Global wildlife populations have fallen by 58% since 1970, BBC reports citing The Living Planet assessment by the Zoological Society of London (ZSL) and WWF. The report adds that if the trend continues, the decline would reach two-thirds among vertebrates by 2020. The figures suggest that animals living in lakes, rivers and wetlands are suffering the biggest losses. Human activity, including habitat loss, wildlife trade, pollution and climate change contributed to the declines. From the report: Dr Mike Barrett. head of science and policy at WWF, said: "It's pretty clear under 'business as usual' we will see continued declines in these wildlife populations. But I think now we've reached a point where there isn't really any excuse to let this carry on. This analysis looked at 3,700 different species of birds, fish, mammals, amphibians and reptiles - about 6% of the total number of vertebrate species in the world. The team collected data from peer-reviewed studies, government statistics and surveys collated by conservation groups and NGOs. Any species with population data going back to 1970, with two or more time points (to show trends) was included in the study.