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)

Firefighters pull a pig as they try to rescue it from a well at a pig farm in Huanghua township of Leqing, Zhejiang province, China, April 25, 2014. Seven local firefighters successfully rescued the 300 kg (661 lbs) pig, local media reported. (Photo by Reuters/China Daily)

A bus goes through a flooded street in Wuhan, Hubei province, China July 6, 2016. (Photo by Reuters/China Daily)

Protester Nadine Wolf demonstrates against the proposed Stop Online Piracy Act (SOPA) and Protect IP Act (PIPA) outside the offices of U.S. Sen. Charles Schumer (D-NY) and U.S. Sen. Kirsten Gillibrand (D-NY) on January 18, 2012 in New York City. (Photo by Mario Tama/Getty Images)

Waverly Fire's Tell Hanes, left, and Southeast Fire's Trey Wayne, right, jump over freezing water to high five while participating in a Surface Ice rescue technician course on Friday, January 6, 2023, at Holmes Lake Park in Lincoln, Neb. The International Rescue and Relief department at Union college held rescue training course at Holmes Lake for students and local fire departments. (Photo by Kenneth Ferriera/Lincoln Journal Star via AP Photo)

Lindsay Heimbach goes airborne while sledding down a hill on Mt. Lemmon December 27, 2008. (Photo by James Gregg/Arizona Daily Star)

A Cambodian girl goes through the garbage dump looking for things to recycle in order to survive July 26, 2003 in Phnom Penh, Cambodia. Rampant corruption in this impoverished country has lead to extreme poverty with many Cambodians living below the poverty line. (Photo by Paula Bronstein/Getty Images)