Wildlife populations around the world have more than halved in just four decades in the face of unsustainable human consumption, a report has warned.
Mammals, birds, reptiles, amphibians and fish have declined on average by 52% from 1970 to 2010, according to WWF's Living Planet Report, which uses information on 10,380 populations of 3,038 species to see how global wildlife is faring.
ITV News Science Correspondent Alok Jha reports.
Experts from the Zoological Society of London (ZSL), which maintains the database of information on the species, said the figures meant that where in 1970 there was a population of 100 animals, now there were only 50.
For freshwater creatures, the situation is even worse, with population declines of more than three-quarters (76%) in 40 years, the "living planet index" of species shows.
The main threats to wildlife populations are loss or damage to their habitat and exploitation through hunting and fishing, the Living Planet Report said, while climate change is already having an impact on wildlife and is set to increase as a threat.
Terrestrial species (like elephants) declined by 39%
Freshwater species (like frogs) declined by 76%
Marine species (life fish) declined by 39%
The situation is worst in low-income countries, where wildlife populations have declined by 58% on average between 1970 and 2010, while the richest countries saw a 10% increase, although those nations have seen significant losses in the more distant past, experts said.
Examples of wildlife that are suffering serious declines include forest elephants in Africa, which are facing habitat loss and poaching for ivory and could become extinct within our lifetime, and marine turtles which have seen an 80% drop in numbers.
In the UK farmland birds have been badly hit by habitat degradation, with major declines in species such as corn buntings, but there is better news for red kites and otters which have seen numbers increase with conservation efforts, experts said.
The Living Planet Report also warned that human activity is outstripping the resources the Earth can provide, cutting down forests too quickly, overfishing and putting out more carbon dioxide than the planet can absorb, leading to climate change.