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 view of trees shrouded in fog on a late summer morning between Tureby and Slimminge on Zealand, Denmark, 10 September 2021. (Photo by Mads Claus Rasmussen/EPA/EFE)

A Southwest Airlines jet takes off from Reagan National Airport with a thunderhead to the east on June 20, 2017 in Alexandria, VA. (Photo by Jonathan Newton/The Washington Post)

Models cool off in front of an air conditioner backstage at the DUNDAS x REVOLVE New York Fashion Week Show in Manhattan, New York City, U.S., September 8, 2021. (Photo by Caitlin Ochs/Reuters)

Urszula Sidoruk, 19, from the paramilitary group SJS Strzelec (Shooters Association), trains her workout at a gym in Siedlce, eastern Poland March 18, 2014. Inspired by the war in Ukraine, growing numbers of Poles are joining volunteer paramilitary groups, where they receive basic army training and prepare to defend their homeland. (Photo by Kacper Pempel/Reuters)

Mateo Santiago, Field Manager at Tropical Bamboo Nursery and Gardens, photographs rain water collecting in the corpse flower as Garden Manager Melanie Benson steadies a ladder. Santiago crinkled his nose up distastefully when he described its odor, which was at its worse Sunday night. “It smelled like a dead rat”. (Photo by Melanie Bell/Palm Beach Daily News)

British tourist participates in a crab race at the annual Tobago Heritage Festival, at Buccoo Integrated Facility, in Tobago island, Trinidad and Tobago on July 29, 2018. (Photo by Andrea De Silva/EPA/EFE)

The #8 DP Starworks Motorsports Ford Rley driven by Enzo Potolicchio, Ryan Dalziel, Alex Popow, Lucas Luhr and Allan McNish runs off the track during the Rolex 24 at Daytona International Speedway on January 28, 2012 in Daytona Beach, Florida. (Photo by John Harrelson/Getty Images)