Wildlife around the planet has suffered far greater losses over the past 40 years than originally assumed, according to a new report issued by the World Wildlife Fund. According to the authors, animal populations have fallen on average by 52 percent since 1970. The findings pertain mostly to vertebrate species, including mammals, birds, fish, amphibians and reptiles.
The team analyzed more than 10,000 population figures representing over 3,000 species, the Guardian describes. They then used those data to extrapolate figures for all 45,000 known vertebrate species on the planet. They also analyzed the reasons behind species decline, finding that over exploitation (including hunting for food, medicine and animal products), habitat loss and climate change all serve as primary drivers of population loss.
The same survey carried out two years ago found that global populations had declined by just 28 percent, rather than 52 percent, Reuters writes. But this is because that previous report relied on data mostly reported in Europe and North America, rather than a globally representative survey. Significant numbers of species disappeared from Europe and North America centuries ago, but animal populations there have increased slightly in recent years. Developing countries generally show the opposite trend.
“If half the animals died in London zoo next week it would be front page news,” Ken Norris, director of science at the Zoological Society London, told the Guardian. “But that is happening in the great outdoors."