Causes of the Loss of Biodiversity
Biodiversity is a compound term.It includes all species of plants and animals.Not only this,the variety found among different species is also included in it.Briefly,we may say that variety of lifeforms in any part or region or the earth as a whole is called biodiversity.It is a combination of two words:Bio meaning 'life' and diversity meaning 'variety'.
With the increase in human population,there has been corresponding increase in demand for food,clothing and shelter.To meet this demand,man makes use of forest lands and they are consequently reduced in area.The habitats of wildlife are lost with the loss of forests .As a result,many of the lifeforms have become endangered and some have also become extinct.At the global level ,the loss of biodiversity is heart rending.More than 4000 lifeforms are put in danger or are becoming extinct every year.
The causes of the loss of biodiversity are many but some chief ones are deforestation,intensive grazing,mining,agriculture,urbanisation and development plans such as dams,industries,roads etc through forests,construction sites on forest land and other projects.These have also caused loss of habitats of wild animals.In addition to these,illegal hunting and poaching has caused enormous loss of biodiversity.We can understand this better by explaining the causes of loss under the following heads:
- Changes in habitats:The chief cause is loss of habitats.The man has illegally usurped the forestlands,grasslands and other natural habitats of wild animals and used these for variety of purposes to meet his needs of agriculture ,industry,construction of roads and railways etc.This has considerably reduced the number of original plants and animals found in these areas.There is break in food chain and consequent loss of wild animals.Man uses certain parts of natural habitats for other uses but it causes disruption of the entire ecosystem.There are obstacles in the movement of wild animals to obtain their food and thus obstructions in the food chain.Gradually with the loss of food chain,the wild animals also began to disappear.Man also uses plants and certain useful trees like teak,sal etc.This causes fragmentation of the original ecosystem and consequently the habitats are lost.
- Rise in Population: There has been a rapid rise in human population .To meet the needs of growing population,man resorts to deforestation and destruction of forests and grasslands.The entire ecosystems are thus destroyed consequently leading to loss of plants and animals.So far about two thirds of natural habitats in Africa and Asia have been destroyed as a result of rapid increase in the population.
- Pollution:Pollution especially water pollution is extremely dangerous to wildlife.In the Bay of Mexico,over 20,000 sq km area has become the death trap of wildlife due to pollution of sediments brought by Mississippi river.At this particular place,no lifeform is found.Some scientists think that Global Warming is the main cause of loss of biodiversity.Pollution has begun since the dawn of Industrial Revolution.It is greatest in developed countries and from them it has been copied by the developing nations as well.
- Exotic Species:When a plant or animal species is introduced in a foreign land without consideration of ecology,it cannot grow with the same vitality under new conditions and generally withers away.But sometimes these exotic species are so strong that they dominate the endemic plants and animals.For ex-the water hyacinth has created problems for many nations.Similarly,many plants and animals brought from islands or other nations have threatened the endemic plants and animals growing at many places.
- Over Exploitation:Unnatural morbidity has caused extinction of many plants and animals like whales.The population of wild animals can remain stable only when there is balance in their rate of reproduction and the rate at which they are caught.If the rate at which they are caught exceeds the rate of their reproduction,the number of population of these animals is bound to be considerably reduced.On account of high morbidity and many superstitions ,many of the animals are killed and their parts are used in the manufacture of medicines.This encourages illegal hunting and trading of rare animals.As a result of this,many animals have become endangered species.