The weaknesses, gaps, difficulties, and other problems faced by Nepal in conserving biological diversity have been collated and analysed above, and the major threats they pose have been identified. Some of the symptoms of these problems may need immediate attention due to the severity of their impact. However, addressing the symptoms does not remove the problem and any benefits are likely to be short-term. More long-term, sustainable benefits will be obtained by addressing both the immediate and root causes of the problems. Following a general discussion of the main perceived causes of the problems of biodiversity degradation in Nepal, this section undertakes a preliminary causal chain analysis for each of the three major causes of threats, socio-economic, natural and anthropogenic, in an attempt to discover the root causes. The Nepal Biodiversity Implementation Plan that will arise from this Strategy will repeat this exercise more thoroughly, and with the participation of critical stakeholders.
4.2.1 SOCIO-ECONOMIC CAUSES
Nepal is one of the least developed countries of the world. With an estimated annual per capita income of US$ 210, open natural resources such as land and forests are the main sources of livelihood for a large proportion of the population.
Poverty is intimately related to environmental degradation and loss of biodiversity. World-wide, the poor do not have access to non-natural resources. They depend on their own direct exploitation of natural resources. Poor people have no choice but to engage in unsustainable uses of natural resources, and Nepal is no exception. Some 44% of people in rural areas and 23% in urban areas live below the national poverty line (World Bank 1999). A large number of poor families have small farms and over two-thirds of rural households own less than half an hectare of land (APP 1995; HMGN-NPC 1999). Most of the people in these groups collect and sell forest products to survive from one day to the next. In efforts to increase production, poor farmers expand cultivation into highlands that are not suitable for agriculture. The result is accelerated soil erosion, land degradation, declining productivity of farmland, and sedimentation in downstream areas.
Until the late 1980s, the forests of Nepal were considered as a major source of revenue, and people used to say Hariyo Ban Nepal Ko Dhan, or ‘the green forests of Nepal are her wealth’. However, agriculture has always been the main source of livelihood of the rural people, who make up 90% of the country’s 23 million people. With the growing population, more trees were cut to export logs to India for foreign exchange and more forests were cleared to increase land for food production, which also provided employment.
The fast population growth (see Table 4.5) has led to a rapid increase in demand for fuelwood (more than 90% of Nepal’s energy needs are met through the combustion of biomass), timber, fodder, and land to grow more food. These heavy pressures are destroying forest ecosystems and habitats and driving some species of plants and animals to a threatened existence.
Over a few years, the Terai has changed from being a densely forested and sparsely populated area to a sparsely forested and densely populated region. The suppression of malaria through the Rapti Valley Development Programme in Chitwan Valley in 1956, the establishment of the Nepal Resettlement Company in 1964 and the Resettlement Department in 1969 dramatically increased migration of people from the hills to the Terai. Forests were cleared and converted to agriculture (Soussan et al. 1995), and the process is continuing today.
Table 4.5 Population change in the different regions of Nepal between 1971 and 2001
Source: CBS 1998; 2001 figures are from 2001 provisional Census
4.2.2 NATURAL CAUSES
Landslides in the hilly regions not only damage the landscape but often cause loss of life and property. Seventy-five percent of the landslides in Nepal occur naturally (MOPE 1998). However, Laban (1979), who analysed landslides triggered by both natural and anthropogenic causes in the Mid-hills, discovered that natural large landslides occur at a frequency of 0.2/km2, but that this increases to 2.8/km2 in areas of human interference. Landslides mainly occur during the monsoon (June-September) when the topsoil gets soaked with rainwater. Hill roads are very susceptible to landslides, and according to one estimate, about 400-700m3 of landslides per square kilometre occur on hill roads every year.
Topsoil erosion has been one of the factors contributing to declining plant productivity. Soil erosion is caused by natural as well as anthropogenic actions. The steep slopes, tectonic instability, and relatively young age of the Himalayas all contribute to high natural erosion (Jha 1992). Soil loss in non-degraded forest areas tends to be below 1.0t/ha/yr, whereas in more degraded areas it is over 4.0t/ha/yr and can go up to 200t/ha/yr in critical areas. Every year, 1-2mm of fertile topsoil is lost throughout Nepal, leading to desertification and low productivity.
4.2.3 ANTHROPOGENIC CAUSES
Toxic substances and other pollutants affect biodiversity at the ecosystem level by disturbing vital ecological processes and modifying the species composition of plant and animal communities. On a local and regional scale, significant populations of lichens, bryophytes, algae and freshwater life, particularly fish, have been eliminated, and air pollutants pose a serious threat to many birds and mammals. But there is no known case of pollutants being the main cause of a species disappearing altogether. Plants have varied responses to air pollution, and Jha et al. (1997) have recorded a reduction in the flowering period of roadside trees (Callistemon citrinus, Grevillea robusta, Jacaranda mimosaefolia, and Melia azedarach) because of pollution. In the last two decades, the Mid-hills in general and Kathmandu in particular have witnessed increased numbers of mosquitoes and other insects mainly as a result of pollution.
In several habitats, fire plays a critical role in the health of ecosystems and in maintaining their biological diversity. In the central region, fires are common in the Pinus roxburghii and Shorea robusta forests of the Terai and Mid-hills during the dry months (March to May). Fires are only occasional in Quercus (oak) forests. Forest fires in Nepal are perhaps less severe than in other countries, but are still capable of doing considerable damage, especially to young plantations (Jackson 1994).
Very few fires are naturally caused in Nepal. Karkee (1991) found that 40% of forest fires in the Mid-hills are started by accident and 60% are started deliberately. Accidental causes include carelessness with cigarettes and matches, fires which are set to clear for cultivation and which then burn out of control, smouldering charcoal left by charcoal burners, fires set to smoke out wild bees when collecting honey and which go out of control, etc. Fires are also set deliberately in forests to kill trees so that the dead wood can then be collected and used for firewood, to induce new grass growth for cattle grazing, to clear land for farming, to make firewood and fodder easier to collect, and for hunting. Fires are also sometimes started maliciously by people with a grudge or complaint against the forest owner or manager.
The Department of Forests has recognised fire as a serious threat to ecosystems and biodiversity, and has allocated some budget for fire control. However, there is no systematic and complete record of forest fires or their impacts in Nepal.
Uncontrolled overgrazing by livestock directly affects the species composition and productivity of the grassland vegetation. Due to relative preferences for different plant species, overgrazing allows an increase in the populations of those species undesirable or unpalatable to the grazing animals. Overgrazing by domestic and wild animals may arrest succession or even reverse it. Overgrazing also causes changes in the diversity of the fauna. The loss of grass cover reduces insect populations, which in turn changes the bird life. Birds found on grazed grasslands are largely seedeaters, while those on non-grazed grasslands are insectivores. Overgrazing also affects the quality of the grazers themselves. Some of the effects of overgrazing on the grazers include low body weight, poor health, low milk production. Reasons for overgrazing in Nepal include too many animals on limited grazing land (more cattle than the land’s carrying capacity), and lack of organised fodder production and pasture management.
126.96.36.199 Introduction of alien species
Some species have disappeared from Nepal over the past years. However, the total number of species has increased due to the deliberate or accidental introduction of exotic species. Immigration of species is also rising with increased human movement. The introduction of three fish species (Salmo guirdneri, S. trutta and Oncorhychus rhodurus) from India, England and Japan between 1971 and 1975 (Shrestha 1994) is an example of a deliberate introduction. Similarly, new fruit species (e.g. strawberries and grapes) have been introduced in Nepal in the last three decades.
There are over one hundred non-native plant species that are so well established that they have become weeds in Nepal. Eupatorium adenophorum, Lantana camara, Mikania micrantha,Bidens pilosa, Amaranthus viridis, A. spinosus, Cassia tora, and C. sophera are so common that they have changed the species composition of fallow and cultivated lands. The introduction of Eucalyptus, Pinus and Populus species has also affected the composition of Nepal’s biodiversity.
188.8.131.52 Illegal trade and hunting
Control of illegal trade in plant and animal species, their parts or products, is a world-wide concern these days. The illegal trade is directly correlated with demographic factors, potentials for profit, and lack of adequate resources for law enforcement.
Reports of illegal hunting from some parts of Nepal are common. Poaching of wildlife and illegal collection of rare, threatened and endangered plant species has always been a serious problem in and outside PAs in Nepal. Fish stocks are over-exploited from the rivers, dolphins, pheasants, and ungulates are hunted for their meat, and carnivores are hunted for their pelts and bones. Sloth and Himalayan black bear gall bladders, rhinoceros horns, and tiger bones are smuggled out of Nepal. Poaching of one-horned rhinoceros and royal Bengal tigers is frequently reported (BPP 1995i). Penalties (fines and imprisonment) set by the NPWC Act (1993 amendment) for killing or trading in wild animals have been effective in deterring poachers, but the high price for gall bladders, rhinoceros horns and tiger bones on the international market encourages poaching of these species. Similarly, the growing demand for certain endangered plants like Panch Aule (Dactylorhiza hatagirea) and Yarsa gumba (Cordyceps sinensis) on the domestic and international markets has created a serious threat to these plant species.
Nepal is a signatory to CITES, the Ramsar Convention and the Convention on Biological Diversity. These Conventions as well as national legislation prohibit or limit trade in endangered and rare species, their parts or products within and outside the country. The Royal Nepalese Army is involved in protecting national parks and reserves. However, they do not have the jurisdiction to protect wildlife outside these PAs. Illegal trade in some of the high-value medicinal plants and wildlife species continues to be a threat to the long-term conservation of these species.
The International Trust for Nature Conservation (ITNC), in collaboration with the Royal Chitwan National Park management, provided financial support to the government’s Anti-Poaching Unit in the early 1990s to control and discourage poaching. The Anti-Poaching Unit was assigned the task of patrolling national parks and reserves and collecting information on poaching activities from villages scattered around PAs. With the support from WWF-Nepal, two additional anti-poaching units were formed in January 1993. One of these is active along the north-western border and the other in the eastern area of Royal Chitwan National Park. Rhinoceros mortality reached a peak in 1993, both due to natural causes and poaching. Between 1992-1997, a total of 76 poachers were caught in relation to rhinoceros and tiger poaching and trade. HMGN, in collaboration with ITNC, WWF-Nepal Program, KMTNC and Buffer Zone Development Committee has established anti-poaching units in different national parks and reserves.
4.2.4 PRELIMINARY CAUSAL CHAIN ANALYSIS
184.108.40.206 Root causes of the threats to ecosystem loss