An ethnobotanical note on wild edible plants of Upper Eastern Himalaya, India

The present article deals with the documentation of tribal knowledge on wild edible plants in Upper Eastern Himalayan Region of India. In total, 269 plant species belonging to 77 families were recorded in the study area of Upper Subansiri District of Arunachal Pradesh. Dioscoreaceae, Rutaceae, Cucurbitaceae and Arecaceae were the dominant families with 16, 13, 12 and 11 plant species, respectively, while Moraceae and Asteraceae followed with 10 species each. Four major life forms were trees, shrubs, herbs and climbers. Trees made the highest proportion of the edible species (81) followed by shrubs (74), herbs (71) and climbers (37). Availability of some of these species might be a serious constraint in near future due to various anthropogenic factors. Need for undertaking vigorous environmental awareness campaign among local tribes has been stressed upon in the article for conserving this valuable biological resource of Eastern Himalayan region of India.


Introduction
Arunachal Pradesh is one of the biodiversity rich states of India in terms of flora and fauna. The state is the largest one among all north eastern states of India situated in the lap of eastern Himalayan region of the country. Varied climatic, topographical and soil conditions favour high species richness and support different types of forests. Broad forest types include tropical moist deciduous, tropical semi evergreen, tropical evergreen, subtropical, temperate and alpine forests. Recorded number of flowering plant species (>5,000) are the highest among all North Eastern states (Hegde, 2000).The state is inhabited by 28 major tribes and 110 sub tribes (Khongsai et al., 2011) who depend immensely on forest flora and fauna for their day to day needs and requirements. It is estimated that, in India about 800 species are consumed as food plants whereas the corresponding figure for north east (NE) India is around 300. Almost all the edible plants of NE region are represented in Arunachal Pradesh (Arora, 1981;Haridasan et al., 1990).
Many research studies have been conducted on the diversity and traditional uses of wild plants from Arunachal Pradesh state, particularly on medicinal plants (Pal, 1984(Pal, , 1992Rawat et al., 1996Rawat et al., , 1998Tag and Das, 2004;Shankar et al., 2008Shankar et al., , 2011Shankar et al., , 2016Goswami et al., 2009;Khongsai et al., 2011). Although much has been reported on ethnomedicinal aspects of plants of the region, little has been reported about the wild edible plants of the state. Keeping this aspect in view, a study was conducted as an attempt to explore and identify the wild edible plant resources and indigenous traditional knowledge about their utilization in the Upper Subansiri district of Arunachal Pradesh during 2010-2012 by the State Forest Research Institute, Itanagar, Arunachal Pradesh. The Upper Subansiri District of Arunachal Pradesh lies in the central part of the state in between 28.5° and 28.25° latitudes N and 93.15° and 94.20° longitudes E covering a geographical area on 7,032 km² ( Figure 1). The high mountain region near northern boundary of the district is generally cold as remain covered with snow almost throughout the year. The plain areas in foothills are intersected by number of water bodies mainly streams and rivers in the lap of forests (Goswami et al., 2009). The district is inhabited by three major tribes namely Tagin, Hill Miri (now Nyishi) and Galo.

Methodology
The ethnobotanical information was collected by field works/survey among aboriginal community, by study with herbaria and museum, by study of rituals, myths and folklores and through folk market survey. Tribal markets or weekly haats (local market) were also visited to study the plants sold there. Maps prepared by the Directorate of Economics and Statistics, Government of Arunachal Pradesh were also consulted for identification of approaching routes and location of the select villages. The villages inhabited by the tribesmen were selected randomly for each tribe for the purpose of survey (Table 1).

Results and discussion
The present investigation comprising of 269 species of plants belonging to 77 families and details like botanical name, local name, family, parts used have been enumerated in Table 2. These species are used by the tribes as wild fruits, vegetables, beverages or in other preparations.        From the ethno botanical survey, it was noted that tribes were consuming the edible plants in raw or cooked form. The plant parts used were fruits, leaves, tubers, whole plant, stem/bark, seeds and flowers in descending order ( Figure  2). The fruits of 121 species are eaten as raw and sometimes made in to salads or pickles. Leaves of 84 species are used as vegetables.
Trees made the highest proportion of edible species followed by shrubs, herbs, climbers in descending order (Figure 3).The time and frequency of collecting various plants varied from plant to plant depending upon their availability. Sometimes more than one part of the species is edible like both leaves and fruits are edible in Spondias pinnata, Luffa acutangula; seeds and young leaves are edible in Lathyrus sativus; young leaves, pods and flowers are edible in Bauhinia purpurea, B. variegata; fruits, young leaf tendrils and flowers are eaten in Cucurbita moschata; leaves and tubers are edible in Manihot esculenta; tubers, stem and leaves are edible in Colocasia antiquorum.

Conclusion
The discussions with local people revealed that the wild edibles were being used as common household foods and make a substantial contribution to food security of the tribes of the region. Therefore necessary steps should be taken to assess the nutritional value of these plant species/parts to serve as a direct or indirect source of food to the local people (Tiwari et al., 2010). There is ample scope for improving the growth forms of wild edible species by using latest agronomic research and experimental cytogenetical studies (Yesodharan and Sujana, 2007). It was commonly noticed during survey that many of the wild food may not be available in plenty as of now due to various reasons mainly over exploitation, habitat destruction, forest fires, encroachments and invasion of exotic plant species. Wherever possible, efforts should be made to bring some of them under cultivation in order to maintain regular supply. Therefore awareness must be created among the indigenous communities stressing the need of conserving rich biodiversity, especially plants of ethnobotanical importance. The Government agencies must support the conservation measures of biodiversity by the indigenous groups. The conservation policies should be based on the recognition of indigenous people's right to conservation. The effective system of community right and benefit sharing mechanism are needed at local level, which will provide incentives for indigenous people for managing, conserving and using biological resources in sustainable manner.