Locality: Bhutan (27.332740, 90.439450)

Abstract: A species that restricts its occurrence to a specic geographic area is known as endemic to that area. The geographic area could be dened by a political boundary e.g. country, or by a broader geographical unit e.g. Himalaya, or by an ecological boundary e.g. Alpine meadow. This checklist takes into account only those species endemic to Bhutan, which have not been recorded from any other Himalayan country up to now.

The Eastern Himalaya is one of the global biodiversity hotspots well known for its high level of endemicity (Brooks et al. 2002, Dhar 2002, Vetaas 8: Grytnes 2002). The Bhutan Himalaya forms a substantial part of the Eastern Himalaya with a huge elevation gradient from the low southern foothills with sub-tropical forests to the high northern Himalayas with alpine meadows. Its high variations of climatic and geographic factors contribute to high oral endemism. For a country that champions the cause of conservation and is blessed with natural forests, we still do not have in-depth knowledge of the endemic ora in our country. Endemic species require special attention because of their highly restricted distribution and consequent susceptibility to endangerment and potential loss. Knowledge based on botanical diversity and plant endemism can also be a potential tool to prioritize conservation areas and formulate appropriate action plans and government policies (Kerr 1997, Dhar 2002).

Many species in the past considered to be endemic to Bhutan are now known to be distributed beyond its political boundaries. The Flora of Bhutan and later publications have recorded some 212 species of plants as endemic to Bhutan. However, through taxonomic reviews, updates and researches, over 100 of these species earlier reported only from Bhutan are now recorded from other countries in the Eastern Himalayan region, mainly China (Tibet & Yunnan), India (Sikkim & Arunachal Pradesh) and Eastern Nepal. No doubt all these 212 species are endemic to the Eastern Himalayas but it is beyond the scope of this checklist to list all species. For example, Meconopsis primulina is confined to W & NW Bhutan and SE Tibet (Churnbi and Phari). Similarly, Meconopsis primulina is restricted to NE Bhutan and its adjacent parts of Arunachal Pradesh and Agapetex hhnlonim occurs in SE Bhutan and its adjacent Bengal Duars of India. Therefore, many rare and important species go unaccounted in this checklist , as the geographical area is limited to the political boundary of Bhutan. These East Himalayan endemics are worthy of similar treatment in the future.

Over 5600 species of vascular plants occur in Bhutan, of which 423 are orchids including 54 species of new records (Gurung 2006) and some 46 Rhododendrons (Flora of Bhutan 1991). The family of orchids, Orchidaceae, is the largest, followed by Poaceae, the grass family This checklist lists some 126 species and 18 infraspecic taxa (varieties/ subspecies), within 37 families, currently considered endemic to Bhutan, including 23 new species described after the Flora of Bhutan (1983-2002) publications.

Considering the small size of our country in the region, 144 plants is a great diversity of endemism attributed to Bhutan’s high altitudinal and climatic variations and strong conservation ideals of the country under the leadership of our noble Kings. And without this detailed account of endemic species, few people would be aware of such a biological treasure trove of the country. Therefore, this checklist is mainly designed to make the general public aware of the endemic plant species that Bhutan harbors before many become threatened or disappear completely due to several anthropogenic pressures, and serve as a scientically accurate guide to researchers and plant enthusiasts enabling them to develop and support species-based conservation programs in the country Most importantly, the list will be used to assign conservation status using IUCN Red List categories and criteria. This will be first of its kind from Bhutan to attain IUCN threatened list accreditation globally.

This checklist also includes those species with no evidences of records published yet from other countries in the region. For example, Rhododendron hhntanenre is expected to be found in Arunachal Pradesh; however, the recent revision of Ericaceae by the Botanical Survey of India (2014) makes no mention of it. Likewise, Meconopsis superba is expected in S. Tibet but was not included in recent Chinese Papaverance publication (Grey-Wson 2014). This checklist includes some 126 species and 18 infraspecific taxa (varieties and subspecies), within 37 families, currently considered endemic to Bhutan, including 23 new species described after the Flora of Bhutan (1983-2002) publications. Currently, a total of 144 species of plants are recognized to be endemic in Bhutan. The list will in the future be subject to change with regular new discoveries in Bhutan and the surrounding Himalayan region.

This handbook follows the Angiosperm Phylogeny Group III, (APG III) system of classication, unlike the Flora of Bhutan, which follows the older Engler and Prantl system. APG III is the latest molecular-based classication system of the plant kingdom. Instead of using only traditional morphology and biochemistry to understand plant relationships like the past. systems, the APG system is based on phylogenetic studies incorporating molecular data. It will start with families of monocots followed by dicots families. However, within each family species are arranged in alphabetical order for easy use. All plants are presented here with either specimen images or color photos, plant information restricted to striking morphological characteristics of the species that distinguish it from other close relatives or similar species in the region, its place of occurrence (limited to administrative district) and flowering time of the species.

Reference: Yangzom, Rinchen and David G. Long. Eds. 2015. Plants Endemic to Bhutan Himalaya. National Biodiversity Centre, Ministry of Agriculture and Forests, Serbithang, Thimphu, Bhutan. 160 p.

Notes: Project supported by the United States Fulbright Scholar Program, Washington, D.C. (2017). The Fulbright Program is the flagship international educational exchange program sponsored by the U.S. government.