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)

A military police officer patrols in the Roquette Pinto shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, Wednesday, April 1, 2015. The Brazilian army has begun to pull out of one of Rio de Janeiro's most violent slums, with police assuming responsibility for security in the area. (Photo by Felipe Dana/AP Photo)

A resident types a text message on her mobile phone, as she sits on a bench made from a tree, which is a creation by Brazilian artist Hugo Franca at Largo da Batata square in Sao Paulo March 17, 2015. Franca, a designer from Sao Paulo is working with the city to make use of fallen trees to turn them into sculpture furniture to line the city's parks, streets and plazas. Brazil's largest city was slammed by several strong storms this rainy season that brought with them heavy rain, lightning and winds as high as 90 kilometres (55 miles) per hour. (Photo by Nacho Doce/Reuters)

A male puma, named Bordo arrives for an examination and tests at a veterinary in Brasilia, Brazil, 31 October 2017 (issued 01 November 2017). Bordo, a young male puma, captured when he was a cub, will become the first animal of his species to be released in a sanctuary in the Brazilian savannah in Goias State close to Brasilia. The sanctuary, a preserve for wild cats, is in the first phase and is located on private lands but state funded. (Photo by Joedson Alves/EPA/EFE)

Brazilian model and actress Alessandra Ambrosio seen wearing a Gucci fanny pack and boots from Dior on April 15, 2018 in Indio, California. (Photo by Timur Emek/GC Images)

A vervet monkey walks over a parked car in the Park 'N Fly airport lot which lies adjacent to the mangrove preserve where the monkey colony lives, Tuesday, March 1, 2022, in Dania Beach, Fla. For 70 years, a group of non-native monkeys has made their home next to a South Florida airport, delighting visitors and becoming local celebrities. (Photo by Rebecca Blackwell/AP Photo)

Little owl chicks in Northumberland, UK on August 19, 2018. Strutting up and down and barrelling through the air, these Little Owl chicks will soon be fending for themselves. The intense little birds were snapped by wildlife photographer Bill Doherty in his native Northumberland. The chicks have about seven or eight weeks to learn their survival skills before their parents drive them away to fend for themselves. (Photo by Bill Doherty/South West News Service)

A full moon rises behind Glastonbury Tor as people gather to celebrate the summer solstice on June 20, 2016 in Somerset, England. Tonight's strawberry moon, a name given to the full moon in June by Native Americans because it marks the beginning of strawberry picking season, last occurred on the solstice on June 22, 1967 and it will not happen again on the summer solstice for another 46 years until June 21, 2062. (Photo by Matt Cardy/Getty Images)