Human appetite pushing big animals at risk of extinction
New Delhi, Feb 08: Earth is home to millions of species. Just one dominates it. Humans have explored and left footprint on nearly every corner of the globe. As our population and needs grow, we are leaving less and less room for wildlife.
In a stratling revealation, a new study has found that Humans' meat-eating habits may be pushing at least 150 species of the planet's largest animals towards the threat of extinction.
In new research published in the journal Conservation Letters, scientists surveyed the populations of nearly 300 species of megafauna around the world, and saw some troubling trends emerge.
According to the authors, at least 200 species (70 percent) of the world's largest animals are seeing their populations dwindle, and more than 150 face the risk of outright extinction.
The species at risk range from lions, elephants, giraffes, rhinos, whales, sharks, sea turtles, alligators and flightless birds like the ostrich as well.
The primary reason humans kill large reptiles is for their eggs, the data show. Other leading reasons humans are killing these animals is for medicinal use, for their fur and fins, and unintentionally (such as sharks getting caught in fishing nets).
"Direct harvest for human consumption of meat or body parts is the biggest danger to nearly all of the large species with threat data available," said William Ripple, a professor at the Oregon State University in the US.
"Thus, minimising the direct killing of these vertebrate animals is an important conservation tactic that might save many of these iconic species as well as all of the contributions they make to their ecosystems," said Ripple.
Researchers were part of an international collaboration that built a list of megafauna based on body size and taxonomy - qualifying for the list were species unusually large in comparison to other species in the same class.
The mass thresholds the researchers decided on were 100 kg for mammals, ray-finned fish and cartilaginous fish and 40 kg for amphibians, birds and reptiles since species within these classes are generally smaller.
"Those new thresholds extended the number and diversity of species included as megafauna, allowing for a broader analysis of the status and ecological effects of the world's largest vertebrate animals," Ripple said.
Over the past 500 years, as humans' ability to kill wildlife at a safe distance has become highly refined, two per cent of megafauna species have gone extinct. For all sizes of vertebrates, the figure is 0.8 per cent.
"Our results suggest we're in the process of eating megafauna to extinction," Ripple said.
"Through the consumption of various body parts, users of Asian traditional medicine also exert heavy tolls on the largest species," he said.
"In the future, 70 per cent will experience further population declines and 60 per cent of the species could become extinct or very rare," he added.
Nine megafauna species have either gone extinct overall, or gone extinct in all wild habitats, in the past 250 years, including two species of giant tortoise, one of which disappeared in 2012, and two species of deer.
"In addition to intentional harvesting, a lot of land animals get accidentally caught in snares and traps, and the same is true of gillnets, trawls and longlines in aquatic systems," Ripple said.