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Friday, August 6, 2010

Some factors responsible for losses in biodiversity

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Varieties of Biological Resources are in International demands today. To meet this international demand illegal activities of smuggling of these resources are being done through illegal routes. Some of the species of plants and animals have gone to the status of threatened, rare, endangered or critically endangered due to such types of practices. A number of valuable species of plants and animals have become extinct due to these activities. The international trade in the body parts of animals is increasing rather more rapidly due to their high prices in the international markets. Where possible the trade of whole animals is also in the full swing. Here are some examples.

1.    The market price for the body parts of a single tiger has been found to be US$ 5 million.    The good quality dried sea horses sell for as much as US$1200 per kg in some areas of China,
3.    According to the TRAFFIC, the Annual Trade of tortoises and river turtles in North East Asia accounts about 300 000 kg of live animals. In economic terms, it accounts upto US$ 1 million.
4.    The Tibetan Antelope Chiru which is found in some of the harshest regions of Tibet and China is hunted for its fine hair for making Shahtoosh Shawls. The price of one kg of shahtoosh is around rupees 60,000 if translated from the international currency.

It has been reported that Queen Elizabeth wore one Shahtoosh shawl to Prince Edward’s wedding and Ms. Julia Roberts, the actress, wore a shahtoosh shawl during the premier of her film the Runaway Bride. Now a ban on shahtoosh shawls has been imposed since 1991. Chiru is now at the verge of extinction due to its brutal killing for its fine hair.

According to an estimate of Food and Agricultural Organization (FAO), from 4000 to 6000 species of medicinal plants are in the routes of international trade. About 30 percent of export of plant resources is done by the People’s Republic of China alone. Varieties of plants are in high international demand due to high value of their wood.

1. The Asian Rattan Palm is in high international demand due to its wood for the making of furniture. The international furniture making industry earns about US$ 3.5 to 6.5 billion annually from the Rattan Palm alone. This has resulted into the decline of the palm species. This is reflected in the fact that furniture industry of Asia is importing Rattan Palm from countries other than Asia, like Nigeria and other Countries of Central Africa.

2. The Wood’s Cycad or the Encephallartos woodii has become extinct in the wild due to its severe exploitation for the medicinal purposes. Now only male plants are in existence and they too are to be vanished one day. In the absence of female plants we cannot expect their regeneration now.

Image 1: Wood's Cycad

Population Growth, Urbanization and Poverty

The growth of human population and urbanization are imposing degrading pressures on biodiversity through following ways-
(i)    These are causing encroachments into natural habitats,
(ii)  These are leading to the conversion of natural habitats into human settlements,
(iii) The increasing population is causing an increase in the demands of food which is met through the expansion of agriculture. This is done through clearing of natural forests, reclaiming of wetlands or through the fragmentation of vast areas of natural habitat,
(iv) Use of hybrid seeds and agro-chemicals like pesticides, fungicides, insecticides, rodenticides and hormones etc.

Poverty is another and underlying factor which is responsible for the loss of biodiversity in the world. This is because of the fact that the poor are frequently forced to occupy the marginal lands and so to encroach upon the fragile ecosystems. This is evident from the examples of Wetlands in Bangladesh; hill forests in India and Nepal; and Mangroves in Thailand that are ecologically disturbed due to their occupation by the poor people for settlements and agriculture. This problem can be addressed by focusing on developing alternative livelihood strategies for the poor people who currently rely on protected natural habitats for their living.  Thus we see that both the poverty as well as affluence causes pressures on natural ecosystems that finally lead to greater degradation of resources, environment and thus to the biodiversity. However, the growth of human population, either directly or indirectly, is one biggest cause of the losses experienced by the environment.

The process by which a new species is introduced into a habitat is called as Bioinvasion. The new species that is introduced in the new habitat is called as the exotic species or the Invasive Species. According to a report of the International Union for Conservation of Nature and Natural Resources (IUCN) -

“Invasive species are organisms (usually transported by humans) which successfully establish themselves in, and then overcome, otherwise intact, pre-existing native ecosystems. Biologists are still trying to characterize this capability to invade in the hope that incipient invasions can be predicted and stopped. Factors may include: an organism has been relieved of the pressures of predators or parasites of its native country; being biologically "hardy", for example, has short generations and a generalist diet; arriving in an ecosystem already disturbed by humans or some other factor. But whatever the causes, the consequences of such invasions - including alteration of habitat and disruption of natural ecosystem processes - are often catastrophic for native species.” 

 Invasive species are organisms that are usually transported by human beings from foreign areas. These species successively colonize native ecosystems. These have been a major threat to native species because these species show predatory behavior, cause changes in habitat and often disrupt the process of ecosystems. One example is the introduction of Australian Brush Tail Possum which caused decline in the number of native birds in New Zealand. There are a number of other examples also that justify the degrading impacts of invasive species in a new habitat. The spice cardamom is a problem in the lowland moist forests of Sri Lanka and Southern India. On the other hand, the invasion of Black Pepper is causing serious threats to the biodiversity in the forest edges of Malaysia. The Chromolaena odorata which is a shrub and which has its own values as a fallow crop in Indonesia has become the single most invasive plant in the Nature Reserves of the Tropical Regions. The Parthenium hysterophorus, a noxious weed which competes with crop plants, causes health hazards to humans and cattle. This weed is highly allergic and reportedly causes asthma and other diseases in human beings. This exotic species was introduced from the tropical America. It was first reported in 1957 from Maharashtra.

 The increasing applications of genetically engineered microorganisms and their establishments in the natural habitats are causing potential risks to the existing plants and animals. Some traits of the genetically engineered microorganisms harm the species on which most of the natural organisms depend for their survival. Secondly, the mixing of the genetic stock and the subsequent loss caused by this event and, the general competitive superiority of the genetically modified organisms lead to the degradation of biodiversity in a region.

Image 2 : Parthenium sp.

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