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)

Germany's Nikias Arndt, left, receives encouragement from a spectator during the men's elite road race at the world road cycling championships in Wollongong, Australia, Sunday, September 25, 2022. (Photo by Rick Rycroft/AP Photo)

An aerial view shows the the Mountain Bike course at the X-Park at Deodoro Olympic Park ahead of the 2016 Rio Olympics in Rio de Janeiro, Brazil, July 16, 2016. (Photo by Ricardo Moraes/Reuters)

Switzerland's cyclist Marlen Reusser reacts after placing second in the women' elite time trial race of the UCI World Championships Road Cycling Flanders 2021, in Bruges, on September 20, 2021. UCI World Championships Road Cycling Flanders 2021 takes place from September 19 until September 26, 2021, in several cities in the Belgian region of Flanders. (Photo by Simon Wilkinson/BELGA via AFP Photo)

Two boys look out from the Mangueira slum towards the Maracana Stadium that is hosting the Rio's 2016 Summer Olympics opening ceremonies, in Rio de Janeiro, Brazil, Friday, August 5, 2016. (Photo by Leo Correa/AP Photo)

A couple shelter under an umbrella during a heavy downpour of rain in Belfast, Ireland on Monday, July 31, 2023. (Photo by Liam McBurney/PA Images via Getty Images)

Ellie Alderson partner of Ollie Watkins (ENG) and Lewis Capaldi the wife of Dean Henderson (ENG) Aine May Kennedy partner of Conor Gallagher (ENG) Megan Davison wife of Jordan Pickford (ENG) at Arena Aufschalke, Gelsenkirchen, Germany on June 16, 2024. (Photo by Moritz Muller/Alamy Live News)

“Ring Girls” attend the undercard bouts before Oleksandr Usyk of Ukraine faces Daniel Dubois of Great Britain in their undisputed heavyweight title bout at the Wembley Stadium in London, Great Britain, 19 July 2025. It is the second meeting between the WBA (Super), WBO and WBC champion Usyk and IBF title-holder Dubois following their fight in 2023 which Usyk won. (Photo by Daniel Hambury/EPA)