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)

Tourists from the Middle East take pictures at Vrelo Bosne nature park in Ilidza near Sarajevo, Bosnia and Herzegovina, August 19, 2016. They discovered mountainous Bosnia, where half the population is Muslim, after the Arab Spring which destabilized many traditional holiday destinations such as Libya, Tunisia and Egypt. (Photo by Dado Ruvic/Reuters)

Gaza authorities say two newborn lion cubs just unveiled by Hamas as prized additions in a zoo they run have died. Mohammad Abdel-Rahman, the acting manager of the Beit Lahiya zoo in northern Gaza, said Thursday the cubs died of an unspecified illness. He said the zoo's staff was unable to save them because they lacked experience in caring for newborn cubs. Photo: Two-day-old lion cubs Fajr and Sjel are fed at a zoo in the northern Gaza Strip town of Beit Lahia, on November 19, 2013. (Photo by Mohammed Abed/AFP Photo)

The giant inflatable Rubber Duck installation by Dutch artist Florentijn Hofman floats on the Parramatta River, as part of the 2014 Sydney Festival, in Western Sydney, January 10, 2014. The creation is five stories tall and five stories wide and has been seen floating in various cities around the world since 2007. (Photo by Jason Reed/Reuters)

Revellers take part in an annual block party known as “Cordao de Prata Preta”, one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, February 6, 2016. (Photo by Pilar Olivares/Reuters)

A Bengal tiger licks a glass enclosure during a presentation of Bengial tiger cubs at the Malabon Zoo in Malabon City, north of Manila, Philippines, 14 July 2016. The Bengal tiger cubs, which were born at the zoo, are two months old and named “Tiger Duterte” and “Tiger Leni”. The Malabon Zoo has one of the largest private collections of exotic and endemic animals in the Philippines. (Photo by Mark R. Cristino/EPA)

“Birmingham is a city and metropolitan borough in the West Midlands of England. It is the most populous British city outside the capital London with 1,074,300 residents (2011 census), an increase of 96,000 over the previous decade. The city lies within the West Midlands conurbation, the third most populous urban area in the United Kingdom with a population of 2,440,986 (2011 census) of which the Birmingham built-up area was 1,085,810. Its metropolitan area is the United Kingdom's second most populous with 3,683,000 residents”. – Wikipedia. (Photo by Adrian Saker)