Biodiversity of Bhutan
"The following is an excerpt from the National Biodiversity Strategies and Action Plan, Bhutan 2014."
Bhutan's Conservation History
Formal conservation programs in Bhutan started as early as the 1960s, when Bhutan embarked on the Five Year Plan (FYP) development cycle in 1961, with the designation of the Northern and the Southern Wildlife Circles and the subsequent designation of the first protected area, the Manas Wildlife Sanctuary in 1966. The Forest Act of Bhutan 1969 was the first modern Act to be enacted by the Royal Government of Bhutan (RGoB), which stipulated the requirement for the maintenance of a minimum of 60 per cent of the total land area under forest cover for all time. This was further enshrined in the Constitution of the Kingdom of Bhutan enacted in 2008. Currently, the country has 70.46 per cent of the total area under forest cover1 (LCMP, 2010) and 51.44 per cent of the total area secured as protected areas and biological corridors.
Bhutan’s current status of conservation and biodiversity is a result of the far-sighted vision and leadership of our Kings and our rich tradition of living in harmony with nature throughout the centuries. This has been further strengthened through the formal adoption of the development philosophy of Gross National Happiness (GNH), which categorically states environmental conservation as one of the four pillars of Gross National Happiness.
This effectively ensures that development is never achieved at the cost of the environment. The Public Environmental Expenditure Review (PEER, 2014) of the Royal Government of Bhutan shows that a substantial portion of the public expenditures is spent on the environment for achievement of the government’s environmental related policy objectives. From 2010 to 2013, seven per cent of the public expenditures went into RGoB’s environment related programs.
Overview of Biodiversity of Bhutan
Forests2 constitute the dominant ecosystem in Bhutan, with 70.46 per cent (LCMP, 2010) of the country under forest cover. Further, as a result of variance in the altitudinal range, with corresponding variation in climatic conditions, the country supports a wide range of forest types and vegetation zones. Broadly speaking, the country can be divided into three distinct eco-floristic zones with different forest types.
The aquatic ecosystems of Bhutan consist mainly of rivers, lakes, marshlands and hot springs.
Due to the presence of a large number of glaciers and glacial lakes, high level of precipitation and the relatively well-preserved forests and watersheds, Bhutan is endowed with tremendous
inland water resources in the form of rivers, rivulets, springs and streams. The four major river basins are Amo Chhu (Torsa), Drangme Chhu (Manas), Puna Tsang Chhu (Sunkosh) and Wang Chhu. Drangme Chhu, the largest river basin, drains more than one-third of the country's area.
There are large numbers of small and medium-sized lakes spread across the country. Rajbanshi and Csavas (1982) had listed some 52 lakes in Bhutan from which about 24 were above 3,000 masl and added another eight as unexplored High Altitude Wetlands (HAWs3) in the Dagala area. Further, Mool et al. (2001) recorded a total of 2,674 glacial lakes in the country, with 24 posing potentially high risks. An inventory of HAW by the Ugyen Wangchuck Institute for Conservation and Environment (UWICE) reports about 3,027 HAWs (2,963 lakes and 63 marshes) covering 0.26 per cent of the country’s total land cover with sizes varying from the smallest at about 35 sq.m to the largest at about 1.5 sq.km. The HAWs in Bhutan serve as the main source of freshwater in the country. The largest of all the lakes is the glacial lake at the terminus of Luggye glaciers at 4,506 masl (UWICE and WWF, 2010). However, currently, except for glacial lakes and HAWs, there is inadequate assessment of the area and location of lakes in other parts of the country.
In addition to rivers and lakes, marshlands in the form of depressions and water-logged areas are envisaged to be a major part of the aquatic ecosystem in the country. However, there has been no proper assessment carried out so far, except for 63 high altitude marshlands reported
by UWICE. Marshlands are generally known to be rich in biota and are good habitats for resident as well as migratory birds, reptiles, amphibians and fishes. The best-known marshland in the country is the Phobjikha valley (1,244 ha.) at an altitude of 2,900 masl, where the globally threatened Black-necked Cranes roost in large numbers during winter. The valley is also highly valued for its outstanding scenery and cultural ethnicity. Other important marshlands recognized as wetlands of international importance are Bumdeling (142 ha) (Ramsar site No. 2032) and Khotokha (114 ha) (Ramsar Site No. 2033) (www.ramsar.org).
Hot springs, known as Tshachu in Dzongkha, are very popular in Bhutan. People in Bhutan mainly use hot springs for therapeutic benefits to ease ailments, especially those affecting bone and skin. So far, ten hot springs have been officially reported in the country but the number could be more. Some of the popular hot springs are Gasa Tshachu (Gasa), Duenmang
Tshachu (Zhemgang), Dhur Tshachu (Bumthang) and Chubu Tshachu (Punakha).
The country has six major agro-ecological zones corresponding with different altitudinal ranges and climatic conditions. The main land uses defined for agriculture include the Chhuzhing (Wetland Cultivation), Kamzhing (Dry land Cultivation), Apple Orchard, Citrus Orchard, Arecanut and Cardamom Plantation.
Wild Species Diversity
The country’s diverse ecosystems and eco-floristic zones harbour a rich array of vascular plants. The Flora of Bhutan records more than 5,600 species of seed plants out of which approximately 94 per cent are native species and about 105 species are currently endemic to Bhutan. The Bhutanese flora is also rich in plant species with enormous commercial value and scientific intrigue. The Institute of Traditional Medicine Services (ITMS) uses more than 200 plant species for formulation of various kinds of traditional medicines. Local healers are known to use more than 160 species as recorded in the National Traditional Knowledge (TK) database housed within the National Biodiversity Centre (NBC).
In terms of Pteridophyte diversity (Ferns and allies), currently 411 species in 27 families are recorded from the country (NBC, 2009).
Although there are many species of non-vascular plants, such as sphagnum mosses, liverworts and hornworts, there is no detailed inventory of this group of plants. Currently, only 282 species under 156 genera of mosses are recorded from Bhutan (Long, 1994).
In terms of fungal diversity in the country, currently, about 350 species have been identified and recorded, although the number could be much higher once a complete survey is carried out and species identity determined. The current number is based on a partial inventory carried in the country and only of those species whose identity is confirmed. Out of this, about 53 are edible mushroom species. Many of these edible mushrooms are local delicacies and contribute to the livelihoods and nutrition of the rural poor (Mata et al., 2010).
The diversity and complexity of the associations of fungi and insects are poorly understood worldwide and more so in Bhutan. However, even with the limited studies on this group of organisms, more than 100 species are currently recorded from Bhutan and several species are suspected to be new to science (Mata et al., 2010).
Lichens and Lichenicolous fungus
Lichens are a conspicuous element of biodiversity in Bhutan. However, very little studies are undertaken in this group. Currently only about 287 lichens and lichenicolous fungi are known from Bhutan, although experts estimate the occurrence of more than 1,000 species.
Most species are those common to the Himalayas, except for some eastern North American species also found in Bhutan. For example, the rare Ropalospora chlorantha, so far only known from eastern North America is reported to occur in Bhutan. Lepraria nigrocincta is another species first reported in the Northern Hemisphere from Bhutan while Pyrrhospora bhutanensis is described as new to science (Aptroot and Feijen, 2002).
Close to 200 species of mammals are known to occur in the country, including 27 globally threatened species. Bhutan is also known to be rich in wild felids, harbouring 11 of the 36 globally recorded species. A study conducted in Royal Manas National Park in 2012, in an area as small as 74 sq. km, recorded six felid species, which is about 16 per cent of the global felid species confirming Bhutan as a hotspot for wild felids (Tempa et al.,2013).
Bhutan is recognized as a part of several globally important bird areas, such as Sino-Himalayan mountain forests, Indo-Burmese forests, Indo-Gangetic grasslands, South Asian arid habitats, and Tibetan plateau wetlands (Bird Life International 2014). This explains the rich bird diversity that Bhutan has within its small geographic area. Currently, around 700 species are estimated to be found in Bhutan out of which 18 are globally threatened. Of the three critically endangered species found in Bhutan, the White-bellied Heron is the most studied species with a population of 22 individuals5 out of the estimated global population of 50-200 birds.
In terms of herpetofauna, there are limited studies and documentation carried out in the country so far. Nevertheless compiling all the past records, Bhutan has 61 species of amphibians (59 anurans, one caudata, one caecilian) and 124 species of reptiles (82 snakes, 20 lizards, two crocodile, 20 turtles and tortoise) recorded thus far (Wangyal, 2013, Wangyal, pers.com. Aug, 2014).
Invertebrates are one of the least studied groups in the country giving an incomplete picture of the diversity of this species-rich group. The information presented here are of those groups, which have been studied to some extent. Although, Bhutan is reportedly expected to have 800 to 900 species of butterfly (van der Poel and Wangchuk, 2007), currently only about 586 species of butterfly and 69 species of moth are recorded (Singh, 2014). The first preliminary report on macro-invertebrates at Nika Chhu, Mangde Chhu, Chamkhar Chhu and Kuri Chhu and their tributaries catalogued about 1,107 fresh water insects belonging to nine orders (WCP and WWF, 2012). There is also a record of a relict species of dragon fly, Epiophlebia laidlawii, an indicator of pristine water quality, from the head waters of Dreychhu stream above Dechencholing, Thimphu and Lamchela Chhu in Chendebji, Trongsa (BEO, 2008).
Odonates have been studied to some extent. Currently, from an inventory done in a few selected pockets in the country, 50 species of Odonata are recorded (Mitra, 2008). In case of hymenopterans, about six species of bees are recorded from Bhutan, out of which two are native honeybees (Apis cerana and Trigona iridipennis), while Apis mellifera is an exotic species introduced for commercial beekeeping. The other native bee species are Apis laboriosa, Apis dorsata and Apis florea.
Recent studies have reported a total of 91 freshwater native fish species6 from Bhutan (Gurung, et al., 2013) inclusive of the 49 species identified earlier (Dubey, 1978). However, it is widely believed that the current list of fish species in Bhutan is a gross underestimate of the actual freshwater fish diversity. Amongst the known species, Golden Mahaseer (Tor putitora) is considered endangered and is enlisted as a totally protected species in the Forest and Nature Conservation Act of Bhutan 1995. Apart from the currently known native species, there are nine introduced fish species7 being promoted to increase fish production to enhance rural income and household nutrition and food security.
As a predominantly agricultural country, Bhutan is rich in agricultural diversity. More than 100 species of agricultural crops are known to occur in the country. As a consequence of adaptation to microenvironments created by altitudinal and climatic variations, there are numerous landraces of crop species. NBC has so far recorded 384 landraces of rice, 105 of maize, 36 of wheat, 10 of sweet buckwheat, 11 of bitter buckwheat, 32 of barley, 22 of amaranth and 36 of millets. Several of the varieties and landraces represent adaptation to some of the highest agricultural lands in the world, with cultivation in the alpine agro-ecological zone extending up to 4,600 masl. While wheat is not an indigenous crop, varieties grown around Laya at 3,839 masl, are adapted to higher altitudes and colder climatic conditions than wheat varieties in other parts of the world. Similarly, maize and barley have undergone a natural process of breeding and selection to evolve into high-elevation varieties.
In terms of Crop Wild Relatives (CWR), around 230 species belonging to 120 genera in 51 families are expected to occur in Bhutan (Tamang, 2003). For example, Fagopyrum debotrys, a putative wild relative of buckwheat and Setaria viridis of Foxtail millet are reported from Bhutan. Further, at least three wild relatives of rice Oryza minuta and Oryza rufipogon are reported in the Flora of Bhutan, while Oryza officinalis was recorded from Southern Bhutan in 2012 (NBC, 2013). In terms of horticultural crops, while the country is believed to have rich diversity, there have been no detailed assessments carried out so far.
At the species level, the livestock diversity of Bhutan is not different from those commonly occurring elsewhere in the Himalayas. However, there are many livestock breeds with marked genetic differences. For example, amongst the cattle breeds, Nublang, a traditional cattle breed of Bhutan believed to have originated in Sangbay Gewog of Haa, is genetically distinct from any other cattle breeds (Tshering and Rai, 2008). Another important animal genetic resource is the Mithun, a descendant of Gaur, which originated in Northeast India but has been bred in Bhutan since the 17th century. Mithuns are important due to the unique tradition of crossbreeding Mithun (male) with Nublang (female) to produce Jatsa and Jatsham, which are superior compared to either of the parent breeds. Similarly, yaks in Bhutan have distinct genetic differences between the population in Eastern and Western Bhutan.
Horse breeds found in the country are also considered to be unique. These breeds are Yuta, Boeta, Merak-Saktenpa, and Jata. Bhutanese sheep have been genetically investigated and classified into three types, namely Jakar, Sipsu and Sakten types. In particular, the Jakar type is unique to central Bhutan and is highly endangered as farmers are giving up sheep husbandry since it is no longer economically viable. Traditional Poultry breeds are classified into nine types with the popular Yubja Naap, Belochem and Bailetey featuring amongst them.