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)

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 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)

A protester gestures as he holds a dog before a burning barricade during protests in Harare, Zimbabwe on January 15, 2019. (Photo by Philimon Bulawayo/Reuters)

A Selkirk Rex cat is one of more than 400 breeds of cats being presented at the World Cat Federation two-day show in Dortmund, Germany, on April 21, 2013. (Photo by Frank Augstein/Associated Press)

UFC women's bantamweight champion Holly Holm and Miesha Tate face off during the UFC 196 weigh ins at the MGM Grand Garden Arena in Las Vegas on Friday, March 4, 2016. (Photo by L.E. Baskow/Las Vegas Sun via AP Photo)

Ashley Ward kayaks down a flooded street that has been inundated with water from Hurricane Harvey on August 27, 2017 in Houston, Texas. Harvey, which made landfall north of Corpus Christi late Friday evening, is expected to dump upwards to 40 inches of rain in areas of Texas over the next couple of days. (Photo by Scott Olson/Getty Images)

Russian soldiers rehearse ahead of a forthcoming parade on Red Square in Moscow on November 5, 2017 The event will take place on November 7, marking the 76 th anniversary of a 1941 parade, when Red Army soldiers marched past the Kremlin walls towards the front line to fight Nazi Germany troops during World War Two. (Photo by Mladen Antonov/AFP Photo)