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)

A person wearing a face mask holds a cat on Swanston Street after cases of the coronavirus were confirmed in Melbourne, Victoria, Australia, January 29, 2020. (Photo by Andrew Kelly/Reuters)

Commuters by with the buildings of the banking district in background in Frankfurt, Germany, Thursday, February 6, 2020. (Photo by Michael Probst/AP Photo)

Wakodahatchee wetlands, Delray Beach, Florida, US. Equipped with sinewy necks and spear-like bills, great blue herons can lunge with fearsome speed to strike their aquatic prey. Adults will also employ rapid stabbing motions as one aspect of their complex courtship displays; they’re seemingly dangerous moves, but fitting to the intensity of mating season. (Photo by Melissa Rowell/Audubon Photography Awards)

An elephant from Earl's Court Circus with a man in its mouth, 1928. P.S. All pictures are presented in high resolution.

Co-Host Kristin Chenoweth speaks onstage at the American Country Awards 2011 at the MGM Grand Garden Arena on December 5, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

A groom leads his horse in the equine pool after working out on the track, during early morning workouts for the upcoming Derby race in Mumbai January 29, 2015. (Photo by Danish Siddiqui/Reuters)

1: Dubai's Burj Khalifa is the tallest building in the world, but perhaps not for long. Saudi Arabia has announced plans to build a 1 kilometer (3,280 foot) tower into the sky, to be named the Jeddah Tower, scheduled for completion in 2020. The Burj Khallifa currently stands at 2,716 ft. (Photo by Matthias Seifert/Reuters)