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 photo taken Wednesday, March 8, 2017, a woman herder sits with her goats in a remote desert area near Bandar Beyla in Somalia's semiautonomous northeastern state of Puntland. Somalia has declared the drought a national disaster, part of what the United Nations calls the largest humanitarian crisis since the world body was founded in 1945, and with animals being central to many the drought threatens their main sources of nutrition and survival. (Photo by Ben Curtis/AP Photo)

Nepalese Hindu devotees take part in a bathing ritual on the last day of the month-long Swasthani Festival in the Hanumante River at Bhaktapur on the outskirts of Kathmandu on February 22, 2016. Devotees mark the Swasthani Festival with fasting, and with women in particular undertaking rituals in the hope of a prosperous life for her family and conjugal happiness. (Photo by Prakash Mathema/AFP Photo)

Dogs rest during the Sedivackuv Long dog sled race in Destne v Orlickych horach January 23, 2015. Each year, racers from all over Europe arrive at the village of Destne in the Orlicke mountains in Czech Republic to take part in the race. (Photo by David W. Cerny/Reuters)

A 17ft anaconda which ate a pet dog seen blindfolded with a t-shirt is examined by Mano Bascoules in Montsinery, French Guiana. (Photo by Sebastien Bascoules/Barcroft Media/ABACAPress)

“Joey”, a dwarf Siamese rabbit, is dressed as Batman's sidekick Robin at a Halloween dog costume parade and contest in Long Beach, California, October 28, 2012. (Photo by Robyn Beck/AFP Pfoto)

Maria Ines Banegas portraying “La Pirata” (The Pirate) takes part in a human living statues contest in Buenos Aires, Argentina, September 24, 2016. (Photo by Enrique Marcarian/Reuters)