The average size of animals will fall by a quarter over the next century as larger creatures are increasingly driven to extinction by human actions.
That’s the verdict from a new report published by researchers at the University of Southampton, which estimates that more than 1,000 larger species of mammals and birds will go extinct as the climate changes, forests are cut down, animals are hunted and intensive farming continues to take up vast swathes of the planet.
The study warns the extinction of large species could lead to the collapse of ecosystems that millions of people rely upon to provide their food and water.
It notes wind animal populations have plummeted in the last few decades and stresses radical steps now need to be taken to protect wildlife and their habitats.
The researchers studied 15,500 species of mammals and birds – the troubling results suggest half of natural ecosystems around the globe have been destroyed and as many as a million species are now at risk of extinction.
The scientists found animals such as rodents and birds were more likely to survive because they are small, highly fertile and very adaptable – they warn that creatures such as rhinos, tigers and eagles are at much higher risk because they are more frequently targeted by hunters, need more space to survive and reproduce more slowly than their smaller counterparts.
The report reads: “Maintaining biodiversity is crucial to the functioning of ecosystems and the delivery of ecosystem services, yet biodiversity is disappearing.
“Mammals and birds, in particular, are diverse—comprising more than 15,000 living species—and are important ecological components in nutrient distribution, propagule (e.g. seed) dispersal, and as interactive connectors between species and habitats, However, mammals and birds are subject to strong human pressure, leading to high extinction rates.”