He estimates 52 % of wildlife died between 1970 and 2010 . The decline in animals living in rivers , lakes and ponds is the worst . Animals living in tropics are the worst hit by what WWF calls `` the biggest recorded threats to our planet 's wildlife '' as 63 % of wildlife living in tropics has vanished . The alarming trend could cost the world billions in economic losses .
He estimates 52 % of wildlife died between 1970 and 2010 . The decline in animals living in rivers , lakes and ponds is the worst . The alarming trend could cost the world billions in economic losses .