The report notes that human activities are directly to blame for the steep declines. Habitat degradation, exploitation and climate change were pointed to as the most impactful pressures on wildlife.
The report's authors, the World Wildlife Fund and ZSL, say that the need for sustainable resource management and reducing our global ecological footprint is essential.
"Biodiversity is a crucial part of the systems that sustain life on Earth – and the barometer of what we are doing to this planet, our only home. We urgently need bold global action in all sectors of society to build a more sustainable future," said WWF International Director General Marco Lambertini.