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)

Photographer Gregg Segal travelled the world to document children and the food they eat in a week. Partly inspired by the increasing problems of childhood obesity, he tracked traditional regional diets as yet unaffected by globalisation, and ironically, found that the healthiest diets were often eaten by the least well off. (Photo by Gregg Segal/The Guardian)

An arctic tern feeds its chick on the Farne Islands off the Northumberland coast, northern England July 8, 2013. The Farne Islands, which lie off the coast of northeast England, are home to a huge array of wildlife. The islands are owned and protected by the British conservation charity, the National Trust, which says they host some 23 species of seabird, as well as a substantial colony of grey seals, who come to have their pups there in the autumn. Every five years the National Trust carries out a census of the islands' population of puffins, and this year's survey showed there were almost 40,000 nesting pairs on the islands – an 8 percent rise from 2008. (Photo by Nigel Roddis/Reuters)

“Francois' langur is one of several species of leaf monkeys. Over 50% of its diet is made up of young leaves. It will also consume fruits (17.2%), seeds, flowers, stems, roots, bark and occasionally minerals and insects off of rock surfaces and cliffs. This langur consumes its favorite food, young leaves, at the highest rate during the dry season, April through September, also known as the young leaf-lean period”. – Wikipedia

Photo: An endangered baby Francois' Langur monkey called Laa Laa settles in following her July 6 birth at London Zoo, Regent's Park on August 5, 2004 in London. The bright ginger youngster was born to glossy black parents Max and Shaneka and has the typical orange baby coat which is in stark contrast against the black of her parent's and older brother Grub's fur. (Photo by Steve Finn/Getty Images)

“The Rothschild Giraffe (Giraffa camelopardalis rothschildi) is among the most endangered giraffe subspecies with only a few hundred members in the wild. It is named after the famous family of the Tring Museum's founder, Lord Walter Rothschild, and is also known as the Baringo Giraffe, after the Lake Baringo area of Kenya, or as the Ugandan Giraffe. All of those that are living in the wild are in protected areas in Kenya and Uganda. (Recently it has been proposed that the Rothschild Giraffe is actually a separate species from other giraffes and not a giraffe subspecies).” – Wikipedia

Photo: Margaret, the 10-day-old Giraffestands beside Chester Zoo keeper Tim Rowlands on January 30, 2008, in Chester, England. Margaret is the first Rothschild giraffe born at the zoo. (Photo by Christopher Furlong/Getty Images)

A Puffin returns to it's nest with a beak full of sand eels on June 25, 2011 on Inner Farne, England. The Farne Islands, which are run by the National Trust, are situated two to three miles off the Northumberland coastline. The archipeligo of 16-28 separate islands (depending on the tide) make the summer home to approximately 100,000 pairs of breeding seabirds including around 36,000 Puffins, 32,000 Guillemots and 2,000 pairs of Arctic Terns. The species of birds which nest in internationally important numbers include Shag, Sandwich Tern and Arctic Tern. The coastline around The Farnes are also the breeding ground to one of Europe's largest Grey Seal colonies with around 4,000 adults giving birth to 1500 pups every year. (Photo by Dan Kitwood/Getty Images)

“The aye-aye (Daubentonia madagascariensis) is a lemur, a strepsirrhine primate native to Madagascar that combines rodent-like teeth and a special thin middle finger to fill the same ecological niche as a woodpecker. It is the world's largest nocturnal primate, and is characterized by its unusual method of finding food; it taps on trees to find grubs, then gnaws holes in the wood and inserts its narrow middle finger to pull the grubs out. The only other animal species known to find food in this way is the striped possum. From an ecological point of view the aye-aye fills the niche of a woodpecker as it is capable of penetrating wood to extract the invertebrates within”. – Wikipedia

Photo: In this handout image from Bristol Zoo is seen the first captive bred aye-aye in the UK named “Kintana” (meaning star in Malagasy) April 15, 2005 at Bristol Zoo Gardens, England. The zoo announced today only the second baby aye-aye to be hand-reared in the world (the first was in Jersey Zoo) and has now made his first public appearance since his birth on 11 February 2005. (Photo by Rob Cousins/Bristol Zoo via Getty Images)

“The Southern Tamandua, Collared Anteater or Lesser Anteater (Tamandua tetradactyla) is a species of anteater from South America. It is a solitary animal, found in many habitats from mature to highly disturbed secondary forests and arid savannas. It feeds on ants, termites and bees. It has very strong foreclaws that can be used to break insect nests or to defend itself”. – Wikipedia

Photo: A three-month-old baby Southern Tamandua “Konbu” lies on its mother Tae's back at Sunshine International Aquarium on July 7, 2009 in Tokyo, Japan. Baby Southern Tamandua feels safe and comfortable holding onto something and normally stays on the mother's back until around 3 months old. (Photo by Junko Kimura/Getty Images)