Biological diversity in the Himalayas
Stretching in an arc over 3,000 kilometers of northern Pakistan, Nepal, Bhutan and the northwestern and northeastern states of India, the Himalaya hotspot includes all of the world's mountain peaks higher than 8,000 meters. This includes the world's highest mountain, Sagarmatha (Mt. Everest) as well as several of the world's deepest river gorges.
This immense mountain range, which covers nearly 750,000 km2, has been divided into two regions: the Eastern Himalaya, which covers parts of Nepal, Bhutan, the northeast Indian states of West Bengal, Sikkim, Assam, and Arunachal Pradesh, southeast Tibet (China), and northern Myanmar; and the Western Himalaya, covering the Kumaon-Garhwal, northwest Kashmir, and northern Pakistan. While these divisions are largely artificial, the deep defile carved by the antecedent Kali Gandaki River between the Annapurna and Dhaulagiri mountains has been an effective dispersal barrier to many species.
The abrupt rise of the Himalayan Mountains from less than 500 meters to more than 8,000 meters results in a diversity of ecosystems that range, in only a couple of hundred kilometers, from alluvial grasslands (among the tallest in the world) and subtropical broadleaf forests along the foothills to temperate broadleaf forests in the mid hills, mixed conifer and conifer forests in the higher hills, and alpine meadows above the treeline.
Unique and Threatened Biodiversity
Biogeographically, the Himalayan Mountain Range straddles a transition zone between the Palearctic and Indo-Malayan realms. Species from both realms are represented in the hotspot. In addition, geological, climatic and altitudinal variations in the hotspot, as well as topographic complexity, contribute to the biological diversity of the mountains along their east-west and north-south axes.
Of the estimated 10,000 species of plants in the Himalaya hotspot, about 3,160 are endemic, as are 71 genera. Furthermore, five plant families are endemic to the region, the Tetracentraceae, Hamamelidaceae, Circaesteraceae, Butomaceae and Stachyuraceae. The largest family of flowering plants in the hotspot is the Orchidacea, with 750 species, and a large number of orchids, many representing rather young endemic species, have recently been reported from the hotspot, indicating that further exploration will probably reveal a much higher degree of plant endemism. The Eastern Himalaya is also a center of diversity for several widely distributed plant taxa, such as Rhododendron, Primula, and Pedicularis.
In the Himalaya Hotspot, a zone of permanent rock and ice begins at about 5,500-6,000 meters; in spite of these harsh conditions, there are records of vascular plants occurring at some of the highest elevations on Earth. Cushion plants have been recorded at more than 6,100 meters, while a high-altitude scree plant in the mustard family, Ermania himalayensis, was found at 6,300 meters on the slopes of Mt. Kamet in the northwestern Himalayas.
Nearly 980 birds have been recorded in the hotspot, but only 15 are endemic. The Critically Endangered Himalayan quail (Ophrysia superciliosa) represents an endemic genus in the region, although it has not been recorded with certainty since 1876, despite reports of possible sightings around Nainital in 2003.
BirdLife International has identified four Endemic Bird Areas that overlap partially or fully with the Himalaya hotspot. The Western Himalaya EBA has 11 species restricted to it, including the Himalayan quail as well as the cheer pheasant (Catreus wallichii, VU) and the western tragopan (Tragopan melanocephalus, VU). The Eastern Himalaya EBA, which also overlaps with part of the Indo-Burma Hotspot, has nearly 20 endemic species, including four that are fully endemic to the Himalayas: the chestnut-breasted partridge (Arborophila mandellii, VU) and rusty-throated wren babbler (Spelaeornis badeigularis, VU), plus the white-throated tit (Aegithalos niveogularis) and orange bullfinch (Pyrrhula aurantiaca).
Some of Asia’s largest birds live in this hotspot, and many are threatened by human activities. For example, some of the region’s vultures (Gyps spp.) have undergone dramatic declines after feeding on the carcasses of cattle that have been treated with the anti-inflammatory drug diclofenac. Of other birds present in the hotspot, the greater and lesser adjutants (Leptoptilos spp.) in the foothill grasslands and broadleaf forests, as well as the hornbills in the broadleaf forests, are threatened by loss of nesting trees and lack of food sources.
Other avian flagships include the white-winged duck (Cairina scutulata, EN), the endemic white-bellied heron (Ardea insignis, EN), and the Bengal florican (Houbaropsis bengalensis, EN).
About 300 mammal species have been recorded in the Himalayas, including a dozen that are endemic to the hotspot. Among the endemic species are the golden langur (Trachypithecus geei, EN), restricted to a small area in the Eastern Himalaya, the Himalayan tahr (Hemitragus jemlahicus, VU) and the pygmy hog (Sus salvanius, CR), which has its stronghold in the Manas National Park. The only endemic genus in the hotspot is the Namadapha flying squirrel (Biswamoyopterus biswasi, CR), described only from a single specimen from Namdapha National Park.
The mammalian fauna in the lowlands is typically Indo-Malayan, consisting of langurs (Semnopithecus spp.), Asiatic wild dogs (Cuon alpinus, VU), sloth bears (Melursus ursinus, VU), gaurs (Bos gaurus, VU), and several species of deer, such as muntjac (Muntiacus muntjak) and sambar (Cervus unicolor). In the mountains, the fauna transitions into Palearctic species, consisting of snow leopard (Uncia uncia, EN), black bear (Ursus thibetanus, VU), and a diverse ungulate assemblage that includes blue sheep (Pseudois nayaur), takin (Budorcas taxicolor, VU), and argali (Ovis ammon, VU).
The alluvial grasslands support some of the highest densities of tigers (Panthera tigris, EN) in the world, while the Brahmaputra and Ganges rivers that flow along the foothills also support globally important populations of the freshwater Gangetic dolphin (Platanista gangetica). Some of the world’s last remaining populations of wild water buffalo (Bubalus bubalis, EN) and swamp deer (Cervus duvaucelii, VU) are restricted to protected areas in southern Nepal and northeastern India.
Alhough there has been little systematic study of reptiles and amphibians in the Himalaya hotspot, at least 175 reptiles have been documented, of which nearly 50 are endemic. There is just one endemic genus, represented by a single species, the lizard Mictopholis austeniana, known only from the holotype. Other genera are well represented, and have many endemic species. These include Oligodon, Cyrtodactylus, and Japalura.
Among amphibians, there are 105 species known to occur in the hotspot, more than 40 of which are endemic. Most of these are frogs and toads, although there are also two species of caecilians, one of which, (Ichthyophis sikkimensis, is endemic and occurs in northern India (in the States of Sikkim and West Bengal) and extreme eastern Nepal (in Dabugaun in the Ilam District) at elevations of 1,000 to 1,550 meters.
Fish species from three major drainage systems, the Indus, Ganges, and Brahmaputra, inhabit the Himalaya hotspot, although the ranges of many species only just reach into the cold, high-altitude waterways of this region. As a result, only 30 of nearly 270 species are endemic.
The three most diverse of the 30 different families represented here are minnows and carps (Cyprinidae; 93 species and 11 endemics), river loaches (Balitoridae; 47 species and 14 endemics), and sisorid catfishes (Sisoridae; 34 species and four endemics). The genus Schizothorax is represented by at least six endemic species in the high mountain lakes and streams, while two other genera of these snowtrout, the genus Ptychobarbus and the Ladakh snowtrout (Gymnocypris biswasi) — a monotypic genus now thought to be extinct — are also unique to the Himalaya Hotspot.
Despite their apparent remoteness and inaccessibility, the Himalayas have not been spared human-induced biodiversity loss. People have lived in the mountains of the Himalayas for thousands of years. In recent decades, greater access to the global market has increased the demand for natural resources in the area encouraged both immigration from outside (such as Arunachal Pradesh) and movement within the region (such as in Nepal). As a result, populations are growing in the most productive ecosystems, which are also some of the richest in biodiversity.
Today, remaining habitat in the Himalaya is patchy. The steadily increasing population in the hotspot has led to extensive clearing of forests and grasslands for cultivation, and widespread logging. Both legal and illegal logging often occurs on extremely steep slopes, resulting in severe erosion. Although cultivation has a general upper limit of about 2,100 meters on slopes exposed to monsoons, people farm crops such as barley, potato and buckwheat at high elevations in the inner valleys and transmontane regions, and in some areas, such as Jumla, Kashmir, Lahoul, and Ladakh, there are major agriculturally based population centers well above this elevation. The land is also often cleared in the summer months for livestock; the use of fire to clear land poses an additional threat to forest land, as fires sometimes spread out of control. The conversion of forests and grasslands for agriculture and settlements has led to large-scale deforestation and habitat fragmentation in Nepal, and in the Indian States of Sikkim, Darjeeling, and Assam.
Large areas of remaining habitat in the hotspot are highly degraded. Overgrazing by domestic livestock, including cattle and domesticated yak, is widespread in the lowlands and alpine ecosystems. The flora of fragile alpine meadows has been overexploited for traditional medicine (because medicinal plant collectors invariably uproot the entire plant, regrowth is retarded). Fuelwood collection and non-timber forest product extraction, both for domestic consumption and export, has inflicted severe damage to some forest ecosystems. Unplanned and poorly managed tourism has led to environmental deterioration. Political unrest, often in the form of insurgencies, also threatens the integrity of some protected areas.
In addition to habitat loss and degradation, which has led to perhaps no more than 25 percent of the original vegetation in this hotspot still intact, poaching is a serious problem in the Himalayan Mountains, with tigers and rhinoceros hunted for their body parts for traditional Chinese medicine, while snow leopards (Uncia uncia, EN) and red pandas (Ailurus fulgens, EN) are sought for their beautiful pelts.
Other threats to biodiversity and forest integrity include mining, the construction of roads and large dams, and pollution due to the use of agrochemicals.
Conservation Action and Protected Areas
About 113,000 km2 (15 percent of the land area of the hotspot), is under some form of protection in the Himalaya region, although only 78,000 km2 (roughly 10 percent) are in protected areas in IUCN categories I to IV.
While the earliest protected areas, in Assam, were established as wildlife sanctuaries in 1928 and 1934, most other protected areas in the region are relatively new, having been established only in the last three or four decades. However, many hill-tribe communities have traditionally recognized and protected sacred groves, which have served as effective refuges for biodiversity for centuries. Today, several protected areas (Corbett National Park, Manas National Park, Kaziranga National Park, Chitwan National Park, and Sagarmatha National Park) have been distinguished as World Heritage Sites for their contribution to global biodiversity.
In the northeastern Himalayan states of India, a network of protected areas established in the 1970s and 1980s, including Corbett and Rajaji National Parks. These protected areas harbor important populations of elephants and tigers. In Nepal, 21 protected areas cover at least 26,666 km2 of land. Chitwan, which was established as the country's first national park in 1973, is well known for its tiger and greater one-horned rhinoceros (Rhinoceros unicornis, EN) populations. Also in Nepal, the Annapurna Conservation Area, the Kanchenjunga Conservation Area and the Makalu-Barun National Park are all run through community-based biodiversity management.
Although a protected area system was established in Bhutan as early as the 1960s, this system was dominated by the Jigme Dorji Wangchuck National Park. The park was mostly confined to the north of the country, and did little to contribute towards biodiversity conservation because most of the park protected vast areas of permanent rock and ice. In 1995, the protected area system was revised to include all nine of the current protected areas (five national parks, three wildlife sanctuaries, and one strict nature reserve) accounting for almost 26 percent of the total land area in Bhutan. In 1999, based on a WWF field survey, another 9 percent was added to the system in the form of 12 biological corridors, which linked the protected areas to create a conservation landscape extending across the country. The biological corridors provide connectivity between parks and reserves for wildlife species such as tigers and snow leopard to follow seasonal movement of their prey species. The Royal Government of Bhutan is committed to maintaining 60 percent of their forest cover in perpetuity along with the biological corridors.
Transboundary conservation areas offer an important opportunity for conservation in the Himalaya region. The adjoining Manas National Park in Bhutan and Manas Tiger Reserve in Assam, India, is one such complex. Another important initiative is the plan to create a tri-national peace park with the Kanchanjunga Conservation Area in Nepal, the Kanchendzoga National Park in Sikkim, India, and an extension of the Qomolungma Nature Reserve in the Tibet Autonomous Region of China.
Nevertheless, many of the protected areas in the Himalayas, particularly in the lowlands along south-facing slopes, are too small to maintain viable populations of threatened species, and efforts should be made to expand conservation benefits to adjacent areas. Furthermore, about 17 percent of the protected area system across the Himalayan Mountains consists of permanent rock and ice, majestic, but biologically impoverished habitats.
The protected area network in the Himalaya Hotspot needs to be expanded in a way that best protects biodiversity over the long term. In addition to biological corridors and conservation landscapes, biodiversity is best conserved through the conservation of Key Biodiversity Areas (KBAs), sites holding populations of globally threatened or geographically restricted species. KBAs are discrete biological units that contain species of global conservation concern and that can be potentially managed for conservation as a single unit. Building from the network of Important Bird Areas, data on globally threatened species in other taxonomic groups were synthesized from a number of sources, and in collaboration with local partners, to identify an initial set of 175 KBAs in the Himalaya Hotspot.
Investment in biodiversity conservation in the Himalayan Region comes primarily from national governments, bilateral and multilateral agencies, and international and regional NGOs. The national governments, backed by international agencies such as the Global Environmental Facility (GEF), United Nations Development Program (UNDP), the World Bank, the European Union (EU), the Danish International Development Agency (DANIDA), WWF, and the MacArthur Foundation, are supporting projects to improve protected area management, sustainable natural resources, and livelihoods.
Many of the largest projects target communities living in and around forested areas, with the idea that decreasing poverty and increasing awareness and ownership over resources will result in greater biodiversity conservation. For instance, the Livelihoods and Forestry Program, to be implemented by The British Aid Agency (DFID), calls for GBP 8.2 million to be spent over 10 years on promoting active community management of forests in the Terai Arc Landscape of Nepal. Other projects are targeted towards the conservation of specific species, such as the snow leopard.
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