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)

This August 28, 2017 photo shows eight-year-old Indian girl Bharti performing a balancing act on a rope during a street show in Batala, India. Travelling Indian performers, who earn a meagre income from putting on shows on the streets, often scout areas to gather a large street audience who then give money on a collection plate at the end of the show. (Photo by Narinder Nanu/AFP Photo)

A villager offers prayer to a dead body of an elephant, which is killed by lightning at atop of Bamuni hill in Assam's Nagaon district, on May 14, 2021. 18 wild elephants were found dead atop Bamuni Hills in Assam's Nagaon district today after lightning struck them during the showers in the area on May 12, 2021. At least 18 elephants are suspected to have been killed by lightning in northeastern India, officials said on May 13 as they launched a probe into the incident. (Photo by Biju Boro/AFP Photo)

A students with her face smeared in coloured powder, celebrates Holi at a university campus in Chandigarh, India March 23, 2016. (Photo by Ajay Verma/Reuters)

Students with faces painted as Hindu goddess Kali, take part in a cultural event ahead of the Janmashtami festival, or the birth anniversary of Hindu Lord Krishna, inside a college in Mumbai, India on September 4, 2023. (Photo by Francis Mascarenhas/Reuters)

A devotee immerses an idol of elephant-headed Hindu god Ganesha in an artificial pond during Ganesh Chaturthi festival in Mumbai, India on September 20, 2023. (Photo by Aditya/NurPhoto/Rex Features/Shutterstock)

In this Friday, May 10, 2019, file photo, rescuers help a baby wild elephant cross the wetland to return to the forest at Deepor Beel wildlife sanctuary in Gauhati, India. The elephant had gotten stuck in the waters of Deepor Beel after it was separated from a herd of wild elephant that came down in search of food last night. (Photo by Anupam Nath/AP Photo)

A Sadhu or a Hindu holy man offers prayers while sitting inside a circle of burning “Upale” (or dried cow dung cakes) on the occasion to mark the Basant or spring festival, on the banks of river Ganga in the northern Indian city of Allahabad January 24, 2015. Basant is celebrated mainly in the northern Indian states marking the start of the spring season. (Photo by Jitendra Prakash/Reuters)