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 Turkana man and a boy carrying a gun look on as a G3 battle rifle hangs from a structure used to dry fish at a fishing camp on the shores of Lake Turkana, some kilometres from Todonyang near the Kenya-Ethiopia border in northwestern Kenya October 12, 2013The Turkana are traditionally nomadic pastoralists, but they have seen the pasture that they need to feed their herds suffer from recurring droughts and many have turned to fishing. However, Lake Turkana is overfished, and scarcity of food and pastureland is fuelling long-standing conflict with Ethiopian indigenous Dhaasanac, who have seen grazing grounds squeezed by large-scale government agricultural schemes in southern Ethiopia. The Dhaasanac now venture ever deeper into Kenyan territory in search of fish and grass, clashing with neighbours. Fighting between the communities has a long history, but the conflict has become ever more fatal as automatic weapons from other regional conflicts seep into the area. While the Turkana region is short of basics like grass and ground-water, it contains other resources including oil reserves and massive, newly discovered underground aquifers. (Photo by Siegfried Modola/Reuters)

Farmers use tractors and burn tires, hay and manure as they block the highway between Morlaix and Brest during a demonstration against the market prices of their product, on July 22, 2015 in Morlaix, western of France. French farmers protesting over falling food prices threatened to step up blockades of cities, roads and tourist sites, as the government prepared to unveil emergency aid for them. Farmers have dumped manure in cities, blocked access roads and motorways and hindered tourists from reaching Mont St-Michel in northern France, one of France's most visited sites. (Photo by Fred Tanneau/AFP Photo)

Warriors from the Suri tribe in Ethiopia still stage the savage “Donga” battles – even after many fighters have been died from their injuries. Donga stick fights take place after the harvests, the Surmas count days owing to knots on a long stem of grass or jags on the trunk of a tree dedicated to that specific use. Here: A tribeswoman sporting a huge lip plate and wearing a skinned animal carcass on her head. (Photo by Eric Lafforgue/Exclusivepix Media)

St. Mark's and Panagia Erithiani church congregations perform “Rocket War” by firing thousands of home-made rockets across the sky during Greek Orthodox Easter celebrations in the town of Vrontados on the Greek island of Chios on April 19, 2014. Greek habit of throwing handmade rockets with the aim of hitting the bell tower of the church at the other side during the celebration of the service at midnight before Easter Sunday. (Photo by Cem Oksuz/Anadolu Agency/Getty Images)

A mouse rides on the back of a frog in floodwaters in the northern Indian city Lucknow June 30, 2006. (Photo by Pawan Kumar/Reuters)

The sun sets on Walney Island, Cumbria, county in North West England on October 10, 2019. Today will be unsettled with spells of heavy rain. (Photo by GREENBURN/Alamy Live News)

People wash in water from a broken water pipeline on the outskirts of Kolkata, India, March 30, 2016. (Photo by Rupak De Chowdhuri/Reuters)