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)

(L-R) Actors Oscar Sinela, Luis Fernandez, Ursula Corbero, Amaia Salamanca, Maxi Iglesias and Alba Ribas attend “XP3D” premiere at the Callao cinema on December 27, 2011 in Madrid, Spain. (Photo by Carlos Alvarez/Getty Images)

Alison Brie and Betty Gilpin host in the Netflix comedy-drama“Glow” Season 1 TV Series, 2017. (Photo by Erica Parise/Netflix/Kobal/Rex Features/Shutterstock)

Hindu priests wash the head of a buffalo calf which was sacrificed as part of a ritual at a temple during the Durga Puja festival in Agartala, India, October 10, 2016. (Photo by Jayanta Dey/Reuters)

Some bats in the forested area of Guapiles, Costa Rica, 21 April 2020. (Photo by Jeffrey Arguedas/EPA/EFE)

A red deer stag takes a mud bath in Wollaton Park near Nottingham, England on May 23, 2020. Gareth Williams, who took the photograph, said it was a “once in a lifetime shot”. (Photo by Gareth Williams/Kennedy News)

Women stand on a street ahead of the Lunar New Year celebration at the Chinatown in Bangkok, Thailand, February 10, 2021. (Photo by Chalinee Thirasupa/Reuters)

Germany's Darja Varfolomeev competes in the individual all-around final of the Olympic qualifier 40th FIG Rhythmic Gymnastics World Championships in Valencia on August 26, 2023. (Photo by Jose Jordan/AFP Photo)