Diversity and Conservation of Rare and Endemic Orchids of North East India - A Review

Northeast India, a mega-diversity centre, comprises eight states, viz., Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura. It occupies 7.7% of India’s total geographical area supporting 50% of the flora (ca. 8000 species), of which 31.58% (ca. 2526 species) are endemic. The region is rich in orchids, ferns, oaks (Quercus spp.), bamboos, rhododendrons (Rhododendron spp.), magnolias (Magnolia spp.) etc. Orchids, believed to have evolved in this region, form a very noticeable feature of the vegetation here. Of about 1331 species of orchids, belonging to 186 genera reported from India; Northeast India sustains the highest number with about 856 species. Amongst them, 34 species of orchids are identified among the threatened plants of India and as many as endemic to different states of this region. Out of the eight orchid habitat regions in India, the two most important areas namely; the Eastern Himalayas and the North Eastern Region fall within the political boundaries of North Eastern Region. Terrestrial orchids are located in humus rich moist earth under tree shades in North Western India. Western Ghats harbour the small flowered orchids. Epiphytic orchids are common in North-Eastern India which grows up to an elevation of 2,000 mmsl. Some of valuable Indian orchids from this region which are used in hybridization programme are Aerides multiflorum, Aerides odoratum, Arundina graminifolia, Arachnis, Bulbophyllum, Calanthe masuca, Coelogyne elata, C. flavida C. corymbosa; Cymbidium aloifolium, C. lowianum, C. devonianum, C. hookerianum, C. lancifolium, Dendrobium aphyllum, D. nobile, D. chrysanthum, D. farmeri, D. chrysanthum, D. densiflorum, D. moschatum, D. fimbriatum, D. jenkinsii, Paphiopedilum venustum, P. spicerianum, P. hirsutissimum, P. insigne, Phaius wallichii, Pleione praecox, Renanthera imschootiana, Rhyncostylis retusa, Thunia alba, Vanda cristata, Vanda coerulea and Vanda coerulescens. Habitat loss, deterioration and fragmentation, introduction of exotic species, over-exploitation, environmental pollution, global warming, commercialization of agriculture and forestry, and jhum cultivation are the major causes for the loss of diversity. India has strengthened on diversity conservation by implementing a series of acts, rules, laws, regulations, agreements and developing network of protected areas.