An assessment of more than 3,700 species of mammals, birds, fish, amphibians and reptiles reveals a fall of 58 per cent between 1970 and 2012, with no sign of a slowdown in the annual two per cent reduction in numbers.
By 2020, populations of vertebrate species could have fallen by 67pc over half a century, unless action is taken to reverse the damaging impacts of human activity, the Living Planet report from WWF and the Zoological Society of London said.
The figures prompted experts to warn that nature was facing a global “mass extinction” for the first time since the demise of the dinosaurs.
African elephants in Tanzania have seen numbers decimated by persistent poaching, while maned wolves in Brazil are threatened by grasslands being turned into farmland. Leatherback turtles in the Atlantic have seen populations reduced by up to 95pc, and European eels are also in decline.
Wildlife faces further threats from over-exploitation, climate change and pollution, the report warns.
Among the species most at risk are tigers, with only 3,900 left in the wild, and Amur leopards, whose numbers have fallen to just 70 in the face of hunting and the destruction of their habitat.
Giant pandas have a population of just 1,864 in the wild in China, and although numbers are increasing, the species is still threatened by climate change and impacts of human activity
Humans themselves are also victims of the deterioration of nature, the report warns, since they depend on breathable air, water and nutritious food.
However, species that depend on certain habitats have seen improvements in recent years.
Grassland creatures have increased slightly since 2004, a factor the report puts down to conservation efforts for some mammals in Africa, though bird populations continued to decline.
Mike Barrett, director of science and policy at WWF-UK, said: “For the first time since the demise of the dinosaurs 65 million years ago, we face a global mass extinction of wildlife.
“We ignore the decline of other species at our peril, for they are the barometer that reveals our impact on the world that sustains us.
“Humanity’s misuse of natural resources is threatening habitats, pushing irreplaceable species to the brink and threatening the stability of our climate.”
But he added: “We know how to stop this. It requires governments, businesses and citizens to rethink how we produce, consume, measure success and value the natural environment.
“In the UK, this demands a serious plan to strengthen protection for habitats and species and new measures to fast-track low-carbon growth.”
Professor Ken Norris, director of science at the Zoological Society, said: “Human behaviour continues to drive the decline of wildlife populations globally, with particular impact on freshwater habitats.
“Importantly, however, these are declines - they are not yet extinctions - and this should be a wake-up call.”
The report highlights the success of habitat protection and strict controls on hunting in Europe to help restore populations of wildlife including bears, lynx, wolverines and wolves.