The World Wildlife Fund (WWF) report, which used 2018 data from ZSL on the status of 32,000 wildlife populations covering more than 5,000 species, found that population sizes had declined by 69% on average.
One population of pink river dolphins in the Brazilian Amazon plummeted by 65% between 1994 and 2016, the report said.
Its findings were broadly similar to those in WWF's last assessment in 2020, with wildlife population sizes continuing to decline at a rate of about 2.5% per year, Terry said.
"Nature was in dire straits and it is still in dire straits," said Mark Wright, director of science at WWF-UK.
Still, the wide-ranging declines have prompted desperate pleas for increased support for nature.