The population of the planet's vertebrates has dropped an average of 60 percent since 1970, according to a report by the conservation organization WWF.
The most striking decline in wildlife populations was in the tropics in South and Central America, with an 89 percent loss compared to 1970. Freshwater species have also significantly fallen — 83 percent since 1970.
The world's seabirds have also been significantly affected by humans, with 90 percent estimated to have plastic in their stomachs today, up from 5 percent in 1960, the report said.
The Living Planet Index, provided by the Zoological Society of London (ZSL) and included in the WWF Living Planet 2018 report, tracks trends in global wildlife and measured the population of vertebrates between 1970 and 2014, the latest year for which data was available.
Other examples of wildlife populations that have dropped include:
- The hedgehog, which has declined 75 percent between 2002 and 2014 in urban areas in the U.K.
- The grey partridge, which has fallen by 85 percent between 1970 and 2004.
- The African grey parrot population in south-west Ghana, which has decreased by 98 percent between 1992 and 2014.
Additionally, since 1950, almost 6 billion tons of fish and invertebrates have been taken from the oceans.
"There cannot be a healthy, happy and prosperous future for people on a planet with a destabilized climate, depleted oceans and rivers, degraded land and empty forests, all stripped of biodiversity, the web of life that sustains us all," WWF Director General Marco Lambertin wrote in the report, which included contributions from more than 50 experts from around the world.
Only a quarter of the planet's land is free from human impact, and this is projected to fall to just a tenth by 2050, the report said. The rate of extinction on Earth is 100 to 1,000 times higher than it would be without pressure from humans.
It urged quick action to avoid irreversible change to the planet, including a shift to green energy and environmentally friendly food production.
"What is clear is that without a dramatic move beyond 'business as usual' the current severe decline of the natural systems that support modern societies will continue," the report said.