Extinction of Species
Since it came into existence, the planet has been subjected to five mass extinctions, resulting in the extinction of 99.9 percent of plant and animal species that have ever existed on the planet. The last of these mass extinctions, the Cretaceous-Tertiary extinction―notorious for having wiped off the dinosaurs―occurred approximately 65 million years ago.
Now, the extinction of species is not unusual. Over the last 200 million years, we have lost a species or two every year. What is unusual, is the rate at which extinctions are occurring over the last few centuries. In fact, it has even left the environmentalists worried, with some of them suggesting that we are closing in on yet another mass extinction.
Major Threats to Biodiversity
The list of threats to the global biodiversity is quite lengthy, and has to its credit threats like 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 on the planet, are discussed ahead.
Human encroachment in the wild has resulted in wide-scale destruction of the natural habitat for wild animals, thus leaving them with no place to live. A large part of this destruction is caused due to the large-scale deforestation to suit the vested interests of agricultural and logging sectors.
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 for food has taken a back seat, while poaching of animals for their body parts, i.e., their skin, tusks, bones, etc., has gained prominence.
The failure to curb poaching has resulted in severe depletion in the population of various animals, including rhinos and tigers, thus making them vulnerable to extinction.
The invasion of non-native species in a particular region is also a threat for species endemic to that region. When a new species is introduced in a particular region, it either feeds on the native species or competes with it for food. In either case, the end result is extinction of the species endemic to the region, either due to predation or food scarcity.
In what is considered one of the best examples of this phenomenon, when the Nile Perch was introduced in Lake Victoria in Africa, it led to the extinction of endemic cichlid fish species.
One of the best examples is the extinction of the Chinese river dolphin which fell prey to industrial pollution and water transport in its natural habitat, the Yangtze River.
The average global temperature on Earth has increased by about 0.8° Celsius (1.4° Fahrenheit) since 1880. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20°C per decade.
At the end of the day, it is the cumulative impact of all these threats that is making the problem worse. It's time we understand the importance of biodiversity and come up with measures to save it. As we mentioned earlier, if a single species becomes extinct, its repercussions are felt by all the other species depending on it directly or indirectly.