Biodiversity

The Kingdom of Bhutan, situated in the Eastern Himalaya, features extremely diverse geophysical elements – high, rugged mountains interlaced with deep valleys – as well as stunning biodiversity at the ecosystem, species and genetic levels. Few countries in the world match this – and fewer still have taken such strong steps to conserve it.

Bhutan ranks in the top ten percent of countries with the highest species density on earth, and it has the highest fraction of land in protected areas as well as the highest proportion of forest cover of any Asian nation. Thus, it is one of a very few countries that have an opportunity to maintain their biodiversity largely intact.

Perhaps most important in the Bhutanese context are the ethical and cultural roles of biodiversity in human affairs. Nature is central to Buddhism, which is crucial to culture here; indeed, respect for all life is a dominant tenet, as is the belief that acts of this life will be rewarded or punished in the next. Moreover, mountains, rivers, rocks and soils have been seen as spirit domains since pre-Buddhist times. All provide a powerful motivational principle for sustaining the nation’s outstanding natural resource base.

Development in Bhutan is guided by principles that emphasise preservation of both natural and cultural heritage, as well as sustainability from subsistence to a more modern economy. Even now, Renewable Natural Resources remains the most important sector, and in 1998 contributed 36.1 percent of the Gross Domestic Product. Thus, short-term profit at the expense of long-term loss of natural heritage is not for Bhutan. Its cautious approach prioritises conservation and relegates economic benefits to a firmly secondary role.

By the late 1970s, Bhutan had established an extensive system of protected areas. Since then, among other actions, the nation has:

  • Established the Bhutan Trust Fund for Environmental Conservation to provide long-term financing for conservation.
  • Revised and identified nine protected areas representative of Bhutan’s diverse ecosystems, comprising 26 percent of land area;
  • Established the Nature Conservation Division within the Department of Forestry Services, with a mandate to oversee and manage the protected areas system;
  • Pledged to maintain, in perpetuity, at least 60 percent of land as forests;
  • Enacted the National Plant Quarantine Act, 1993, to control the movement of diseases, insects and other pests;
  • Included provisions for establishing protected areas and conservation regulations in the Forest and Nature Conservation Act, 1995;
  • Ratified in 1995 the international conventions on Biological Diversity and Climate Change;
  • Adopted the National Biodiversity Action Plan in 1998;
  • Adopted the Middle Path, a National Environmental Strategy in 1998;
  • Initiated in 1998 a National Biodiversity Program to overseeex-situ conservation and sustainable utilisation of biodiversity;
  • Legislated in 2000 Environmental Assessments for all development and industrial activities;

Despite its richness, Bhutan is among the most poorly known countries in the world. Although land cover maps exist, there is no nationwide inventory of ecosystems as such. All potential avenues for expanding economic benefits from biodiversity and better ensuring its conservation are constrained by the shortage of basic scientific knowledge about the identity, status and distribution of species/genetic resources. Indeed, the number of described plants and vertebrates amounts to only three percent of the total number of species estimated to exist.

Terrestrial Biodiversity

The diversity of ecosystems stems in part from Bhutan’s location at the juncture of the Palearctic realm of temperate Euro-Asia and the Indo-Malayan realm of the Indian subcontinent, and in part from its great geological and climatic variations. Valleys in the inner mountains receive less than 800mm of precipitation; rainfall in the lowlands is as high as 5,500mm. The country ranges from subtropical forests in the south, at an elevation of 150 meters to the northern alpine zone above 7,000 meters.

Although few areas have not experienced human activities, most ecosystems remain substantially intact. The total land area under forest is 29,045 square kilometers, or 72.5 percent of the country. Out of this, 8.1 percent has been classified as degraded or natural scrub forest. Coniferous forests constitute 26.5 percent, broadleaf forests 34.3 percent and plantation 0.2 percent. The interaction of topography, climate and human use has resulted in the development of a complex pattern of vegetation and habitat types.

The forests of Bhutan can be divided into the Alpine Zone, above 4000m, where there is no forest cover; the Temperate Zone, between 2000 to 4000m, including major conifer/broadleaf forests; and the Subtropical Zone, 150 to 2000m, characterised by tropical/subtropical vegetation.

Forest types include the following:

  • Fir forests at 2,700 to 3,800m, requiring relatively high precipitation. Hemlock (Tsuga dumosa) and birch (Betula alnoides) also may be present. Toward the tree line, at 3,600-3,800m, fir becomes stunted and grades into juniper (Juniperus recurva) and rhododendron (Rhododendron spp.) scrub. Total area 3,45,302 ha.
  • Mixed conifer forest, which occupies the largest portion of the sub-alpine region, between 2,000 and 2,700m. These forests may be dominated by spruce (Picea spinulosa), hemlock, larch (Larix spp.) or mixtures of these species. Hemlock tends to be found on wetter slopes than spruce and is generally bearded with lichens and mosses. Total area 4,86,827 ha.
  • Blue pine (Pinus wallichiana) forest, found in temperate regions between 1,800 and 3,000m in Haa, Paro and Thimphu valleys in the west and Bumthang and Gyetsa valleys in central Bhutan. Sometimes it is mixed with oak (Quercus spp.) and rhododendron. Total area 1,28,593 ha.
  • Chir pine (Pinus roxburghii) forest, a low-altitude (900-1,800m) forest type occurring in the deep, dry valleys of the Puna Tsang Chhu, Kuri Chhu and Kulong/Dangmechhu river systems, essentially under subtropical conditions. A long dry season is characteristic of these areas. Chir pine forests are heavily influenced by human activities, including tapping for resin, felling for timber and burning to produce fresh grazing for livestock or new lemongrass (Cymbopogon flexuosus) growth. Total area 1,00,899 ha.
  • Broadleaf mixed with conifer in extensive areas where the gradation is very gradual. These are generally oak mixed with blue pine, or upper hill forest mixed with spruce or hemlock. Total area 1,35,789 ha.
  • Upland hardwood forests on temperate hillsides, 2,000 to 2,900m, including evergreen oak forest and cool broad-leaved forest. Total area 4,50,000 ha.
  • Lowland hardwood forests in subtropical hills, 1,000 to 2,000m, very rich and mixed with a wide variety of subtropical and temperate genera.
  • Tropical lowland forests in hills below 700m, a type broadly classified as semi-evergreen, but it varies from almost totally deciduous on exposed dry slopes to almost totally evergreen in moist valleys. These are multi-storeyed, with particularly rich species diversity. Total area under lowland hardwood and tropical lowland forests is 4,40,000 ha.

Aquatic Biodiversity

A large number of high-altitude lakes and river systems originate from the high Himalaya, traversing from the northern mountains to the southern lowlands. The tremendous difference in altitude and climatic contrast from north to south result in a wide variety of ecological conditions, ranging from glacial streams to torrential cold waters in mountain and hill regions to slow-flowing or stagnant warm waters in lowlands. Bhutan’s aquatic habitats are found throughout the ecological zones, including:

  • Rivers, which comprise vast inland resources. The Manas system, with a total length of 3200km, is the principal drainage.
  • Lakes, not all of which have yet been surveyed for area, location and flora/fauna. Most are small or medium-sized.
  • Man-made reservoirs, most prominent being the diversion dam for the Chukha hydropower project.
  • Village ponds, scattered across the south.
  • Irrigated paddy fields, found virtually everywhere.
  • Marshy land, which is rich in biota and serves as good bird habitat.

Species Diversity in the Wild

Within Bhutan, one can distinguish three ecological units with typical fauna:

  • High-altitude fauna include “flagship” species such as snow leopard (Uncia uncia), blue sheep (Pseudouis nayaur), red panda (Ailurus fulgens) tiger (Panthera tigris) and takin (Budorcas taxicolor), as well as marmot (Marmota himalayana) and musk deer (Moshcus chrysogaster);
  • In the temperate zone, tiger, leopard (Panthera pardus), goral (Nemorhedus goral), serow (Capricornis sumatraensi), grey langur (Presbytis entellus) and macaques are found. Old growth in the temperate broadleaf forests provides habitat for Himalayan black bear (Selenarctos thibetanus), red panda, squirrels, sambar (Cervus unicolor), wild pig (Sus scrofa) and barking deer (Muntiacus muntjak);
  • In the lush tropical forests of the south, animals include the tiger, clouded leopard (Neofelis nebulosa), elephant (Elephas maximus), greater one-horned rhinoceros (Rhinoceros unicornis), water buffalo (Bubalus bubalis), golden langur (Presbytis geei), gaur (Bos gaurus), swamp deer (Cervus duvauceli), hog deer (Cervus porcinus), pygmy hog (Sus salvanius), hispid hare (Caprolagus hispidus), piliated langur (Presbytis pileata), sloth bear (Melurus ursinus) and four species of hornbills (Rufousnecked, Wreathed, Pied and Great Indian).

Although Bhutan’s birds also are still little known, 770 species have been recorded, including Indo-Malayan and Palearctic elements. About 73 percent are resident; most move between higher-altitude breeding areas and lower-altitude wintering areas. Also within Bhutan’s borders, one can find more than 60 percent of the endemic plant species of the eastern Himalaya. Of the 5,500 known species of vascular plants, as many as 750 are endemic to the region, with 50 or more endemic to Bhutan itself. No comprehensive description of the Bhutan flora is yet available, however. It is known, nonetheless, that several species are of high conservation value, including some for valuable alkaloids and medicinal properties; some as wild gene pools for crop research, and others as potential horticultural crops of ornamental value.

The herpetofauna of Bhutan are especially poorly documented but are considered rich. Likewise, the invertebrate fauna are poorly known, although Bhutan contains many butterflies, including rare species.

[Source: Biodiversity Action Plan, 2005, Royal Government of Bhutan]



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