This article throws light upon the causes of loss of biodiversity in India. Some of the causes are: 1. Habitat Fragmentation 2. Introduced Species 3. Overexploitation of Plant and Animal Species 4. Pollution of Soil, Water and Atmosphere 5. Global Climate Change 6. Ignorance about Species and Ecosystems and Loss of Traditional Knowledge 7. Unplanned Development 8. Economic Systems and Policies and Others.
Cause # 1. Habitat Fragmentation:
Large areas rich in biodiversity have been reduced to small pockets. This is fragmentation which has occurred as agricultural fields, roads, and housing, industrial hydro-electric and other projects have come up in biodiversity-rich forested areas. Fragmentation of forests, for example, has severely affected the elephant population in India.
Elephants move long distances to ensure that they get adequate water and the choicest plant material available for food. In South India the elephant habitat has been reduced by at least 10 per cent because of the conversion of natural forest to commercial monoculture plantations of eucalyptus, caesarian, teak and silver oak for timber or pulp-wood.
In foothills of eastern Himalaya the conversion of natural forests to plantations has reduced the elephant habitat by approximately 30 per cent. As these forest areas get smaller, they are also over utilised by the elephants.
At the same time the conversion of elephant habitat to other land use purpose blocks the elephants’ traditional migratory paths. This is one reason why these animals increasingly raid agricultural fields, leading to conflict between elephants and people.
Cause # 2. Introduced Species:
Introduction of non-native species (also known as “alien” or “exotic species”), deliberately or accidentally, has been a major threat to biological diversity worldwide as the introduced species have often flourished at the cost of the local species.
One of the best-known examples of the disastrous effects of introducing an alien species is that rabbits in Australia have no predators except crocodiles and humans. Their large numbers seem to be affecting forest regeneration as they overexploit certain forest species for food. The deer are also causing crop damage in the field of island settlers.
Weeds such as Parthenium hyderophorus, which came to India accidentally with a consignment of wheat from the United States, have spread over large forest areas at the expense of native species. The forest floor of several protected areas (areas protected by the Government primarily for conservation of wildlife) has been taken over by Lantana camara, a species brought to India from Mexico to serve as an ornamental plant.
In other parts of the country, indigenous (or native) species are being replaced by commercially useful exotics such as eucalyptus. Several parts of the north-east and also parts of southern and western India have seen the replacement of local crops to accommodate cash crops like coffee, rubber, cardamom and tea.
Cause # 3. Overexploitation of Plant and Animal Species:
Many species have been overexploited by humans, sometimes to the point of extinction. Some species are overexploited for food and shelter. Marine fauna, in particular, is under great threat from overexploitation largely as a result of mechanised fishing and increasing international fishing operations in Indian waters.
Killing for precious commodities, such as ivory, and trapping of birds and mammals as collector’s items, curiosities and for rearing as pets, has threatened other species as well. Various reptiles and amphibians have been exploited for both skin and meat. The trade in live birds for falconry and as ornamental birds has also led to a decline in bird species in India.
Excessive commercial demand from a rapidly expanding pharmaceutical industry, for which no collection regulations exist, affects medicinal plants of various taxa. Dioscorea deltoidea (yam), a species that grows in north-east India, is a major source of diosgenin used in the manufacture of contraceptive pills.
This species has declined in the wild due to over collection. Also threatened in India is the forest shrub Rauvolfia serpentin (Sarpagandha or Indian snakeroot). It has been used in the country for over 4,000 years to treat snakebite, nervous disorders, dysentery, cholera and fever. About 50 years ago an extract (reserpme) from this plant became the base for modern tranquilizers.
Cause # 4. Pollution of Soil, Water and Atmosphere:
Pollution affects the functioning of ecosystems and may reduce or eliminate sensitive species. Little evidence, or data, of air pollution causing a serious decline in the number of species is found in India. However, in one of Poland’s national parks, 43 species of fauna and flora were lost in part due to severe air pollution.
Some studies have been carried out in India on effects of pesticide pollution on species. A long-term study in Keoladeo National Park in Rajasthan showed high levels of pesticide residues in Sarus Cranes. These toxic residues could lead to a high mortality rate among the cranes and eventually a decrease in their population.
Other preliminary studies point to the role of pesticides in the high mortality rates among birds of prey such as the Peregrine Falcon and the Osprey. Pesticides are known to persist in the body of animals and are passed on along the food chain to the next consumer causing further harm.
Water pollution also affects biodiversity. In India industrial effluents are destroying coral reefs and other marine life. About 40 tones of tar balls (by-products of petroleum refining) are deposited on Goa’s beaches every year. These tar balls are washed ashore during the monsoons.
A thin film of oil spreads across the water surface reducing the penetration of sunlight. This affects the plant life found below by reducing their photosynthetic activity. The impermeable oil film also reduces the exchange of gases leading to disruption of respiration, thus killing of many aquatic organisms.
Cause # 5. Global Climate Change:
Global warming, a side effect of air pollution, may play havoc with the world’s ecosystems in the coming decades. Several hypotheses have been proposed on how the increase in global temperatures could affect biodiversity.
Many species that cannot adjust to warmer temperatures are likely to become extinct. Rare and isolated species will be most at risk, being most sensitive to any atmospheric change. Some habitats such as islands and coastal systems, which are at risk of flooding and submergence, will suffer particularly high losses of biodiversity.
Cause # 6. Ignorance about Species and Ecosystems and Loss of Traditional Knowledge:
A species may be lost because we did not know it existed at a site that was developed. In some cases a species may be known locally but the knowledge may die out as traditional ways of life change. In India hundreds of tribal and other communities utilise biodiversity products in their everyday lives.
Tribal groups in India are known to use about 5,000 species of wild plants for many different purposes for food, fibre, antidotes against insect and snakebites, medicines, and for making hunting, fishing, and farm implements.
The traditions, beliefs, needs and cultures of tribal people and subsistence agriculturists are linked to the diversity of life around them. The lifestyles of these communities are fast changing, and if their traditional knowledge is not recorded, understood and passed on, we are likely to lose it all.
Cause # 7. Unplanned Development:
Large-scale development projects have contributed substantially to the loss forests. Between 1951 and 1980, over 5, 02,000 hectares of forests were diverted for river valley projects in India. For instance, the 11 dams constructed on the Periyar river in Kerala not only caused submergence of large tracts of forest but also gave rise to settlements and roads in the forest area.
It is estimated that 60 per cent of the river’s catchment cover is badly fragmented, severely affecting the biodiversity.
The enormous demand for minerals in a rapidly industrialising economy has meant that large areas of forest have been destroyed for mining. In Goa, for example, mining covers 500 sq km, or 14 per cent of the state’s total area. Nearly six hundred mining companies are in force in the 350 sq km of the area which lie within forest areas rich in biodiversity.
Coral reefs, known for the rich biodiversity they harbour, have suffered a similar fate. The coral reefs off Gujarat’s coast offer an example. They were dredged from 1947 for use as raw material in cement manufacture, until the company’s lease to the coral islands was cancelled in the mid-1980s.
Cause # 8. Economic Systems and Policies:
Economic systems and policies that fail to value the environment and its resources contribute to the loss of biodiversity. Biologically diverse natural systems are most often undervalued in monetary terms and, as a result, are converted into agricultural lands or developed for housing or industrial activities that seemingly have more direct economic benefits.
Wetlands in India, such as ponds in urban areas, are being converted for housing and commercial projects every day.
In developing countries particularly, the short-term pressure to address development concerns decreases the value of the future in relation to the present. We need to look at ways to address these real needs while conserving biodiversity.
Cause # 9. Inflexible or Inappropriate Legal and Institutional Systems:
Although laws to protect biodiversity exist, loss of biodiversity continues. This may be because rarely a cross-sectoral approach is adopted which combines ecological and economic realities. Over centralisation of planning hinders local participation which might have brought knowledge, insight and experience of the local environments into the planning process.
Customary law (the traditional law of communities), which by and large promoted the sustainable use of biological resources, is being replaced by a less effective legal system.
Cause # 10. Some Agricultural and Forestry Practices:
Over the years farmers have bred and maintained a tremendous diversity of crops and livestock varieties. The broad genetic base provided insurance against pests, diseases and adverse climatic condition.
But in the last few decades, prompted by the growing demand for food and by market forces, modern agriculture has moved towards fewer crop varieties which are high yielding and respond better to water, chemical fertilisers and pesticides.
Indigenous breeds of cattle have been replaced by cross-breeds and exotics for their higher milk yields. Stability and diversity are thus being replaced by uniformity and productivity. Similarly forestry has also promoted monocultures, leading to substantial loss of biodiversity. In many parts of India commercial plantations of single species have replaced several other species. South India abounds in teak monocultures.
Many southern deciduous and even some evergreen forests have been replaced by eucalyptus monocultures. Many forests on the hills of north-eastern and southern India have been replaced by rubber, tea and coffee plantations.
Cause # 11. Unsustainable Natural Resource Consumption:
If the current demographic trend continues, human population will continue to grow for at least the next half century and probably longer, barring catastrophy. The current world population of 5.5 billion will probably double over the next 50 years. India’s population have crossed 1 billion in the year 2000 and will cross 1.4 billion by the year 2025.
Early in the next century India will surpass China to become the most populated country in the world. As numbers increase and new technologies develop, humanity continues to find more ways to consume the Earth’s natural resources.
Growing population, as well as growing aspirations and consumption-oriented lifestyles of a growing number of people, will make this consumption unsustainable after a point. In addition to rapid population growth, a change in consumption pattern all over the world is causing loss of biodiversity.
Greater demand for food, excessive consumption of minerals and other non-renewable resources, and gross overuse and waste of energy, especially by the industrialised nations, aggravates these problems. In India consumption patterns, particularly of natural resources, differ widely among different income groups.
Consumption by about 50 per cent of the population accounts for a large portion of the country’s use of energy, minerals and chemicals. This consumption encourages the overexploitation of these resources.
The trend is dangerous because the rising demand for minerals, for instance, has led to the de-notification of some protected areas in the country to permit exploitation of the mineral reserves lying within these areas.
The growing pressure on natural resources has affected the poorest people the most. Commercial markets for wood and paper products support commercial forestry but deprive those who depend on a variety of non-timber forest products from natural forests.
Commercial demand for crops residue as fodder, and as fuel along with animal dung, deprive the poor of fuel and fertiliser. Poverty in the urban and cash-driven rural economics compels those who cannot meet their basic survival needs through purchase to rely on a fast depleting natural resource base.
The vicious cycle of uneven consumption patterns and population growth ultimately leads to exhaustion of renewable resources on which local populations depend.
Cause # 12. Inequities:
Inequities in the ownership, management and flow of benefits from the use and consumption of biological resources encourages unsustainable exploitation which leads to loss of biodiversity. Substantial areas in India significant for their biodiversity (expect in the north-east) are owned by the State or Centre as Reserved Forests, Protected Forests, National Parks and Sanctuaries.
In the past local communities living within or around these areas derived benefits from, and in turn were also the local custodians of some of the areas. However, with the curtailment of their traditional rights and benefits, the communities are beginning to wonder who benefits from the protection of these areas.
This conflict is now being seen in several parts of India’s protected areas, these areas, rich in biodiversity and particularly wildlife, have been “kept aside” for conservation. But conservation for whom? The communities living in and around these areas are questioning for whom these areas are really being protected for. An overview of cause of biodiversity loss is shown in Fig. 7.2.
Cause # 13. Global Trading Systems:
Trading systems that favour the growth of monocultures, usually to produce crops for export on a large scale, can have negative effects on biodiversity.
For example, many tropical countries, encouraged by international lending Institutions, have supported the planting of extensive areas of agricultural land with sugarcane, bananas, or pulp trees, to produce commodities for export in order to expand the economy (export-led growth).
Critics point out that such an approach primarily benefits the large plantation owners, usually causing pollution and destroys biodiversity. The root causes of biodiversity loss are interconnected. For example, the global market for prawn and shrimp has encouraged several governments in Asia to create policies favouring investment in shrimp farming.
Shrimp farming uses higher level of fresh water resources. At the same time, the infrastructure for commercial farming pollutes the water, which is flushed into estuaries.
As a result, coastal mangrove swamps, on important habitat for fish, have been destroyed. The costs of habitat loss are borne by local people who depend on the mangrove ecosystems for coastal fish protein, revenue and forest materials.