Monday, July 27, 2009

BIODIVERSITY-CAUSES AND CONSEQUENCES OF ITS DEGENERATION

Biological diversity refers to the variety and variability among living organisms and the ecological complexes in which they occur.The term encompasses different ecosystems, species, genes, and their relative abundance.The biodiversity found on earth consists of millions of biological species as a result of 3.5 billions years of evolution.

Extinction is a natural event and, from a geological perspective, routine.In the modern era, due to human actions, species and ecosystems are threatened with destruction to an extent rarely seen in earth history. Probably only during the handful of mass extinction events have so many species been threatened, in so short a time.Below are the reasons.


Over-hunting has been a significant cause of the extinction of hundreds of species and the endangerment of many more, such as whales and many African large mammals. Most extinctions over past several hundred years are mainly due to over-harvesting for food, fashion, and profit.Commercial hunting, both legal and illegal (poaching), is the principal threat.


Habitat loss/degradation/fragmentation is an important cause of known extinctions. As deforestation proceeds in tropical forests, this promises to become the cause of mass extinctions caused by human activity.All species have specific food and habitat needs. The more specific these needs and localized the habitat, the greater the vulnerability of species to loss of habitat to agricultural land, livestock, roads and cities. In the future, the only species that survive are likely to be those whose habitats are highly protected, or whose habitat corresponds to the degraded state associated with human activity


Pollution from chemical contaminants certainly poses a further threat to species and ecosystems. While not commonly a cause of extinction, it likely can be for species whose range is extremely small, and threatened by contamination. Several species of desert pupfish, occurring in small isolated pools in the US southwest, are examples.A changing global climate threatens species and ecosystems. The distribution of species (biogeography) is largely determined by climate, as is the distribution of ecosystems and plant vegetation zones (biomes) . Climate change may simply shift these distributions but, for a number of reasons, plants and animals may not be able to adjust.


The Military and the Environment

Many military forces of the world also have an effect on the environment. Sometimes, the scale of problems they leave when they move out of a training area or conflict is considerable. In some nations, such as the United States, the military can be exempt from many environmental regulations.

By no means a complete set of examples, the following illustrate some of the issues:

In the Gulf War and Kosovo crisis, the US and UK used depleted Uranium which have environmental consequences as well.

In the Vietnam war, the US used Agent Orange to defoliate the entire Vietnamese rainforest ecosystem. The effects are still being felt.

In the Democratic Republic of Congo, various forces often kill gorillas and other animals as they encroach upon their land.

In Okinawa, the large US military bases also affect the environment for the local population.


Consequences


Food Security:Biodiversity ensures our food security.Thus indiscriminate hunting of animals leads to food crisis.This in turn affects human health as well because of lack of resources for a balanced diet for many communities due to over exploitation of the species.


Natural Disasters: Loss of biodiversity has resulted in increasing natural disasters in the last few decades or so.Various mangroves or coral reefs act as excellent natural buffers to protect the lands from floods or storms.Thus loss of coastal biodiversity makes the coastal communities prone to natural disasters.


Energy security: Even today people of many communities and countries depend upon traditional woods for fuel needed for cooking, heating and other purposes.Unavailability of such fuel resources due to loss of biodiversity creates severe problems and leads to malnutrition,high infant mortality and death.Zambia is a classical case where human problems are mostly due to over exploitation of natural resources.


Water scarcity: Loss of rain forests and watersheds reduces the quality and availability of water resources for drinking and agriculture which in turn produces irreversible impacts on human life.


Social impacts: Eco systems play a great role in binding human beings with socio cultural or religious bonds.Destruction of biodiversity thus changes the social fabric and encroaches upon human relations.The Chipko movement was the manifestation of popular discontent over such social damage caused by loss of biodiversity.

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