The world’s highest mountain range has not been spared from the anthropogenic threats to biodiversity loss that pervade this planet. Historically, the human population densities in the region were relatively low, suppressed by disease, low productivity of the land, and inaccessibility. But in recent years, successful disease control programs, improved road access and other development have been followed by in-migrations that have increased the human populations and overwhelmed the traditional cultures and lifestyles by market economies and increased material aspirations. Since development and access is still variable across the region, the severity of threats and consequent rates of biodiversity loss is also variable, which has to be considered when assessing conservation opportunities and actions.
For instance, until the 1960s the highly productive Terai ecosystem in Nepal was rife with malaria and thus sparsely settled, except by the indigenous Tharu people. But since eradication programs significantly reduced the prevalence of malaria, there has been a massive influx of people into the Terai from the less productive hills, resulting in extensive clearing of forests and grasslands along the foothills and low valleys.
But in northeast India, the migration patterns are reversed. Since political and economic integration of the resource-rich northeastern hill states, there has been an in-migration of people from other parts of India into the natural resource-rich hills, with consequent marginalization of the tribal groups.
Other threats, such as grazing by domestic livestock are common across the different ecosystems. The lowland ecosystems are heavily grazed by large herds of cattle. In the Nepal Terai, free-grazed, “unproductive” cattle have essentially reduced forests to lawns with a few standing trees. The less productive and more inaccessible alpine meadows are becoming degraded because of intense grazing by increasingly larger herds of domestic yak. Although yaks have been grazed in these montane grasslands for centuries, the herds, usually owned by absentee owners, have increased in size. These sensitive ecosystems are placed under added stress by unsustainable harvesting of alpine plants for a lucrative traditional medicine trade. Chronic threats from non-timber forest product collection, cutting and lopping of trees in natural forests for fuel, fodder and timber for house building and agricultural implements also contribute to ecosystem degradation throughout the Himalayas, especially where the human population density is high. Thus, in places like the mid-hills of Nepal and the lowland forests across the Himalayas foothills, the biologically rich subtropical and temperate broadleaf forests have been widely cleared or, at the very least, highly fragmented. Large extents of intact subtropical and temperate forests still remain in Bhutan and northeastern India where human population densities are relatively lower, but changes in shifting cultivation regimes have resulted in more forests being cleared with inadequate fallow periods for regeneration, especially in the latter region.
Timber is widely sought for building. With the depletion of forests elsewhere in the region, the remaining forests in the mid-hills have become attractive commodities. The demand, and economic rewards, has fuelled illegal logging practices in these forests. Because the majority of the remaining forests are on slopes too steep for well-managed, sanctioned forestry practices, the illegal timber harvest—or in some cases legal, but unsuitable practices—pose serious threats to the forests, environment and biodiversity, as well as the socioeconomic dimensions.
Unsustainable and illegal wildlife trade is another major threat in this region. The great demand for wildlife products, especially from the large charismatic species such as tigers, rhinoceros, snow leopards and elephants has driven these populations to the brink of extinction and they now require considerable protection to ensure long-term survival.
The unplanned growth of tourism in this exotic reach of the world has led to environmental and ecosystem deterioration. Despite the socioeconomic returns from tourism as an industry, unless regulated it can affect the ecological integrity and by extension, the industry itself which depends on a sound and attractive environment.
The unstable Himalayas slopes have always been prone to erosion. But the exposure of bare soil and reduced compactness because the ground cover is removed through logging, unsustainable non-timber forest product harvest, intense grazing by domestic livestock, and badly planned infrastructure, has resulted in erosion being more widespread. Consequently landslides are becoming more common with accompanying environmental degradation and economic, livelihood, and human losses.
A consequence of the widespread habitat loss and fragmentation is that the large, wide-ranging species are now virtually confined to remaining scattered habitat patches, mostly within the protected areas. But most of these refuges are small and unable to support ecologically and demographically viable populations over the long term. Therefore, the species are considered to be globally threatened and have been recognized as priority conservation outcomes.
While there is a tendency to be preoccupied with conservation of the larger, charismatic species and threats to these species, many other smaller species go unnoticed. Because large areas of the region are biologically unexplored, it is very likely that there are many species that are as yet unknown and unrecorded. Therefore, a focus on the ecological parameters for conservation of the larger species that require corridor outcomes for effective conservation can serve as umbrellas for many of the smaller species, including those that are, as yet undocumented.
The participants at the expert roundtables identified several of these major sources of threats and underlying causes of these threats across the region (Table 6). The resource documents that were commissioned provide additional information on the regional and local threats to biodiversity. Several of these threats are overarching, but there are others that are specific to certain areas. A more detailed exposition of the overarching threats with underlying causes based on the expert roundtables and resource documents is presented below.
This emerged as a broad, overarching causal factor resulting in biodiversity loss. The underlying causes were identified as unsustainable levels of fuelwood and other non-timber forest product extraction; intense grazing by large herds of domestic livestock in forests, lowland grasslands, and alpine meadows; encroachment into forest lands by landless, migrants, and even ‘land-grabbing’ by rich people; and slash and burn agricultural practices, especially in hill areas.
Conversion of forests and grasslands to agriculture and settlements is most intense in Nepal, and in the Indian States of Sikkim, Darjeeling and Assam. The mountain areas of Bhutan, Arunachal Pradesh, Megalaya, and the other northeastern Indian states have not experienced as much conversion although, in general, shifting cultivation has been a widespread practice in northeast Indian hill states. The Bhutan Biological Conservation Complex is the least impacted by forest conversion from among the corridor outcomes, whereas the foothill landscapes, notably the Terai Arc and North Bank, are highly fragmented.
The northeastern Indian states have the highest forest cover in the country, but are also experiencing losses as high as 31,700 hectares of dense forests annually (Down to Earth 2002). Here, shifting cultivation was, and still remains, the main source of livelihood for most hill tribal communities. On average, 3,869 square kilometers is put under shifting cultivation annually, and an estimated 443,336 households earn their livelihood from this practice. But, while in the past, a 10-30 year fallow period allowed for forest regeneration, the fallow period has now reduced to two years in some areas, making the practice unsustainable. As a result, the landscape has undergone tremendous changes, with extensive bamboo brakes that prevent succession to broadleaf forest. Because of uncertain land-tenure issues and usufruct rights, the incentives for maintaining the traditional sustainable practices are also disappearing.
Extensive grazing by domestic livestock is another pervasive source of biodiversity loss throughout the Eastern Himalayas Region, from the lowlands to the alpine areas. The species-rich alpine meadows, when overgrazed by large herds of domesticated yak, become dominated by a few species of unpalatable shrubs like
Berberis,
Rosa,
Caragana, or forbs like
Euphorbia,
Primula and
Pedicularis. Severe overgrazing creates bare patches that are susceptible to wind erosion, but a more common pattern is for the rangelands to be cropped into lawn-like grasslands. In the lowlands and mid-hills, the forests grazed by herds of cattle have lost all undergrowth, and no longer possess or support the natural ecosystems and associated biodiversity.
The biodiversity and ecological integrity of the alpine meadows, already subject to high grazing pressure, are also threatened by commercial collection of plants used in the traditional medicine trade. Some of these important plants include
Fritillaria cirrhosa,
Sausuria spp. and
Cordyceps sinensis, the latter a species of caterpillar that becomes infected by a fungus and is highly prized by Chinese and Tibetans as a powerful tonic. Although some plants are collected for local use, large quantities are collected for export. Often entire plants are uprooted and removed even though only parts are used; thus regeneration and recovery is retarded (Lama et al. 2001). Despite efforts to regulate this trade, and in some instances to even prohibit it, the remoteness of the region, open borders in the north, and lack of human resources make enforcement of regulations difficult at best.
Lopping and pruning trees for fuelwood and fodder for livestock have inflicted severe damage on forests, including changes in species compositions. The lowland forests are more productive than the montane forests and can withstand greater levels of extraction, but the human populations exploiting the lowland forests are also much greater. Thus, forests with trees lacking branches and sans undergrowth are common sights throughout the mid-hills and lowlands of India and Nepal.
Unsustainable poaching and hunting for commercial wildlife trade was identified as a major threat to several high priority species outcomes. The high demand for tiger and rhinoceros parts places these species under extreme threat. The rhinoceros has even been extirpated from important, high-profile protected areas such as Manas Tiger Reserve. Currently, even relatively well-protected parks such as Chitwan and Bardia national parks in Nepal are subject to frequent rhinoceros poaching. Similarly, tiger parts are highly prized in traditional East Asian medicines, and the open borders encourage poaching since the probability of apprehension is low while the economic returns are high.
Many of the tribal groups across the eastern Himalaya also practice traditional and customary forms of hunting, especially in the northeastern Indian states where animal pelts, feathers, and bird bills are used as adornments. Small projects are now underway to mitigate customary hunting of Endangered species; an example being the project to exchange beaks of Endangered hornbill species for models made of fiberglass.
Wildlife killing also takes place as a result of conflict with humans. Retaliation against tigers and snow leopards for livestock depredation, and against elephants and rhinoceros for crop depredation is prevalent and continue to intensify as humans and wildlife compete for land and other resources. The North Bank Landscape is a prime example of intense human-elephant conflict with fatalities on both sides brought about by extensive and ad hoc land clearing and encroachment of forestlands.
Because of the threats to wildlife from hunting, relevant authorities have imposed prohibitions. Yet, hunting and killing of wildlife continues. While subsistence hunting is largely restricted to the vicinity of settlements or travel routes, commercial hunting takes place in remote areas because of patrolling and policing close to travel routes (Rastogi 2000). The economic incentives from wildlife products are lucrative enough that poachers will suffer the hardships and risks of venturing far from easily accessible areas.
In Nepal, forestry contributes a significant amount to the GDP—up to 15 percent, according to Pudasaini (1993). Bhutan has pledged to maintain more than 60 percent of its forest cover, yet export timber to India and Bangladesh. And northeastern India has several Reserve Forests that are managed for timber. But the threat to biodiversity arises from large numbers of illegal, small-scale logging operations that continue to nibble away around the edges and from within the remaining forest patches. Some of the immediate anthropogenic threats from these logging operations include disturbance and loss of wildlife from the area, habitat degradation, which affects the habitat sensitive species, and hunting. But even more serious is that many of these illegal operations are extracting from slopes too steep to be logged in a sustainable, managed manner. The resulting erosion in steep slopes then triggers a cascading chain of consequential environmental problems which manifest far downslope and downstream from the sources.
High flood events were identified as significant threats in the North Bank and Kaziranga-Karbi Anlong landscapes. During high floods, Endangered species—the greater one-horned rhinoceros in particular—requires high-ground refuges. Since the Kaziranga-Karbi Anlong landscape in particular contains a significant proportion of the global population of greater one-horned rhinoceros, mitigation measures are necessary to provide flood refuges and access to high ground in the foothills to the south.
Pollution
Agrochemicals—fertilizers and pesticides in particular—were identified as significant threats to some globally threatened species. The decline of some large, Endangered birds such as the vultures and adjutants have possibly been attributed to agrochemicals, although it is also likely that there are multiple causes acting in synergy.
Infrastructure is an inevitable part of development. But development also poses inevitable threats to biodiversity, although the severity can be ameliorated with judicious planning, appropriate choice of sites, mitigation, and sound implementation methods and practices. Throughout the Eastern Himalayas Region, large dams and roads are considered to represent development priorities. These same priorities also represent significant sources of threats to biodiversity, and to the corridor outcomes in particular. Roads enable easier access and encourage settlements. Previously inaccessible areas become available for hunting and poaching. Road construction itself causes disturbance, destruction, and degradation of the habitat and biodiversity. Road networks fragment large, intact habitat blocks and disrupt the integrity of corridor outcomes.
In the eastern Himalayas the road network is most dense in the lowlands, where the human population is greatest, and road construction is easier. In the mid-hills regions, the network is relatively denser in Nepal than in Bhutan and the farthest northeastern Indian states.
Large dams built for hydroelectric power generation is another source of threats to biodiversity, especially for the corridor outcomes. In some respects the dams have a positive effect on the eastern Himalayas ecosystems since the availability of hydropower can ease some dependence on fuelwood. However, because of the rugged and difficult terrain, it is unlikely that electricity can be supplied in a cost-effective manner and with minimal environmental costs to all remote villages spread across the Himalayas Mountains. Thus, many people would still depend on fuelwood for energy, and in all likelihood the excess power would be diverted to large cities far from the region.
Dams also take up space. In Nepal, for instance, if all the proposed hydro-projects were actually built, more than 2,000 square kilometers of arable land would become submerged (Zurick and Karan 1999). The reservoirs usually submerge the fertile and arable valleys and displace the people into marginal lands, usually upslope. The generation of surplus energy drives industrial expansion in both surrounding mountainous lands as well as in the lower hills and plains. The seismic activity of the eastern Himalaya is such that a large earthquake could cause the dam to breach, wreaking havoc on the downstream watershed and communities in the densely settled lowlands. Moreover, building dams often require construction of new roads into previously inaccessible areas, opening the areas to settlement by outsiders who are likely to be more interested in higher levels of natural resource extraction than traditional and sustainable modes of existence.
The effect of dams on fisheries and fish ecology is also of concern. Although little is known about the seasonal migration patterns of aquatic species in the Himalayas rivers, there is evidence to suggest that some species of fish and the Gangetic River dolphin move upstream during the monsoon season. Preliminary research at the Kali Gandaki Dam suggests that the fish ladders—designed along the line of ladders built for salmon in North America—do not work. Thus, alternative methods or techniques are required. Along the Karnali River, the dolphin population above the barrage in India is in decline. Dolphins from below the dam barrage cannot negotiate the dam to replenish the upriver population. The barrage also prevents fish migrations; thus, the prey base for the upriver dolphin population is also likely becoming depleted.
The Nepali government has included 18 dam projects in its Ninth Plan. Bhutan tends to favor small, run-of-the-river projects for local energy production, but there is a large 60 MW hydro project—Kurichu Hydro Project—currently under construction close to Thrumsing La National Park. The relevant state governments in northeastern India also look favorably on hydroelectric power development. Sikkim has the potential to produce 8,000 MW of power, but has tapped only 33 MW thus far. The Teesta and the Rangit rivers are recognized as having the most potential for project development. Currently, various micro, small, and medium-sized projects are under construction. Although micro projects cannot provide large amounts of energy for export that large dams would, they would provide electricity for rural villages. Thus, the optimal solution for these areas would be micro hydro plants in villages that can be built and cared for locally, which would also create less damage, and cost relatively little. Further east, the proposed Lower Subansiri hydroelectric project in Arunachal Pradesh with an installed capacity of 4520 MW will flood 4,039 ha of forestlands in Arunachal and Assam, including critical elephant corridors in the North Bank Landscape (Ecologist Asia 2003a). Because the economic interests of the State government officials and policy-makers overrule the ecological impacts, the environmental impact assessments and recommendations have become mere formalities that are often overlooked or ignored, rather than be considered for mitigation that can better inform the project plan. The impact of Loktak hydro scheme in Manipur, started in 1983 is now apparent with the absence of migratory water birds (because of higher water levels) and occurrences of flash floods (Ecologist Asia 2003b), and should serve as an example for development in the region.
Mining is generally quite destructive to habitats and biodiversity. The immediate area around mines can become converted to ecological wastelands as massive amounts of waste materials degrade surrounding land and water bodies, and huge landslides can result from blasting. Fortunately, because of inaccessibility to most deposits there is relatively little mineral extraction in the eastern Himalayas. However, as the road network expands, mining and its side effects could be much more pervasive.
In Nepal, low-grade iron ore, scattered copper deposits, zinc, limestone are mined in some places (Zurick and Karan 1999). Bhutan has significant deposits of dolomite coal, limestone, and gypsum but extraction is currently negligible. In Sikkim, the Rangpo Copper Mine has potential for further development. Open cast mining and oil exploration are, however, major threats in the other northeastern states of India (Goswami 2000), where deforestation, soil erosion and air and water pollution (pH value as low as 2.7) are obvious manifestations.
Fires are lit in the forests to burn the understory and open the forest for easier access and induce a flush of vegetation for livestock. But these fires sometimes spread out of control, burning up into the subalpine zone. Thus, forest fires were identified as a major threat in Bhutan and in the Terai Arc Landscape.
The current use of fire as a management tool in protected areas can also be a threat to some species outcomes. Many of the grasslands in protected areas are maintained by annual burning to provide suitable habitat for large ungulates, especially for rhinoceros and wild water buffalo. However, this management regime is detrimental to smaller, grassland habitat specialists such as the hispid hare, pygmy hog and several grassland birds, which are also Critically Endangered and require conservation management. Thus, the use of fire in these protected areas should be reviewed and appropriate measures taken to use it more judiciously, with due consideration for overall biodiversity characteristics of the grassland communities, rather than a few select species. This is especially important in the sites and corridors identified as outcomes in the Terai and Duar savannas and grasslands.
Poor baseline data and unreliable scientific information are serious impediments to designing appropriate strategies and policies for biodiversity conservation and management in the region. Inadequate species inventories and distribution records, poor documentation of information, and absence of trained manpower to undertake scientific and analytical studies have retarded progress in conservation. In the absence of reliable data, unintentional habitat destruction may have occurred in the context of siting development projects, and even when designing and managing protected areas and conservation landscapes. Even the development of this profile has been hampered by lack of information on the distribution and status of most species, and much of the eastern Himalayas are biologically unknown. Thus, even these priorities are based on limited knowledge.
Political unrest manifested as insurgencies plague the region. Protected areas and forests that harbor wildlife also serve as refuges for insurgents, who indulge in indiscriminate poaching and felling of trees. Effective patrolling and protection in these refuges by protected area staff is then made difficult at best and impossible, usually. Manas National Park in Bhutan and Manas Tiger Reserve in India, where the rhinoceros population has been extirpated and the tiger population severely depleted, are good examples of the threat to biodiversity and conservation efforts caused by insurgencies. Outside protected areas, large tracts of plantation forests throughout the state of Tripura are being destroyed in the absence of Forest Department staff or Joint Forest Management committees due to the insurgency. Similar insurgencies occur in Nagaland. And in Nepal, the Maoist insurgency has severely constrained conservation activities on the ground.
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