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Threat of Biodiversity

Important factors leading to extinction of species and consequent loss of biodiversity are habitat loss and fragmentation; introduction of non-native species; overexploitation; soil, water and atmospheric pollution; and intensive agriculture and forestry.
Habitat Loss and Fragmentation: The destruction of habitats is the primary reason for the loss biodiversity. When people cut down trees, fill a wetland, plough grassland or burn a forest, the natural habitat of a species is changed or destroyed. These changes can kill or force out many plants, animals, and microorganisms, as well as disrupt complex interactions among the species. A forest patch surrounded by croplands, orchards, plantations, or urban areas is an example of fragmented habitats. With the fragmentation of a large forest tract, species occupying deeper parts of forests are the first to disappear. Overexploitation of a particular species reduces the size of its population to an extent that it becomes vulnerable to extinction. Over exploitation of plant and animal species: Human need and greed for various regions have been region for maximization of biomass exploitation, which have been available mostly in our forest. Forests is the bank where whole checks have been drawn without let and hindrance. for this simple regions our forest suffered the most and consequently plant and animal biodiversity has been the major causality.

Disturbance and Pollution of Soil, Water and Environment: Communities are affected by natural disturbances, such as fire, tree fall, and defoliation by insects. Man disturbances differ from natural disturbances in intensity, rate and spatial extent. For example, man, by using fire more frequently may change species richness of a community. Then, some human Impacts are new, never faced before by biota, e.g., the vast number of synthetic compounds, massive releases of radiations or spillover of oil in sea. These impacts lead to a change in the habitat quality. Pollution may reduce and eliminate populations of sensitive species. For example, pesticide linked decline of fish-eating, birds and falcons. Lead poisoning is another major cause of mortality of many species, such as ducks, swans and cranes, as they take in the spent shotgun pellets that fall into lakes and marshes. Eutrophication (nutrient enrichment) of water bodies drastically reduces species diversity.

Global Climate Change: A massive side effect of air pollution is global warming which can pray havoc which biodiversity. Human caused increased in green house effects are likely to create disturbances in atmospheric temperature affecting living flora and fauna. forest is as a whole shall be under stress because environmental condition shall detoriate causing further problem to the biodiversity.

Introduction of Exotic Species: Introduction of species new to the geographical region are basically exotic or alien for the host area. Such exotic invasive species are considered second only to habitat destruction as a major cause of extinction of species. (i) Water hyacinth clogs rivers and lakes and threatens the survival of many aquatic species in lakes and river flood plains in several tropical countries, including India. (ii) Lantana camara, Parthenium have invaded many forestlands in different parts of India, and strongly competes with the native with the native species.

We cannot even estimate the number of species of organisms on Earth to an order of magnitude, an appealing situation in terms of knowledge and our ability to affect the human prospect positively. There are clearly few areas of science about which so little is known, and none of such direct relevance of human beings.