Flowering Plants of Nepal (Phanerogams), (edited by Bista, Adhikari and Rajbhandari, 2001) enumerated 29 species with 3 varieties of Swertia. In this categorization, both S. gracilescens and S. paniculata have kept as distinct species and S. dilatate without varieties. Shah (1990, 1992) and Chassot (2003) has reported new species: Swertia nepalensis and S. barunensis from Nepal respectively. Recently, S. wardii has documented from the foothills of the Kangchenjunga mountain, eastern Nepal (WWF, 2008).
The circumscription of Swertia has been subject to major change ever since its establishment. The identification and systematic arrangement of species have carried out based on only morphological characteristics. These works show controversy in species and varieties boundaries. Some species are excluded in the respective groups and some are placed as synonames and some new species added to the family.
During the present study, a checklist was prepared studying our own collected specimens and checking and reviewing the herbarium specimens stored in universities and research institutions and consulting various relevant documents and papers. Table 1 presents the 31 species of Swertia with varieties and their distribution in Nepal.
Table 1. Species of Swertia and their Distribution in Nepal.
Swertia shows wide range of morphological variation within and among the population resulting a considerable uncertainty about the delimitation of species. Among the collected plant specimens from different areas., S. racemosa shows a pronounced variation in the presence of cilia on margin of leaf, sepals, and bracts as well as on veins. Similarly wide ranges of variation in morphological traits among the population of S. chirayita and S. nervosa were also reported by Raskoti and Sakya (2004) and Pant and Bimb (2005) respectively.
Biogeography of Swertia species
Nepal’s diverse geomorphology over a wide range of latitude, longitude, and elevation has provided an abundance of habitats and ecological niches, which help to explain spectacular diversity of plant species growing in the region (Bajracharya, 1996). Among the phytogeographical features, the Himalaya and adjacent ranges are not only regarded as a ‘meeting places’ of different floristic elements entering from different directions (Banerji, 1963), but also gave rise to many new and endemic species, especially in the alpine zone, i.e. Androsace nortonii, Primula wollastonii, Swertia acaulis. Thus Nepalese flora is not only represented by a mix of the southern slopes of Himalayas, but also a mix of high and dry plateau flora of Tibet (China) with that of the humid monsoon region of Indian sub-continental plains floras (Kanai, 1966; Yoshida, 2006a & b).
Swertia species are widely distributed in tropical to alpine habitats of the Eastern, Central and Western regions. Out of 75 districts of the country, Swertia species have documented from 54 districts so far (Fig.1). Such wide distribution of the species of Swertia and other plant communities could also be highlighted with the help of recent evidence of the geological past of the Asian region and migration of species from the neighboring continents. However, as there are no fossil records relating to the Swertia and other species of Gentiniaceae in Nepal, it is not possible to discuss the phylogeny and biogeographical distribution from the palenological point of view. But formation of Tibetan Plateau and upliftment of Himalyas and other mountain ranges (Karakoram, Kunlun Shan, Tian Shan, Hengduan mountains) due to collide of Deccan plate with the southern Laurasia coastline at about 45 million years BP in Eocene times and geobotanical development of the Himalaya might have changed climatic patterns and encounter some important changes with the dispersal and distribution of plants. At present, it is difficult to interpreate these issues due to lack of data as well as generic relation of inter and intraspecies relationships are not yet well enough resolved. Priority should be given to integrated study of the taxa and its eco-distribution for a conclusive biogeographic interpretation.
Ethnobotanical value of Swertia
The rural people of Nepal rely heavily on plant resources for their primary healthcare and treatment of diseases. The people have developed unique indigenous knowledge related to the uses of plant resources due to constant association with the forests. The traditional knowledge related to the therapeutic uses of plants may be utilized for the improvement of the economic status of the local communities. However, less priority has given to document these valuable practices and plant resources. The works relating to the ethnobotanical investigation and sustainable management of the resources including Swertia species are very sporadic (Baral and Kurmi 2005; Bhattarai, 1992, Bhattarai et al, 2007; Jha et al, 2001; Joshi, 1988; Joshi and Edington, 1990, Lama et al, 2001; Manandhar, 2002; Siwakoti and Siwakoti, 2003, Shrestha, 1991). Recently, Joshi (2008) has documented the medicinal uses of some species of Swertia (Table 2). Besides this, some works on the ethnomedicinal uses of S. alata, S. bimaculata; S. cuneata; S. kingii, S. tetragona have also carried out (Ghimire, 2001; Manandhar, 2002; Sacherer, 1979; Subedi, 2006). Among the species, S. chirayita is the important for its medicinal properties. Herbal medicines such as Diabecon, Melicon V-ointment, Ayush-64 and Mensturyl syrup contain chirata (Swertia) extract in different amount for its antipyretic, hypoglycemic, antifungal and antibacterial properties (Joshi and Dhawan, 2005).
Table 2. Ethnomedicinal uses of some species of Swertia
Source: Joshi (2008)
The rural people collect the ‘Chiraito” (Swertia) or their products directly from the wild populations of the forest, meadow, scrub or shady habitats which are already dwindling due to over-exploitation and unsustainable land-use, thus accelerating their genetic erosion. Unsustainable collection of the species has been done due to their usefulness to cure various ailments, their increasing price, and increasing demand as raw materials for preparation of Ayurvedic and Allopathic medicines. Every year a huge amount of medicinal plants are collected for export. The income from the chiraito was used by collectors for foodstuffs, including salt, clothes, to pay off loans and to buy cattle (Daniggelis, 1999).
The plants are collected before the maturation of seeds. The whole plant is pulled out, sun-dried for a few days, wrapped by bamboo slip and sold to the local traders as dried brownish stems with root and leaves intact. Unsustainable harvesting without considering the age of the plant and seed maturity reduces regeneration significantly. Extensive collection and unscientific harvesting practices of these plants from the natural habitat leads to an increasing danger of extinction (Bhattarai and Shrestha, 1996; Edwards, 1993; Joshi, 2008). The present rate of exploitation has rendered some species to the status of threatened and endangered species (Joshi and Joshi, 2005; Joshi, Joshi and Joshi, 2000; Joshi, Shrestha and Joshi, 2003; Joshi and Joshi 1991).
Swertia species occupies one of the major portions in the trade of medicinal and aromatic plants from Nepal. About Nine species (S. chirayita, S. angustifolia, S. ciliata, S. dilatata, S. multicaulis, S. racemosa, S. tetragona, S. alata, S. nervosa) have been reported under trade in different trading centers of Nepal (Barakoti, 2002) with common name “chiraito” except for Swertia multicaulis (sarmaguru). Among these species, Swertia chirayita plays dominant role in trade and is considered superior in quality. Adulteration of chiraito with other low quality species of Swertia and other related species are very common in the trade of chiraito.
During the field survey, serious threats to the population of Swertia were noticed due to habitat destruction and land use change. Even without tree-removal, extensive grazing of domestic animals in the forests can be damaging to the species. When questioned about the changing status of Swertia, our respondents (villagers and traders) informed that the abundance and production of Swertia is decreasing every year in the central and eastern parts of the country. Therefore, appropriate conservation measures for these species are urgently needed.
Conservation Efforts and Achievements
Government of Nepal has introduced a legal basis for conservation of biodiversity and habitats i.e. Wildlife Protection Act 1958, Forest Act 1961, the Forest Protection (Special Arrangement) Act 1967, Plant Protection Act, 1972, National Parks and Wildlife Conservation Act, 1973 and Environment Protection Act 1997. Some species have also been proposed for legal status under the Forest Regulation 1995 (amended in 2001). A clear shift in legislative provisions was initiated in the protected areas and community forests for species conservation and made special provisions to facilitate public participation in the conservation and sustainable utilization of bioresources. However, the issues of property right, fair and equitable sharing of benefit has yet to materialize by defining these terminologies.
Nepal has also ratified the International Conventions and agreements relevant to species conservation and habitat management i.e. Plant protection Agreement for the South East Asia and Pacific Region, 1956; Convention on Wetlands of International Importance especially as Waterfowl Habitat (Ramsar Convention) 1971; Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) 1973; Convention on Biological Diversity (CBD) 1992. As an obligation of contracting party of Biodiversity Convention, Nepal has formulated a Nepal Biodiversity Strategy and Non-wood Forest Products Policy. Within the constraints of resources and technical know-how, Nepal has been involved in various projects such as survey and documentation of species, ethenobotany and indigenous knowledge, cultivation and conservation of useful species, and researches on molecular structure and make-up and chemical components (Barakoti, 2002; Bimb and Pant, 2006; Chassot et al. 2001; NAST, 2007; Joshi, 2007, 2008; Joshi and Li, 2008; Shrestha, 1991, Shrestha et al., 1998). Molecular studies of some species of Swertia are also under investigation (Joshi, 2007).
Strategy for Sustainable Management
Despite the implementation of various activities for the conservation of the species and their habitats, there is a growing consensus among the conservationists that the conservation of bio-resources is entering into a stage of crisis, since there has been hardly any attempt to conserve these resources in an integrated manner (Joshi and Joshi, 2005). Therefore, the following strategies have been recommended for sustainable management of plant resources in an environmentally sound way.
1. Formulation of Policy, Action Plan and Programmes: Though some initiatives have already taken for conservation and sustainable utilization of the useful species, less priority is given to conserve these resources in an integrated manner. The existing policy related to conservation and sustainable management of useful plants is also fragmented in different sectoral policies. Therefore, priority should be given to formulate integrated national, regional and local policy, action plan and program related to the conservation and sustainable uses of the economic and useful plants, especially Swertia species, taking into consideration of the characteristics of ecosystems, productivity of the species, needs of the people and sustainable management of species.
2. Inventory and Documentation of the Species with Indigenous Uses, knowledge and Practices: Although investigation on species has been conducted in different parts of the country, there is a paucity of quantitative and systematic data on species diversity, phylogeny and biogeographical distribution, chemical constituents of the species and characteristics of habitats. Many biogeographical areas of the country have still remained unexplored. Therefore, it is strongly recommended that major thrust should be given to an intensive inventory and documentation of useful species with their potentiality for utilization and existing indigenous knowledge and practices relating to the uses of the species.
3. Domestication, Income generation and Conservation of useful species: Despite the increasing demand for herbal industry, the plant is still collected from the wild, it is sparsely cultivated and negligible efforts have done for development of proper agro-techniques of the domestication. The people of the studied villages have comprehensive knowledge about plants and their potential uses. Therefore, emphasis should be given to implement some pilot programmes for domestication and cultivation of Swertia species. This will help in providing additional income and benefits to local people contributing to poverty alleviation and sustainable development of the country
For conservation of the species, top priority should be given to in-situ conservation. Such steps will not only contribute to protect the habitats but also help to maintain the ecological processes. Emphasis should also be given to conserve species in ex-situ conservation. The novel technique of in-vitro conservation and micropropogation can help in conservation and production of a large number of disease-free, true-to-type plants (Wawrosch et al. 1999). However, there exists a need to translate these in-vitro studies to the field for practical applications.
4. Involvement of People in integrated management of species and habitats: It is also obvious that the success and sustainability of the conservation activities depend upon the involvement of the local people. Emphasis should be given to initiate a special program for raising people's awareness about domestication, conservation and sustainable management of species. In this program people should also be involved from the planning phases of the activities.
The authors are thankful to the inhabitants of the study areas for their kind cooperation and help during the field survey. The authors acknowledge their gratitude to Dr. John F. Edington, University of Wales, U.K., Dr. S. K. Jain, Founder and Ex-Director, Institute of Ethnobiology, Lucknow, India, and Prof. P.K. Jha, Prof. R.P. Chaudhary, and Prof. K.K. Shrestha, Central Department of Botany, TU, Nepal for constant encouragement. Our special thanks are due to Dr. P. Chassot, Universite de Neuchatel, Switzerland for providing the liltreatures and encouragement. They also thank to Mr. D.P. Rijal for his assistance in the field work and National Herbarium, and Plant Laboratories, Godavari (KATH), Central Department of Botany, Tribhuvan University (TUCH), and Harvard University Herbaria, USA for allowing them to consult herbaria.
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