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)

The Royal Observatory just announced its Astronomy Photographer Of The Year 2013 winners. Australian photographer Mark Gee was chosen among a thousand amateur and professional photographers around the globe to win the top title. His work is part of an exhibition of the winning photographers, which opened on Sept. 19 at the Royal Observatory Greenwich. The Royal Observatory shared with us the winners and notable mentions of the competition. Their descriptions of the prizewinners can be found below the images.

“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)

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)

A rugby fan adjusts his latex mask at the rugby sevens tournament in Hong Kong on March 29, 2014. (Photo by Philippe Lopez/AFP Photo)

A four-year-old bulldog named Goldie wearing spectacles and a nightcap. (Photo by Fox Photos/Getty Images). 9th January 1960

The annual Victory Day military parade takes place at Red Square on May 09, 2008 in Moscow, Russia. Russia's most important national holiday honours over 26 million Soviet soldiers killed during World War II. Around 8,000 soldiers in newly designed uniforms paraded in the largest Victory Day display of heavy weaponry since the collapse of the Soviet Union. (Photo by Dima Korotayev/Epsilon/Getty Images)