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 photographer has weathered some of America's most violent storms to capture these stunning snaps. Storm chaser Mike Mezeul II, 30, has traveled all over the US to shoot the likes of mammoth thunderstorms and surreal cloud patterns. His incredible collection of storm images are the result of more than 15 years of photography and thousands of miles of travel. Here: Mike waiting for the storm at Cheyenne, Wyoming, June 2014. (Photo by Mike Mezeul II/Caters News)

These images are enough to make viewers do a double-take. Although they look like vibrant works of abstract art, they are actually drone photographs taken by brothers J.P. and Mike Andrews, from near Wolverhampton, England. Here: Kickflip. (Photo by J.P. Andrews/Mike Andrews/Caters News Agency)

Elephant fights off hyenas to save baby. “This is the incredible moment an elephant came to the rescue of one of its babies being attacked by a pack of hyenas. The elephant is seen charging at the hyenas to ward them off its offspring. The photos were captured by American photographer Jayesh Mehta, 47, in the Savuti region of the Chobe National Park in Botswana”. Photo: The elephant is seen charging at the hyenas to ward them off its offspring. (Photo by Jayesh Mehta/Caters News)

Portuguese model and Victoria's Secret Angel Sara Sampaio arrives at the amfAR Gala Cannes 2018 at Hotel du Cap-Eden-Roc on May 17, 2018 in Cap d'Antibes, France. (Photo by Mike Marsland/Mike Marsland/WireImage)

A relative of murdered prisoner, lies on a chair next to his coffin during a wake after a prison riot in the city of Altamira, Para state, Brazil on July 30, 2019. At least 57 prisoners were killed by other inmates during clashes between organized crime groups in the Altamira prison in northern Brazil Monday with 16 of the victims being decapitated, according to prison officials. (Photo by Bruno Kelly/Reuters)

A student activist is detained during a silent protest after Thailand's election commission filed charges against a group for posting “foul and strong” comments online criticising a military-backed draft constitution, in Bangkok, Thailand April 27, 2016. (Photo by Jorge Silva/Reuters)