Threats to Biodiversity

Earth's biodiversity engulfs millions of species of plants and animals. It includes all the lifeforms found on the planet, right from the various species of bacteria, which can only be seen under the microscope, to the gigantic blue whales. The fact that the number of species on the planet easily exceeds the million mark may make you feel that the extinction of a species of two won't make a big difference. That, however, is a myth, as the extinction of single species can affect the balance of the ecosystem, as the repercussions of the same start showing on the various other animal species dependent on it.

Extinction of Species

Since the planet came into existence, it has been subjected to five mass extinctions, which have wiped off as many as 99.9 percent of animals and plants that ever existed on the planet. The last of these mass extinctions occurred approximately 65 million years ago. Named the Cretaceous-Tertiary extinction, this event is quite popular as an event that triggered the extinction of dinosaurs. Even though species extinction is a normal phenomenon, and every year is marked by the extinction of a species or two over the last 200 million years, the rate at which it is occurring since the last few centuries has left environmentalists worried.

Major Threats to Biodiversity

The list of threats to the global biodiversity is quite lengthy, and includes some of the most important threats such as habitat loss, over hunting, invasive species, climate change etc. The details of each of these factors which threaten the existence of various plants and animals species on the planet are given below.

Habitat Loss
Human encroachment in the wild has resulted in wide scale destruction of the natural habitat for these wild animals, thus leaving them without a place to live. A large part of this destruction of habitat can be attributed to the large-scale deforestation to suit the agricultural and logging sector. The Javan tiger species endemic to Bali and Java in Indonesia is the best example of extinction triggered due loss of habitat. Other than habitat loss, habitat fragmentation, as a result of construction of roads in the forest areas, has also contributed to the extinction of animals in the wild.

Over Hunting
Yet another human threat to biodiversity, over hunting has brought several animal species to the brink of extinction. Humans have resorted to the practice of hunting for food, since prehistoric times. More recently, however, hunting of animals for food has taken a back seat, and poaching for their skin, tusks or bones has gained prominence. The failure to curb poaching has resulted in severe depletion in population of various species of animals, including rhinos, tigers and elephants, thus making them vulnerable to extinction.

Invasive Species
One of the lesser known causes of extinction, the invasion of non-native species in particular area has also resulted in extinction of species endemic to that region. When a new species is introduced in a particular region, it either tends to feed on the native species, or feed on the food meant for the native species. The end result is extinction of the species endemic to the region, either due to predation or lack of food. One of the best example of such a phenomenon is the introduction of Nile Perch in Lake Victoria in Africa, which led to the extinction of Cichlid fish species native to this lake.

Pollution
One of the major environmental issues on the planet, pollution is also a prominent factor when it comes to extinction of animal and plant species. While the contamination of water bodies can result in extinction of animal species, the contamination of soil can lead to extinction of the plants. Species with limited geographical range are the most affected when it comes to extinction due to pollution. One of the best example of the same is extinction of the Chinese river dolphin which failed to adapt to industrial pollution and water transport in its natural habitat - the Yangtze river.

Climate Change
Over the last few decades, the global surface temperature has experienced an average increase of 1.8 degree Celsius. This has changed the equations in various regions, and affected the plant and animal species native to this region. Global warming has resulted in melting of ice in the polar regions, thus resulting in loss of habitat for polar bears and Arctic foxes. Similarly, the rise in temperature is causing the water bodies in the tropical areas to evaporate at a faster rate, thus resulting is loss of habitat for fish and amphibian species in these areas. One of the best example of extinction triggered by climate change is that of the Monteverde toad endemic to the tropical rainforests of Costa Rica.

At the end of the day, it is the cumulative impact of all these threats which is making the problem even worse. Its high time we understand the importance of biodiversity, and come up with measures to save it. As we mentioned earlier, if a single species of animal becomes extinct, its repercussions are felt by all the other species, including human beings. For instance, the loss of tiger leads to an increase in the number of deer species, which feed on the plants and destroy the vegetation cover, and lack of vegetation cover affects the precipitation in the region. Even though several conservation measures are being drafted to save the ecosystem, the implementation of these measures at the grass root level needs a serious introspection.