Global wildlife populations will decline by 67% by 2020 unless urgent action is taken to reduce human impact on species and ecosystems, warns the biennial Living Planet Index report from WWF (World Wide Fund for Nature) and ZSL (Zoological Society of London). From elephants to eels, here are some of the wildlife populations most affected by human activity. Here: The maned wolf is among the large mammals in the Brazilian Cerrado that are threatened by the increasing conversion of grasslands into farmland for grazing and growing crops. (Photo by Ben Cranke/Nature Picture Library/Alamy Stock Photo)

In this March 21, 2015 photo, 15-year-old Guerline Augustin carries river water on her head, back to a borderland encampment outside the southeast Haitian town of Anse-a-Pitres, Haiti. The encampment is filled with people who either fled or were forcibly removed from the neighboring Dominican Republic amid an immigration crackdown. Within the next month, authorities hope to move nearly 2,400 people out of six encampments by providing subsidies for them to rent homes for a year in southeastern Haiti. The International Organization for Migration is coordinating the effort with $2 million from a U.N. emergency fund. (Photo by David McFadden/AP Photo)

Elephant polo players in action during the King's Cup Elephant Polo event 2016 final between teams King Power (blue) and The Elephant Story, in Bangkok, Thailand, March 13, 2016. Team King Power won the annual charity event, which is now in its 14th edition. This year's edition involved 18 elephants brought from tourist trekking camps in Pattaya as well as some unemployed in Surin, and a total of 10 teams encompassing over 40 players, in this event directed at raising funds to improve the lives of elephants and elephant conservation. (Photo by Diego Azubel/EPA)

A member of the German wireless police picks up signals on the radio equipment he carries on his back, while his colleague takes notes. (Photo by General Photographic Agency/Getty Images). Circa 1925

A workman takes a siesta on a girder during the building of Radio City, the city of New York spread out below. (Photo by General Photographic Agency/Getty Images). Circa 1933

A view of a vintage Rolls Royce limousine with a female driver. (Photo by General Photographic Agency/Getty Images). Circa 1935

A supporter of presidential candidate and former chairman of the NATO Military Committee and Czech Army General Petr Pavel hands out leaflets, ahead of a direct presidential election that will start on January 13, in Prague, Czech Republic on January 5, 2023. (Photo by David W. Cerny/Reuters)

Ukraine's Viktoriia Onopriienko competes in the individual all-around qualification round during the Rhythmic Gymnastics World Championships at the West Japan General Exhibition Center in Kitakyushu, Fukuoka prefecture on October 27, 2021. (Photo by Charly Triballeau/AFP Photo)