Ethnobotany of Dioscorea L. (Dioscoreaceae), a Major Food Plant of the Sakai Tribe at Banthad Range, Peninsular Thailand Katesarin Maneenoon, Puangpen Sirirugsa and Kitichate Sridith Research Abstract Dioscorea is the main source of carbohydrate for the Sakai been classified as part of the Negrito group (Duangchan tribe at Banthad Range, Peninsular Thailand. Nine sub- 1980). In Thailand, the current Sakai population is around groups of Sakai wander in this area where fifteen species 500 and they live in small groups. At least nine groups of the genus have been found. Thirteen of the species from this tribe can be found in the Banthad Range, an are consumed by the Sakai. The remaining two species area which covers parts of Trang, Phatthalung and Satun are inedible. This study investigates the Sakai population provinces (Maneenoon 2001). pyramid, the Sakai living areas, the species diversity and ethnobotany of Dioscorea as well as the nutritional com- The Sakai people depend on plant products in the forest positions of selected Dioscorea species. for their main essentials in life. Examples include food, medicines and shelters. The traditional knowledge of us- ing plants for their continuing survival has been passed Introduction down from generation to generation. The genus Dioscorea L., a monocotyledon, belongs to Nowadays, forests in Peninsular Thailand are being de- the family Dioscoreaceae. It comprises 350-400 species stroyed and this affects the availability of plant products (Caddick et al. 2002), and is distributed throughout the that are necessary for Sakai’s way of life. This means that tropics and subtropic regions especially in West Africa, the food and other supplies from plants, which are nec- parts of Central America and the Caribbean, the Pacific essary for their daily needs are in short supply. In addi- Islands and Southeast Asia. tion, Sakai people are being dominated by non-indige- nous people around their habitats. Consequently, the eth- The genus Dioscorea has been the main food source for nobotany and culture of the Sakai, specifically the use tribal people particularly in many parts of West Africa since of Dioscorea as a staple food, the nutritional composi- prehistoric times because its tubers are rich in essential tion of Dioscorea tubers is changing and perhaps lost be- dietary nutrients. (Coursey 1967, Hladik & Dounias 1993). It is the main food source for the Mbuti pygmies of Eastern Zaire (Hart & Hart 1986, Milton 1985), the Batek of Pen- insular Malaysia (Endicott & Bellwood 1991), the Baka pygmies in the forests of Southern Cameroon (Dounias Correspondence 2001, Sato 2001), and people at Kuk Swamp of Papua Katesarin Maneenoon, Department of Biology, Prince of Song- New Guinea (Fullagar et al. 2006). kla University, Songkla 90112, Thailand [email protected] In some forest areas of Southern Thailand specifically Puangpen Sirirugsa, Department of Biology, Prince of Songkla Trang, Phatthalung, Satun, Songkla, Yala and Narathi- University, Songkla 90112, Thailand [email protected] wat provinces which are situated in the tropical rain forest Kitichate Sridith, Department of Biology, Prince of Songkla Uni- zone of Southeast Asia, a tribe known as the Sakai (Orang versity, Songkla 90112, Thailand Asli) can be found. The Sakai have inhabited these parts [email protected] for more than ten thousand years. They are an indige- nous minority people of the Malay Peninsula who have Ethnobotany Research & Applications 6:385-394 (2008) Published December 8, 2008 www.ethnobotanyjournal.org/vol6/i1547-3465-06-385.pdf 386 Ethnobotany Research & Applications fore publicly available, This present study documents the oscorea calcicola Prain & Burkill, D. glabra Roxb., D. wal- ethnobotanical knowledge of the Sakai and evaluates the lichii Hook. f., and D. stemonoides Prain & Burkill were nutritional values of different Dioscorea species. selected to compare against the substitute species, D. daunea Prain & Burkill, which was the only species that Materials and Methods could be found. Tubers of these species were prepared for nutritional analysis. The tubers were peeled, cut into Study sites small pieces and stored in a refrigerator until ready to be analyzed. Protein content, crude fat, moisture, ash and The living areas of the Sakai tribe at Banthad Range crude fiber were determined in accordance with the stan- were surveyed and marked by a Global Positioning Sys- dard method of the AOAC as developed by Agro-Industry tem (GPS) unit. Scattered groups of Sakai people in the Development Center for Export (ADCET, Agro-Industry study areas were observed as they searched and utilized Faculty, PSU). The calorific values were obtained by the food plants from the forest. All surveys were conducted summation of the mean values of protein, fat and carbo- between January 2005 and April 2007. The population of hydrate which were multiplied by their respective factors each group was counted. Gender and age statistics were of 4, 9 and 4 (Bhandari et al. 2003). All results for proxi- also gathered for each group. A population pyramid for all mate composition were recorded on the basis of edible the Sakai living in Banthad Range was created. portion as g/100 g fresh weight. Plant specimen studies Results and Discussion Specimens of Dioscorea species in the living areas of the Sakai population and their living areas Sakai tribe were collected in triplicates whenever possi- ble for identification and analysis. Herbarium specimens There are 139 members of the Sakai tribe living in the were prepared following the method of Bridson & Forman Banthad Range. Based on living area and behavior, these (1992). The voucher specimens were deposited at the Sakai can be classified into two main groups. Group 1 or herbarium of Prince of Songkla University (PSU), Princess the “semi-nomadic” group, consists of those who settle Maha Chakri Sirindhorn Natural History Museum, Faculty into permanent living areas and collect natural products of Science, Prince of Songkla University, Hat Yai, Song- from nearby areas for subsistence. This group can be fur- khla, Thailand and The Forest Herbarium (BKF), Depart- ther sub-divided into four subgroups (Figure 1). Group ment of National Park, Wildlife and Plant Conservation, 2 or the “nomadic” group consists of those who wander Ministry of Natural Resource, Bangkok, Thailand. Flowers throughout the forest collecting natural products for their were preserved in 70% ethanol. Field data on plant hab- subsistence and have no permanent living areas. This its and localities were recorded. Notes on plant morpho- group can be further sub-divided into five subgroups (Fig- logical characters such as the twinning of stems, tubers, ure 1). leaves, flowers and fruits were collected to aid in the plant identification process. Underground parts were also col- According to the population pyramid of the Sakai (Fig- lected for nutritional analysis and identification. ure 2), the majority of the Sakai is either children or adult. There are very few old Sakai in the population. Males out- Ethnobotanical investigations number females. The way of life of the Sakai tribe was investigated through The living style of the nomadic group is simple as they nor- interviews and by observing all members of each group mally live in traditionally small shelters or in front of caves. in the study sites as they conducted their daily activities. Their shelters are made from the leaves of Calamus cas- Ethnobotanical and other relevant information pertaining taneus Griff, Licuala distans Ridl. or Zingiber spectabile to Dioscorea were investigated by interviewing all mem- Griff. Most of their daily living needs are acquired from bers including teenagers. (Ages of informants were es- the forest. Their main food source is Dioscorea tubers. timated by the researchers). The questions asked were They usually wander throughout the forest without main- about the plants used by the Sakai tribe. Specific informa- taining any permanent home shelter. Upon harvesting all tion about Sakai names of the plants, utilized plant parts, the forest products they need in one area, they move on cooking and harvesting methods were collected. The in- to another area where they continue their nomadic life- terviews were conducted individually as a way to ensure style. The living style of the semi-nomadic group is dif- that data supplied by each informant was reliable. ferent from the nomadic group in that the former sets up in permanent living areas and build small huts. Some of Nutritional analyses their daily needs for subsistence are imported from out- side the forest. However, they still hunt and harvest the To compare nutritional compositions between staple forest products. and substitute species, four common staple species, Di- www.ethnobotanyjournal.org/vol6/i1547-3465-06-385.pdf Maneenoon et al. - Ethnobotany of Dioscorea L. (Dioscoreaceae), a Major 387 Food Plant of the Sakai Tribe at Banthad Range, Peninsular Thailand THAILAND Trang Contour Lines 1 - 4 “Semi-Nomadic” Phatthalung 5 - 9 “Nomadic” T. Thung Yao 5 6 T. Khlong Yai 1 2 T. Li Phang N 3 T. Nong Thong 7 4 8 T . Cha- 9 muang 0 3 6 9 T. Thung Wa Kilometers Satun Songkhla Figure 1. The living areas of the Sakai tribe at Banthad Range, Peninsular Thailand. Species of Dioscorea at Banthad range Burkill and an unidentified Dioscorea species are substi- tuted species during famine. All the substitute species are Fifteen species of Dioscorea were found at the Banthad bitter and have an unpleasant taste. The two inedible spe- Range. Thirteen species are edible but only eight of these cies are D. bulbifera L. and D. laurifolia Wall. Dioscorea which are D. calcicola, D. filiformis Griseb., D. glabra, D. bulbifera is inedible because it is bitter and has a coarse orbiculata Hook. f., D. pentaphylla L., D. pyrifolia Kunth, fiber and hard texture whileD. laurifolia is so toxic that it is D. stemonoides and D. wallichii serve as main sources impossible to detoxify.